rm.c

   1 /*      $OpenBSD: rm.c,v 1.21 2007/06/06 00:08:57 ray Exp $     */
   2 /*      $NetBSD: rm.c,v 1.19 1995/09/07 06:48:50 jtc Exp $      */
   3
   4 /*-
   5  * Copyright (c) 1990, 1993, 1994
   6  *      The Regents of the University of California.  All rights reserved.
   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  * 3. 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 #ifndef lint
  34 static char copyright[] =
  35 "@(#) Copyright (c) 1990, 1993, 1994\n\
  36         The Regents of the University of California.  All rights reserved.\n";
  37 #endif /* not lint */
  38
  39 #ifndef lint
  40 #if 0
  41 static char sccsid[] = "@(#)rm.c        8.8 (Berkeley) 4/27/95";
  42 #else
  43 static char rcsid[] = "$OpenBSD: rm.c,v 1.21 2007/06/06 00:08:57 ray Exp $";
  44 #endif
  45 #endif /* not lint */
  46
  47 #include <sys/types.h>
  48 #include <sys/stat.h>
  49 #include <sys/param.h>
  50 #include <sys/mount.h>
  51
  52 #include <locale.h>
  53 #include <err.h>
  54 #include <errno.h>
  55 #include <fcntl.h>
  56 #include <fts.h>
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61 #include <pwd.h>
  62 #include <grp.h>
  63
  64 extern char *__progname;
  65
  66 int dflag, eval, fflag, iflag, Pflag, stdin_ok;
  67
  68 int     check(char *, char *, struct stat *);
  69 void    checkdot(char **);
  70 void    rm_file(char **);
  71 int     rm_overwrite(char *, struct stat *);
  72 int     pass(int, int, off_t, char *, size_t);
  73 void    rm_tree(char **);
  74 void    usage(void);
  75
  76 /*
  77  * rm --
  78  *      This rm is different from historic rm's, but is expected to match
  79  *      POSIX 1003.2 behavior.  The most visible difference is that -f
  80  *      has two specific effects now, ignore non-existent files and force
  81  *      file removal.
  82  */
  83 int
  84 main(int argc, char *argv[])
  85 {
  86         int ch, rflag;
  87
  88         setlocale(LC_ALL, "");
  89
  90         Pflag = rflag = 0;
  91         while ((ch = getopt(argc, argv, "dfiPRr")) != -1)
  92                 switch(ch) {
  93                 case 'd':
  94                         dflag = 1;
  95                         break;
  96                 case 'f':
  97                         fflag = 1;
  98                         iflag = 0;
  99                         break;
 100                 case 'i':
 101                         fflag = 0;
 102                         iflag = 1;
 103                         break;
 104                 case 'P':
 105                         Pflag = 1;
 106                         break;
 107                 case 'R':
 108                 case 'r':                       /* Compatibility. */
 109                         rflag = 1;
 110                         break;
 111                 default:
 112                         usage();
 113                 }
 114         argc -= optind;
 115         argv += optind;
 116
 117         if (argc < 1 && fflag == 0)
 118                 usage();
 119
 120         checkdot(argv);
 121
 122         if (*argv) {
 123                 stdin_ok = isatty(STDIN_FILENO);
 124
 125                 if (rflag)
 126                         rm_tree(argv);
 127                 else
 128                         rm_file(argv);
 129         }
 130
 131         exit (eval);
 132 }
 133
 134 void
 135 rm_tree(char **argv)
 136 {
 137         FTS *fts;
 138         FTSENT *p;
 139         int needstat;
 140         int flags;
 141
 142         /*
 143          * Remove a file hierarchy.  If forcing removal (-f), or interactive
 144          * (-i) or can't ask anyway (stdin_ok), don't stat the file.
 145          */
 146         needstat = !fflag && !iflag && stdin_ok;
 147
 148         /*
 149          * If the -i option is specified, the user can skip on the pre-order
 150          * visit.  The fts_number field flags skipped directories.
 151          */
 152 #define SKIPPED 1
 153
 154         flags = FTS_PHYSICAL;
 155         if (!needstat)
 156                 flags |= FTS_NOSTAT;
 157         if (!(fts = fts_open(argv, flags, NULL)))
 158                 err(1, NULL);
 159         while ((p = fts_read(fts)) != NULL) {
 160                 switch (p->fts_info) {
 161                 case FTS_DNR:
 162                         if (!fflag || p->fts_errno != ENOENT) {
 163                                 warnx("%s: %s",
 164                                     p->fts_path, strerror(p->fts_errno));
 165                                 eval = 1;
 166                         }
 167                         continue;
 168                 case FTS_ERR:
 169                         errx(1, "%s: %s", p->fts_path, strerror(p->fts_errno));
 170                 case FTS_NS:
 171                         /*
 172                          * FTS_NS: assume that if can't stat the file, it
 173                          * can't be unlinked.
