1 PROC(4) File Formats and Configurations PROC(4)
2
3
4
5 NAME
6 proc - /proc, the process file system
7
8 DESCRIPTION
9 /proc is a file system that provides access to the state of each
10 process and light-weight process (lwp) in the system. The name of each
11 entry in the /proc directory is a decimal number corresponding to a
12 process-ID. These entries are themselves subdirectories. Access to
13 process state is provided by additional files contained within each
14 subdirectory; the hierarchy is described more completely below. In this
15 document, ``/proc file'' refers to a non-directory file within the
16 hierarchy rooted at /proc. The owner of each /proc file and
17 subdirectory is determined by the user-ID of the process.
18
19
20 /proc can be mounted on any mount point, in addition to the standard
21 /proc mount point, and can be mounted several places at once. Such
22 additional mounts are allowed in order to facilitate the confinement of
23 processes to subtrees of the file system via chroot(1M) and yet allow
24 such processes access to commands like ps(1).
25
26
27 Standard system calls are used to access /proc files: open(2),
28 close(2), read(2), and write(2) (including readv(2), writev(2),
29 pread(2), and pwrite(2)). Most files describe process state and can
30 only be opened for reading. ctl and lwpctl (control) files permit
31 manipulation of process state and can only be opened for writing. as
32 (address space) files contain the image of the running process and can
33 be opened for both reading and writing. An open for writing allows
34 process control; a read-only open allows inspection but not control. In
35 this document, we refer to the process as open for reading or writing
36 if any of its associated /proc files is open for reading or writing.
37
38
39 In general, more than one process can open the same /proc file at the
40 same time. Exclusive open is an advisory mechanism provided to allow
41 controlling processes to avoid collisions with each other. A process
42 can obtain exclusive control of a target process, with respect to other
43 cooperating processes, if it successfully opens any /proc file in the
44 target process for writing (the as or ctl files, or the lwpctl file of
45 any lwp) while specifying O_EXCL in the open(2). Such an open will fail
46 if the target process is already open for writing (that is, if an as,
47 ctl, or lwpctl file is already open for writing). There can be any
48 number of concurrent read-only opens; O_EXCL is ignored on opens for
49 reading. It is recommended that the first open for writing by a
50 controlling process use the O_EXCL flag; multiple controlling processes
51 usually result in chaos.
52
53
54 If a process opens one of its own /proc files for writing, the open
55 succeeds regardless of O_EXCL and regardless of whether some other
56 process has the process open for writing. Self-opens do not count when
57 another process attempts an exclusive open. (A process cannot exclude a
58 debugger by opening itself for writing and the application of a
59 debugger cannot prevent a process from opening itself.) All self-opens
60 for writing are forced to be close-on-exec (see the F_SETFD operation
61 of fcntl(2)).
62
63
64 Data may be transferred from or to any locations in the address space
65 of the traced process by applying lseek(2) to position the as file at
66 the virtual address of interest followed by read(2) or write(2) (or by
67 using pread(2) or pwrite(2) for the combined operation). The address-
68 map files /proc/pid/map and /proc/pid/xmap can be read to determine the
69 accessible areas (mappings) of the address space. I/O transfers may
70 span contiguous mappings. An I/O request extending into an unmapped
71 area is truncated at the boundary. A write request beginning at an
72 unmapped virtual address fails with EIO; a read request beginning at an
73 unmapped virtual address returns zero (an end-of-file indication).
74
75
76 Information and control operations are provided through additional
77 files. <procfs.h> contains definitions of data structures and message
78 formats used with these files. Some of these definitions involve the
79 use of sets of flags. The set types sigset_t, fltset_t, and sysset_t
80 correspond, respectively, to signal, fault, and system call
81 enumerations defined in <sys/signal.h>, <sys/fault.h>, and
82 <sys/syscall.h>. Each set type is large enough to hold flags for its
83 own enumeration. Although they are of different sizes, they have a
84 common structure and can be manipulated by these macros:
85
86 prfillset(&set); /* turn on all flags in set */
87 premptyset(&set); /* turn off all flags in set */
88 praddset(&set, flag); /* turn on the specified flag */
89 prdelset(&set, flag); /* turn off the specified flag */
90 r = prismember(&set, flag); /* != 0 iff flag is turned on */
91
92
93
94 One of prfillset() or premptyset() must be used to initialize set
95 before it is used in any other operation. flag must be a member of the
96 enumeration corresponding to set.
97
98
99 Every process contains at least one light-weight process, or lwp. Each
100 lwp represents a flow of execution that is independently scheduled by
101 the operating system. All lwps in a process share its address space as
102 well as many other attributes. Through the use of lwpctl and ctl files
103 as described below, it is possible to affect individual lwps in a
104 process or to affect all of them at once, depending on the operation.
105
106
107 When the process has more than one lwp, a representative lwp is chosen
108 by the system for certain process status files and control operations.
109 The representative lwp is a stopped lwp only if all of the process's
110 lwps are stopped; is stopped on an event of interest only if all of the
111 lwps are so stopped (excluding PR_SUSPENDED lwps); is in a PR_REQUESTED
112 stop only if there are no other events of interest to be found; or,
113 failing everything else, is in a PR_SUSPENDED stop (implying that the
114 process is deadlocked). See the description of the status file for
115 definitions of stopped states. See the PCSTOP control operation for the
116 definition of ``event of interest''.
117
118
119 The representative lwp remains fixed (it will be chosen again on the
120 next operation) as long as all of the lwps are stopped on events of
121 interest or are in a PR_SUSPENDED stop and the PCRUN control operation
122 is not applied to any of them.
123
124
125 When applied to the process control file, every /proc control operation
126 that must act on an lwp uses the same algorithm to choose which lwp to
127 act upon. Together with synchronous stopping (see PCSET), this enables
128 a debugger to control a multiple-lwp process using only the process-
129 level status and control files if it so chooses. More fine-grained
130 control can be achieved using the lwp-specific files.
131
132
133 The system supports two process data models, the traditional 32-bit
134 data model in which ints, longs and pointers are all 32 bits wide (the
135 ILP32 data model), and on some platforms the 64-bit data model in which
136 longs and pointers, but not ints, are 64 bits in width (the LP64 data
137 model). In the LP64 data model some system data types, notably size_t,
138 off_t, time_t and dev_t, grow from 32 bits to 64 bits as well.
139
140
141 The /proc interfaces described here are available to both 32-bit and
142 64-bit controlling processes. However, many operations attempted by a
143 32-bit controlling process on a 64-bit target process will fail with
144 EOVERFLOW because the address space range of a 32-bit process cannot
145 encompass a 64-bit process or because the data in some 64-bit system
146 data type cannot be compressed to fit into the corresponding 32-bit
147 type without loss of information. Operations that fail in this
148 circumstance include reading and writing the address space, reading the
149 address-map files, and setting the target process's registers. There is
150 no restriction on operations applied by a 64-bit process to either a
151 32-bit or a 64-bit target processes.
152
153
154 The format of the contents of any /proc file depends on the data model
155 of the observer (the controlling process), not on the data model of the
156 target process. A 64-bit debugger does not have to translate the
157 information it reads from a /proc file for a 32-bit process from 32-bit
158 format to 64-bit format. However, it usually has to be aware of the
159 data model of the target process. The pr_dmodel field of the status
160 files indicates the target process's data model.
161
162
163 To help deal with system data structures that are read from 32-bit
164 processes, a 64-bit controlling program can be compiled with the C
165 preprocessor symbol _SYSCALL32 defined before system header files are
166 included. This makes explicit 32-bit fixed-width data structures (like
167 cstruct stat32) visible to the 64-bit program. See types32.h(3HEAD).
168
169 DIRECTORY STRUCTURE
170 At the top level, the directory /proc contains entries each of which
171 names an existing process in the system. These entries are themselves
172 directories. Except where otherwise noted, the files described below
173 can be opened for reading only. In addition, if a process becomes a
174 zombie (one that has exited but whose parent has not yet performed a
175 wait(3C) upon it), most of its associated /proc files disappear from
176 the hierarchy; subsequent attempts to open them, or to read or write
177 files opened before the process exited, will elicit the error ENOENT.
178
179
180 Although process state and consequently the contents of /proc files can
181 change from instant to instant, a single read(2) of a /proc file is
182 guaranteed to return a sane representation of state; that is, the read
183 will be atomic with respect to the state of the process. No such
184 guarantee applies to successive reads applied to a /proc file for a
185 running process. In addition, atomicity is not guaranteed for I/O
186 applied to the as (address-space) file for a running process or for a
187 process whose address space contains memory shared by another running
188 process.
189
190
191 A number of structure definitions are used to describe the files. These
192 structures may grow by the addition of elements at the end in future
193 releases of the system and it is not legitimate for a program to assume
194 that they will not.
195
196 STRUCTURE OF /proc/pid
197 A given directory /proc/pid contains the following entries. A process
198 can use the invisible alias /proc/self if it wishes to open one of its
199 own /proc files (invisible in the sense that the name ``self'' does not
200 appear in a directory listing of /proc obtained from ls(1),
201 getdents(2), or readdir(3C)).
202
203 contracts
204 A directory containing references to the contracts held by the process.
205 Each entry is a symlink to the contract's directory under
206 /system/contract. See contract(4).
207
208 as
209 Contains the address-space image of the process; it can be opened for
210 both reading and writing. lseek(2) is used to position the file at the
211 virtual address of interest and then the address space can be examined
212 or changed through read(2) or write(2) (or by using pread(2) or
213 pwrite(2) for the combined operation).
214
215 ctl
216 A write-only file to which structured messages are written directing
217 the system to change some aspect of the process's state or control its
218 behavior in some way. The seek offset is not relevant when writing to
219 this file. Individual lwps also have associated lwpctl files in the lwp
220 subdirectories. A control message may be written either to the
221 process's ctl file or to a specific lwpctl file with operation-specific
222 effects. The effect of a control message is immediately reflected in
223 the state of the process visible through appropriate status and
224 information files. The types of control messages are described in
225 detail later. See CONTROL MESSAGES.
226
227 status
228 Contains state information about the process and the representative
229 lwp. The file contains a pstatus structure which contains an embedded
230 lwpstatus structure for the representative lwp, as follows:
231
232 typedef struct pstatus {
233 int pr_flags; /* flags (see below) */
234 int pr_nlwp; /* number of active lwps in the process */
235 int pr_nzomb; /* number of zombie lwps in the process */
236 pid_tpr_pid; /* process id */
237 pid_tpr_ppid; /* parent process id */
238 pid_tpr_pgid; /* process group id */
239 pid_tpr_sid; /* session id */
240 id_t pr_aslwpid; /* obsolete */
241 id_t pr_agentid; /* lwp-id of the agent lwp, if any */
242 sigset_t pr_sigpend; /* set of process pending signals */
243 uintptr_t pr_brkbase; /* virtual address of the process heap */
244 size_t pr_brksize; /* size of the process heap, in bytes */
245 uintptr_t pr_stkbase; /* virtual address of the process stack */
246 size_tpr_stksize; /* size of the process stack, in bytes */
247 timestruc_t pr_utime; /* process user cpu time */
248 timestruc_t pr_stime; /* process system cpu time */
249 timestruc_t pr_cutime; /* sum of children's user times */
250 timestruc_t pr_cstime; /* sum of children's system times */
251 sigset_t pr_sigtrace; /* set of traced signals */
252 fltset_t pr_flttrace; /* set of traced faults */
253 sysset_t pr_sysentry; /* set of system calls traced on entry */
254 sysset_t pr_sysexit; /* set of system calls traced on exit */
255 char pr_dmodel; /* data model of the process */
256 taskid_t pr_taskid; /* task id */
257 projid_t pr_projid; /* project id */
258 zoneid_t pr_zoneid; /* zone id */
259 lwpstatus_t pr_lwp; /* status of the representative lwp */
260 } pstatus_t;
261
262
263
264 pr_flags is a bit-mask holding the following process flags. For
265 convenience, it also contains the lwp flags for the representative lwp,
266 described later.
