1 /* vi: set sw=4 ts=4: */
5 * usually setuid root, -c option only works if getuid() == geteuid()
7 * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
8 * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002
10 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
25 #include <sys/ioctl.h>
28 #include <sys/resource.h>
31 #define CRONTABS "/var/spool/cron/crontabs"
34 #define TMPDIR "/var/spool/cron"
37 #define CRONUPDATE "cron.update"
40 #define PATH_VI "/bin/vi" /* location of vi */
45 static const char *CDir = CRONTABS;
47 static void EditFile(const char *user, const char *file);
48 static int GetReplaceStream(const char *user, const char *file);
49 static int ChangeUser(const char *user, short dochdir);
52 crontab_main(int ac, char **av)
54 enum { NONE, EDIT, LIST, REPLACE, DELETE } option = NONE;
55 const struct passwd *pas;
56 const char *repFile = NULL;
59 char caller[256]; /* user that ran program */
63 if ((pas = getpwuid(UserId)) == NULL)
64 bb_perror_msg_and_die("getpwuid");
66 strncpy(caller, pas->pw_name, sizeof(caller));
70 if (av[1][0] == '-' && av[1][1] == 0) {
73 } else if (av[1][0] != '-') {
101 if (i + 1 < ac && av[i+1][0] != '-') {
103 if (getuid() == geteuid()) {
104 pas = getpwnam(av[i]);
106 UserId = pas->pw_uid;
108 bb_error_msg_and_die("user %s unknown", av[i]);
111 bb_error_msg_and_die("only the superuser may specify a user");
116 if (getuid() == geteuid()) {
117 CDir = (*ptr) ? ptr : av[++i];
119 bb_error_msg_and_die("-c option: superuser only");
127 if (i != ac || option == NONE)
134 if ((pas = getpwuid(UserId)) == NULL)
135 bb_perror_msg_and_die("getpwuid");
138 * If there is a replacement file, obtain a secure descriptor to it.
142 repFd = GetReplaceStream(caller, repFile);
144 bb_error_msg_and_die("unable to read replacement file");
148 * Change directory to our crontab directory
154 * Handle options as appropriate
163 if ((fi = fopen(pas->pw_name, "r"))) {
164 while (fgets(buf, sizeof(buf), fi) != NULL)
168 bb_error_msg("no crontab for %s", pas->pw_name);
180 snprintf(tmp, sizeof(tmp), TMPDIR "/crontab.%d", getpid());
181 fd = bb_xopen3(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600);
182 chown(tmp, getuid(), getgid());
183 if ((fi = fopen(pas->pw_name, "r"))) {
184 while ((n = fread(buf, 1, sizeof(buf), fi)) > 0)
187 EditFile(caller, tmp);
201 snprintf(path, sizeof(path), "%s.new", pas->pw_name);
202 if ((fd = open(path, O_CREAT|O_TRUNC|O_APPEND|O_WRONLY, 0600)) >= 0) {
203 while ((n = read(repFd, buf, sizeof(buf))) > 0) {
207 rename(path, pas->pw_name);
209 bb_error_msg("unable to create %s/%s", CDir, path);
215 remove(pas->pw_name);
223 * Bump notification file. Handle window where crond picks file up
224 * before we can write our entry out.
227 if (option == REPLACE || option == DELETE) {
231 while ((fo = fopen(CRONUPDATE, "a"))) {
232 fprintf(fo, "%s\n", pas->pw_name);
234 if (fstat(fileno(fo), &st) != 0 || st.st_nlink != 0) {
242 bb_error_msg("unable to append to %s/%s", CDir, CRONUPDATE);
249 GetReplaceStream(const char *user, const char *file)
257 if (pipe(filedes) < 0) {
261 if ((pid = fork()) < 0) {
271 if (read(filedes[0], buf, 1) != 1) {
284 if (ChangeUser(user, 0) < 0)
287 bb_default_error_retval = 0;
288 fd = bb_xopen3(file, O_RDONLY, 0);
290 write(filedes[1], buf, 1);
291 while ((n = read(fd, buf, sizeof(buf))) > 0) {
292 write(filedes[1], buf, n);
298 EditFile(const char *user, const char *file)
302 if ((pid = fork()) == 0) {
304 * CHILD - change user and run editor
309 if (ChangeUser(user, 1) < 0)
311 if ((ptr = getenv("VISUAL")) == NULL || strlen(ptr) > 256)
314 snprintf(visual, sizeof(visual), "%s %s", ptr, file);
315 execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", visual, NULL);
323 bb_perror_msg_and_die("fork");
325 wait4(pid, NULL, 0, NULL);
329 ChangeUser(const char *user, short dochdir)
334 * Obtain password entry and change privileges
337 if ((pas = getpwnam(user)) == NULL) {
338 bb_perror_msg_and_die("failed to get uid for %s", user);
341 setenv("USER", pas->pw_name, 1);
342 setenv("HOME", pas->pw_dir, 1);
343 setenv("SHELL", DEFAULT_SHELL, 1);
346 * Change running state to the user in question
348 change_identity(pas);
351 if (chdir(pas->pw_dir) < 0) {
352 bb_perror_msg("chdir failed: %s %s", user, pas->pw_dir);