1/* 2 * Copyright (C) 1984-2017 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, see the README file. 8 */ 9 10 11/* 12 * Operating system dependent routines. 13 * 14 * Most of the stuff in here is based on Unix, but an attempt 15 * has been made to make things work on other operating systems. 16 * This will sometimes result in a loss of functionality, unless 17 * someone rewrites code specifically for the new operating system. 18 * 19 * The makefile provides defines to decide whether various 20 * Unix features are present. 21 */ 22 23#include "less.h" 24#include <signal.h> 25#include <setjmp.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/* 37 * BSD setjmp() saves (and longjmp() restores) the signal mask. 38 * This costs a system call or two per setjmp(), so if possible we clear the 39 * signal mask with sigsetmask(), and use _setjmp()/_longjmp() instead. 40 * On other systems, setjmp() doesn't affect the signal mask and so 41 * _setjmp() does not exist; we just use setjmp(). 42 */ 43#if HAVE__SETJMP && HAVE_SIGSETMASK 44#define SET_JUMP _setjmp 45#define LONG_JUMP _longjmp 46#else 47#define SET_JUMP setjmp 48#define LONG_JUMP longjmp 49#endif 50 51public int reading; 52 53static jmp_buf read_label; 54 55extern int sigs; 56 57/* 58 * Like read() system call, but is deliberately interruptible. 59 * A call to intread() from a signal handler will interrupt 60 * any pending iread(). 61 */ 62 public int 63iread(fd, buf, len) 64 int fd; 65 unsigned char *buf; 66 unsigned int len; 67{ 68 int n; 69 70start: 71#if MSDOS_COMPILER==WIN32C 72 if (ABORT_SIGS()) 73 return (READ_INTR); 74#else 75#if MSDOS_COMPILER && MSDOS_COMPILER != DJGPPC 76 if (kbhit()) 77 { 78 int c; 79 80 c = getch(); 81 if (c == '\003') 82 return (READ_INTR); 83 ungetch(c); 84 } 85#endif 86#endif 87 if (SET_JUMP(read_label)) 88 { 89 /* 90 * We jumped here from intread. 91 */ 92 reading = 0; 93#if HAVE_SIGPROCMASK 94 { 95 sigset_t mask; 96 sigemptyset(&mask); 97 sigprocmask(SIG_SETMASK, &mask, NULL); 98 } 99#else 100#if HAVE_SIGSETMASK 101 sigsetmask(0); 102#else 103#ifdef _OSK 104 sigmask(~0); 105#endif 106#endif 107#endif 108 return (READ_INTR); 109 } 110 111 flush(); 112 reading = 1; 113#if MSDOS_COMPILER==DJGPPC 114 if (isatty(fd)) 115 { 116 /* 117 * Don't try reading from a TTY until a character is 118 * available, because that makes some background programs 119 * believe DOS is busy in a way that prevents those 120 * programs from working while "less" waits. 121 */ 122 fd_set readfds; 123 124 FD_ZERO(&readfds); 125 FD_SET(fd, &readfds); 126 if (select(fd+1, &readfds, 0, 0, 0) == -1) 127 return (-1); 128 } 129#endif 130 n = read(fd, buf, len); 131#if 1 132 /* 133 * This is a kludge to workaround a problem on some systems 134 * where terminating a remote tty connection causes read() to 135 * start returning 0 forever, instead of -1. 136 */ 137 { 138 extern int ignore_eoi; 139 if (!ignore_eoi) 140 { 141 static int consecutive_nulls = 0; 142 if (n == 0) 143 consecutive_nulls++; 144 else 145 consecutive_nulls = 0; 146 if (consecutive_nulls > 20) 147 quit(QUIT_ERROR); 148 } 149 } 150#endif 151 reading = 0; 152 if (n < 0) 153 { 154#if HAVE_ERRNO 155 /* 156 * Certain values of errno indicate we should just retry the read. 157 */ 158#if MUST_DEFINE_ERRNO 159 extern int errno; 160#endif 161#ifdef EINTR 162 if (errno == EINTR) 163 goto start; 164#endif 165#ifdef EAGAIN 166 if (errno == EAGAIN) 167 goto start; 168#endif 169#endif 170 return (-1); 171 } 172 return (n); 173} 174 175/* 176 * Interrupt a pending iread(). 