 174                          */
 175                         if (!needstat)
 176                                 break;
 177                         if (!fflag || p->fts_errno != ENOENT) {
 178                                 warnx("%s: %s",
 179                                     p->fts_path, strerror(p->fts_errno));
 180                                 eval = 1;
 181                         }
 182                         continue;
 183                 case FTS_D:
 184                         /* Pre-order: give user chance to skip. */
 185                         if (!fflag && !check(p->fts_path, p->fts_accpath,
 186                             p->fts_statp)) {
 187                                 (void)fts_set(fts, p, FTS_SKIP);
 188                                 p->fts_number = SKIPPED;
 189                         }
 190                         continue;
 191                 case FTS_DP:
 192                         /* Post-order: see if user skipped. */
 193                         if (p->fts_number == SKIPPED)
 194                                 continue;
 195                         break;
 196                 default:
 197                         if (!fflag &&
 198                             !check(p->fts_path, p->fts_accpath, p->fts_statp))
 199                                 continue;
 200                 }
 201
 202                 /*
 203                  * If we can't read or search the directory, may still be
 204                  * able to remove it.  Don't print out the un{read,search}able
 205                  * message unless the remove fails.
 206                  */
 207                 switch (p->fts_info) {
 208                 case FTS_DP:
 209                 case FTS_DNR:
 210                         if (!rmdir(p->fts_accpath) ||
 211                             (fflag && errno == ENOENT))
 212                                 continue;
 213                         break;
 214
 215                 default:
 216                         if (Pflag)
 217                                 rm_overwrite(p->fts_accpath, NULL);
 218                         if (!unlink(p->fts_accpath) ||
 219                             (fflag && errno == ENOENT))
 220                                 continue;
 221                 }
 222                 warn("%s", p->fts_path);
 223                 eval = 1;
 224         }
 225         if (errno)
 226                 err(1, "fts_read");
 227         fts_close(fts);
 228 }
 229
 230 void
 231 rm_file(char **argv)
 232 {
 233         struct stat sb;
 234         int rval;
 235         char *f;
 236
 237         /*
 238          * Remove a file.  POSIX 1003.2 states that, by default, attempting
 239          * to remove a directory is an error, so must always stat the file.
 240          */
 241         while ((f = *argv++) != NULL) {
 242                 /* Assume if can't stat the file, can't unlink it. */
 243                 if (lstat(f, &sb)) {
 244                         if (!fflag || errno != ENOENT) {
 245                                 warn("%s", f);
 246                                 eval = 1;
 247                         }
 248                         continue;
 249                 }
 250
 251                 if (S_ISDIR(sb.st_mode) && !dflag) {
 252                         warnx("%s: is a directory", f);
 253                         eval = 1;
 254                         continue;
 255                 }
 256                 if (!fflag && !check(f, f, &sb))
 257                         continue;
 258                 else if (S_ISDIR(sb.st_mode))
 259                         rval = rmdir(f);
 260                 else {
 261                         if (Pflag)
 262                                 rm_overwrite(f, &sb);
 263                         rval = unlink(f);
 264                 }
 265                 if (rval && (!fflag || errno != ENOENT)) {
 266                         warn("%s", f);
 267                         eval = 1;
 268                 }
 269         }
 270 }
 271
 272 /*
 273  * rm_overwrite --
 274  *      Overwrite the file 3 times with varying bit patterns.
 275  *
 276  * XXX
 277  * This is a cheap way to *really* delete files.  Note that only regular
 278  * files are deleted, directories (and therefore names) will remain.
 279  * Also, this assumes a fixed-block file system (like FFS, or a V7 or a
 280  * System V file system).  In a logging file system, you'll have to have
 281  * kernel support.
 282  * Returns 1 for success.
