mirror of
https://git.busybox.net/busybox.git
synced 2024-12-01 01:23:32 +08:00
357 lines
7.0 KiB
C
357 lines
7.0 KiB
C
/* vi: set sw=4 ts=4: */
|
|
/*
|
|
* CRONTAB
|
|
*
|
|
* usually setuid root, -c option only works if getuid() == geteuid()
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include "busybox.h"
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <stdarg.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
#include <time.h>
|
|
#include <dirent.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#include <syslog.h>
|
|
#include <signal.h>
|
|
#include <getopt.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/wait.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/resource.h>
|
|
|
|
#ifndef CRONTABS
|
|
#define CRONTABS "/var/spool/cron/crontabs"
|
|
#endif
|
|
#ifndef TMPDIR
|
|
#define TMPDIR "/var/spool/cron"
|
|
#endif
|
|
#ifndef CRONUPDATE
|
|
#define CRONUPDATE "cron.update"
|
|
#endif
|
|
#ifndef PATH_VI
|
|
#define PATH_VI "/bin/vi" /* location of vi */
|
|
#endif
|
|
|
|
static const char *CDir = CRONTABS;
|
|
|
|
static void EditFile(const char *user, const char *file);
|
|
static int GetReplaceStream(const char *user, const char *file);
|
|
static int ChangeUser(const char *user, short dochdir);
|
|
|
|
int
|
|
crontab_main(int ac, char **av)
|
|
{
|
|
enum { NONE, EDIT, LIST, REPLACE, DELETE } option = NONE;
|
|
const struct passwd *pas;
|
|
const char *repFile = NULL;
|
|
int repFd = 0;
|
|
int i;
|
|
char caller[256]; /* user that ran program */
|
|
int UserId;
|
|
|
|
UserId = getuid();
|
|
if ((pas = getpwuid(UserId)) == NULL)
|
|
bb_perror_msg_and_die("getpwuid");
|
|
|
|
safe_strncpy(caller, pas->pw_name, sizeof(caller));
|
|
|
|
i = 1;
|
|
if (ac > 1) {
|
|
if (av[1][0] == '-' && av[1][1] == 0) {
|
|
option = REPLACE;
|
|
++i;
|
|
} else if (av[1][0] != '-') {
|
|
option = REPLACE;
|
|
++i;
|
|
repFile = av[1];
|
|
}
|
|
}
|
|
|
|
for (; i < ac; ++i) {
|
|
char *ptr = av[i];
|
|
|
|
if (*ptr != '-')
|
|
break;
|
|
ptr += 2;
|
|
|
|
switch(ptr[-1]) {
|
|
case 'l':
|
|
if (ptr[-1] == 'l')
|
|
option = LIST;
|
|
/* fall through */
|
|
case 'e':
|
|
if (ptr[-1] == 'e')
|
|
option = EDIT;
|
|
/* fall through */
|
|
case 'd':
|
|
if (ptr[-1] == 'd')
|
|
option = DELETE;
|
|
/* fall through */
|
|
case 'u':
|
|
if (i + 1 < ac && av[i+1][0] != '-') {
|
|
++i;
|
|
if (getuid() == geteuid()) {
|
|
pas = getpwnam(av[i]);
|
|
if (pas) {
|
|
UserId = pas->pw_uid;
|
|
} else {
|
|
bb_error_msg_and_die("user %s unknown", av[i]);
|
|
}
|
|
} else {
|
|
bb_error_msg_and_die("only the superuser may specify a user");
|
|
}
|
|
}
|
|
break;
|
|
case 'c':
|
|
if (getuid() == geteuid()) {
|
|
CDir = (*ptr) ? ptr : av[++i];
|
|
} else {
|
|
bb_error_msg_and_die("-c option: superuser only");
|
|
}
|
|
break;
|
|
default:
|
|
i = ac;
|
|
break;
|
|
}
|
|
}
|
|
if (i != ac || option == NONE)
|
|
bb_show_usage();
|
|
|
|
/*
|
|
* Get password entry
|
|
*/
|
|
|
|
if ((pas = getpwuid(UserId)) == NULL)
|
|
bb_perror_msg_and_die("getpwuid");
|
|
|
|
/*
|
|
* If there is a replacement file, obtain a secure descriptor to it.
