chown.c revision dd7bc3319deb2b77c5d07a51b7d6cd7e11b5beb0 
1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#include <sys/types.h>
5#include <dirent.h>
6#include <errno.h>
7#include <pwd.h>
8#include <grp.h>
9
10#include <unistd.h>
11#include <time.h>
12
13int chown_main(int argc, char **argv)
14{
15    int i;
16
17    if (argc < 3) {
18        fprintf(stderr, "Usage: chown <USER>[.GROUP] <FILE1> [FILE2] ...\n");
19        return 10;
20    }
21
22    // Copy argv[1] to 'user' so we can truncate it at the period
23    // if a group id specified.
24    char user[32];
25    char *group = NULL;
26    strncpy(user, argv[1], sizeof(user));
27    if ((group = strchr(user, '.')) != NULL) {
28        *group++ = '\0';
29    }
30
31    // Lookup uid (and gid if specified)
32    struct passwd *pw;
33    struct group *grp = NULL;
34    uid_t uid;
35    gid_t gid = -1; // passing -1 to chown preserves current group
36
37    pw = getpwnam(user);
38    if (pw == NULL) {
39        fprintf(stderr, "No such user '%s'\n", user);
40        return 10;
41    }
42    uid = pw->pw_uid;
43
44    if (group != NULL) {
45        grp = getgrnam(group);
46        if (grp == NULL) {
47            fprintf(stderr, "No such group '%s'\n", group);
48            return 10;
49        }
50        gid = grp->gr_gid;
51    }
52
53    for (i = 2; i < argc; i++) {
54        if (chown(argv[i], uid, gid) < 0) {
55            fprintf(stderr, "Unable to chmod %s: %s\n", argv[i], strerror(errno));
56            return 10;
57        }
58    }
59
60    return 0;
61}
62
63