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 #if HAVE_TIME_H
27 #include <time.h>
28 #endif
29 #if HAVE_ERRNO_H
30 #include <errno.h>
31 #endif
32 #if HAVE_VALUES_H
33 #include <values.h>
34 #endif
35
36 #if HAVE_TIME_T
37 #define time_type time_t
38 #else
39 #define time_type long
40 #endif
41
42 extern int sigs;
43
44 /*
45 * Like read() system call, but is deliberately interruptible.
46 */
47 public int
iread(fd,buf,len)48 iread(fd, buf, len)
49 int fd;
50 char *buf;
51 unsigned int len;
52 {
53 register int n;
54
55 #if MSDOS_COMPILER==WIN32C
56 if (ABORT_SIGS())
57 return (READ_INTR);
58 #else
59 #if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC
60 if (kbhit())
61 {
62 int c;
63
64 c = getch();
65 if (c == '\003')
66 return (READ_INTR);
67 ungetch(c);
68 }
69 #endif
70 #endif
71
72 flush();
73 #if MSDOS_COMPILER==DJGPPC
74 if (isatty(fd))
75 {
76 /*
77 * Don't try reading from a TTY until a character is
78 * available, because that makes some background programs
79 * believe DOS is busy in a way that prevents those
80 * programs from working while "less" waits.
81 */
82 fd_set readfds;
83
84 FD_ZERO(&readfds);
85 FD_SET(fd, &readfds);
86 if (select(fd+1, &readfds, 0, 0, 0) == -1)
87 return (-1);
88 }
89 #endif
90 n = read(fd, buf, len);
91 #if 1
92 /*
93 * This is a kludge to workaround a problem on some systems
94 * where terminating a remote tty connection causes read() to
95 * start returning 0 forever, instead of -1.
96 */
97 {
98 extern int ignore_eoi;
99 if (!ignore_eoi)
100 {
101 static int consecutive_nulls = 0;
102 if (n == 0)
103 consecutive_nulls++;
104 else
105 consecutive_nulls = 0;
106 if (consecutive_nulls > 20)
107 quit(QUIT_ERROR);
108 }
109 }
110 #endif
111 if (n < 0)
112 return (errno == EINTR ? READ_INTR : -1);
113 return (n);
114 }
115
116 /*
117 * Return the current time.
118 */
119 #if HAVE_TIME
120 public long
get_time()121 get_time()
122 {
123 time_type t;
124
125 time(&t);
126 return (t);
127 }
128 #endif
129
130
131 #if !HAVE_STRERROR
132 /*
133 * Local version of strerror, if not available from the system.
134 */
135 static char *
strerror(err)136 strerror(err)
137 int err;
138 {
139 #if HAVE_SYS_ERRLIST
140 static char buf[16];
141 extern char *sys_errlist[];
142 extern int sys_nerr;
143
144 if (err < sys_nerr)
145 return sys_errlist[err];
146 snprintf(buf, sizeof(buf), "Error %d", err);
147 return buf;
148 #else
149 return ("cannot open");
150 #endif
151 }
152 #endif
153
154 /*
155 * errno_message: Return an error message based on the value of "errno".
156 */
157 public char *
errno_message(filename)158 errno_message(filename)
159 char *filename;
160 {
161 register char *p;
162 register char *m;
163 size_t len;
164 #if HAVE_ERRNO
165 #if MUST_DEFINE_ERRNO
166 extern int errno;
167 #endif
168 p = strerror(errno);
169 #else
170 p = "cannot open";
171 #endif
172 len = strlen(filename) + strlen(p) + 3;
173 m = (char *) ecalloc(len, sizeof(char));
174 snprintf(m, len, "%s: %s", filename, p);
175 return (m);
176 }
177
178 /*
179 * Return the ratio of two POSITIONS, as a percentage.
180 * {{ Assumes a POSITION is a long int. }}
181 */
182 public int
percentage(num,den)183 percentage(num, den)
184 POSITION num, den;
185 {
186 POSITION num100 = num * 100;
187
188 if (num100 / 100 == num)
189 return (num100 / den);
190 else
191 return (num / (den / 100));
192 }
193
194 /*
195 * Return the specified percentage of a POSITION.
196 */
197 public POSITION
percent_pos(pos,percent)198 percent_pos(pos, percent)
199 POSITION pos;
200 int percent;
201 {
202 POSITION result100;
203
204 if (percent == 0)
205 return (0);
206 else if ((result100 = pos * percent) / percent == pos)
207 return (result100 / 100);
208 else
209 return (percent * (pos / 100));
210 }
211
212 #if !HAVE_STRCHR
213 /*
214 * strchr is used by regexp.c.
215 */
216 char *
strchr(s,c)217 strchr(s, c)
218 char *s;
219 int c;
220 {
221 for ( ; *s != '\0'; s++)
222 if (*s == c)
223 return (s);
224 if (c == '\0')
225 return (s);
226 return (NULL);
227 }
228 #endif
229
230 #if !HAVE_MEMCPY
231 VOID_POINTER
memcpy(dst,src,len)232 memcpy(dst, src, len)
233 VOID_POINTER dst;
234 VOID_POINTER src;
235 int len;
236 {
237 char *dstp = (char *) dst;
238 char *srcp = (char *) src;
239 int i;
240
241 for (i = 0; i < len; i++)
242 dstp[i] = srcp[i];
243 return (dst);
244 }
245 #endif
246
247 #ifdef _OSK_MWC32
248
249 /*
250 * This implements an ANSI-style intercept setup for Microware C 3.2
251 */
252 public int
os9_signal(type,handler)253 os9_signal(type, handler)
254 int type;
255 RETSIGTYPE (*handler)();
256 {
257 intercept(handler);
258 }
259
260 #include <sgstat.h>
261
262 int
isatty(f)263 isatty(f)
264 int f;
265 {
266 struct sgbuf sgbuf;
267
268 if (_gs_opt(f, &sgbuf) < 0)
269 return -1;
270 return (sgbuf.sg_class == 0);
271 }
272
273 #endif
274