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    } else if ((group = strchr(user, '.')) != NULL) {
30        *group++ = '\0';
31    }
32
33    // Lookup uid (and gid if specified)
34    struct passwd *pw;
35    struct group *grp = NULL;
36    uid_t uid;
37    gid_t gid = -1; // passing -1 to chown preserves current group
38
39    pw = getpwnam(user);
40    if (pw != NULL) {
41        uid = pw->pw_uid;
42    } else {
43        char* endptr;
44        uid = (int) strtoul(user, &endptr, 0);
45        if (endptr == user) {  // no conversion
46          fprintf(stderr, "No such user '%s'\n", user);
47          return 10;
48        }
49    }
50
51    if (group != NULL) {
52        grp = getgrnam(group);
53        if (grp != NULL) {
54            gid = grp->gr_gid;
55        } else {
56            char* endptr;
57            gid = (int) strtoul(group, &endptr, 0);
58            if (endptr == group) {  // no conversion
59                fprintf(stderr, "No such group '%s'\n", group);
60                return 10;
61            }
62        }
63    }
64
65    for (i = 2; i < argc; i++) {
66        if (chown(argv[i], uid, gid) < 0) {
67            fprintf(stderr, "Unable to chown %s: %s\n", argv[i], strerror(errno));
68            return 10;
69        }
70    }
71
72    return 0;
73}
74