267
268 PR_ISSYS
269 process is a system process (see PCSTOP).
270
271
272 PR_VFORKP
273 process is the parent of a vforked child (see PCWATCH).
274
275
276 PR_FORK
277 process has its inherit-on-fork mode set (see PCSET).
278
279
280 PR_RLC
281 process has its run-on-last-close mode set (see PCSET).
282
283
284 PR_KLC
285 process has its kill-on-last-close mode set (see PCSET).
286
287
288 PR_ASYNC
289 process has its asynchronous-stop mode set (see PCSET).
290
291
292 PR_MSACCT
293 Set by default in all processes to indicate that
294 microstate accounting is enabled. However, this flag has
295 been deprecated and no longer has any effect. Microstate
296 accounting may not be disabled; however, it is still
297 possible to toggle the flag.
298
299
300 PR_MSFORK
301 Set by default in all processes to indicate that
302 microstate accounting will be enabled for processes that
303 this parent forks(). However, this flag has been
304 deprecated and no longer has any effect. It is possible to
305 toggle this flag; however, it is not possible to disable
306 microstate accounting.
307
308
309 PR_BPTADJ
310 process has its breakpoint adjustment mode set (see
311 PCSET).
312
313
314 PR_PTRACE
315 process has its ptrace-compatibility mode set (see PCSET).
316
317
318
319 pr_nlwp is the total number of active lwps in the process. pr_nzomb is
320 the total number of zombie lwps in the process. A zombie lwp is a non-
321 detached lwp that has terminated but has not been reaped with
322 thr_join(3C) or pthread_join(3C).
323
324
325 pr_pid, pr_ppid, pr_pgid, and pr_sid are, respectively, the process ID,
326 the ID of the process's parent, the process's process group ID, and the
327 process's session ID.
328
329
330 pr_aslwpid is obsolete and is always zero.
331
332
333 pr_agentid is the lwp-ID for the /proc agent lwp (see the PCAGENT
334 control operation). It is zero if there is no agent lwp in the process.
335
336
337 pr_sigpend identifies asynchronous signals pending for the process.
338
339
340 pr_brkbase is the virtual address of the process heap and pr_brksize is
341 its size in bytes. The address formed by the sum of these values is the
342 process break (see brk(2)). pr_stkbase and pr_stksize are,
343 respectively, the virtual address of the process stack and its size in
344 bytes. (Each lwp runs on a separate stack; the distinguishing
345 characteristic of the process stack is that the operating system will
346 grow it when necessary.)
347
348
349 pr_utime, pr_stime, pr_cutime, and pr_cstime are, respectively, the
350 user CPU and system CPU time consumed by the process, and the
351 cumulative user CPU and system CPU time consumed by the process's
352 children, in seconds and nanoseconds.
353
354
355 pr_sigtrace and pr_flttrace contain, respectively, the set of signals
356 and the set of hardware faults that are being traced (see PCSTRACE and
357 PCSFAULT).
358
359
360 pr_sysentry and pr_sysexit contain, respectively, the sets of system
361 calls being traced on entry and exit (see PCSENTRY and PCSEXIT).
362
363
364 pr_dmodel indicates the data model of the process. Possible values are:
365
366 PR_MODEL_ILP32
367 process data model is ILP32.
368
369
370 PR_MODEL_LP64
371 process data model is LP64.
372
373
374 PR_MODEL_NATIVE
375 process data model is native.
376
377
378
379 The pr_taskid, pr_projid, and pr_zoneid fields contain respectively,
380 the numeric IDs of the task, project, and zone in which the process was
381 running.
382
383
384 The constant PR_MODEL_NATIVE reflects the data model of the controlling
385 process, that is, its value is PR_MODEL_ILP32 or PR_MODEL_LP64
386 according to whether the controlling process has been compiled as a
387 32-bit program or a 64-bit program, respectively.
388
389
390 pr_lwp contains the status information for the representative lwp:
391
392 typedef struct lwpstatus {
393 int pr_flags; /* flags (see below) */
394 id_t pr_lwpid; /* specific lwp identifier */
395 short pr_why; /* reason for lwp stop, if stopped */
396 short pr_what; /* more detailed reason */
397 short pr_cursig; /* current signal, if any */
398 siginfo_t pr_info; /* info associated with signal or fault */
399 sigset_t pr_lwppend; /* set of signals pending to the lwp */
400 sigset_t pr_lwphold; /* set of signals blocked by the lwp */
401 struct sigaction pr_action;/* signal action for current signal */
402 stack_t pr_altstack; /* alternate signal stack info */
403 uintptr_t pr_oldcontext; /* address of previous ucontext */
404 short pr_syscall; /* system call number (if in syscall) */
405 short pr_nsysarg; /* number of arguments to this syscall */
406 int pr_errno; /* errno for failed syscall */
407 long pr_sysarg[PRSYSARGS]; /* arguments to this syscall */
408 long pr_rval1; /* primary syscall return value */
409 long pr_rval2; /* second syscall return value, if any */
410 char pr_clname[PRCLSZ]; /* scheduling class name */
411 timestruc_t pr_tstamp; /* real-time time stamp of stop */
412 timestruc_t pr_utime; /* lwp user cpu time */
413 timestruc_t pr_stime; /* lwp system cpu time */
414 uintptr_t pr_ustack; /* stack boundary data (stack_t) address */
415 ulong_t pr_instr; /* current instruction */
416 prgregset_t pr_reg; /* general registers */
417 prfpregset_t pr_fpreg; /* floating-point registers */
418 } lwpstatus_t;
419
420
421
422 pr_flags is a bit-mask holding the following lwp flags. For
423 convenience, it also contains the process flags, described previously.
424
425 PR_STOPPED
426 The lwp is stopped.
427
428
429 PR_ISTOP
430 The lwp is stopped on an event of interest (see PCSTOP).
431
432
433 PR_DSTOP
434 The lwp has a stop directive in effect (see PCSTOP).
435
436
437 PR_STEP
438 The lwp has a single-step directive in effect (see
439 PCRUN).
440
441
442 PR_ASLEEP
443 The lwp is in an interruptible sleep within a system
444 call.
445
446
447 PR_PCINVAL
448 The lwp's current instruction (pr_instr) is undefined.
449
450
451 PR_DETACH
452 This is a detached lwp (see pthread_create(3C) and
453 pthread_join(3C)).
454
455
456 PR_DAEMON
457 This is a daemon lwp (see pthread_create(3C)).
458
459
460 PR_ASLWP
461 This flag is obsolete and is never set.
462
463
464 PR_AGENT
465 This is the /proc agent lwp for the process.
466
467
468
469 pr_lwpid names the specific lwp.
470
471
472 pr_why and pr_what together describe, for a stopped lwp, the reason for
473 the stop. Possible values of pr_why and the associated pr_what are:
474
475 PR_REQUESTED
476 indicates that the stop occurred in response to a stop
477 directive, normally because PCSTOP was applied or
478 because another lwp stopped on an event of interest
479 and the asynchronous-stop flag (see PCSET) was not set
480 for the process. pr_what is unused in this case.
481
482
483 PR_SIGNALLED
484 indicates that the lwp stopped on receipt of a signal
485 (see PCSTRACE); pr_what holds the signal number that
486 caused the stop (for a newly-stopped lwp, the same
487 value is in pr_cursig).
488
489
490 PR_FAULTED
491 indicates that the lwp stopped on incurring a hardware
492 fault (see PCSFAULT); pr_what holds the fault number
493 that caused the stop.
494
495
496 PR_SYSENTRY
497 PR_SYSEXIT
498 indicate a stop on entry to or exit from a system call
499 (see PCSENTRY and PCSEXIT); pr_what holds the system
500 call number.
501
502
503 PR_JOBCONTROL
504 indicates that the lwp stopped due to the default
505 action of a job control stop signal (see
506 sigaction(2)); pr_what holds the stopping signal
507 number.
508
509
510 PR_SUSPENDED
511 indicates that the lwp stopped due to internal
512 synchronization of lwps within the process. pr_what is
513 unused in this case.
514
515
516 PR_BRAND
517 indicates that the lwp stopped for a brand-specific
518 reason. Interpretation of the value of pr_what
519 depends on which zone brand is in use. It is not
520 generally expected that an lwp stopped in this state
521 will be restarted by native proc(4) consumers.
522
523
524
525 pr_cursig names the current signal, that is, the next signal to be
526 delivered to the lwp, if any. pr_info, when the lwp is in a
527 PR_SIGNALLED or PR_FAULTED stop, contains additional information
528 pertinent to the particular signal or fault (see <sys/siginfo.h>).
529
530
531 pr_lwppend identifies any synchronous or directed signals pending for
532 the lwp. pr_lwphold identifies those signals whose delivery is being
533 blocked by the lwp (the signal mask).
534
535
536 pr_action contains the signal action information pertaining to the
537 current signal (see sigaction(2)); it is undefined if pr_cursig is
538 zero. pr_altstack contains the alternate signal stack information for
539 the lwp (see sigaltstack(2)).
540
541
542 pr_oldcontext, if not zero, contains the address on the lwp stack of a
543 ucontext structure describing the previous user-level context (see
544 ucontext.h(3HEAD)). It is non-zero only if the lwp is executing in the
545 context of a signal handler.
546
547
548 pr_syscall is the number of the system call, if any, being executed by
549 the lwp; it is non-zero if and only if the lwp is stopped on
550 PR_SYSENTRY or PR_SYSEXIT, or is asleep within a system call (
551 PR_ASLEEP is set). If pr_syscall is non-zero, pr_nsysarg is the number
552 of arguments to the system call and pr_sysarg contains the actual
553 arguments.
554
555
556 pr_rval1, pr_rval2, and pr_errno are defined only if the lwp is stopped
557 on PR_SYSEXIT or if the PR_VFORKP flag is set. If pr_errno is zero,
558 pr_rval1 and pr_rval2 contain the return values from the system call.
559 Otherwise, pr_errno contains the error number for the failing system
560 call (see <sys/errno.h>).
561
562
563 pr_clname contains the name of the lwp's scheduling class.
564
565
566 pr_tstamp, if the lwp is stopped, contains a time stamp marking when
567 the lwp stopped, in real time seconds and nanoseconds since an
568 arbitrary time in the past.
569
570
571 pr_utime is the amount of user level CPU time used by this LWP.
572
573
574 pr_stime is the amount of system level CPU time used by this LWP.
575
576
577 pr_ustack is the virtual address of the stack_t that contains the stack
578 boundaries for this LWP. See getustack(2) and _stack_grow(3C).
