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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>
#include <pwd.h>
#include <grp.h>
#include <unistd.h>
#include <time.h>
int main(int argc, char **argv)
{
int i;
if (argc < 3) {
fprintf(stderr, "Usage: chown <USER>[:GROUP] <FILE1> [FILE2] ...\n");
return 10;
}
// Copy argv[1] to 'user' so we can truncate it at the period
// if a group id specified.
char user[32];
char *group = NULL;
strncpy(user, argv[1], sizeof(user));
if ((group = strchr(user, ':')) != NULL) {
*group++ = '\0';
} else if ((group = strchr(user, '.')) != NULL) {
*group++ = '\0';
}
// Lookup uid (and gid if specified)
struct passwd *pw;
struct group *grp = NULL;
uid_t uid;
gid_t gid = -1; // passing -1 to chown preserves current group
pw = getpwnam(user);
if (pw != NULL) {
uid = pw->pw_uid;
} else {
char* endptr;
uid = (int) strtoul(user, &endptr, 0);
if (endptr == user) { // no conversion
fprintf(stderr, "No such user '%s'\n", user);
return 10;
}
}
if (group != NULL) {
grp = getgrnam(group);
if (grp != NULL) {
gid = grp->gr_gid;
} else {
char* endptr;
gid = (int) strtoul(group, &endptr, 0);
if (endptr == group) { // no conversion
fprintf(stderr, "No such group '%s'\n", group);
return 10;
}
}
}
for (i = 2; i < argc; i++) {
if (chown(argv[i], uid, gid) < 0) {
fprintf(stderr, "Unable to chown %s: %s\n", argv[i], strerror(errno));
return 10;
}
}
return 0;
}
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