chown.c revision 715c889713a7b3bd2f487dd14482af9675afc5cf 
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        uid = pw->pw_uid;
40    } else {
41        char* endptr;
42        uid = (int) strtoul(user, &endptr, 0);
43        if (endptr == user) {  // no conversion
44          fprintf(stderr, "No such user '%s'\n", user);
45          return 10;
46        }
47    }
48
49    if (group != NULL) {
50        grp = getgrnam(group);
51        if (grp != NULL) {
52            gid = grp->gr_gid;
53        } else {
54            char* endptr;
55            gid = (int) strtoul(group, &endptr, 0);
56            if (endptr == group) {  // no conversion
57                fprintf(stderr, "No such group '%s'\n", group);
58                return 10;
59            }
60        }
61    }
62
63    for (i = 2; i < argc; i++) {
64        if (chown(argv[i], uid, gid) < 0) {
65            fprintf(stderr, "Unable to chmod %s: %s\n", argv[i], strerror(errno));
66            return 10;
67        }
68    }
69
70    return 0;
71}
72