579
580
581 pr_instr contains the machine instruction to which the lwp's program
582 counter refers. The amount of data retrieved from the process is
583 machine-dependent. On SPARC based machines, it is a 32-bit word. On
584 x86-based machines, it is a single byte. In general, the size is that
585 of the machine's smallest instruction. If PR_PCINVAL is set, pr_instr
586 is undefined; this occurs whenever the lwp is not stopped or when the
587 program counter refers to an invalid virtual address.
588
589
590 pr_reg is an array holding the contents of a stopped lwp's general
591 registers.
592
593 SPARC
594 On SPARC-based machines, the predefined constants
595 R_G0 ... R_G7, R_O0 ... R_O7, R_L0 ... R_L7, R_I0
596 ... R_I7, R_PC, R_nPC, and R_Y can be used as
597 indices to refer to the corresponding registers;
598 previous register windows can be read from their
599 overflow locations on the stack (however, see the
600 gwindows file in the /proc/pid/lwp/lwpid
601 subdirectory).
602
603
604 SPARC V8 (32-bit)
605 For SPARC V8 (32-bit) controlling processes, the
606 predefined constants R_PSR, R_WIM, and R_TBR can
607 be used as indices to refer to the corresponding
608 special registers. For SPARC V9 (64-bit)
609 controlling processes, the predefined constants
610 R_CCR, R_ASI, and R_FPRS can be used as indices to
611 refer to the corresponding special registers.
612
613
614 x86 (32-bit)
615 For 32-bit x86 processes, the predefined constants
616 listed belowcan be used as indices to refer to the
617 corresponding registers.
618
619 SS
620 UESP
621 EFL
622 CS
623 EIP
624 ERR
625 TRAPNO
626 EAX
627 ECX
628 EDX
629 EBX
630 ESP
631 EBP
632 ESI
633 EDI
634 DS
635 ES
636 GS
637
638 The preceding constants are listed in
639 <sys/regset.h>.
640
641 Note that a 32-bit process can run on an x86
642 64-bit system, using the constants listed above.
643
644
645 x86 (64-bit)
646 To read the registers of a 32- or a 64-bit
647 process, a 64-bit x86 process should use the
648 predefined constants listed below.
649
650 REG_GSBASE
651 REG_FSBASE
652 REG_DS
653 REG_ES
654 REG_GS
655 REG_FS
656 REG_SS
657 REG_RSP
658 REG_RFL
659 REG_CS
660 REG_RIP
661 REG_ERR
662 REG_TRAPNO
663 REG_RAX
664 REG_RCX
665 REG_RDX
666 REG_RBX
667 REG_RBP
668 REG_RSI
669 REG_RDI
670 REG_R8
671 REG_R9
672 REG_R10
673 REG_R11
674 REG_R12
675 REG_R13
676 REG_R14
677 REG_R15
678
679 The preceding constants are listed in
680 <sys/regset.h>.
681
682
683
684 pr_fpreg is a structure holding the contents of the floating-point
685 registers.
686
687
688 SPARC registers, both general and floating-point, as seen by a 64-bit
689 controlling process are the V9 versions of the registers, even if the
690 target process is a 32-bit (V8) process. V8 registers are a subset of
691 the V9 registers.
692
693
694 If the lwp is not stopped, all register values are undefined.
695
696 psinfo
697 Contains miscellaneous information about the process and the
698 representative lwp needed by the ps(1) command. psinfo remains
699 accessible after a process becomes a zombie. The file contains a psinfo
700 structure which contains an embedded lwpsinfo structure for the
701 representative lwp, as follows:
702
703 typedef struct psinfo {
704 int pr_flag; /* process flags (DEPRECATED: see below) */
705 int pr_nlwp; /* number of active lwps in the process */
706 int pr_nzomb; /* number of zombie lwps in the process */
707 pid_t pr_pid; /* process id */
708 pid_t pr_ppid; /* process id of parent */
709 pid_t pr_pgid; /* process id of process group leader */
710 pid_t pr_sid; /* session id */
711 uid_t pr_uid; /* real user id */
712 uid_t pr_euid; /* effective user id */
713 gid_t pr_gid; /* real group id */
714 gid_t pr_egid; /* effective group id */
715 uintptr_t pr_addr; /* address of process */
716 size_t pr_size; /* size of process image in Kbytes */
717 size_t pr_rssize; /* resident set size in Kbytes */
718 dev_t pr_ttydev; /* controlling tty device (or PRNODEV) */
719 ushort_t pr_pctcpu; /* % of recent cpu time used by all lwps */
720 ushort_t pr_pctmem; /* % of system memory used by process */
721 timestruc_t pr_start; /* process start time, from the epoch */
722 timestruc_t pr_time; /* cpu time for this process */
723 timestruc_t pr_ctime; /* cpu time for reaped children */
724 char pr_fname[PRFNSZ]; /* name of exec'ed file */
725 char pr_psargs[PRARGSZ]; /* initial characters of arg list */
726 int pr_wstat; /* if zombie, the wait() status */
727 int pr_argc; /* initial argument count */
728 uintptr_t pr_argv; /* address of initial argument vector */
729 uintptr_t pr_envp; /* address of initial environment vector */
730 char pr_dmodel; /* data model of the process */
731 lwpsinfo_t pr_lwp; /* information for representative lwp */
732 taskid_t pr_taskid; /* task id */
733 projid_t pr_projid; /* project id */
734 poolid_t pr_poolid; /* pool id */
735 zoneid_t pr_zoneid; /* zone id */
736 ctid_t pr_contract; /* process contract id */
737 } psinfo_t;
738
739
740
741 Some of the entries in psinfo, such as pr_addr, refer to internal
742 kernel data structures and should not be expected to retain their
743 meanings across different versions of the operating system.
744
745
746 psinfo_t.pr_flag is a deprecated interface that should no longer be
747 used. Applications currently relying on the SSYS bit in pr_flag should
748 migrate to checking PR_ISSYS in the pstatus structure's pr_flags field.
749
750
751 pr_pctcpu and pr_pctmem are 16-bit binary fractions in the range 0.0 to
752 1.0 with the binary point to the right of the high-order bit (1.0 ==
753 0x8000). pr_pctcpu is the summation over all lwps in the process.
754
755
756 The pr_fname and pr_psargs are writable by the owner of the process. To
757 write to them, the psinfo file should be open for writing and the
758 desired value for the field should be written at the file offset that
759 corresponds to the member of structure. No other entry may be written
760 to; if a write is attempted to an offset that does not represent one of
761 these two memers, or if the size of the write is not exactly the size
762 of the member being written, no bytes will be written and zero will be
763 returned.
764
765
766 pr_lwp contains the ps(1) information for the representative lwp. If
767 the process is a zombie, pr_nlwp, pr_nzomb, and pr_lwp.pr_lwpid are
768 zero and the other fields of pr_lwp are undefined:
769
770 typedef struct lwpsinfo {
771 int pr_flag; /* lwp flags (DEPRECATED: see below) */
772 id_t pr_lwpid; /* lwp id */
773 uintptr_t pr_addr; /* internal address of lwp */
774 uintptr_t pr_wchan; /* wait addr for sleeping lwp */
775 char pr_stype; /* synchronization event type */
776 char pr_state; /* numeric lwp state */
777 char pr_sname; /* printable character for pr_state */
778 char pr_nice; /* nice for cpu usage */
779 short pr_syscall; /* system call number (if in syscall) */
780 char pr_oldpri; /* pre-SVR4, low value is high priority */
781 char pr_cpu; /* pre-SVR4, cpu usage for scheduling */
782 int pr_pri; /* priority, high value = high priority */
783 ushort_t pr_pctcpu; /* % of recent cpu time used by this lwp */
784 timestruc_t pr_start; /* lwp start time, from the epoch */
785 timestruc_t pr_time; /* cpu time for this lwp */
786 char pr_clname[PRCLSZ]; /* scheduling class name */
787 char pr_name[PRFNSZ]; /* name of system lwp */
788 processorid_t pr_onpro; /* processor which last ran this lwp */
789 processorid_t pr_bindpro;/* processor to which lwp is bound */
790 psetid_t pr_bindpset; /* processor set to which lwp is bound */
791 lgrp_id_t pr_lgrp /* home lgroup */
792 } lwpsinfo_t;
793
794
795
796 Some of the entries in lwpsinfo, such as pr_addr, pr_wchan, pr_stype,
797 pr_state, and pr_name, refer to internal kernel data structures and
798 should not be expected to retain their meanings across different
799 versions of the operating system.
800
801
802 lwpsinfo_t.pr_flag is a deprecated interface that should no longer be
803 used.
804
805
806 pr_pctcpu is a 16-bit binary fraction, as described above. It
807 represents the CPU time used by the specific lwp. On a multi-processor
808 machine, the maximum value is 1/N, where N is the number of CPUs.
809
810
811 pr_contract is the id of the process contract of which the process is a
812 member. See contract(4) and process(4).
813
814 cred
815 Contains a description of the credentials associated with the process:
816
817 typedef struct prcred {
818 uid_t pr_euid; /* effective user id */
819 uid_t pr_ruid; /* real user id */
820 uid_t pr_suid; /* saved user id (from exec) */
821 gid_t pr_egid; /* effective group id */
822 gid_t pr_rgid; /* real group id */
823 gid_t pr_sgid; /* saved group id (from exec) */
824 int pr_ngroups; /* number of supplementary groups */
825 gid_t pr_groups[1]; /* array of supplementary groups */
826 } prcred_t;
827
828
829
830
831 The array of associated supplementary groups in pr_groups is of
832 variable length; the cred file contains all of the supplementary
833 groups. pr_ngroups indicates the number of supplementary groups. (See
834 also the PCSCRED and PCSCREDX control operations.)
835
836 priv
837 Contains a description of the privileges associated with the process:
838
839 typedef struct prpriv {
840 uint32_t pr_nsets; /* number of privilege set */
841 uint32_t pr_setsize; /* size of privilege set */
842 uint32_t pr_infosize; /* size of supplementary data */
843 priv_chunk_t pr_sets[1]; /* array of sets */
844 } prpriv_t;
845
846
847
848 The actual dimension of the pr_sets[] field is
849
850 pr_sets[pr_nsets][pr_setsize]
851
852
853
854 which is followed by additional information about the process state
855 pr_infosize bytes in size.
856
857
858 The full size of the structure can be computed using
859 PRIV_PRPRIV_SIZE(prpriv_t *).
860
861 sigact
862 Contains an array of sigaction structures describing the current
863 dispositions of all signals associated with the traced process (see
864 sigaction(2)). Signal numbers are displaced by 1 from array indices, so
865 that the action for signal number n appears in position n-1 of the
866 array.
867
868 auxv
869 Contains the initial values of the process's aux vector in an array of
870 auxv_t structures (see <sys/auxv.h>). The values are those that were
871 passed by the operating system as startup information to the dynamic
872 linker.
873
874 argv
875 Contains the concatenation of each of the argument strings, including
876 their NUL terminators, in the argument vector (argv) for the process.
877 If the process has modified either its argument vector, or the contents
878 of any of the strings referenced by that vector, those changes will be
879 visible here.
880
881 ldt
882 This file exists only on x86-based machines. It is non-empty only if
883 the process has established a local descriptor table (LDT). If non-
884 empty, the file contains the array of currently active LDT entries in
885 an array of elements of type struct ssd, defined in <sys/sysi86.h>, one
886 element for each active LDT entry.
