misc-utils/namei.c

   1 /*-------------------------------------------------------------
   2
   3 The namei program
   4
   5 By: Roger S. Southwick
   6
   7 May 2, 1990
   8
   9
  10 Modifications by Steve Tell  March 28, 1991
  11
  12 usage: namei pathname [pathname ... ]
  13
  14 This program reads it's arguments as pathnames to any type
  15 of Unix file (symlinks, files, directories, and so forth).
  16 The program then follows each pathname until a terminal
  17 point is found (a file, directory, char device, etc).
  18 If it finds a symbolic link, we show the link, and start
  19 following it, indenting the output to show the context.
  20
  21 This program is useful for finding a "too many levels of
  22 symbolic links" problems.
  23
  24 For each line output, the program puts a file type first:
  25
  26    f: = the pathname we are currently trying to resolve
  27     d = directory
  28     D = directory that is a mount point
  29     l = symbolic link (both the link and it's contents are output)
  30     s = socket
  31     b = block device
  32     c = character device
  33     p = FIFO (named pipe)
  34     - = regular file
  35     ? = an error of some kind
  36
  37 The program prints an informative messages when we exceed
  38 the maximum number of symbolic links this system can have.
  39
  40 The program exits with a 1 status ONLY if it finds it cannot
  41 chdir to /,  or if it encounters an unknown file type.
  42
  43 1999-02-22 Arkadiusz Mi¶kiewicz <misiek@pld.ORG.PL>
  44 - added Native Language Support
  45
  46 2006-12-15 Karel Zak <kzak@redhat.com>
  47 - fixed logic; don't follow the path if a component is not directory
  48 - fixed infinite loop of symbolic links; stack size is very limited
  49
  50 2007-09-10 Li Zefan <lizf@cn.fujitsu.com>
  51 - added to identify FIFO
  52
  53 -------------------------------------------------------------*/
  54
  55 #include <stdio.h>
  56 #include <unistd.h>
  57 #include <string.h>
  58 #include <strings.h>
  59 #include <stdlib.h>
  60 #include <errno.h>
  61 #include <sys/types.h>
  62 #include <sys/stat.h>
  63 #include <sys/param.h>
  64 #include "nls.h"
  65
  66 #define ERR     strerror(errno),errno
  67
  68 int symcount;
  69 int mflag = 0;
  70 int xflag = 0;
  71
  72 #ifndef MAXSYMLINKS
  73 #define MAXSYMLINKS 256
  74 #endif
  75
  76 static char *pperm(unsigned short);
  77 static void namei(char *, int, mode_t *);
  78 static void usage(void);
  79
  80 int
  81 main(int argc, char **argv) {
  82     extern int optind;
  83     int c;
  84     char curdir[MAXPATHLEN];
  85
  86     setlocale(LC_ALL, "");
  87     bindtextdomain(PACKAGE, LOCALEDIR);
  88     textdomain(PACKAGE);
  89
  90     if(argc < 2)
  91         usage();
  92
  93     while((c = getopt(argc, argv, "mx")) != -1){
  94         switch(c){
  95             case 'm':
  96                 mflag = !mflag;
  97                 break;
  98
  99             case 'x':
 100                 xflag = !xflag;
 101                 break;
 102
 103             case '?':
 104             default:
 105                 usage();
 106         }
 107     }
 108
 109     if(getcwd(curdir, sizeof(curdir)) == NULL){
 110         (void)fprintf(stderr,
 111                       _("namei: unable to get current directory - %s\n"),
 112                       curdir);
 113         exit(1);
 114     }
 115
 116
 117     for(; optind < argc; optind++){
 118         mode_t lastmode = 0;
 119         (void)printf("f: %s\n", argv[optind]);
 120         symcount = 1;
 121         namei(argv[optind], 0, &lastmode);
 122
 123         if(chdir(curdir) == -1){
 124             (void)fprintf(stderr,
 125                           _("namei: unable to chdir to %s - %s (%d)\n"),
 126                           curdir, ERR);
 127             exit(1);
 128         }
 129     }
 130     return 0;
 131 }
 132
 133 static void
 134 usage(void) {
 135     (void)fprintf(stderr,_("usage: namei [-mx] pathname [pathname ...]\n"));
