Start 1.33.0 development cycle

[oweals/busybox.git] / miscutils / crontab.c

diff --git a/miscutils/crontab.c b/miscutils/crontab.c
index 67b10f684180fd16516e6237cb5e08af3705644e..c71d914fcea05a1ceb3a58225e5a3f5cb704745b 100644 (file)
--- a/miscutils/crontab.c
+++ b/miscutils/crontab.c
@@ -7,8 +7,31 @@
  * Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
  * Vladimir Oleynik <dzo@simtreas.ru> (C) 2002
  *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
+//config:config CRONTAB
+//config:      bool "crontab (10 kb)"
+//config:      default y
+//config:      help
+//config:      Crontab manipulates the crontab for a particular user. Only
+//config:      the superuser may specify a different user and/or crontab directory.
+//config:      Note that busybox binary must be setuid root for this applet to
+//config:      work properly.
+
+/* Needs to be run by root or be suid root - needs to change /var/spool/cron* files: */
+//applet:IF_CRONTAB(APPLET(crontab, BB_DIR_USR_BIN, BB_SUID_REQUIRE))
+
+//kbuild:lib-$(CONFIG_CRONTAB) += crontab.o
+
+//usage:#define crontab_trivial_usage
+//usage:       "[-c DIR] [-u USER] [-ler]|[FILE]"
+//usage:#define crontab_full_usage "\n\n"
+//usage:       "       -c      Crontab directory"
+//usage:     "\n       -u      User"
+//usage:     "\n       -l      List crontab"
+//usage:     "\n       -e      Edit crontab"
+//usage:     "\n       -r      Delete crontab"
+//usage:     "\n       FILE    Replace crontab by FILE ('-': stdin)"
 
 #include "libbb.h"
 
@@ -17,36 +40,23 @@
 #define CRONUPDATE      "cron.update"
 #endif
 
-static void change_user(const struct passwd *pas)
-{
-       xsetenv("USER", pas->pw_name);
-       xsetenv("HOME", pas->pw_dir);
-       xsetenv("SHELL", DEFAULT_SHELL);
-
-       /* initgroups, setgid, setuid */
-       change_identity(pas);
-
-       if (chdir(pas->pw_dir) < 0) {
-               bb_perror_msg("chdir(%s) by %s failed",
-                               pas->pw_dir, pas->pw_name);
-               xchdir("/tmp");
-       }
-}
-
 static void edit_file(const struct passwd *pas, const char *file)
 {
        const char *ptr;
-       int pid = vfork();
+       pid_t pid;
 
-       if (pid < 0) /* failure */
-               bb_perror_msg_and_die("vfork");
+       pid = xvfork();
        if (pid) { /* parent */
                wait4pid(pid);
                return;
        }
 
        /* CHILD - change user and run editor */
-       change_user(pas);
+       /* initgroups, setgid, setuid */
+       change_identity(pas);
+       setup_environment(pas->pw_shell,
+                       SETUP_ENV_CHANGEENV | SETUP_ENV_TO_TMP,
+                       pas);
        ptr = getenv("VISUAL");
        if (!ptr) {
                ptr = getenv("EDITOR");
@@ -55,31 +65,7 @@ static void edit_file(const struct passwd *pas, const char *file)
        }
 
        BB_EXECLP(ptr, ptr, file, NULL);
-       bb_perror_msg_and_die("exec %s", ptr);
-}
-
-static int open_as_user(const struct passwd *pas, const char *file)
-{
-       pid_t pid;
-       char c;
-
-       pid = vfork();
-       if (pid < 0) /* ERROR */
-               bb_perror_msg_and_die("vfork");
-       if (pid) { /* PARENT */
-               if (wait4pid(pid) == 0) {
-                       /* exitcode 0: child says it can read */
-                       return open(file, O_RDONLY);
-               }
-               return -1;
-       }
-
-       /* CHILD */
-       /* initgroups, setgid, setuid */
-       change_identity(pas);
-       /* We just try to read one byte. If it works, file is readable
-        * under this user. We signal that by exiting with 0. */
-       _exit(safe_read(xopen(file, O_RDONLY), &c, 1) < 0);
+       bb_perror_msg_and_die("can't execute '%s'", ptr);
 }
 
 int crontab_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -113,14 +99,15 @@ int crontab_main(int argc UNUSED_PARAM, char **argv)
                OPT_ler = OPT_l + OPT_e + OPT_r,
        };
 
-       opt_complementary = "?1:dr"; /* max one argument; -d implies -r */
-       opt_ler = getopt32(argv, "u:c:lerd", &user_name, &crontab_dir);
+       opt_ler = getopt32(argv, "^" "u:c:lerd" "\0" "?1:dr"/*max one arg; -d implies -r*/,
+                               &user_name, &crontab_dir
+       );
        argv += optind;
 
        if (sanitize_env_if_suid()) { /* Clears dangerous stuff, sets PATH */
-               /* run by non-root? */
+               /* Run by non-root */
                if (opt_ler & (OPT_u|OPT_c))
-                       bb_error_msg_and_die("only root can use -c or -u");
+                       bb_simple_error_msg_and_die(bb_msg_you_must_be_root);
        }
 
        if (opt_ler & OPT_u) {
@@ -142,10 +129,7 @@ int crontab_main(int argc UNUSED_PARAM, char **argv)
                if (!argv[0])
                        bb_show_usage();
                if (NOT_LONE_DASH(argv[0])) {
-                       src_fd = open_as_user(pas, argv[0]);
-                       if (src_fd < 0)
-                               bb_error_msg_and_die("user %s cannot read %s",
-                                               pas->pw_name, argv[0]);
+                       src_fd = xopen_as_uid_gid(argv[0], O_RDONLY, pas->pw_uid, pas->pw_gid);
                }
        }
 
@@ -200,7 +184,6 @@ int crontab_main(int argc UNUSED_PARAM, char **argv)
                        unlink(tmp_fname);
                /*free(tmp_fname);*/
                /*free(new_fname);*/
-
        } /* switch */
 
        /* Bump notification file.  Handle window where crond picks file up