887
888 map, xmap
889 Contain information about the virtual address map of the process. The
890 map file contains an array of prmap structures while the xmap file
891 contains an array of prxmap structures. Each structure describes a
892 contiguous virtual address region in the address space of the traced
893 process:
894
895 typedef struct prmap {
896 uintptr_tpr_vaddr; /* virtual address of mapping */
897 size_t pr_size; /* size of mapping in bytes */
898 char pr_mapname[PRMAPSZ]; /* name in /proc/pid/object */
899 offset_t pr_offset; /* offset into mapped object, if any */
900 int pr_mflags; /* protection and attribute flags */
901 int pr_pagesize; /* pagesize for this mapping in bytes */
902 int pr_shmid; /* SysV shared memory identifier */
903 } prmap_t;
904
905
906
907 typedef struct prxmap {
908 uintptr_t pr_vaddr; /* virtual address of mapping */
909 size_t pr_size; /* size of mapping in bytes */
910 char pr_mapname[PRMAPSZ]; /* name in /proc/pid/object */
911 offset_t pr_offset; /* offset into mapped object, if any */
912 int pr_mflags; /* protection and attribute flags */
913 int pr_pagesize; /* pagesize for this mapping in bytes */
914 int pr_shmid; /* SysV shared memory identifier */
915 dev_t pr_dev; /* device of mapped object, if any */
916 uint64_t pr_ino; /* inode of mapped object, if any */
917 size_t pr_rss; /* pages of resident memory */
918 size_t pr_anon; /* pages of resident anonymous memory */
919 size_t pr_locked; /* pages of locked memory */
920 uint64_t pr_hatpagesize; /* pagesize of mapping */
921 } prxmap_t;
922
923
924
925
926 pr_vaddr is the virtual address of the mapping within the traced
927 process and pr_size is its size in bytes. pr_mapname, if it does not
928 contain a null string, contains the name of a file in the object
929 directory (see below) that can be opened read-only to obtain a file
930 descriptor for the mapped file associated with the mapping. This
931 enables a debugger to find object file symbol tables without having to
932 know the real path names of the executable file and shared libraries of
933 the process. pr_offset is the 64-bit offset within the mapped file (if
934 any) to which the virtual address is mapped.
935
936
937 pr_mflags is a bit-mask of protection and attribute flags:
938
939 MA_READ
940 mapping is readable by the traced process.
941
942
943 MA_WRITE
944 mapping is writable by the traced process.
945
946
947 MA_EXEC
948 mapping is executable by the traced process.
949
950
951 MA_SHARED
952 mapping changes are shared by the mapped object.
953
954
955 MA_ISM
956 mapping is intimate shared memory (shared MMU
957 resources)
958
959
960 MAP_NORESERVE
961 mapping does not have swap space reserved (mapped with
962 MAP_NORESERVE)
963
964
965 MA_SHM
966 mapping System V shared memory
967
968
969
970 A contiguous area of the address space having the same underlying
971 mapped object may appear as multiple mappings due to varying read,
972 write, and execute attributes. The underlying mapped object does not
973 change over the range of a single mapping. An I/O operation to a
974 mapping marked MA_SHARED fails if applied at a virtual address not
975 corresponding to a valid page in the underlying mapped object. A write
976 to a MA_SHARED mapping that is not marked MA_WRITE fails. Reads and
977 writes to private mappings always succeed. Reads and writes to unmapped
978 addresses fail.
979
980
981 pr_pagesize is the page size for the mapping, currently always the
982 system pagesize.
983
984
985 pr_shmid is the shared memory identifier, if any, for the mapping. Its
986 value is -1 if the mapping is not System V shared memory. See
987 shmget(2).
988
989
990 pr_dev is the device of the mapped object, if any, for the mapping. Its
991 value is PRNODEV (-1) if the mapping does not have a device.
992
993
994 pr_ino is the inode of the mapped object, if any, for the mapping. Its
995 contents are only valid if pr_dev is not PRNODEV.
996
997
998 pr_rss is the number of resident pages of memory for the mapping. The
999 number of resident bytes for the mapping may be determined by
1000 multiplying pr_rss by the page size given by pr_pagesize.
1001
1002
1003 pr_anon is the number of resident anonymous memory pages (pages which
1004 are private to this process) for the mapping.
1005
1006
1007 pr_locked is the number of locked pages for the mapping. Pages which
1008 are locked are always resident in memory.
1009
1010
1011 pr_hatpagesize is the size, in bytes, of the HAT (MMU) translation for
1012 the mapping. pr_hatpagesize may be different than pr_pagesize. The
1013 possible values are hardware architecture specific, and may change over
1014 a mapping's lifetime.
1015
1016 rmap
1017 Contains information about the reserved address ranges of the process.
1018 The file contains an array of prmap structures, as defined above for
1019 the map file. Each structure describes a contiguous virtual address
1020 region in the address space of the traced process that is reserved by
1021 the system in the sense that an mmap(2) system call that does not
1022 specify MAP_FIXED will not use any part of it for the new mapping.
1023 Examples of such reservations include the address ranges reserved for
1024 the process stack and the individual thread stacks of a multi-threaded
1025 process.
1026
1027 cwd
1028 A symbolic link to the process's current working directory. See
1029 chdir(2). A readlink(2) of /proc/pid/cwd yields a null string.
1030 However, it can be opened, listed, and searched as a directory, and can
1031 be the target of chdir(2).
1032
1033 root
1034 A symbolic link to the process's root directory. /proc/pid/root can
1035 differ from the system root directory if the process or one of its
1036 ancestors executed chroot(2) as super user. It has the same semantics
1037 as /proc/pid/cwd.
1038
1039 fd
1040 A directory containing references to the open files of the process.
1041 Each entry is a decimal number corresponding to an open file descriptor
1042 in the process.
1043
1044
1045 If an entry refers to a regular file, it can be opened with normal file
1046 system semantics but, to ensure that the controlling process cannot
1047 gain greater access than the controlled process, with no file access
1048 modes other than its read/write open modes in the controlled process.
1049 If an entry refers to a directory, it can be accessed with the same
1050 semantics as /proc/pid/cwd. An attempt to open any other type of entry
1051 fails with EACCES.
1052
1053 object
1054 A directory containing read-only files with names corresponding to the
1055 pr_mapname entries in the map and pagedata files. Opening such a file
1056 yields a file descriptor for the underlying mapped file associated with
1057 an address-space mapping in the process. The file name a.out appears in
1058 the directory as an alias for the process's executable file.
1059
1060
1061 The object directory makes it possible for a controlling process to
1062 gain access to the object file and any shared libraries (and
1063 consequently the symbol tables) without having to know the actual path
1064 names of the executable files.
1065
1066 path
1067 A directory containing symbolic links to files opened by the process.
1068 The directory includes one entry for cwd and root. The directory also
1069 contains a numerical entry for each file descriptor in the fd
1070 directory, and entries matching those in the object directory. If this
1071 information is not available, any attempt to read the contents of the
1072 symbolic link will fail. This is most common for files that do not
1073 exist in the filesystem namespace (such as FIFOs and sockets), but can
1074 also happen for regular files. For the file descriptor entries, the
1075 path may be different from the one used by the process to open the
1076 file.
1077
1078 pagedata
1079 Opening the page data file enables tracking of address space references
1080 and modifications on a per-page basis.
1081
1082
1083 A read(2) of the page data file descriptor returns structured page data
1084 and atomically clears the page data maintained for the file by the
1085 system. That is to say, each read returns data collected since the last
1086 read; the first read returns data collected since the file was opened.
1087 When the call completes, the read buffer contains the following
1088 structure as its header and thereafter contains a number of section
1089 header structures and associated byte arrays that must be accessed by
1090 walking linearly through the buffer.
1091
1092 typedef struct prpageheader {
1093 timestruc_t pr_tstamp; /* real time stamp, time of read() */
1094 ulong_t pr_nmap; /* number of address space mappings */
1095 ulong_t pr_npage; /* total number of pages */
1096 } prpageheader_t;
1097
1098
1099
1100 The header is followed by pr_nmap prasmap structures and associated
1101 data arrays. The prasmap structure contains the following elements:
1102
1103 typedef struct prasmap {
1104 uintptr_t pr_vaddr; /* virtual address of mapping */
1105 ulong_t pr_npage; /* number of pages in mapping */
1106 char pr_mapname[PRMAPSZ]; /* name in /proc/pid/object */
1107 offset_t pr_offset; /* offset into mapped object, if any */
1108 int pr_mflags; /* protection and attribute flags */
1109 int pr_pagesize; /* pagesize for this mapping in bytes */
1110 int pr_shmid; /* SysV shared memory identifier */
1111 } prasmap_t;
1112
1113
1114
1115 Each section header is followed by pr_npage bytes, one byte for each
1116 page in the mapping, plus 0-7 null bytes at the end so that the next
1117 prasmap structure begins on an eight-byte aligned boundary. Each data
1118 byte may contain these flags:
1119
1120 PG_REFERENCED
1121 page has been referenced.
1122
1123
1124 PG_MODIFIED
1125 page has been modified.
1126
1127
1128
1129 If the read buffer is not large enough to contain all of the page data,
1130 the read fails with E2BIG and the page data is not cleared. The
1131 required size of the read buffer can be determined through fstat(2).
1132 Application of lseek(2) to the page data file descriptor is
1133 ineffective; every read starts from the beginning of the file. Closing
1134 the page data file descriptor terminates the system overhead associated
1135 with collecting the data.
1136
1137
1138 More than one page data file descriptor for the same process can be
1139 opened, up to a system-imposed limit per traced process. A read of one
1140 does not affect the data being collected by the system for the others.
1141 An open of the page data file will fail with ENOMEM if the system-
1142 imposed limit would be exceeded.
1143
1144 watch
1145 Contains an array of prwatch structures, one for each watched area
1146 established by the PCWATCH control operation. See PCWATCH for details.
1147
1148 usage
1149 Contains process usage information described by a prusage structure
1150 which contains at least the following fields:
1151
1152 typedef struct prusage {
1153 id_t pr_lwpid; /* lwp id. 0: process or defunct */
1154 int pr_count; /* number of contributing lwps */
1155 timestruc_t pr_tstamp; /* real time stamp, time of read() */
1156 timestruc_t pr_create; /* process/lwp creation time stamp */
1157 timestruc_t pr_term; /* process/lwp termination time stamp */
1158 timestruc_t pr_rtime; /* total lwp real (elapsed) time */
1159 timestruc_t pr_utime; /* user level CPU time */
1160 timestruc_t pr_stime; /* system call CPU time */
1161 timestruc_t pr_ttime; /* other system trap CPU time */
1162 timestruc_t pr_tftime; /* text page fault sleep time */
1163 timestruc_t pr_dftime; /* data page fault sleep time */
1164 timestruc_t pr_kftime; /* kernel page fault sleep time */
1165 timestruc_t pr_ltime; /* user lock wait sleep time */
1166 timestruc_t pr_slptime; /* all other sleep time */
1167 timestruc_t pr_wtime; /* wait-cpu (latency) time */
1168 timestruc_t pr_stoptime; /* stopped time */
1169 ulong_t pr_minf; /* minor page faults */
1170 ulong_t pr_majf; /* major page faults */
1171 ulong_t pr_nswap; /* swaps */
1172 ulong_t pr_inblk; /* input blocks */
1173 ulong_t pr_oublk; /* output blocks */
1174 ulong_t pr_msnd; /* messages sent */
1175 ulong_t pr_mrcv; /* messages received */
1176 ulong_t pr_sigs; /* signals received */
1177 ulong_t pr_vctx; /* voluntary context switches */
1178 ulong_t pr_ictx; /* involuntary context switches */
1179 ulong_t pr_sysc; /* system calls */
1180 ulong_t pr_ioch; /* chars read and written */
1181 } prusage_t;
1182
1183
1184
1185 Microstate accounting is now continuously enabled. While this
1186 information was previously an estimate, if microstate accounting were
1187 not enabled, the current information is now never an estimate
1188 represents time the process has spent in various states.