 136     exit(1);
 137 }
 138
 139 #ifndef NODEV
 140 #define NODEV           (dev_t)(-1)
 141 #endif
 142
 143 int kzak;
 144
 145 static void
 146 namei(char *file, int lev, mode_t *lastmode) {
 147     char *cp;
 148     char buf[BUFSIZ], sym[BUFSIZ];
 149     struct stat stb;
 150     int i;
 151     dev_t lastdev = NODEV;
 152
 153     /*
 154      * See if the file has a leading /, and if so cd to root
 155      */
 156
 157     if(file && *file == '/'){
 158         while(*file == '/')
 159             file++;
 160
 161         if(chdir("/") == -1){
 162             (void)fprintf(stderr,_("namei: could not chdir to root!\n"));
 163             exit(1);
 164         }
 165         for(i = 0; i < lev; i++)
 166             (void)printf("  ");
 167
 168         if(stat("/", &stb) == -1){
 169             (void)fprintf(stderr, _("namei: could not stat root!\n"));
 170             exit(1);
 171         }
 172         lastdev = stb.st_dev;
 173
 174         if(mflag)
 175             (void)printf(" d%s /\n", pperm(stb.st_mode));
 176         else
 177             (void)printf(" d /\n");
 178     }
 179
 180     for(; file && *file;){
 181
 182         if (strlen(file) >= BUFSIZ) {
 183                 fprintf(stderr,_("namei: buf overflow\n"));
 184                 return;
 185         }
 186
 187         /*
 188          * Copy up to the next / (or nil) into buf
 189          */
 190
 191         for(cp = buf; *file != '\0' && *file != '/'; cp++, file++)
 192             *cp = *file;
 193
 194         while(*file == '/')     /* eat extra /'s        */
 195             file++;
 196
 197         *cp = '\0';
 198
 199         if(buf[0] == '\0'){
 200
 201             /*
 202              * Buf is empty, so therefore we are done
 203              * with this level of file
 204              */
 205
 206             return;
 207         }
 208
 209         for(i = 0; i < lev; i++)
 210             (void)printf("  ");
 211
 212
 213         /*
 214          * We cannot walk on *path* if a previous element, in the path wasn't
 215          * directory, because there could be a component with same name. Try:
 216          *
 217          * $ touch a b
 218          * $ namei a/b    <-- "a" is not directory so namei shouldn't
 219          *                    check for "b"
 220          */
 221         if (*lastmode && S_ISDIR(*lastmode)==0 && S_ISLNK(*lastmode)==0){
 222             (void)printf(" ? %s - %s (%d)\n", buf, strerror(ENOENT), ENOENT);
 223             return;
 224         }
 225
 226         /*
 227          * See what type of critter this file is
 228          */
 229
 230         if(lstat(buf, &stb) == -1){
 231             (void)printf(" ? %s - %s (%d)\n", buf, ERR);
 232             return;
 233         }
 234
 235         *lastmode = stb.st_mode;
 236
 237         switch(stb.st_mode & S_IFMT){
 238             case S_IFDIR:
 239
 240                 /*
 241                  * File is a directory, chdir to it
 242                  */
 243
 244                 if(chdir(buf) == -1){
 245                     (void)printf(_(" ? could not chdir into %s - %s (%d)\n"), buf, ERR );
 246                     return;
 247                 }
 248                 if(xflag && lastdev != stb.st_dev && lastdev != NODEV){
 249                     /* Across mnt point */
 250                     if(mflag)
 251                         (void)printf(" D%s %s\n", pperm(stb.st_mode), buf);
 252                     else
 253                         (void)printf(" D %s\n", buf);
 254                 }
 255                 else {
 256                     if(mflag)
 257                         (void)printf(" d%s %s\n", pperm(stb.st_mode), buf);
 258                     else
 259                         (void)printf(" d %s\n", buf);
 260                 }
 261                 lastdev = stb.st_dev;
 262
 263                 (void)fflush(stdout);
 264                 break;
 265
 266             case S_IFLNK:
