chmod.c

   1 /* `chmod.c` - change the file modes
   2    Copyright (c) 2022, Alan Potteiger
   3    See `LICENSE` for copyright and license details */
   4
   5 #define _POSIX_C_SOURCE 200809L
   6
   7 #include <stdio.h>
   8 #include <unistd.h>
   9 #include <errno.h>
  10 #include <string.h>
  11 #include <sys/stat.h>
  12 #include <ftw.h>
  13
  14 #include "lab.h"
  15
  16 static const char *usage = {
  17         "usage: chmod [-R] mode file...\n"
  18 };
  19
  20 static char *modestr;   /* mode string */
  21
  22 /* callback for ftw(3) to traverse directory tree */
  23 static int
  24 recurse(const char *path, const struct stat *sb, int flag)
  25 {
  26         mode_t m;
  27         switch (flag) {
  28         case FTW_D:
  29                 m = sb->st_mode;
  30                 modeset(modestr, &m);
  31                 if (chmod(path, m) != 0)
  32                         fprintf(stderr, "chmod: %s: %s\n", path,
  33                                                 strerror(errno));
  34                 return 0;
  35         case FTW_F: case FTW_SL: case FTW_SLN:
  36                 m = sb->st_mode;
  37                 modeset(modestr, &m);
  38                 if (chmod(path, m) != 0)
  39                         fprintf(stderr, "chmod: %s: %s\n", path,
  40                                                 strerror(errno));
  41                 return 0;
  42         default:
  43                 return 0;
  44         }
  45 }
  46
  47 int
  48 main(int argc, char *argv[])
  49 {
  50         struct stat st;
  51         int status, Rflag;
  52         char ch;
  53         mode_t mode;
  54
  55         status = 0;
  56         Rflag = 0;
  57
  58         argc--;
  59         argv++;
  60
  61         if (argc < 2) {
  62                 fputs(usage, stderr);
  63                 return 1;
  64         }
  65
  66         if (argv[0][0] == '-' && argv[0][1] == 'R') {
  67                 Rflag = 1;
  68                 argc--;
  69                 argv++;
  70         }
  71
  72         if (argc < 2) {
  73                 fputs(usage, stderr);
  74                 return 1;
  75         }
  76
  77         modestr = argv[0];
  78         argc--; argv++;
  79
  80         for (; argc > 0; argc-- && argv++) {
  81                 if (stat(argv[0], &st) != 0) {
  82                         fprintf(stderr, "chmod: %s: %s\n", argv[0],
  83                                                 strerror(errno));
  84                         status = 1;
  85                         continue;
  86                 }
  87
  88                 mode = st.st_mode;
  89                 if (modeset(modestr, &mode) != 0) {
  90                         fprintf(stderr, "chmod: invalid mode");
  91                         return 1;
  92                 }
  93
  94                 if (Rflag)
  95                         ftw(argv[0], recurse, 1);
  96
  97                 if (chmod(argv[0], mode) != 0) {
  98                         fprintf(stderr, "chmod: %s: %s\n", argv[0],
  99                                                 strerror(errno));
 100                         status = 1;
 101                         continue;
 102                 }
 103         }
 104
 105         return status;
 106 }
 107