1189
1190 lstatus
1191 Contains a prheader structure followed by an array of lwpstatus
1192 structures, one for each active lwp in the process (see also
1193 /proc/pid/lwp/lwpid/lwpstatus, below). The prheader structure describes
1194 the number and size of the array entries that follow.
1195
1196 typedef struct prheader {
1197 long pr_nent; /* number of entries */
1198 size_t pr_entsize; /* size of each entry, in bytes */
1199 } prheader_t;
1200
1201
1202
1203 The lwpstatus structure may grow by the addition of elements at the end
1204 in future releases of the system. Programs must use pr_entsize in the
1205 file header to index through the array. These comments apply to all
1206 /proc files that include a prheader structure (lpsinfo and lusage,
1207 below).
1208
1209 lpsinfo
1210 Contains a prheader structure followed by an array of lwpsinfo
1211 structures, one for eachactive and zombie lwp in the process. See also
1212 /proc/pid/lwp/lwpid/lwpsinfo, below.
1213
1214 lusage
1215 Contains a prheader structure followed by an array of prusage
1216 structures, one for each active lwp in the process, plus an additional
1217 element at the beginning that contains the summation over all defunct
1218 lwps (lwps that once existed but no longer exist in the process).
1219 Excluding the pr_lwpid, pr_tstamp, pr_create, and pr_term entries, the
1220 entry-by-entry summation over all these structures is the definition of
1221 the process usage information obtained from the usage file. (See also
1222 /proc/pid/lwp/lwpid/lwpusage, below.)
1223
1224 lwp
1225 A directory containing entries each of which names an active or zombie
1226 lwp within the process. These entries are themselves directories
1227 containing additional files as described below. Only the lwpsinfo file
1228 exists in the directory of a zombie lwp.
1229
1230 STRUCTURE OF /proc/pid/lwp/lwpid
1231 A given directory /proc/pid/lwp/lwpid contains the following entries:
1232
1233 lwpctl
1234 Write-only control file. The messages written to this file affect the
1235 specific lwp rather than the representative lwp, as is the case for the
1236 process's ctl file.
1237
1238 lwpstatus
1239 lwp-specific state information. This file contains the lwpstatus
1240 structure for the specific lwp as described above for the
1241 representative lwp in the process's status file.
1242
1243 lwpsinfo
1244 lwp-specific ps(1) information. This file contains the lwpsinfo
1245 structure for the specific lwp as described above for the
1246 representative lwp in the process's psinfo file. The lwpsinfo file
1247 remains accessible after an lwp becomes a zombie.
1248
1249 lwpusage
1250 This file contains the prusage structure for the specific lwp as
1251 described above for the process's usage file.
1252
1253 gwindows
1254 This file exists only on SPARC based machines. If it is non-empty, it
1255 contains a gwindows_t structure, defined in <sys/regset.h>, with the
1256 values of those SPARC register windows that could not be stored on the
1257 stack when the lwp stopped. Conditions under which register windows are
1258 not stored on the stack are: the stack pointer refers to nonexistent
1259 process memory or the stack pointer is improperly aligned. If the lwp
1260 is not stopped or if there are no register windows that could not be
1261 stored on the stack, the file is empty (the usual case).
1262
1263 xregs
1264 Extra state registers. The extra state register set is architecture
1265 dependent; this file is empty if the system does not support extra
1266 state registers. If the file is non-empty, it contains an architecture
1267 dependent structure of type prxregset_t, defined in <procfs.h>, with
1268 the values of the lwp's extra state registers. If the lwp is not
1269 stopped, all register values are undefined. See also the PCSXREG
1270 control operation, below.
1271
1272 asrs
1273 This file exists only for 64-bit SPARC V9 processes. It contains an
1274 asrset_t structure, defined in <sys/regset.h>, containing the values of
1275 the lwp's platform-dependent ancillary state registers. If the lwp is
1276 not stopped, all register values are undefined. See also the PCSASRS
1277 control operation, below.
1278
1279 spymaster
1280 For an agent lwp (see PCAGENT), this file contains a psinfo_t structure
1281 that corresponds to the process that created the agent lwp at the time
1282 the agent was created. This structure is identical to that retrieved
1283 via the psinfo file, with one modification: the pr_time field does not
1284 correspond to the CPU time for the process, but rather to the creation
1285 time of the agent lwp.
1286
1287 templates
1288 A directory which contains references to the active templates for the
1289 lwp, named by the contract type. Changes made to an active template
1290 descriptor do not affect the original template which was activated,
1291 though they do affect the active template. It is not possible to
1292 activate an active template descriptor. See contract(4).
1293
1294 CONTROL MESSAGES
1295 Process state changes are effected through messages written to a
1296 process's ctl file or to an individual lwp's lwpctl file. All control
1297 messages consist of a long that names the specific operation followed
1298 by additional data containing the operand, if any.
1299
1300
1301 Multiple control messages may be combined in a single write(2) (or
1302 writev(2)) to a control file, but no partial writes are permitted. That
1303 is, each control message, operation code plus operand, if any, must be
1304 presented in its entirety to the write(2) and not in pieces over
1305 several system calls. If a control operation fails, no subsequent
1306 operations contained in the same write(2) are attempted.
1307
1308
1309 Descriptions of the allowable control messages follow. In all cases,
1310 writing a message to a control file for a process or lwp that has
1311 terminated elicits the error ENOENT.
1312
1313 PCSTOP PCDSTOP PCWSTOP PCTWSTOP
1314 When applied to the process control file, PCSTOP directs all lwps to
1315 stop and waits for them to stop, PCDSTOP directs all lwps to stop
1316 without waiting for them to stop, and PCWSTOP simply waits for all lwps
1317 to stop. When applied to an lwp control file, PCSTOP directs the
1318 specific lwp to stop and waits until it has stopped, PCDSTOP directs
1319 the specific lwp to stop without waiting for it to stop, and PCWSTOP
1320 simply waits for the specific lwp to stop. When applied to an lwp
1321 control file, PCSTOP and PCWSTOP complete when the lwp stops on an
1322 event of interest, immediately if already so stopped; when applied to
1323 the process control file, they complete when every lwp has stopped
1324 either on an event of interest or on a PR_SUSPENDED stop.
1325
1326
1327 PCTWSTOP is identical to PCWSTOP except that it enables the operation
1328 to time out, to avoid waiting forever for a process or lwp that may
1329 never stop on an event of interest. PCTWSTOP takes a long operand
1330 specifying a number of milliseconds; the wait will terminate
1331 successfully after the specified number of milliseconds even if the
1332 process or lwp has not stopped; a timeout value of zero makes the
1333 operation identical to PCWSTOP.
1334
1335
1336 An ``event of interest'' is either a PR_REQUESTED stop or a stop that
1337 has been specified in the process's tracing flags (set by PCSTRACE,
1338 PCSFAULT, PCSENTRY, and PCSEXIT). PR_JOBCONTROL and PR_SUSPENDED stops
1339 are specifically not events of interest. (An lwp may stop twice due to
1340 a stop signal, first showing PR_SIGNALLED if the signal is traced and
1341 again showing PR_JOBCONTROL if the lwp is set running without clearing
1342 the signal.) If PCSTOP or PCDSTOP is applied to an lwp that is stopped,
1343 but not on an event of interest, the stop directive takes effect when
1344 the lwp is restarted by the competing mechanism. At that time, the lwp
1345 enters a PR_REQUESTED stop before executing any user-level code.
1346
1347
1348 A write of a control message that blocks is interruptible by a signal
1349 so that, for example, an alarm(2) can be set to avoid waiting forever
1350 for a process or lwp that may never stop on an event of interest. If
1351 PCSTOP is interrupted, the lwp stop directives remain in effect even
1352 though the write(2) returns an error. (Use of PCTWSTOP with a non-zero
1353 timeout is recommended over PCWSTOP with an alarm(2).)
1354
1355
1356 A system process (indicated by the PR_ISSYS flag) never executes at
1357 user level, has no user-level address space visible through /proc, and
1358 cannot be stopped. Applying one of these operations to a system process
1359 or any of its lwps elicits the error EBUSY.
1360
1361 PCRUN
1362 Make an lwp runnable again after a stop. This operation takes a long
1363 operand containing zero or more of the following flags:
1364
1365 PRCSIG
1366 clears the current signal, if any (see PCCSIG).
1367
1368
1369 PRCFAULT
1370 clears the current fault, if any (see PCCFAULT).
1371
1372
1373 PRSTEP
1374 directs the lwp to execute a single machine instruction. On
1375 completion of the instruction, a trace trap occurs. If
1376 FLTTRACE is being traced, the lwp stops; otherwise, it is
1377 sent SIGTRAP. If SIGTRAP is being traced and is not
1378 blocked, the lwp stops. When the lwp stops on an event of
1379 interest, the single-step directive is cancelled, even if
1380 the stop occurs before the instruction is executed. This
1381 operation requires hardware and operating system support
1382 and may not be implemented on all processors. It is
1383 implemented on SPARC and x86-based machines.
1384
1385
1386 PRSABORT
1387 is meaningful only if the lwp is in a PR_SYSENTRY stop or
1388 is marked PR_ASLEEP; it instructs the lwp to abort
1389 execution of the system call (see PCSENTRY and PCSEXIT).
1390
1391
1392 PRSTOP
1393 directs the lwp to stop again as soon as possible after
1394 resuming execution (see PCDSTOP). In particular, if the lwp
1395 is stopped on PR_SIGNALLED or PR_FAULTED, the next stop
1396 will show PR_REQUESTED, no other stop will have intervened,
1397 and the lwp will not have executed any user-level code.
1398
1399
1400
1401 When applied to an lwp control file, PCRUN clears any outstanding
1402 directed-stop request and makes the specific lwp runnable. The
1403 operation fails with EBUSY if the specific lwp is not stopped on an
1404 event of interest or has not been directed to stop or if the agent lwp
1405 exists and this is not the agent lwp (see PCAGENT).
1406
1407
1408 When applied to the process control file, a representative lwp is
1409 chosen for the operation as described for /proc/pid/status. The
1410 operation fails with EBUSY if the representative lwp is not stopped on
1411 an event of interest or has not been directed to stop or if the agent
1412 lwp exists. If PRSTEP or PRSTOP was requested, the representative lwp
1413 is made runnable and its outstanding directed-stop request is cleared;
1414 otherwise all outstanding directed-stop requests are cleared and, if it
1415 was stopped on an event of interest, the representative lwp is marked
1416 PR_REQUESTED. If, as a consequence, all lwps are in the PR_REQUESTED or
1417 PR_SUSPENDED stop state, all lwps showing PR_REQUESTED are made
1418 runnable.
1419
1420 PCSTRACE
1421 Define a set of signals to be traced in the process. The receipt of one
1422 of these signals by an lwp causes the lwp to stop. The set of signals
1423 is defined using an operand sigset_t contained in the control message.
