blob: 96dc4741afbd11eb3a1d4d6dbba0329ba56659a6 [file] [log] [blame]
Bernhard Reutner-Fischerd9cf7ac2006-04-12 18:39:58 +00001/* vi: set sw=4 ts=4: */
Eric Andersenf6f7bfb2002-10-22 12:24:59 +00002/*
3 * CRONTAB
4 *
5 * usually setuid root, -c option only works if getuid() == geteuid()
6 *
7 * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
Mike Frysingerf284c762006-04-16 20:38:26 +00008 * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002
Eric Andersenf6f7bfb2002-10-22 12:24:59 +00009 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +020010 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
Eric Andersenf6f7bfb2002-10-22 12:24:59 +000011 */
Denys Vlasenkofb4da162016-11-22 23:14:24 +010012//config:config CRONTAB
Denys Vlasenkob097a842018-12-28 03:20:17 +010013//config: bool "crontab (10 kb)"
Denys Vlasenkofb4da162016-11-22 23:14:24 +010014//config: default y
15//config: help
Denys Vlasenko72089cf2017-07-21 09:50:55 +020016//config: Crontab manipulates the crontab for a particular user. Only
17//config: the superuser may specify a different user and/or crontab directory.
Denys Vlasenko68b653b2017-07-27 10:53:09 +020018//config: Note that busybox binary must be setuid root for this applet to
Denys Vlasenko72089cf2017-07-21 09:50:55 +020019//config: work properly.
Eric Andersenf6f7bfb2002-10-22 12:24:59 +000020
Denys Vlasenkof88e3bf2016-11-22 23:54:17 +010021/* Needs to be run by root or be suid root - needs to change /var/spool/cron* files: */
22//applet:IF_CRONTAB(APPLET(crontab, BB_DIR_USR_BIN, BB_SUID_REQUIRE))
23
24//kbuild:lib-$(CONFIG_CRONTAB) += crontab.o
25
Pere Orga5bc8c002011-04-11 03:29:49 +020026//usage:#define crontab_trivial_usage
27//usage: "[-c DIR] [-u USER] [-ler]|[FILE]"
28//usage:#define crontab_full_usage "\n\n"
29//usage: " -c Crontab directory"
30//usage: "\n -u User"
31//usage: "\n -l List crontab"
32//usage: "\n -e Edit crontab"
33//usage: "\n -r Delete crontab"
34//usage: "\n FILE Replace crontab by FILE ('-': stdin)"
35
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000036#include "libbb.h"
Eric Andersenf6f7bfb2002-10-22 12:24:59 +000037
Denis Vlasenkoded5dfe2009-02-03 23:59:41 +000038#define CRONTABS CONFIG_FEATURE_CROND_DIR "/crontabs"
Eric Andersenf6f7bfb2002-10-22 12:24:59 +000039#ifndef CRONUPDATE
40#define CRONUPDATE "cron.update"
41#endif
Eric Andersenf6f7bfb2002-10-22 12:24:59 +000042
Denis Vlasenko069e3472008-02-16 13:17:13 +000043static void edit_file(const struct passwd *pas, const char *file)
44{
45 const char *ptr;
Denys Vlasenko681efe22011-03-08 21:00:36 +010046 pid_t pid;
Denis Vlasenko069e3472008-02-16 13:17:13 +000047
Denys Vlasenko681efe22011-03-08 21:00:36 +010048 pid = xvfork();
Denis Vlasenko069e3472008-02-16 13:17:13 +000049 if (pid) { /* parent */
50 wait4pid(pid);
51 return;
52 }
53
54 /* CHILD - change user and run editor */
Bernhard Reutner-Fischer99709ab2010-02-24 16:10:09 +010055 /* initgroups, setgid, setuid */
56 change_identity(pas);
Denys Vlasenko681efe22011-03-08 21:00:36 +010057 setup_environment(pas->pw_shell,
Denys Vlasenkofd686a22010-02-26 09:52:45 +010058 SETUP_ENV_CHANGEENV | SETUP_ENV_TO_TMP,
59 pas);
Denis Vlasenko069e3472008-02-16 13:17:13 +000060 ptr = getenv("VISUAL");
61 if (!ptr) {
62 ptr = getenv("EDITOR");
63 if (!ptr)
