Merge hell test

*** 25,34 ****
--- 25,35 ----
  
  /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  /*         All Rights Reserved  */
  /*
   * Copyright 2019 Joyent, Inc.
+  * Copyright 2021 Oxide Computer Company
   */
  
  #include <sys/types.h>
  #include <sys/param.h>
  #include <sys/thread.h>
*** 92,107 ****
--- 93,110 ----
      size_t, size_t *, size_t *);
  
  #ifdef _ELF32_COMPAT
  /* Link against the non-compat instances when compiling the 32-bit version. */
  extern size_t elf_datasz_max;
+ extern size_t elf_zeropg_sz;
  extern void elf_ctx_resize_scratch(elf_core_ctx_t *, size_t);
  extern uint_t elf_nphdr_max;
  extern uint_t elf_nshdr_max;
  extern size_t elf_shstrtab_max;
  #else
  size_t elf_datasz_max = 1 * 1024 * 1024;
+ size_t elf_zeropg_sz = 4 * 1024;
  uint_t elf_nphdr_max = 1000;
  uint_t elf_nshdr_max = 10000;
  size_t elf_shstrtab_max = 100 * 1024;
  #endif
  
*** 2262,2272 ****
          u_offset_t poffset, soffset, doffset;
          int error;
          uint_t i, nphdrs, nshdrs;
          struct seg *seg;
          struct as *as = p->p_as;
!         void *bigwad;
          size_t bigsize, phdrsz, shdrsz;
          Ehdr *ehdr;
          Phdr *phdr;
          Shdr shdr0;
          caddr_t brkbase, stkbase;
--- 2265,2275 ----
          u_offset_t poffset, soffset, doffset;
          int error;
          uint_t i, nphdrs, nshdrs;
          struct seg *seg;
          struct as *as = p->p_as;
!         void *bigwad, *zeropg = NULL;
          size_t bigsize, phdrsz, shdrsz;
          Ehdr *ehdr;
          Phdr *phdr;
          Shdr shdr0;
          caddr_t brkbase, stkbase;
*** 2574,2596 ****
  
                  if (phdr[i].p_filesz == 0)
                          continue;
  
                  /*
                   * If dumping out this segment fails, rather than failing
                   * the core dump entirely, we reset the size of the mapping
                   * to zero to indicate that the data is absent from the core
                   * file and or in the PF_SUNW_FAILURE flag to differentiate
                   * this from mappings that were excluded due to the core file
                   * content settings.
                   */
!                 if ((error = core_seg(p, vp, phdr[i].p_offset,
!                     (caddr_t)(uintptr_t)phdr[i].p_vaddr, phdr[i].p_filesz,
!                     rlimit, credp)) == 0) {
!                         continue;
                  }
  
                  if ((sig = lwp->lwp_cursig) == 0) {
                          /*
                           * We failed due to something other than a signal.
                           * Since the space reserved for the segment is now
                           * unused, we stash the errno in the first four
--- 2577,2629 ----
  
                  if (phdr[i].p_filesz == 0)
                          continue;
  
                  /*
+                  * If we hit a region that was mapped PROT_NONE then we cannot
+                  * continue dumping this normally as the kernel would be unable
+                  * to read from the page and that would result in us failing to
+                  * dump the page. As such, any region mapped PROT_NONE, we dump
+                  * as a zero-filled page such that this is still represented in
+                  * the map.
+                  *
                   * If dumping out this segment fails, rather than failing
                   * the core dump entirely, we reset the size of the mapping
                   * to zero to indicate that the data is absent from the core
                   * file and or in the PF_SUNW_FAILURE flag to differentiate
                   * this from mappings that were excluded due to the core file
                   * content settings.
                   */
!                 if ((phdr[i].p_flags & (PF_R | PF_W | PF_X)) == 0) {
!                         size_t towrite = phdr[i].p_filesz;
!                         size_t curoff = 0;
! 
!                         if (zeropg == NULL) {
!                                 zeropg = kmem_zalloc(elf_zeropg_sz, KM_SLEEP);
                          }
  
+                         error = 0;
+                         while (towrite != 0) {
+                                 size_t len = MIN(towrite, elf_zeropg_sz);
+ 
+                                 error = core_write(vp, UIO_SYSSPACE,
+                                     phdr[i].p_offset + curoff, zeropg, len,
+                                     rlimit, credp);
+                                 if (error != 0)
+                                         break;
+ 
+                                 towrite -= len;
+                                 curoff += len;
+                         }
+                 } else {
+                         error = core_seg(p, vp, phdr[i].p_offset,
+                             (caddr_t)(uintptr_t)phdr[i].p_vaddr,
+                             phdr[i].p_filesz, rlimit, credp);
+                 }
+                 if (error == 0)
+                         continue;
+ 
                  if ((sig = lwp->lwp_cursig) == 0) {
                          /*
                           * We failed due to something other than a signal.
                           * Since the space reserved for the segment is now
                           * unused, we stash the errno in the first four