1424 Receipt of SIGKILL cannot be traced; if specified, it is silently
1425 ignored.
1426
1427
1428 If a signal that is included in an lwp's held signal set (the signal
1429 mask) is sent to the lwp, the signal is not received and does not cause
1430 a stop until it is removed from the held signal set, either by the lwp
1431 itself or by setting the held signal set with PCSHOLD.
1432
1433 PCCSIG
1434 The current signal, if any, is cleared from the specific or
1435 representative lwp.
1436
1437 PCSSIG
1438 The current signal and its associated signal information for the
1439 specific or representative lwp are set according to the contents of the
1440 operand siginfo structure (see <sys/siginfo.h>). If the specified
1441 signal number is zero, the current signal is cleared. The semantics of
1442 this operation are different from those of kill(2) in that the signal
1443 is delivered to the lwp immediately after execution is resumed (even if
1444 it is being blocked) and an additional PR_SIGNALLED stop does not
1445 intervene even if the signal is traced. Setting the current signal to
1446 SIGKILL terminates the process immediately.
1447
1448 PCKILL
1449 If applied to the process control file, a signal is sent to the process
1450 with semantics identical to those of kill(2). If applied to an lwp
1451 control file, a directed signal is sent to the specific lwp. The signal
1452 is named in a long operand contained in the message. Sending SIGKILL
1453 terminates the process immediately.
1454
1455 PCUNKILL
1456 A signal is deleted, that is, it is removed from the set of pending
1457 signals. If applied to the process control file, the signal is deleted
1458 from the process's pending signals. If applied to an lwp control file,
1459 the signal is deleted from the lwp's pending signals. The current
1460 signal (if any) is unaffected. The signal is named in a long operand in
1461 the control message. It is an error (EINVAL) to attempt to delete
1462 SIGKILL.
1463
1464 PCSHOLD
1465 Set the set of held signals for the specific or representative lwp
1466 (signals whose delivery will be blocked if sent to the lwp). The set of
1467 signals is specified with a sigset_t operand. SIGKILL and SIGSTOP
1468 cannot be held; if specified, they are silently ignored.
1469
1470 PCSFAULT
1471 Define a set of hardware faults to be traced in the process. On
1472 incurring one of these faults, an lwp stops. The set is defined via the
1473 operand fltset_t structure. Fault names are defined in <sys/fault.h>
1474 and include the following. Some of these may not occur on all
1475 processors; there may be processor-specific faults in addition to
1476 these.
1477
1478 FLTILL
1479 illegal instruction
1480
1481
1482 FLTPRIV
1483 privileged instruction
1484
1485
1486 FLTBPT
1487 breakpoint trap
1488
1489
1490 FLTTRACE
1491 trace trap (single-step)
1492
1493
1494 FLTWATCH
1495 watchpoint trap
1496
1497
1498 FLTACCESS
1499 memory access fault (bus error)
1500
1501
1502 FLTBOUNDS
1503 memory bounds violation
1504
1505
1506 FLTIOVF
1507 integer overflow
1508
1509
1510 FLTIZDIV
1511 integer zero divide
1512
1513
1514 FLTFPE
1515 floating-point exception
1516
1517
1518 FLTSTACK
1519 unrecoverable stack fault
1520
1521
1522 FLTPAGE
1523 recoverable page fault
1524
1525
1526
1527 When not traced, a fault normally results in the posting of a signal to
1528 the lwp that incurred the fault. If an lwp stops on a fault, the signal
1529 is posted to the lwp when execution is resumed unless the fault is
1530 cleared by PCCFAULT or by the PRCFAULT option of PCRUN. FLTPAGE is an
1531 exception; no signal is posted. The pr_info field in the lwpstatus
1532 structure identifies the signal to be sent and contains machine-
1533 specific information about the fault.
1534
1535 PCCFAULT
1536 The current fault, if any, is cleared; the associated signal will not
1537 be sent to the specific or representative lwp.
1538
1539 PCSENTRY PCSEXIT
1540 These control operations instruct the process's lwps to stop on entry
1541 to or exit from specified system calls. The set of system calls to be
1542 traced is defined via an operand sysset_t structure.
1543
1544
1545 When entry to a system call is being traced, an lwp stops after having
1546 begun the call to the system but before the system call arguments have
1547 been fetched from the lwp. When exit from a system call is being
1548 traced, an lwp stops on completion of the system call just prior to
1549 checking for signals and returning to user level. At this point, all
1550 return values have been stored into the lwp's registers.
1551
1552
1553 If an lwp is stopped on entry to a system call (PR_SYSENTRY) or when
1554 sleeping in an interruptible system call (PR_ASLEEP is set), it may be
1555 instructed to go directly to system call exit by specifying the
1556 PRSABORT flag in a PCRUN control message. Unless exit from the system
1557 call is being traced, the lwp returns to user level showing EINTR.
1558
1559 PCWATCH
1560 Set or clear a watched area in the controlled process from a prwatch
1561 structure operand:
1562
1563 typedef struct prwatch {
1564 uintptr_t pr_vaddr; /* virtual address of watched area */
1565 size_t pr_size; /* size of watched area in bytes */
1566 int pr_wflags; /* watch type flags */
1567 } prwatch_t;
1568
1569
1570
1571 pr_vaddr specifies the virtual address of an area of memory to be
1572 watched in the controlled process. pr_size specifies the size of the
1573 area, in bytes. pr_wflags specifies the type of memory access to be
1574 monitored as a bit-mask of the following flags:
1575
1576 WA_READ
1577 read access
1578
1579
1580 WA_WRITE
1581 write access
1582
1583
1584 WA_EXEC
1585 execution access
1586
1587
1588 WA_TRAPAFTER
1589 trap after the instruction completes
1590
1591
1592
1593 If pr_wflags is non-empty, a watched area is established for the
1594 virtual address range specified by pr_vaddr and pr_size. If pr_wflags
1595 is empty, any previously-established watched area starting at the
1596 specified virtual address is cleared; pr_size is ignored.
1597
1598
1599 A watchpoint is triggered when an lwp in the traced process makes a
1600 memory reference that covers at least one byte of a watched area and
1601 the memory reference is as specified in pr_wflags. When an lwp triggers
1602 a watchpoint, it incurs a watchpoint trap. If FLTWATCH is being traced,
1603 the lwp stops; otherwise, it is sent a SIGTRAP signal; if SIGTRAP is
1604 being traced and is not blocked, the lwp stops.
1605
1606
1607 The watchpoint trap occurs before the instruction completes unless
1608 WA_TRAPAFTER was specified, in which case it occurs after the
1609 instruction completes. If it occurs before completion, the memory is
1610 not modified. If it occurs after completion, the memory is modified (if
1611 the access is a write access).
1612
1613
1614 Physical i/o is an exception for watchpoint traps. In this instance,
1615 there is no guarantee that memory before the watched area has already
1616 been modified (or in the case of WA_TRAPAFTER, that the memory
1617 following the watched area has not been modified) when the watchpoint
1618 trap occurs and the lwp stops.
1619
1620
1621 pr_info in the lwpstatus structure contains information pertinent to
1622 the watchpoint trap. In particular, the si_addr field contains the
1623 virtual address of the memory reference that triggered the watchpoint,
1624 and the si_code field contains one of TRAP_RWATCH, TRAP_WWATCH, or
1625 TRAP_XWATCH, indicating read, write, or execute access, respectively.
1626 The si_trapafter field is zero unless WA_TRAPAFTER is in effect for
1627 this watched area; non-zero indicates that the current instruction is
1628 not the instruction that incurred the watchpoint trap. The si_pc field
1629 contains the virtual address of the instruction that incurred the trap.
1630
1631
1632 A watchpoint trap may be triggered while executing a system call that
1633 makes reference to the traced process's memory. The lwp that is
1634 executing the system call incurs the watchpoint trap while still in the
1635 system call. If it stops as a result, the lwpstatus structure contains
1636 the system call number and its arguments. If the lwp does not stop, or
1637 if it is set running again without clearing the signal or fault, the
1638 system call fails with EFAULT. If WA_TRAPAFTER was specified, the
1639 memory reference will have completed and the memory will have been
1640 modified (if the access was a write access) when the watchpoint trap
1641 occurs.
1642
1643
1644 If more than one of WA_READ, WA_WRITE, and WA_EXEC is specified for a
1645 watched area, and a single instruction incurs more than one of the
1646 specified types, only one is reported when the watchpoint trap occurs.
1647 The precedence is WA_EXEC, WA_READ, WA_WRITE (WA_EXEC and WA_READ take
1648 precedence over WA_WRITE), unless WA_TRAPAFTER was specified, in which
1649 case it is WA_WRITE, WA_READ, WA_EXEC (WA_WRITE takes precedence).
1650
1651
1652 PCWATCH fails with EINVAL if an attempt is made to specify overlapping
1653 watched areas or if pr_wflags contains flags other than those specified
1654 above. It fails with ENOMEM if an attempt is made to establish more
1655 watched areas than the system can support (the system can support
1656 thousands).
1657
1658
1659 The child of a vfork(2) borrows the parent's address space. When a
1660 vfork(2) is executed by a traced process, all watched areas established
1661 for the parent are suspended until the child terminates or performs an
1662 exec(2). Any watched areas established independently in the child are
1663 cancelled when the parent resumes after the child's termination or
1664 exec(2). PCWATCH fails with EBUSY if applied to the parent of a
1665 vfork(2) before the child has terminated or performed an exec(2). The
1666 PR_VFORKP flag is set in the pstatus structure for such a parent
1667 process.
1668
1669
1670 Certain accesses of the traced process's address space by the operating
1671 system are immune to watchpoints. The initial construction of a signal
1672 stack frame when a signal is delivered to an lwp will not trigger a
1673 watchpoint trap even if the new frame covers watched areas of the
1674 stack. Once the signal handler is entered, watchpoint traps occur
1675 normally. On SPARC based machines, register window overflow and
1676 underflow will not trigger watchpoint traps, even if the register
1677 window save areas cover watched areas of the stack.
1678
1679
1680 Watched areas are not inherited by child processes, even if the traced
1681 process's inherit-on-fork mode, PR_FORK, is set (see PCSET, below).
1682 All watched areas are cancelled when the traced process performs a
1683 successful exec(2).
1684
1685 PCSET PCUNSET
1686 PCSET sets one or more modes of operation for the traced process.
1687 PCUNSET unsets these modes. The modes to be set or unset are specified
1688 by flags in an operand long in the control message:
1689
1690 PR_FORK
1691 (inherit-on-fork): When set, the process's tracing flags
1692 and its inherit-on-fork mode are inherited by the child of
1693 a fork(2), fork1(2), or vfork(2). When unset, child
1694 processes start with all tracing flags cleared.
1695
1696
1697 PR_RLC
1698 (run-on-last-close): When set and the last writable /proc
1699 file descriptor referring to the traced process or any of
1700 its lwps is closed, all of the process's tracing flags and
1701 watched areas are cleared, any outstanding stop directives
1702 are canceled, and if any lwps are stopped on events of
1703 interest, they are set running as though PCRUN had been
1704 applied to them. When unset, the process's tracing flags
1705 and watched areas are retained and lwps are not set
1706 running on last close.
