1 /*
2 * Copyright (C) 1984-2002 Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information about less, or for information on how to
8 * contact the author, see the README file.
9 */
10
11
12 /*
13 * Operating system dependent routines.
14 *
15 * Most of the stuff in here is based on Unix, but an attempt
16 * has been made to make things work on other operating systems.
17 * This will sometimes result in a loss of functionality, unless
18 * someone rewrites code specifically for the new operating system.
19 *
20 * The makefile provides defines to decide whether various
21 * Unix features are present.
22 */
23
24 #include "less.h"
25 #include <signal.h>
26 #include <setjmp.h>
27 #if HAVE_TIME_H
28 #include <time.h>
29 #endif
30 #if HAVE_ERRNO_H
31 #include <errno.h>
32 #endif
33 #if HAVE_VALUES_H
34 #include <values.h>
35 #endif
36
37 #if HAVE_TIME_T
38 #define time_type time_t
39 #else
40 #define time_type long
41 #endif
42
43 /*
44 * BSD setjmp() saves (and longjmp() restores) the signal mask.
45 * This costs a system call or two per setjmp(), so if possible we clear the
46 * signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead.
47 * On other systems, setjmp() doesn't affect the signal mask and so
48 * _setjmp() does not exist; we just use setjmp().
49 */
50 #if HAVE__SETJMP && HAVE_SIGSETMASK
51 #define SET_JUMP _setjmp
52 #define LONG_JUMP _longjmp
53 #else
54 #define SET_JUMP setjmp
55 #define LONG_JUMP longjmp
56 #endif
57
58 public int reading;
59
60 static jmp_buf read_label;
61
62 extern int sigs;
63
64 /*
65 * Like read() system call, but is deliberately interruptible.
66 * A call to intread() from a signal handler will interrupt
67 * any pending iread().
68 */
69 public int
iread(fd,buf,len)70 iread(fd, buf, len)
71 int fd;
72 char *buf;
73 unsigned int len;
74 {
75 register int n;
76
77 #if MSDOS_COMPILER==WIN32C
78 if (ABORT_SIGS())
79 return (READ_INTR);
80 #else
81 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
82 if (kbhit())
83 {
84 int c;
85
86 c = getch();
87 if (c == '\003')
88 return (READ_INTR);
89 ungetch(c);
90 }
91 #endif
92 #endif
93 if (SET_JUMP(read_label))
94 {
95 /*
96 * We jumped here from intread.
97 */
98 reading = 0;
99 #if HAVE_SIGPROCMASK
100 {
101 sigset_t mask;
102 sigemptyset(&mask);
103 sigprocmask(SIG_SETMASK, &mask, NULL);
104 }
105 #else
106 #if HAVE_SIGSETMASK
107 sigsetmask(0);
108 #else
109 #ifdef _OSK
110 sigmask(~0);
111 #endif
112 #endif
113 #endif
114 return (READ_INTR);
115 }
116
117 flush();
118 reading = 1;
119 #if MSDOS_COMPILER==DJGPPC
120 if (isatty(fd))
121 {
122 /*
123 * Don't try reading from a TTY until a character is
124 * available, because that makes some background programs
125 * believe DOS is busy in a way that prevents those
126 * programs from working while "less" waits.
127 */
128 fd_set readfds;
129
130 FD_ZERO(&readfds);
131 FD_SET(fd, &readfds);
132 if (select(fd+1, &readfds, 0, 0, 0) == -1)
133 return (-1);
134 }
135 #endif
136 n = read(fd, buf, len);
137 #if 1
138 /*
139 * This is a kludge to workaround a problem on some systems
140 * where terminating a remote tty connection causes read() to
141 * start returning 0 forever, instead of -1.
142 */
143 {
144 extern int ignore_eoi;
145 if (!ignore_eoi)
146 {
147 static int consecutive_nulls = 0;
148 if (n == 0)
149 consecutive_nulls++;
150 else
151 consecutive_nulls = 0;
152 if (consecutive_nulls > 20)
153 quit(QUIT_ERROR);
154 }
155 }
156 #endif
157 reading = 0;
158 if (n < 0)
159 return (-1);
160 return (n);
161 }
162
163 /*
164 * Interrupt a pending iread().