177 */ 178 public void 179intread() 180{ 181 LONG_JUMP(read_label, 1); 182} 183 184/* 185 * Return the current time. 186 */ 187#if HAVE_TIME 188 public time_type 189get_time() 190{ 191 time_type t; 192 193 time(&t); 194 return (t); 195} 196#endif 197 198 199#if !HAVE_STRERROR 200/* 201 * Local version of strerror, if not available from the system. 202 */ 203 static char * 204strerror(err) 205 int err; 206{ 207#if HAVE_SYS_ERRLIST 208 static char buf[16]; 209 extern char *sys_errlist[]; 210 extern int sys_nerr; 211 212 if (err < sys_nerr) 213 return sys_errlist[err]; 214 sprintf(buf, "Error %d", err); 215 return buf; 216#else 217 return ("cannot open"); 218#endif 219} 220#endif 221 222/* 223 * errno_message: Return an error message based on the value of "errno". 224 */ 225 public char * 226errno_message(filename) 227 char *filename; 228{ 229 char *p; 230 char *m; 231 int len; 232#if HAVE_ERRNO 233#if MUST_DEFINE_ERRNO 234 extern int errno; 235#endif 236 p = strerror(errno); 237#else 238 p = "cannot open"; 239#endif 240 len = (int) (strlen(filename) + strlen(p) + 3); 241 m = (char *) ecalloc(len, sizeof(char)); 242 SNPRINTF2(m, len, "%s: %s", filename, p); 243 return (m); 244} 245 246/* #define HAVE_FLOAT 0 */ 247 248 static POSITION 249muldiv(val, num, den) 250 POSITION val, num, den; 251{ 252#if HAVE_FLOAT 253 double v = (((double) val) * num) / den; 254 return ((POSITION) (v + 0.5)); 255#else 256 POSITION v = ((POSITION) val) * num; 257 258 if (v / num == val) 259 /* No overflow */ 260 return (POSITION) (v / den); 261 else 262 /* Above calculation overflows; 263 * use a method that is less precise but won't overflow. */ 264 return (POSITION) (val / (den / num)); 265#endif 266} 267 268/* 269 * Return the ratio of two POSITIONS, as a percentage. 270 * {{ Assumes a POSITION is a long int. }} 271 */ 272 public int 273percentage(num, den) 274 POSITION num; 275 POSITION den; 276{ 277 return (int) muldiv(num, (POSITION) 100, den); 278} 279 280/* 281 * Return the specified percentage of a POSITION. 282 */ 283 public POSITION 284percent_pos(pos, percent, fraction) 285 POSITION pos; 286 int percent; 287 long fraction; 288{ 289 /* Change percent (parts per 100) to perden (parts per NUM_FRAC_DENOM). */ 290 POSITION perden = (percent * (NUM_FRAC_DENOM / 100)) + (fraction / 100); 291 292 if (perden == 0) 293 return (0); 294 return (POSITION) muldiv(pos, perden, (POSITION) NUM_FRAC_DENOM); 295} 296 297#if !HAVE_STRCHR 298/* 299 * strchr is used by regexp.c. 300 */ 301 char * 302strchr(s, c) 303 char *s; 304 int c; 305{ 306 for ( ; *s != '\0'; s++) 307 if (*s == c) 308 return (s); 309 if (c == '\0') 310 return (s); 311 return (NULL); 312} 313#endif 314 315#if !HAVE_MEMCPY 316 VOID_POINTER 317memcpy(dst, src, len) 318 VOID_POINTER dst; 319 VOID_POINTER src; 320 int len; 321{ 322 char *dstp = (char *) dst; 323 char *srcp = (char *) src; 324 int i; 325 326 for (i = 0; i < len; i++) 327 dstp[i] = srcp[i]; 328 return (dst); 329} 330#endif 331 332#ifdef _OSK_MWC32 333 334/* 335 * This implements an ANSI-style intercept setup for Microware C 3.2 336 */ 337 public int 338os9_signal(type, handler) 339 int type; 340 RETSIGTYPE (*handler)(); 341{ 342 intercept(handler); 343} 344 345#include <sgstat.h> 346 347 int 348isatty(f) 349 int f; 350{ 351 struct sgbuf sgbuf; 352 353 if (_gs_opt(f, &sgbuf) < 0) 354 return -1; 355 return (sgbuf.sg_class == 0); 356} 357 358#endif 359