 283  */
 284 int
 285 rm_overwrite(char *file, struct stat *sbp)
 286 {
 287         struct stat sb;
 288         struct statfs fsb;
 289         size_t bsize;
 290         int fd;
 291         char *buf = NULL;
 292
 293         fd = -1;
 294         if (sbp == NULL) {
 295                 if (lstat(file, &sb))
 296                         goto err;
 297                 sbp = &sb;
 298         }
 299         if (!S_ISREG(sbp->st_mode))
 300                 return (1);
 301         if (sbp->st_nlink > 1) {
 302                 warnx("%s (inode %u): not overwritten due to multiple links",
 303                     file, sbp->st_ino);
 304                 return (0);
 305         }
 306         if ((fd = open(file, O_WRONLY, 0)) == -1)
 307                 goto err;
 308         if (fstatfs(fd, &fsb) == -1)
 309                 goto err;
 310         bsize = MAX(fsb.f_iosize, 1024U);
 311         if ((buf = malloc(bsize)) == NULL)
 312                 err(1, "%s: malloc", file);
 313
 314         if (!pass(0xff, fd, sbp->st_size, buf, bsize) || fsync(fd) ||
 315             lseek(fd, (off_t)0, SEEK_SET))
 316                 goto err;
 317         if (!pass(0x00, fd, sbp->st_size, buf, bsize) || fsync(fd) ||
 318             lseek(fd, (off_t)0, SEEK_SET))
 319                 goto err;
 320         if (!pass(0xff, fd, sbp->st_size, buf, bsize) || fsync(fd))
 321                 goto err;
 322         close(fd);
 323         free(buf);
 324         return (1);
 325
 326 err:
 327         warn("%s", file);
 328         close(fd);
 329         eval = 1;
 330         free(buf);
 331         return (0);
 332 }
 333
 334 int
 335 pass(int val, int fd, off_t len, char *buf, size_t bsize)
 336 {
 337         size_t wlen;
 338
 339         memset(buf, val, bsize);
 340         for (; len > 0; len -= wlen) {
 341                 wlen = len < bsize ? len : bsize;
 342                 if (write(fd, buf, wlen) != wlen)
 343                         return (0);
 344         }
 345         return (1);
 346 }
 347
 348 int
 349 check(char *path, char *name, struct stat *sp)
 350 {
 351         int ch, first;
 352         char modep[15];
 353
 354         /* Check -i first. */
 355         if (iflag)
 356                 (void)fprintf(stderr, "remove %s? ", path);
 357         else {
 358                 /*
 359                  * If it's not a symbolic link and it's unwritable and we're
 360                  * talking to a terminal, ask.  Symbolic links are excluded
 361                  * because their permissions are meaningless.  Check stdin_ok
 362                  * first because we may not have stat'ed the file.
 363                  */
 364                 if (!stdin_ok || S_ISLNK(sp->st_mode) || !access(name, W_OK))
 365                         return (1);
 366                 strmode(sp->st_mode, modep);
 367                 (void)fprintf(stderr, "override %s%s%s/%s for %s? ",
 368                     modep + 1, modep[9] == ' ' ? "" : " ",
 369                     user_from_uid(sp->st_uid, 0),
 370                     group_from_gid(sp->st_gid, 0), path);
 371         }
 372         (void)fflush(stderr);
 373
 374         first = ch = getchar();
 375         while (ch != '\n' && ch != EOF)
 376                 ch = getchar();
 377         return (first == 'y' || first == 'Y');
 378 }
 379
 380 /*
 381  * POSIX.2 requires that if "." or ".." are specified as the basename
 382  * portion of an operand, a diagnostic message be written to standard
 383  * error and nothing more be done with such operands.
 384  *
 385  * Since POSIX.2 defines basename as the final portion of a path after
 386  * trailing slashes have been removed, we'll remove them here.
 387  */
 388 #define ISDOT(a)        ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2])))
 389 void
 390 checkdot(char **argv)
 391 {
 392         char *p, **save, **t;
 393         int complained;
 394
 395         complained = 0;
 396         for (t = argv; *t;) {
 397                 /* strip trailing slashes */
 398                 p = strrchr (*t, '\0');
 399                 while (--p > *t && *p == '/')
 400                         *p = '\0';
 401
 402                 /* extract basename */
 403                 if ((p = strrchr(*t, '/')) != NULL)
 404                         ++p;
 405                 else
 406                         p = *t;
 407
 408                 if (ISDOT(p)) {
 409                         if (!complained++)
 410                                 warnx("\".\" and \"..\" may not be removed");
 411                         eval = 1;
 412                         for (save = t; (t[0] = t[1]) != NULL; ++t)
 413                                 continue;
 414                         t = save;
 415                 } else
 416                         ++t;
 417         }
 418 }
 419
 420 void
 421 usage(void)
 422 {
 423         (void)fprintf(stderr, "usage: %s [-dfiPRr] file ...\n", __progname);
 424         exit(1);
 425 }