| 1 | /* |
| 2 | * chmod [ugoa][+-=][rwxstugo] files |
| 3 | * change mode of files |
| 4 | */ |
| 5 | #include <stdio.h> |
| 6 | #include <sys/types.h> |
| 7 | #include <sys/stat.h> |
| 8 | |
| 9 | #define USER 05700 /* user's bits */ |
| 10 | #define GROUP 02070 /* group's bits */ |
| 11 | #define OTHER 00007 /* other's bits */ |
| 12 | #define ALL 01777 /* all (note absence of setuid, etc) */ |
| 13 | |
| 14 | #define READ 00444 /* read permit */ |
| 15 | #define WRITE 00222 /* write permit */ |
| 16 | #define EXEC 00111 /* exec permit */ |
| 17 | #define SETID 06000 /* set[ug]id */ |
| 18 | #define STICKY 01000 /* sticky bit */ |
| 19 | |
| 20 | char *ms; |
| 21 | int um; |
| 22 | struct stat st; |
| 23 | |
| 24 | main(argc,argv) |
| 25 | char **argv; |
| 26 | { |
| 27 | register i; |
| 28 | register char *p; |
| 29 | int status = 0; |
| 30 | |
| 31 | if (argc < 3) { |
| 32 | fprintf(stderr, "Usage: chmod [ugoa][+-=][rwxstugo] file ...\n"); |
| 33 | exit(255); |
| 34 | } |
| 35 | ms = argv[1]; |
| 36 | um = umask(0); |
| 37 | newmode(0); |
| 38 | for (i = 2; i < argc; i++) { |
| 39 | p = argv[i]; |
| 40 | if (stat(p, &st) < 0) { |
| 41 | fprintf(stderr, "chmod: can't access %s\n", p); |
| 42 | ++status; |
| 43 | continue; |
| 44 | } |
| 45 | ms = argv[1]; |
| 46 | if (chmod(p, newmode(st.st_mode)) < 0) { |
| 47 | fprintf(stderr, "chmod: can't change %s\n", p); |
| 48 | ++status; |
| 49 | continue; |
| 50 | } |
| 51 | } |
| 52 | exit(status); |
| 53 | } |
| 54 | |
| 55 | newmode(nm) |
| 56 | unsigned nm; |
| 57 | { |
| 58 | register o, m, b; |
| 59 | |
| 60 | m = abs(); |
| 61 | if (!*ms) |
| 62 | return(m); |
| 63 | do { |
| 64 | m = who(); |
| 65 | while (o = what()) { |
| 66 | b = where(nm); |
| 67 | switch (o) { |
| 68 | case '+': |
| 69 | nm |= b & m; |
| 70 | break; |
| 71 | case '-': |
| 72 | nm &= ~(b & m); |
| 73 | break; |
| 74 | case '=': |
| 75 | nm &= ~m; |
| 76 | nm |= b & m; |
| 77 | break; |
| 78 | } |
| 79 | } |
| 80 | } while (*ms++ == ','); |
| 81 | if (*--ms) { |
| 82 | fprintf(stderr, "chmod: invalid mode\n"); |
| 83 | exit(255); |
| 84 | } |
| 85 | return(nm); |
| 86 | } |
| 87 | |
| 88 | abs() |
| 89 | { |
| 90 | register c, i; |
| 91 | |
| 92 | i = 0; |
| 93 | while ((c = *ms++) >= '0' && c <= '7') |
| 94 | i = (i << 3) + (c - '0'); |
| 95 | ms--; |
| 96 | return(i); |
| 97 | } |
| 98 | |
| 99 | who() |
| 100 | { |
| 101 | register m; |
| 102 | |
| 103 | m = 0; |
| 104 | for (;;) switch (*ms++) { |
| 105 | case 'u': |
| 106 | m |= USER; |
| 107 | continue; |
| 108 | case 'g': |
| 109 | m |= GROUP; |
| 110 | continue; |
| 111 | case 'o': |
| 112 | m |= OTHER; |
| 113 | continue; |
| 114 | case 'a': |
| 115 | m |= ALL; |
| 116 | continue; |
| 117 | default: |
| 118 | ms--; |
| 119 | if (m == 0) |
| 120 | m = ALL & ~um; |
| 121 | return m; |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | what() |
| 126 | { |
| 127 | switch (*ms) { |
| 128 | case '+': |
| 129 | case '-': |
| 130 | case '=': |
| 131 | return *ms++; |
| 132 | } |
| 133 | return(0); |
| 134 | } |
| 135 | |
| 136 | where(om) |
| 137 | register om; |
| 138 | { |
| 139 | register m; |
| 140 | |
| 141 | m = 0; |
| 142 | switch (*ms) { |
| 143 | case 'u': |
| 144 | m = (om & USER) >> 6; |
| 145 | goto dup; |
| 146 | case 'g': |
| 147 | m = (om & GROUP) >> 3; |
| 148 | goto dup; |
| 149 | case 'o': |
| 150 | m = (om & OTHER); |
| 151 | dup: |
| 152 | m &= (READ|WRITE|EXEC); |
| 153 | m |= (m << 3) | (m << 6); |
| 154 | ++ms; |
| 155 | return m; |
| 156 | } |
| 157 | for (;;) switch (*ms++) { |
| 158 | case 'r': |
| 159 | m |= READ; |
| 160 | continue; |
| 161 | case 'w': |
| 162 | m |= WRITE; |
| 163 | continue; |
| 164 | case 'x': |
| 165 | m |= EXEC; |
| 166 | continue; |
| 167 | case 's': |
| 168 | m |= SETID; |
| 169 | continue; |
| 170 | case 't': |
| 171 | m |= STICKY; |
| 172 | continue; |
| 173 | default: |
| 174 | ms--; |
| 175 | return m; |
| 176 | } |
| 177 | } |