|
|
*/
|
|
|
|
if (repFile) {
|
|
repFd = GetReplaceStream(caller, repFile);
|
|
if (repFd < 0)
|
|
bb_error_msg_and_die("unable to read replacement file");
|
|
}
|
|
|
|
/*
|
|
* Change directory to our crontab directory
|
|
*/
|
|
|
|
bb_xchdir(CDir);
|
|
|
|
/*
|
|
* Handle options as appropriate
|
|
*/
|
|
|
|
switch(option) {
|
|
case LIST:
|
|
{
|
|
FILE *fi;
|
|
char buf[1024];
|
|
|
|
if ((fi = fopen(pas->pw_name, "r"))) {
|
|
while (fgets(buf, sizeof(buf), fi) != NULL)
|
|
fputs(buf, stdout);
|
|
fclose(fi);
|
|
} else {
|
|
bb_error_msg("no crontab for %s", pas->pw_name);
|
|
}
|
|
}
|
|
break;
|
|
case EDIT:
|
|
{
|
|
FILE *fi;
|
|
int fd;
|
|
int n;
|
|
char tmp[128];
|
|
char buf[1024];
|
|
|
|
snprintf(tmp, sizeof(tmp), TMPDIR "/crontab.%d", getpid());
|
|
fd = bb_xopen3(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600);
|
|
chown(tmp, getuid(), getgid());
|
|
if ((fi = fopen(pas->pw_name, "r"))) {
|
|
while ((n = fread(buf, 1, sizeof(buf), fi)) > 0)
|
|
write(fd, buf, n);
|
|
}
|
|
EditFile(caller, tmp);
|
|
remove(tmp);
|
|
lseek(fd, 0L, 0);
|
|
repFd = fd;
|
|
}
|
|
option = REPLACE;
|
|
/* fall through */
|
|
case REPLACE:
|
|
{
|
|
char buf[1024];
|
|
char path[1024];
|
|
int fd;
|
|
int n;
|
|
|
|
snprintf(path, sizeof(path), "%s.new", pas->pw_name);
|
|
if ((fd = open(path, O_CREAT|O_TRUNC|O_APPEND|O_WRONLY, 0600)) >= 0) {
|
|
while ((n = read(repFd, buf, sizeof(buf))) > 0) {
|
|
write(fd, buf, n);
|
|
}
|
|
close(fd);
|
|
rename(path, pas->pw_name);
|
|
} else {
|
|
bb_error_msg("unable to create %s/%s", CDir, path);
|
|
}
|
|
close(repFd);
|
|
}
|
|
break;
|
|
case DELETE:
|
|
remove(pas->pw_name);
|
|
break;
|
|
case NONE:
|
|
default:
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Bump notification file. Handle window where crond picks file up
|
|
* before we can write our entry out.
|
|
*/
|
|
|
|
if (option == REPLACE || option == DELETE) {
|
|
FILE *fo;
|
|
struct stat st;
|
|
|
|
while ((fo = fopen(CRONUPDATE, "a"))) {
|
|
fprintf(fo, "%s\n", pas->pw_name);
|
|
fflush(fo);
|
|
if (fstat(fileno(fo), &st) != 0 || st.st_nlink != 0) {
|
|
fclose(fo);
|
|
break;
|
|
}
|
|
fclose(fo);
|
|
/* loop */
|
|
}
|
|
if (fo == NULL) {
|
|
bb_error_msg("unable to append to %s/%s", CDir, CRONUPDATE);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
GetReplaceStream(const char *user, const char *file)
|
|
{
|
|
int filedes[2];
|
|
int pid;
|
|
int fd;
|
|
int n;
|
|
char buf[1024];
|
|
|
|
if (pipe(filedes) < 0) {
|
|
perror("pipe");
|
|
return(-1);
|
|
}
|
|
if ((pid = fork()) < 0) {
|
|
perror("fork");
|
|
return(-1);
|
|
}
|
|
if (pid > 0) {
|
|
/*
|
|
* PARENT
|
|
*/
|
|
|
|
close(filedes[1]);
|
|
if (read(filedes[0], buf, 1) != 1) {
|
|
close(filedes[0]);
|
|
filedes[0] = -1;
|
|
}
|
|
return(filedes[0]);
|
|
}
|
|
|
|
/*
|
|
* CHILD
|
|
*/
|
|
|
|
close(filedes[0]);
|
|
|
|
if (ChangeUser(user, 0) < 0)
|
|
exit(0);
|
|
|
|
bb_default_error_retval = 0;
|
|
fd = bb_xopen3(file, O_RDONLY, 0);
|
|
buf[0] = 0;
|
|
write(filedes[1], buf, 1);
|
|
while ((n = read(fd, buf, sizeof(buf))) > 0) {
|
|
write(filedes[1], buf, n);
|
|
}
|
|
exit(0);
|
|
}
|
|
|
|
static void
|
|
EditFile(const char *user, const char *file)
|
|
{
|
|
int pid;
|
|
|
|
if ((pid = fork()) == 0) {
|
|
/*
|
|
* CHILD - change user and run editor
|
|
*/
|
|
char *ptr;
|
|
char visual[1024];
|
|
|
|
if (ChangeUser(user, 1) < 0)
|
|
exit(0);
|
|
if ((ptr = getenv("VISUAL")) == NULL || strlen(ptr) > 256)
|
|
ptr = PATH_VI;
|
|
|
|
snprintf(visual, sizeof(visual), "%s %s", ptr, file);
|
|
execl(DEFAULT_SHELL, DEFAULT_SHELL, "-c", visual, NULL);
|
|
perror("exec");
|
|
exit(0);
|
|
}
|
|
if (pid < 0) {
|
|
/*
|
|
* PARENT - failure
|
|
*/
|
|
bb_perror_msg_and_die("fork");
|
|
}
|
|
wait4(pid, NULL, 0, NULL);
|
|
}
|
|
|
|
static int
|
|
ChangeUser(const char *user, short dochdir)
|
|
{
|
|
struct passwd *pas;
|
|
|
|
/*
|
|
* Obtain password entry and change privileges
|
|
*/
|
|
|
|
if ((pas = getpwnam(user)) == NULL) {
|
|
bb_perror_msg_and_die("failed to get uid for %s", user);
|
|
return(-1);
|
|
}
|
|
setenv("USER", pas->pw_name, 1);
|
|
setenv("HOME", pas->pw_dir, 1);
|
|
setenv("SHELL", DEFAULT_SHELL, 1);
|
|
|
|
/*
|
|
* Change running state to the user in question
|
|
*/
|
|
change_identity(pas);
|
|
|
|
if (dochdir) {
|
|
if (chdir(pas->pw_dir) < 0) {
|
|
bb_perror_msg("chdir failed: %s %s", user, pas->pw_dir);
|
|
bb_xchdir(TMPDIR);
|
|
}
|
|
}
|
|
return(pas->pw_uid);
|
|
}
|