 267                 /*
 268                  * Sigh, another symlink.  Read its contents and
 269                  * call namei()
 270                  */
 271                 bzero(sym, BUFSIZ);
 272                 if(readlink(buf, sym, BUFSIZ) == -1){
 273                     (void)printf(_(" ? problems reading symlink %s - %s (%d)\n"), buf, ERR);
 274                     return;
 275                 }
 276
 277                 if(mflag)
 278                     (void)printf(" l%s %s -> %s", pperm(stb.st_mode), buf, sym);
 279                 else
 280                     (void)printf(" l %s -> %s", buf, sym);
 281
 282                 if(symcount > 0 && symcount++ > MAXSYMLINKS){
 283                     (void)printf(_("  *** EXCEEDED UNIX LIMIT OF SYMLINKS ***\n"));
 284                 } else {
 285                     (void)printf("\n");
 286                     namei(sym, lev + 1, lastmode);
 287                 }
 288                 if (symcount > MAXSYMLINKS)
 289                     return;
 290                 break;
 291
 292             case S_IFCHR:
 293                 if(mflag)
 294                     (void)printf(" c%s %s\n", pperm(stb.st_mode), buf);
 295                 else
 296                     (void)printf(" c %s\n", buf);
 297                 break;
 298
 299             case S_IFBLK:
 300                 if(mflag)
 301                     (void)printf(" b%s %s\n", pperm(stb.st_mode), buf);
 302                 else
 303                     (void)printf(" b %s\n", buf);
 304                 break;
 305
 306             case S_IFSOCK:
 307                 if(mflag)
 308                     (void)printf(" s%s %s\n", pperm(stb.st_mode), buf);
 309                 else
 310                     (void)printf(" s %s\n", buf);
 311                 break;
 312
 313                 case S_IFIFO:
 314                 if (mflag)
 315                         printf(" p%s %s\n", pperm(stb.st_mode), buf);
 316                 else
 317                         printf(" p %s\n", buf);
 318                 break;
 319
 320             case S_IFREG:
 321                 if(mflag)
 322                     (void)printf(" -%s %s\n", pperm(stb.st_mode), buf);
 323                 else
 324                     (void)printf(" - %s\n", buf);
 325                 break;
 326
 327             default:
 328                 (void)fprintf(stderr,_("namei: unknown file type 0%06o on file %s\n"), stb.st_mode, buf );
 329                 exit(1);
 330
 331         }
 332     }
 333 }
 334
 335 /* Take a
 336  * Mode word, as from a struct stat, and return
 337  * a pointer to a static string containing a printable version like ls.
 338  * For example 0755 produces "rwxr-xr-x"
 339  */
 340 static char *
 341 pperm(unsigned short mode) {
 342         unsigned short m;
 343         static char buf[16];
 344         char *bp;
 345         char *lschars = "xwrxwrxwr";  /* the complete string backwards */
 346         char *cp;
 347         int i;
 348
 349         for(i = 0, cp = lschars, m = mode, bp = &buf[8];
 350             i < 9;
 351             i++, cp++, m >>= 1, bp--) {
 352
 353                 if(m & 1)
 354                         *bp = *cp;
 355                 else
 356                         *bp = '-';
 357             }
 358         buf[9] = '\0';
 359
 360         if(mode & S_ISUID)  {
 361                 if(buf[2] == 'x')
 362                         buf[2] = 's';
 363                 else
 364                         buf[2] = 'S';
 365         }
 366         if(mode & S_ISGID)  {
 367                 if(buf[5] == 'x')
 368                         buf[5] = 's';
 369                 else
 370                         buf[5] = 'S';
 371         }
 372         if(mode & S_ISVTX)  {
 373                 if(buf[8] == 'x')
 374                         buf[8] = 't';
 375                 else
 376                         buf[8] = 'T';
 377         }
 378
 379         return &buf[0];
 380 }
 381
 382