Denis Vlasenkob44c7902008-03-17 09:29:43 +000064 ptr = "vi";
Denis Vlasenko069e3472008-02-16 13:17:13 +000065 }
66
Denis Vlasenko7fc294c2008-02-16 13:47:57 +000067 BB_EXECLP(ptr, ptr, file, NULL);
Denys Vlasenko681efe22011-03-08 21:00:36 +010068 bb_perror_msg_and_die("can't execute '%s'", ptr);
Denis Vlasenko069e3472008-02-16 13:17:13 +000069}
70
Denis Vlasenko069e3472008-02-16 13:17:13 +000071int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +000072int crontab_main(int argc UNUSED_PARAM, char **argv)
Denis Vlasenko069e3472008-02-16 13:17:13 +000073{
74 const struct passwd *pas;
75 const char *crontab_dir = CRONTABS;
76 char *tmp_fname;
77 char *new_fname;
78 char *user_name; /* -u USER */
79 int fd;
Denis Vlasenko30cfdf92008-09-21 15:29:29 +000080 int src_fd;
Denis Vlasenko069e3472008-02-16 13:17:13 +000081 int opt_ler;
Denis Vlasenko069e3472008-02-16 13:17:13 +000082
83 /* file [opts] Replace crontab from file
84 * - [opts] Replace crontab from stdin
85 * -u user User
86 * -c dir Crontab directory
87 * -l List crontab for user
88 * -e Edit crontab for user
89 * -r Delete crontab for user
90 * bbox also supports -d == -r, but most other crontab
91 * implementations do not. Deprecated.
92 */
93 enum {
94 OPT_u = (1 << 0),
95 OPT_c = (1 << 1),
96 OPT_l = (1 << 2),
97 OPT_e = (1 << 3),
98 OPT_r = (1 << 4),
99 OPT_ler = OPT_l + OPT_e + OPT_r,
100 };
101
Denys Vlasenko22542ec2017-08-08 21:55:02 +0200102 opt_ler = getopt32(argv, "^" "u:c:lerd" "\0" "?1:dr"/*max one arg; -d implies -r*/,
103 &user_name, &crontab_dir
104 );
Denis Vlasenko069e3472008-02-16 13:17:13 +0000105 argv += optind;
106
Denis Vlasenkoc9ca0a32008-02-18 11:08:33 +0000107 if (sanitize_env_if_suid()) { /* Clears dangerous stuff, sets PATH */
Denys Vlasenkob2e5fc32009-11-25 14:52:47 +0100108 /* Run by non-root */
Denis Vlasenko7fc294c2008-02-16 13:47:57 +0000109 if (opt_ler & (OPT_u|OPT_c))
Denys Vlasenkob2e5fc32009-11-25 14:52:47 +0100110 bb_error_msg_and_die(bb_msg_you_must_be_root);
Denis Vlasenko7fc294c2008-02-16 13:47:57 +0000111 }
Denis Vlasenko069e3472008-02-16 13:17:13 +0000112
113 if (opt_ler & OPT_u) {
Denis Vlasenkod7a805e2008-12-03 19:05:55 +0000114 pas = xgetpwnam(user_name);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000115 } else {
Denis Vlasenko0c68a872008-12-02 22:56:59 +0000116 pas = xgetpwuid(getuid());
Denis Vlasenko069e3472008-02-16 13:17:13 +0000117 }
118
119#define user_name DONT_USE_ME_BEYOND_THIS_POINT
Denis Vlasenko069e3472008-02-16 13:17:13 +0000120
121 /* From now on, keep only -l, -e, -r bits */
122 opt_ler &= OPT_ler;
123 if ((opt_ler - 1) & opt_ler) /* more than one bit set? */
124 bb_show_usage();
125
126 /* Read replacement file under user's UID/GID/group vector */
Denis Vlasenko30cfdf92008-09-21 15:29:29 +0000127 src_fd = STDIN_FILENO;
Denis Vlasenko069e3472008-02-16 13:17:13 +0000128 if (!opt_ler) { /* Replace? */
129 if (!argv[0])
130 bb_show_usage();
131 if (NOT_LONE_DASH(argv[0])) {
Ryan Mallon1d30b3f2013-10-08 14:53:29 +0200132 src_fd = xopen_as_uid_gid(argv[0], O_RDONLY, pas->pw_uid, pas->pw_gid);
Denis Vlasenko94d5d822006-09-27 19:48:56 +0000133 }
134 }
Denis Vlasenko069e3472008-02-16 13:17:13 +0000135
136 /* cd to our crontab directory */
137 xchdir(crontab_dir);
138
139 tmp_fname = NULL;
140
