usr/src/lib/gss_mechs/mech_krb5/krb5/os/safechown.c

   1 /*
   2  * Copyright (c) 1998, by Sun Microsystems, Inc.
   3  * All rights reserved.
   4  */
   5
   6 #pragma ident   "%Z%%M% %I%     %E% SMI"
   7
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <stdlib.h>
  11 #include <unistd.h>
  12 #include <sys/types.h>
  13 #include <sys/stat.h>
  14 #include <fcntl.h>
  15
  16 /*
  17  * safechown changes the owner ship of src to uid. If the mode parameter
  18  * does not equal -1 changes the mode of src as well.
  19  *
  20  * return -1 on failure and 0 on success.
  21  */
  22
  23 int
  24 safechown(const char *src, uid_t uid, gid_t gid, int mode)
  25 {
  26 int fd;
  27 struct stat fdbuf;
  28 struct stat lbuf;
  29
  30         if ((fd = open(src, O_RDONLY, 0)) == -1)
  31                 return (-1);
  32
  33         if (fstat(fd, &fdbuf)) {
  34                 close(fd);
  35                 return (-1);
  36         }
  37
  38         /* Make sure non directories are not hard links */
  39         if (!S_ISDIR(fdbuf.st_mode) && fdbuf.st_nlink != 1) {
  40                 close(fd);
  41                 return (-1);
  42         }
  43
  44         if (lstat(src, &lbuf)) {
  45                 close(fd);
  46                 return (-1);
  47         }
  48
  49         /* Make sure file is not a symlink */
  50         if (fdbuf.st_ino != lbuf.st_ino || fdbuf.st_dev != lbuf.st_dev ||
  51                 fdbuf.st_mode != lbuf.st_mode) {
  52
  53                 close(fd);
  54                 return (-1);
  55         }
  56
  57         /* we should probably get the primary group id for uid here */
  58         if (fchown(fd, uid, gid)) {
  59                 close(fd);
  60                 return (-1);
  61         }
  62
  63         if (mode != -1) {
  64                 if (fchmod(fd, (mode_t)mode)) {
  65                     close(fd);
  66                     return (-1);
  67                 }
  68         }
  69
  70         close(fd);
  71
  72         return (0);
  73 }
  74
  75 #ifdef TEST
  76 void
  77 usage(char *prg)
  78 {
  79         fprintf(stderr, "Usage %s [-u uid] [-m mode] source\n", prg);
  80         exit(1);
  81 }
  82
  83 main(int argc, char *argv[])
  84 {
  85         int opt;
  86         int mode = -1;
  87         uid_t uid = 0;
  88
  89         while ((opt = getopt(argc, argv, "m:u:")) != EOF) {
  90                 switch (opt) {
  91                 case 'm':
  92                         mode = strtol(optarg, 0, 8);
  93                         break;
  94                 case 'u':
  95                         uid = atoi(optarg);
  96                         break;
  97                 default:
  98                         usage(argv[0]);
  99         }
 100 }
 101
 102     if (argc - optind != 1)
 103         usage(argv[0]);
 104
 105     if (safechown(argv[optind], uid, getgid(), mode)) {
 106         perror("safechown");
 107         exit(1);
 108     }
 109
 110     return (0);
 111 }
 112
 113 #endif  /* TEST */