usr/src/usr.sbin/chown/chgrp.c

#ifndef lint
static  char *sccsid = "@(#)chgrp.c     4.4 83/01/20";
#endif

/*
 * chgrp gid file ...
 */

#include <stdio.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <grp.h>
#include <pwd.h>

struct  group *gr, *getgrnam(), *getgrgid();
struct  passwd *getpwuid(), *pwd;
struct  stat stbuf;
int     gid, uid;
int     status;
/* VARARGS */
int     fprintf();

main(argc, argv)
        int argc;
        char *argv[];
{
        register c, i;

        argc--, argv++;
        if (argc < 2) {
                printf("usage: chgrp gid file ...\n");
                exit(2);
        }
        uid = getuid();
        if (isnumber(argv[0])) {
                gid = atoi(argv[0]);
                gr = getgrgid(gid);
                if (uid && gr == NULL) {
                        printf("%s: unknown group\n", argv[0]);
                        exit(2);
                }
        } else {
                gr = getgrnam(argv[0]);
                if (gr == NULL) {
                        printf("%s: unknown group\n", argv[0]);
                        exit(2);
                }
                gid = gr->gr_gid;
        }
        pwd = getpwuid(uid);
        if (pwd == NULL) {
                fprintf(stderr, "Who are you?\n");
                exit(2);
        }
        if (uid && pwd->pw_gid != gid) {
                for (i=0; gr->gr_mem[i]; i++)
                        if (!(strcmp(pwd->pw_name, gr->gr_mem[i])))
                                goto ok;
                fprintf(stderr, "You are not a member of the %s group.\n",
                    argv[0]);
                exit(2);
        }
ok:
        for (c = 1; c < argc; c++) {
                if (stat(argv[c], &stbuf)) {
                        perror(argv[c]);
                        continue;
                }
                if (uid && uid != stbuf.st_uid) {
                        fprintf(stderr, "You are not the owner of %s\n",
                            argv[c]);
                        status = 1;
                        continue;
                }
                if (chown(argv[c], stbuf.st_uid, gid))
                        perror(argv[c]);
        }
        exit(status);
}

isnumber(s)
        char *s;
{
        register int c;

        while (c = *s++)
                if (!isdigit(c))
                        return (0);
        return (1);
}