1 /*
2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26 /*
27 * Simple paged-output and paged-viewing functions
28 */
29
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <sys/types.h>
34 #include <sys/stat.h>
35 #include <fcntl.h>
36 #include <errno.h>
37 #include <termios.h>
38 #include <unistd.h>
39 #include <stropts.h>
40
41 static int p_maxlines = -1;
42 static int p_freelines;
43
44 static struct termios orig_termios;
45 static char *pager_prompt1 = \
46 " --more-- <space> page down <enter> line down <q> quit ";
47 static char *pager_blank = \
48 " ";
49
50 /*
51 * 'open' the pager
52 */
53 void
54 pager_open(void)
55 {
56 int nlines;
57 char *cp, *lp;
58 struct termios raw;
59 struct winsize ws;
60
61 tcgetattr(0, &orig_termios);
62 raw = orig_termios;
63 raw.c_lflag &= ~(ICANON | ECHO);
64 raw.c_cc[VMIN] = 1;
65 raw.c_cc[VTIME] = 0;
66 (void) tcsetattr(0, TCSAFLUSH, &raw);
67
68 nlines = 24; /* sensible default */
69 if (ioctl(1, TIOCGWINSZ, &ws) == -1 || ws.ws_row == 0) {
70 if ((cp = getenv("LINES")) != NULL) {
71 nlines = strtol(cp, &lp, 0);
72 }
73 } else
74 nlines = ws.ws_row;
75
76 p_maxlines = nlines - 1;
77 if (p_maxlines < 1)
78 p_maxlines = 1;
79 p_freelines = p_maxlines;
80 }
81
82 /*
83 * 'close' the pager
84 */
85 void
86 pager_close(void)
87 {
88 (void) fflush(stdout);
89 p_maxlines = -1;
90 (void) tcsetattr(0, TCSAFLUSH, &orig_termios);
91 }
92
93 /*
94 * Emit lines to the pager; may not return until the user
95 * has responded to the prompt.
96 *
97 * Will return nonzero if the user enters 'q' or 'Q' at the prompt.
98 *
99 * XXX note that this watches outgoing newlines (and eats them), but
100 * does not handle wrap detection (req. count of columns).
101 */
102 int
103 pager_output(const char *cp)
104 {
105 int action;
106
107 if (cp == NULL)
108 return (0);
109
110 for (;;) {
111 if (*cp == 0)
112 return (0);
113
114 putchar(*cp); /* always emit character */
115
116 if (*(cp++) == '\n') { /* got a newline? */
117 p_freelines--;
118 if (p_freelines <= 0) {
119 printf("%s", pager_prompt1);
120 action = 0;
121 while (action == 0) {
122 switch (getchar()) {
123 case '\r':
124 case '\n':
125 p_freelines = 1;
126 action = 1;
127 break;
128 case ' ':
129 p_freelines = p_maxlines;
130 action = 1;
131 break;
132 case 'q':
133 case 'Q':
134 action = 2;
135 break;
136 default:
137 break;
138 }
139 }
140 printf("\r%s\r", pager_blank);
141 if (action == 2)
142 return (1);
143 }
144 }
145 }
146 }
147
148 /*
149 * Display from (fd).
150 */
151 int
152 pager_file(const char *fname)
153 {
154 char buf[80];
155 size_t hmuch;
156 int fd;
157 int result;
158
159 if ((fd = open(fname, O_RDONLY)) == -1) {
160 printf("can't open '%s': %s\n", fname, strerror(errno));
161 return (-1);
162 }
163
164 for (;;) {
165 hmuch = read(fd, buf, sizeof (buf) - 1);
166 if (hmuch == -1) {
167 result = -1;
168 break;
169 }
170 if (hmuch == 0) {
171 result = 0;
172 break;
173 }
174 buf[hmuch] = 0;
175 if (pager_output(buf)) {
176 result = 1;
177 break;
178 }
179 }
180 close(fd);
181 return (result);
182 }