165 */
166 public void
intread()167 intread()
168 {
169 LONG_JUMP(read_label, 1);
170 }
171
172 /*
173 * Return the current time.
174 */
175 #if HAVE_TIME
176 public long
get_time()177 get_time()
178 {
179 time_type t;
180
181 time(&t);
182 return (t);
183 }
184 #endif
185
186
187 #if !HAVE_STRERROR
188 /*
189 * Local version of strerror, if not available from the system.
190 */
191 static char *
strerror(err)192 strerror(err)
193 int err;
194 {
195 #if HAVE_SYS_ERRLIST
196 static char buf[16];
197 extern char *sys_errlist[];
198 extern int sys_nerr;
199
200 if (err < sys_nerr)
201 return sys_errlist[err];
202 sprintf(buf, "Error %d", err);
203 return buf;
204 #else
205 return ("cannot open");
206 #endif
207 }
208 #endif
209
210 /*
211 * errno_message: Return an error message based on the value of "errno".
212 */
213 public char *
errno_message(filename)214 errno_message(filename)
215 char *filename;
216 {
217 register char *p;
218 register char *m;
219 int len;
220 #if HAVE_ERRNO
221 #if MUST_DEFINE_ERRNO
222 extern int errno;
223 #endif
224 p = strerror(errno);
225 #else
226 p = "cannot open";
227 #endif
228 len = strlen(filename) + strlen(p) + 3;
229 m = (char *) ecalloc(len, sizeof(char));
230 snprintf(m, len, "%s: %s", filename, p);
231 return (m);
232 }
233
234 /*
235 * Return the ratio of two POSITIONS, as a percentage.
236 * {{ Assumes a POSITION is a long int. }}
237 */
238 public int
percentage(num,den)239 percentage(num, den)
240 POSITION num, den;
241 {
242 POSITION num100 = num * 100;
243
244 if (num100 / 100 == num)
245 return (num100 / den);
246 else
247 return (num / (den / 100));
248 }
249
250 /*
251 * Return the specified percentage of a POSITION.
252 */
253 public POSITION
percent_pos(pos,percent)254 percent_pos(pos, percent)
255 POSITION pos;
256 int percent;
257 {
258 POSITION result100;
259
260 if (percent == 0)
261 return (0);
262 else if ((result100 = pos * percent) / percent == pos)
263 return (result100 / 100);
264 else
265 return (percent * (pos / 100));
266 }
267
268 #if !HAVE_STRCHR
269 /*
270 * strchr is used by regexp.c.
271 */
272 char *
strchr(s,c)273 strchr(s, c)
274 char *s;
275 int c;
276 {
277 for ( ; *s != '\0'; s++)
278 if (*s == c)
279 return (s);
280 if (c == '\0')
281 return (s);
282 return (NULL);
283 }
284 #endif
285
286 #if !HAVE_MEMCPY
287 VOID_POINTER
memcpy(dst,src,len)288 memcpy(dst, src, len)
289 VOID_POINTER dst;
290 VOID_POINTER src;
291 int len;
292 {
293 char *dstp = (char *) dst;
294 char *srcp = (char *) src;
295 int i;
296
297 for (i = 0; i < len; i++)
298 dstp[i] = srcp[i];
299 return (dst);
300 }
301 #endif
302
303 #ifdef _OSK_MWC32
304
305 /*
306 * This implements an ANSI-style intercept setup for Microware C 3.2
307 */
308 public int
os9_signal(type,handler)309 os9_signal(type, handler)
310 int type;
311 RETSIGTYPE (*handler)();
312 {
313 intercept(handler);
314 }
315
316 #include <sgstat.h>
317
318 int
isatty(f)319 isatty(f)
320 int f;
321 {
322 struct sgbuf sgbuf;
323
324 if (_gs_opt(f, &sgbuf) < 0)
325 return -1;
326 return (sgbuf.sg_class == 0);
327 }
328
329 #endif
330