1707
1708
1709 PR_KLC
1710 (kill-on-last-close): When set and the last writable /proc
1711 file descriptor referring to the traced process or any of
1712 its lwps is closed, the process is terminated with
1713 SIGKILL.
1714
1715
1716 PR_ASYNC
1717 (asynchronous-stop): When set, a stop on an event of
1718 interest by one lwp does not directly affect any other lwp
1719 in the process. When unset and an lwp stops on an event of
1720 interest other than PR_REQUESTED, all other lwps in the
1721 process are directed to stop.
1722
1723
1724 PR_MSACCT
1725 (microstate accounting): Microstate accounting is now
1726 continuously enabled. This flag is deprecated and no
1727 longer has any effect upon microstate accounting.
1728 Applications may toggle this flag; however, microstate
1729 accounting will remain enabled regardless.
1730
1731
1732 PR_MSFORK
1733 (inherit microstate accounting): All processes now inherit
1734 microstate accounting, as it is continuously enabled. This
1735 flag has been deprecated and its use no longer has any
1736 effect upon the behavior of microstate accounting.
1737
1738
1739 PR_BPTADJ
1740 (breakpoint trap pc adjustment): On x86-based machines, a
1741 breakpoint trap leaves the program counter (the EIP)
1742 referring to the breakpointed instruction plus one byte.
1743 When PR_BPTADJ is set, the system will adjust the program
1744 counter back to the location of the breakpointed
1745 instruction when the lwp stops on a breakpoint. This flag
1746 has no effect on SPARC based machines, where breakpoint
1747 traps leave the program counter referring to the
1748 breakpointed instruction.
1749
1750
1751 PR_PTRACE
1752 (ptrace-compatibility): When set, a stop on an event of
1753 interest by the traced process is reported to the parent
1754 of the traced process by wait(3C), SIGTRAP is sent to the
1755 traced process when it executes a successful exec(2),
1756 setuid/setgid flags are not honored for execs performed by
1757 the traced process, any exec of an object file that the
1758 traced process cannot read fails, and the process dies
1759 when its parent dies. This mode is deprecated; it is
1760 provided only to allow ptrace(3C) to be implemented as a
1761 library function using /proc.
1762
1763
1764
1765 It is an error (EINVAL) to specify flags other than those described
1766 above or to apply these operations to a system process. The current
1767 modes are reported in the pr_flags field of /proc/pid/status and
1768 /proc/pid/lwp/lwp/lwpstatus.
1769
1770 PCSREG
1771 Set the general registers for the specific or representative lwp
1772 according to the operand prgregset_t structure.
1773
1774
1775 On SPARC based systems, only the condition-code bits of the processor-
1776 status register (R_PSR) of SPARC V8 (32-bit) processes can be modified
1777 by PCSREG. Other privileged registers cannot be modified at all.
1778
1779
1780 On x86-based systems, only certain bits of the flags register (EFL) can
1781 be modified by PCSREG: these include the condition codes, direction-
1782 bit, and overflow-bit.
1783
1784
1785 PCSREG fails with EBUSY if the lwp is not stopped on an event of
1786 interest.
1787
1788 PCSVADDR
1789 Set the address at which execution will resume for the specific or
1790 representative lwp from the operand long. On SPARC based systems, both
1791 %pc and %npc are set, with %npc set to the instruction following the
1792 virtual address. On x86-based systems, only %eip is set. PCSVADDR fails
1793 with EBUSY if the lwp is not stopped on an event of interest.
1794
1795 PCSFPREG
1796 Set the floating-point registers for the specific or representative lwp
1797 according to the operand prfpregset_t structure. An error (EINVAL) is
1798 returned if the system does not support floating-point operations (no
1799 floating-point hardware and the system does not emulate floating-point
1800 machine instructions). PCSFPREG fails with EBUSY if the lwp is not
1801 stopped on an event of interest.
1802
1803 PCSXREG
1804 Set the extra state registers for the specific or representative lwp
1805 according to the architecture-dependent operand prxregset_t structure.
1806 An error (EINVAL) is returned if the system does not support extra
1807 state registers. PCSXREG fails with EBUSY if the lwp is not stopped on
1808 an event of interest.
1809
1810 PCSASRS
1811 Set the ancillary state registers for the specific or representative
1812 lwp according to the SPARC V9 platform-dependent operand asrset_t
1813 structure. An error (EINVAL) is returned if either the target process
1814 or the controlling process is not a 64-bit SPARC V9 process. Most of
1815 the ancillary state registers are privileged registers that cannot be
1816 modified. Only those that can be modified are set; all others are
1817 silently ignored. PCSASRS fails with EBUSY if the lwp is not stopped on
1818 an event of interest.
1819
1820 PCAGENT
1821 Create an agent lwp in the controlled process with register values from
1822 the operand prgregset_t structure (see PCSREG, above). The agent lwp is
1823 created in the stopped state showing PR_REQUESTED and with its held
1824 signal set (the signal mask) having all signals except SIGKILL and
1825 SIGSTOP blocked.
1826
1827
1828 The PCAGENT operation fails with EBUSY unless the process is fully
1829 stopped via /proc, that is, unless all of the lwps in the process are
1830 stopped either on events of interest or on PR_SUSPENDED, or are stopped
1831 on PR_JOBCONTROL and have been directed to stop via PCDSTOP. It fails
1832 with EBUSY if an agent lwp already exists. It fails with ENOMEM if
1833 system resources for creating new lwps have been exhausted.
1834
1835
1836 Any PCRUN operation applied to the process control file or to the
1837 control file of an lwp other than the agent lwp fails with EBUSY as
1838 long as the agent lwp exists. The agent lwp must be caused to terminate
1839 by executing the SYS_lwp_exit system call trap before the process can
1840 be restarted.
1841
1842
1843 Once the agent lwp is created, its lwp-ID can be found by reading the
1844 process status file. To facilitate opening the agent lwp's control and
1845 status files, the directory name /propc/pid/lwp/agent is accepted for
1846 lookup operations as an invisible alias for /proc/pid/lwp/lwpid, lwpid
1847 being the lwp-ID of the agent lwp (invisible in the sense that the name
1848 ``agent'' does not appear in a directory listing of /proc/pid/lwp
1849 obtained from ls(1), getdents(2), or readdir(3C)).
1850
1851
1852 The purpose of the agent lwp is to perform operations in the controlled
1853 process on behalf of the controlling process: to gather information not
1854 directly available via /proc files, or in general to make the process
1855 change state in ways not directly available via /proc control
1856 operations. To make use of an agent lwp, the controlling process must
1857 be capable of making it execute system calls (specifically, the
1858 SYS_lwp_exit system call trap). The register values given to the agent
1859 lwp on creation are typically the registers of the representative lwp,
1860 so that the agent lwp can use its stack.
1861
1862
1863 If the controlling process neglects to force the agent lwp to execute
1864 the SYS_lwp_exit system call (due to either logic error or fatal
1865 failure on the part of the controlling process), the agent lwp will
1866 remain in the target process. For purposes of being able to debug
1867 these otherwise rogue agents, information as to the creator of the
1868 agent lwp is reflected in that lwp's spymaster file in /proc. Should
1869 the target process generate a core dump with the agent lwp in place,
1870 this information will be available via the NT_SPYMASTER note in the
1871 core file (see core(4)).
1872
1873
1874 The agent lwp is not allowed to execute any variation of the SYS_fork
1875 or SYS_exec system call traps. Attempts to do so yield ENOTSUP to the
1876 agent lwp.
1877
1878
1879 Symbolic constants for system call trap numbers like SYS_lwp_exit and
1880 SYS_lwp_create can be found in the header file <sys/syscall.h>.
1881
1882 PCREAD PCWRITE
1883 Read or write the target process's address space via a priovec
1884 structure operand:
1885
1886 typedef struct priovec {
1887 void *pio_base; /* buffer in controlling process */
1888 size_t pio_len; /* size of read/write request in bytes */
1889 off_t pio_offset; /* virtual address in target process */
1890 } priovec_t;
1891
1892
1893
1894 These operations have the same effect as pread(2) and pwrite(2),
1895 respectively, of the target process's address space file. The
1896 difference is that more than one PCREAD or PCWRITE control operation
1897 can be written to the control file at once, and they can be
1898 interspersed with other control operations in a single write to the
1899 control file. This is useful, for example, when planting many
1900 breakpoint instructions in the process's address space, or when
1901 stepping over a breakpointed instruction. Unlike pread(2) and
1902 pwrite(2), no provision is made for partial reads or writes; if the
1903 operation cannot be performed completely, it fails with EIO.
1904
1905 PCNICE
1906 The traced process's nice(2) value is incremented by the amount in the
1907 operand long. Only a process with the {PRIV_PROC_PRIOCNTL} privilege
1908 asserted in its effective set can better a process's priority in this
1909 way, but any user may lower the priority. This operation is not
1910 meaningful for all scheduling classes.
1911
1912 PCSCRED
1913 Set the target process credentials to the values contained in the
1914 prcred_t structure operand (see /proc/pid/cred). The effective, real,
1915 and saved user-IDs and group-IDs of the target process are set. The
1916 target process's supplementary groups are not changed; the pr_ngroups
1917 and pr_groups members of the structure operand are ignored. Only the
1918 privileged processes can perform this operation; for all others it
1919 fails with EPERM.
1920
1921 PCSCREDX
1922 Operates like PCSCRED but also sets the supplementary groups; the
1923 length of the data written with this control operation should be
1924 "sizeof (prcred_t) + sizeof (gid_t) * (#groups - 1)".
1925
1926 PCSPRIV
1927 Set the target process privilege to the values contained in the
1928 prpriv_t operand (see /proc/pid/priv). The effective, permitted,
1929 inheritable, and limit sets are all changed. Privilege flags can also
1930 be set. The process is made privilege aware unless it can relinquish
1931 privilege awareness. See privileges(5).
1932
1933
1934 The limit set of the target process cannot be grown. The other
1935 privilege sets must be subsets of the intersection of the effective set
1936 of the calling process with the new limit set of the target process or
1937 subsets of the original values of the sets in the target process.
1938
1939
1940 If any of the above restrictions are not met, EPERM is returned. If the
1941 structure written is improperly formatted, EINVAL is returned.
1942
1943 PROGRAMMING NOTES
1944 For security reasons, except for the psinfo, usage, lpsinfo, lusage,
1945 lwpsinfo, and lwpusage files, which are world-readable, and except for
1946 privileged processes, an open of a /proc file fails unless both the
1947 user-ID and group-ID of the caller match those of the traced process
1948 and the process's object file is readable by the caller. The effective
1949 set of the caller is a superset of both the inheritable and the
1950 permitted set of the target process. The limit set of the caller is a
1951 superset of the limit set of the target process. Except for the world-
1952 readable files just mentioned, files corresponding to setuid and setgid
1953 processes can be opened only by the appropriately privileged process.
1954
1955
1956 A process that is missing the basic privilege {PRIV_PROC_INFO} cannot
1957 see any processes under /proc that it cannot send a signal to.
1958
1959
1960 A process that has {PRIV_PROC_OWNER} asserted in its effective set can
1961 open any file for reading. To manipulate or control a process, the
1962 controlling process must have at least as many privileges in its
1963 effective set as the target process has in its effective, inheritable,
1964 and permitted sets. The limit set of the controlling process must be a
1965 superset of the limit set of the target process. Additional
1966 restrictions apply if any of the uids of the target process are 0. See
1967 privileges(5).