141 /* Handle requested operation */
142 switch (opt_ler) {
143
144 default: /* case OPT_r: Delete */
Denis Vlasenko03b4c142008-02-17 14:30:03 +0000145 unlink(pas->pw_name);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000146 break;
147
148 case OPT_l: /* List */
149 {
150 char *args[2] = { pas->pw_name, NULL };
151 return bb_cat(args);
152 /* list exits,
153 * the rest go play with cron update file */
154 }
155
156 case OPT_e: /* Edit */
Denis Vlasenko7fc294c2008-02-16 13:47:57 +0000157 tmp_fname = xasprintf("%s.%u", crontab_dir, (unsigned)getpid());
Denis Vlasenkob44c7902008-03-17 09:29:43 +0000158 /* No O_EXCL: we don't want to be stuck if earlier crontabs
159 * were killed, leaving stale temp file behind */
Denis Vlasenko30cfdf92008-09-21 15:29:29 +0000160 src_fd = xopen3(tmp_fname, O_RDWR|O_CREAT|O_TRUNC, 0600);
161 fchown(src_fd, pas->pw_uid, pas->pw_gid);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000162 fd = open(pas->pw_name, O_RDONLY);
163 if (fd >= 0) {
Denis Vlasenko30cfdf92008-09-21 15:29:29 +0000164 bb_copyfd_eof(fd, src_fd);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000165 close(fd);
Denis Vlasenko30cfdf92008-09-21 15:29:29 +0000166 xlseek(src_fd, 0, SEEK_SET);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000167 }
Denis Vlasenko30cfdf92008-09-21 15:29:29 +0000168 close_on_exec_on(src_fd); /* don't want editor to see this fd */
Denis Vlasenko069e3472008-02-16 13:17:13 +0000169 edit_file(pas, tmp_fname);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000170 /* fall through */
171
172 case 0: /* Replace (no -l, -e, or -r were given) */
173 new_fname = xasprintf("%s.new", pas->pw_name);
174 fd = open(new_fname, O_WRONLY|O_CREAT|O_TRUNC|O_APPEND, 0600);
175 if (fd >= 0) {
Denis Vlasenko30cfdf92008-09-21 15:29:29 +0000176 bb_copyfd_eof(src_fd, fd);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000177 close(fd);
Denis Vlasenko03b4c142008-02-17 14:30:03 +0000178 xrename(new_fname, pas->pw_name);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000179 } else {
Denys Vlasenko6331cf02009-11-13 09:08:27 +0100180 bb_error_msg("can't create %s/%s",
Denis Vlasenko069e3472008-02-16 13:17:13 +0000181 crontab_dir, new_fname);
182 }
183 if (tmp_fname)
Denis Vlasenko03b4c142008-02-17 14:30:03 +0000184 unlink(tmp_fname);
Denis Vlasenko069e3472008-02-16 13:17:13 +0000185 /*free(tmp_fname);*/
186 /*free(new_fname);*/
Denis Vlasenko069e3472008-02-16 13:17:13 +0000187 } /* switch */
188
189 /* Bump notification file. Handle window where crond picks file up
190 * before we can write our entry out.
191 */
Bernhard Reutner-Fischer27dd4952008-02-18 18:35:53 +0000192 while ((fd = open(CRONUPDATE, O_WRONLY|O_CREAT|O_APPEND, 0600)) >= 0) {
Denis Vlasenko069e3472008-02-16 13:17:13 +0000193 struct stat st;
194
195 fdprintf(fd, "%s\n", pas->pw_name);
196 if (fstat(fd, &st) != 0 || st.st_nlink != 0) {
197 /*close(fd);*/
198 break;
199 }
200 /* st.st_nlink == 0:
201 * file was deleted, maybe crond missed our notification */
202 close(fd);
203 /* loop */
204 }
205 if (fd < 0) {
Denys Vlasenko6331cf02009-11-13 09:08:27 +0100206 bb_error_msg("can't append to %s/%s",
Denis Vlasenko069e3472008-02-16 13:17:13 +0000207 crontab_dir, CRONUPDATE);
208 }
209 return 0;
Eric Andersenf6f7bfb2002-10-22 12:24:59 +0000210}