1 /* 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Edward Sze-Tyan Wang. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /* 34 * Solaris porting notes: the original FreeBSD version made use of the 35 * BSD kqueue event notification framework; this 36 * was changed to use usleep() 37 */ 38 39 #include <sys/param.h> 40 #include <sys/mount.h> 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 #include <sys/statfs.h> 44 #include <sys/statvfs.h> 45 #include <sys/time.h> 46 #include <sys/mman.h> 47 #include <sys/poll.h> 48 #include <port.h> 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <limits.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 #include "extern.h" 59 60 static void rlines(FILE *, const char *fn, off_t, struct stat *); 61 static int show(file_info_t *); 62 static void set_events(file_info_t *files); 63 64 /* defines for inner loop actions */ 65 #define USE_SLEEP 0 66 #define ADD_EVENTS 2 67 68 int action = USE_SLEEP; 69 70 static const file_info_t *last; 71 72 /* 73 * forward -- display the file, from an offset, forward. 74 * 75 * There are eight separate cases for this -- regular and non-regular 76 * files, by bytes or lines and from the beginning or end of the file. 77 * 78 * FBYTES byte offset from the beginning of the file 79 * REG seek 80 * NOREG read, counting bytes 81 * 82 * FLINES line offset from the beginning of the file 83 * REG read, counting lines 84 * NOREG read, counting lines 85 * 86 * RBYTES byte offset from the end of the file 87 * REG seek 88 * NOREG cyclically read characters into a wrap-around buffer 89 * 90 * RLINES 91 * REG mmap the file and step back until reach the correct offset. 92 * NOREG cyclically read lines into a wrap-around array of buffers 93 */ 94 void 95 forward(FILE *fp, const char *fn, enum STYLE style, off_t off, struct stat *sbp) 96 { 97 int ch; 98 99 switch (style) { 100 case FBYTES: 101 if (off == 0) 102 break; 103 if (S_ISREG(sbp->st_mode)) { 104 if (sbp->st_size < off) 105 off = sbp->st_size; 106 if (fseeko(fp, off, SEEK_SET) == -1) { 107 ierr(fn); 108 return; 109 } 110 } else while (off--) 111 if ((ch = getc(fp)) == EOF) { 112 if (ferror(fp)) { 113 ierr(fn); 114 return; 115 } 116 break; 117 } 118 break; 119 case FLINES: 120 if (off == 0) 121 break; 122 for (;;) { 123 if ((ch = getc(fp)) == EOF) { 124 if (ferror(fp)) { 125 ierr(fn); 126 return; 127 } 128 break; 129 } 130 if (ch == '\n' && !--off) 131 break; 132 } 133 break; 134 case RBYTES: 135 if (S_ISREG(sbp->st_mode)) { 136 if (sbp->st_size >= off && 137 fseeko(fp, -off, SEEK_END) == -1) { 138 ierr(fn); 139 return; 140 } 141 } else if (off == 0) { 142 while (getc(fp) != EOF) 143 ; 144 if (ferror(fp)) { 145 ierr(fn); 146 return; 147 } 148 } else 149 if (bytes(fp, fn, off)) 150 return; 151 break; 152 case RLINES: 153 if (S_ISREG(sbp->st_mode)) 154 if (!off) { 155 if (fseeko(fp, (off_t)0, SEEK_END) == -1) { 156 ierr(fn); 157 return; 158 } 159 } else 160 rlines(fp, fn, off, sbp); 161 else if (off == 0) { 162 while (getc(fp) != EOF) 163 ; 164 if (ferror(fp)) { 165 ierr(fn); 166 return; 167 } 168 } else 169 if (lines(fp, fn, off)) 170 return; 171 break; 172 default: 173 break; 174 } 175 176 while ((ch = getc(fp)) != EOF) 177 if (putchar(ch) == EOF) 178 oerr(); 179 if (ferror(fp)) { 180 ierr(fn); 181 return; 182 } 183 (void) fflush(stdout); 184 } 185 186 /* 187 * rlines -- display the last offset lines of the file. 188 */ 189 static void 190 rlines(FILE *fp, const char *fn, off_t off, struct stat *sbp) 191 { 192 struct mapinfo map; 193 off_t curoff, size; 194 int i; 195 196 if ((size = sbp->st_size) == 0) 197 return; 198 map.start = NULL; 199 map.fd = fileno(fp); 200 map.mapoff = map.maxoff = size; 201 202 /* 203 * Last char is special, ignore whether newline or not. Note that 204 * size == 0 is dealt with above, and size == 1 sets curoff to -1. 