1968
1969
1970 Even if held by a privileged process, an open process or lwp file
1971 descriptor (other than file descriptors for the world-readable files)
1972 becomes invalid if the traced process performs an exec(2) of a
1973 setuid/setgid object file or an object file that the traced process
1974 cannot read. Any operation performed on an invalid file descriptor,
1975 except close(2), fails with EAGAIN. In this situation, if any tracing
1976 flags are set and the process or any lwp file descriptor is open for
1977 writing, the process will have been directed to stop and its run-on-
1978 last-close flag will have been set (see PCSET). This enables a
1979 controlling process (if it has permission) to reopen the /proc files to
1980 get new valid file descriptors, close the invalid file descriptors,
1981 unset the run-on-last-close flag (if desired), and proceed. Just
1982 closing the invalid file descriptors causes the traced process to
1983 resume execution with all tracing flags cleared. Any process not
1984 currently open for writing via /proc, but that has left-over tracing
1985 flags from a previous open, and that executes a setuid/setgid or
1986 unreadable object file, will not be stopped but will have all its
1987 tracing flags cleared.
1988
1989
1990 To wait for one or more of a set of processes or lwps to stop or
1991 terminate, /proc file descriptors (other than those obtained by opening
1992 the cwd or root directories or by opening files in the fd or object
1993 directories) can be used in a poll(2) system call. When requested and
1994 returned, either of the polling events POLLPRI or POLLWRNORM indicates
1995 that the process or lwp stopped on an event of interest. Although they
1996 cannot be requested, the polling events POLLHUP, POLLERR, and POLLNVAL
1997 may be returned. POLLHUP indicates that the process or lwp has
1998 terminated. POLLERR indicates that the file descriptor has become
1999 invalid. POLLNVAL is returned immediately if POLLPRI or POLLWRNORM is
2000 requested on a file descriptor referring to a system process (see
2001 PCSTOP). The requested events may be empty to wait simply for
2002 termination.
2003
2004 FILES
2005 /proc
2006
2007 directory (list of processes)
2008
2009
2010 /proc/pid
2011
2012 specific process directory
2013
2014
2015 /proc/self
2016
2017 alias for a process's own directory
2018
2019
2020 /proc/pid/as
2021
2022 address space file
2023
2024
2025 /proc/pid/ctl
2026
2027 process control file
2028
2029
2030 /proc/pid/status
2031
2032 process status
2033
2034
2035 /proc/pid/lstatus
2036
2037 array of lwp status structs
2038
2039
2040 /proc/pid/psinfo
2041
2042 process ps(1) info
2043
2044
2045 /proc/pid/lpsinfo
2046
2047 array of lwp ps(1) info structs
2048
2049
2050 /proc/pid/map
2051
2052 address space map
2053
2054
2055 /proc/pid/xmap
2056
2057 extended address space map
2058
2059
2060 /proc/pid/rmap
2061
2062 reserved address map
2063
2064
2065 /proc/pid/cred
2066
2067 process credentials
2068
2069
2070 /proc/pid/priv
2071
2072 process privileges
2073
2074
2075 /proc/pid/sigact
2076
2077 process signal actions
2078
2079
2080 /proc/pid/auxv
2081
2082 process aux vector
2083
2084
2085 /proc/pid/argv
2086
2087 process argument vector
2088
2089
2090 /proc/pid/ldt
2091
2092 process LDT (x86 only)
2093
2094
2095 /proc/pid/usage
2096
2097 process usage
2098
2099
2100 /proc/pid/lusage
2101
2102 array of lwp usage structs
2103
2104
2105 /proc/pid/path
2106
2107 symbolic links to process open files
2108
2109
2110 /proc/pid/pagedata
2111
2112 process page data
2113
2114
2115 /proc/pid/watch
2116
2117 active watchpoints
2118
2119
2120 /proc/pid/cwd
2121
2122 alias for the current working directory
2123
2124
2125 /proc/pid/root
2126
2127 alias for the root directory
2128
2129
2130 /proc/pid/fd
2131
2132 directory (list of open files)
2133
2134
2135 /proc/pid/fd/*
2136
2137 aliases for process's open files
2138
2139
2140 /proc/pid/object
2141
2142 directory (list of mapped files)
2143
2144
2145 /proc/pid/object/a.out
2146
2147 alias for process's executable file
2148
2149
2150 /proc/pid/object/*
2151
2152 aliases for other mapped files
2153
2154
2155 /proc/pid/lwp
2156
2157 directory (list of lwps)
2158
2159
2160 /proc/pid/lwp/lwpid
2161
2162 specific lwp directory
2163
2164
2165 /proc/pid/lwp/agent
2166
2167 alias for the agent lwp directory
2168
2169
2170 /proc/pid/lwp/lwpid/lwpctl
2171
2172 lwp control file
2173
2174
2175 /proc/pid/lwp/lwpid/lwpstatus
2176
2177 lwp status
2178
2179
2180 /proc/pid/lwp/lwpid/lwpsinfo
2181
2182 lwp ps(1) info
2183
2184
2185 /proc/pid/lwp/lwpid/lwpusage
2186
2187 lwp usage
2188
2189
2190 /proc/pid/lwp/lwpid/gwindows
2191
2192 register windows (SPARC only)
2193
2194
2195 /proc/pid/lwp/lwpid/xregs
2196
2197 extra state registers
2198
2199
2200 /proc/pid/lwp/lwpid/asrs
2201
2202 ancillary state registers (SPARC V9 only)
2203
2204
2205 /proc/pid/lwp/lwpid/spymaster
2206
2207 For an agent LWP, the controlling process
2208
2209
2210 SEE ALSO
2211 ls(1), ps(1), chroot(1M), alarm(2), brk(2), chdir(2), chroot(2),
2212 close(2), creat(2), dup(2), exec(2), fcntl(2), fork(2), fork1(2),
2213 fstat(2), getdents(2), getustack(2), kill(2), lseek(2), mmap(2),
2214 nice(2), open(2), poll(2), pread(2), ptrace(3C), pwrite(2), read(2),
2215 readlink(2), readv(2), shmget(2), sigaction(2), sigaltstack(2),
2216 vfork(2), write(2), writev(2), _stack_grow(3C), readdir(3C),
2217 pthread_create(3C), pthread_join(3C), siginfo.h(3HEAD),
2218 signal.h(3HEAD), thr_create(3C), thr_join(3C), types32.h(3HEAD),
2219 ucontext.h(3HEAD), wait(3C), contract(4), core(4), process(4),
2220 lfcompile(5), privileges(5)
2221
2222 DIAGNOSTICS
2223 Errors that can occur in addition to the errors normally associated
2224 with file system access:
2225
2226 E2BIG
2227 Data to be returned in a read(2) of the page data file
2228 exceeds the size of the read buffer provided by the
2229 caller.
2230
2231
2232 EACCES
2233 An attempt was made to examine a process that ran under a
2234 different uid than the controlling process and
2235 {PRIV_PROC_OWNER} was not asserted in the effective set.
2236
2237
2238 EAGAIN
2239 The traced process has performed an exec(2) of a
2240 setuid/setgid object file or of an object file that it
2241 cannot read; all further operations on the process or lwp
2242 file descriptor (except close(2)) elicit this error.
2243
2244
2245 EBUSY
2246 PCSTOP, PCDSTOP, PCWSTOP, or PCTWSTOP was applied to a
2247 system process; an exclusive open(2) was attempted on a
2248 /proc file for a process already open for writing; PCRUN,
2249 PCSREG, PCSVADDR, PCSFPREG, or PCSXREG was applied to a
2250 process or lwp not stopped on an event of interest; an
2251 attempt was made to mount /proc when it was already
2252 mounted; PCAGENT was applied to a process that was not
2253 fully stopped or that already had an agent lwp.
2254
2255
2256 EINVAL
2257 In general, this means that some invalid argument was
2258 supplied to a system call. A non-exhaustive list of
2259 conditions eliciting this error includes: a control
2260 message operation code is undefined; an out-of-range
2261 signal number was specified with PCSSIG, PCKILL, or
2262 PCUNKILL; SIGKILL was specified with PCUNKILL; PCSFPREG
2263 was applied on a system that does not support floating-
2264 point operations; PCSXREG was applied on a system that
2265 does not support extra state registers.
2266
2267
2268 EINTR
2269 A signal was received by the controlling process while
2270 waiting for the traced process or lwp to stop via PCSTOP,
2271 PCWSTOP, or PCTWSTOP.
2272
2273
2274 EIO
2275 A write(2) was attempted at an illegal address in the
2276 traced process.
2277
2278
2279 ENOENT
2280 The traced process or lwp has terminated after being
2281 opened. The basic privilege {PRIV_PROC_INFO} is not
2282 asserted in the effective set of the calling process and
2283 the calling process cannot send a signal to the target
2284 process.
2285
2286
2287 ENOMEM
2288 The system-imposed limit on the number of page data file
2289 descriptors was reached on an open of /proc/pid/pagedata;
2290 an attempt was made with PCWATCH to establish more watched
2291 areas than the system can support; the PCAGENT operation
2292 was issued when the system was out of resources for
2293 creating lwps.
2294
2295
2296 ENOSYS
2297 An attempt was made to perform an unsupported operation
2298 (such as creat(2), link(2), or unlink(2)) on an entry in
2299 /proc.
2300
2301
2302 EOVERFLOW
2303 A 32-bit controlling process attempted to read or write
2304 the as file or attempted to read the map, rmap, or
2305 pagedata file of a 64-bit target process. A 32-bit
2306 controlling process attempted to apply one of the control
2307 operations PCSREG, PCSXREG, PCSVADDR, PCWATCH, PCAGENT,
2308 PCREAD, PCWRITE to a 64-bit target process.
2309
2310
2311 EPERM
2312 The process that issued the PCSCRED or PCSCREDX operation
2313 did not have the {PRIV_PROC_SETID} privilege asserted in
2314 its effective set, or the process that issued the PCNICE
2315 operation did not have the {PRIV_PROC_PRIOCNTL} in its
2316 effective set.
2317
2318 An attempt was made to control a process of which the E,
2319 P, and I privilege sets were not a subset of the effective
2320 set of the controlling process or the limit set of the
2321 controlling process is not a superset of limit set of the
2322 controlled process.
2323
2324 Any of the uids of the target process are 0 or an attempt
2325 was made to change any of the uids to 0 using PCSCRED and
2326 the security policy imposed additional restrictions. See
2327 privileges(5).
2328
2329
2330 NOTES
2331 Descriptions of structures in this document include only interesting
2332 structure elements, not filler and padding fields, and may show
2333 elements out of order for descriptive clarity. The actual structure
2334 definitions are contained in <procfs.h>.
2335
2336 BUGS
2337 Because the old ioctl(2)-based version of /proc is currently supported
2338 for binary compatibility with old applications, the top-level directory
2339 for a process, /proc/pid, is not world-readable, but it is world-
2340 searchable. Thus, anyone can open /proc/pid/psinfo even though ls(1)
2341 applied to /proc/pid will fail for anyone but the owner or an
2342 appropriately privileged process. Support for the old ioctl(2)-based
2343 version of /proc will be dropped in a future release, at which time the
2344 top-level directory for a process will be made world-readable.
2345
2346
2347 On SPARC based machines, the types gregset_t and fpregset_t defined in
2348 <sys/regset.h> are similar to but not the same as the types prgregset_t
2349 and prfpregset_t defined in <procfs.h>.
2350
2351
2352
2353 May 19, 2014 PROC(4)