205 */ 206 curoff = size - 2; 207 while (curoff >= 0) { 208 if (curoff < map.mapoff && maparound(&map, curoff) != 0) { 209 ierr(fn); 210 return; 211 } 212 for (i = curoff - map.mapoff; i >= 0; i--) 213 if (map.start[i] == '\n' && --off == 0) 214 break; 215 /* `i' is either the map offset of a '\n', or -1. */ 216 curoff = map.mapoff + i; 217 if (i >= 0) 218 break; 219 } 220 curoff++; 221 if (mapprint(&map, curoff, size - curoff) != 0) { 222 ierr(fn); 223 exit(1); 224 } 225 226 /* Set the file pointer to reflect the length displayed. */ 227 if (fseeko(fp, sbp->st_size, SEEK_SET) == -1) { 228 ierr(fn); 229 return; 230 } 231 if (map.start != NULL && munmap(map.start, map.maplen)) { 232 ierr(fn); 233 return; 234 } 235 } 236 237 static int 238 show(file_info_t *file) 239 { 240 int ch; 241 242 while ((ch = getc(file->fp)) != EOF) { 243 if (last != file && no_files > 1) { 244 if (!qflag) 245 (void) printf("\n==> %s <==\n", 246 file->file_name); 247 last = file; 248 } 249 if (putchar(ch) == EOF) 250 oerr(); 251 } 252 (void) fflush(stdout); 253 if (ferror(file->fp)) { 254 (void) fclose(file->fp); 255 file->fp = NULL; 256 ierr(file->file_name); 257 return (0); 258 } 259 clearerr(file->fp); 260 return (1); 261 } 262 263 static void 264 set_events(file_info_t *files) 265 { 266 int i; 267 file_info_t *file; 268 269 for (i = 0, file = files; i < no_files; i++, file++) { 270 if (! file->fp) 271 continue; 272 273 (void) fstat(fileno(file->fp), &file->st); 274 } 275 } 276 277 /* 278 * follow -- display the file, from an offset, forward. 279 * 280 */ 281 void 282 follow(file_info_t *files, enum STYLE style, off_t off) 283 { 284 int active, ev_change, i, n = -1; 285 struct stat sb2; 286 file_info_t *file; 287 288 /* Position each of the files */ 289 290 file = files; 291 active = 0; 292 n = 0; 293 for (i = 0; i < no_files; i++, file++) { 294 if (file->fp) { 295 active = 1; 296 n++; 297 if (no_files > 1 && !qflag) 298 (void) printf("\n==> %s <==\n", 299 file->file_name); 300 forward(file->fp, file->file_name, style, off, 301 &file->st); 302 if (Fflag && fileno(file->fp) != STDIN_FILENO) 303 n++; 304 } 305 } 306 if (!Fflag && !active) 307 return; 308 309 last = --file; 310 set_events(files); 311 312 for (;;) { 313 ev_change = 0; 314 if (Fflag) { 315 for (i = 0, file = files; i < no_files; i++, file++) { 316 if (!file->fp) { 317 file->fp = fopen(file->file_name, "r"); 318 if (file->fp != NULL && 319 fstat(fileno(file->fp), &file->st) 320 == -1) { 321 (void) fclose(file->fp); 322 file->fp = NULL; 323 } 324 if (file->fp != NULL) 325 ev_change++; 326 continue; 327 } 328 if (fileno(file->fp) == STDIN_FILENO) 329 continue; 330 if (stat(file->file_name, &sb2) == -1) { 331 if (errno != ENOENT) 332 ierr(file->file_name); 333 (void) show(file); 334 (void) fclose(file->fp); 335 file->fp = NULL; 336 ev_change++; 337 continue; 338 } 339 340 if (sb2.st_ino != file->st.st_ino || 341 sb2.st_dev != file->st.st_dev || 342 sb2.st_nlink == 0) { 343 (void) show(file); 344 file->fp = freopen(file->file_name, "r", 345 file->fp); 346 if (file->fp != NULL) 347 (void) memcpy(&file->st, &sb2, 348 sizeof (struct stat)); 349 else if (errno != ENOENT) 350 ierr(file->file_name); 351 ev_change++; 352 } 353 } 354 } 355 356 for (i = 0, file = files; i < no_files; i++, file++) 357 if (file->fp && !show(file)) 358 ev_change++; 359 360 if (ev_change) 361 set_events(files); 362 363 switch (action) { 364 case USE_SLEEP: 365 (void) usleep(250000); 366 break; 367 } 368 } 369 } 370