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busybox/miscutils/crontab.c
Eric Andersen aff114c33d Larry Doolittle writes: 
This is a bulk spelling fix patch against busybox-1.00-pre10.
If anyone gets a corrupted copy (and cares), let me know and
I will make alternate arrangements.

Erik - please apply.

Authors - please check that I didn't corrupt any meaning.

Package importers - see if any of these changes should be
passed to the upstream authors.

I glossed over lots of sloppy capitalizations, missing apostrophes,
mixed American/British spellings, and German-style compound words.

What is "pretect redefined for test" in cmdedit.c?

Good luck on the 1.00 release!

      - Larry
2004-04-14 17:51:38 +00:00

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/*
* CRONTAB
*
* usually setuid root, -c option only works if getuid() == geteuid()
*
* Copyright 1994 Matthew Dillon (dillon@apollo.west.oic.com)
* May be distributed under the GNU General Public License
*
* Vladimir Oleynik <dzo@simtreas.ru> (C) 2002 to be used in busybox
*
*/
#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
#include "busybox.h"
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");
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
*/
if (chdir(CDir) < 0)
bb_perror_msg_and_die("cannot change dir to %s", 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());
if ((fd = open(tmp, O_RDWR|O_CREAT|O_TRUNC|O_EXCL, 0600)) >= 0) {
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;
} else {
bb_error_msg_and_die("unable to create %s", tmp);
}
}
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);
fd = open(file, O_RDONLY);
if (fd < 0) {
bb_error_msg("unable to open %s", file);
exit(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)) == 0) {
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_and_die("chdir failed: %s %s", user, pas->pw_dir);
if (chdir(TMPDIR) < 0) {
bb_perror_msg_and_die("chdir failed: %s %s", user, TMPDIR);
return(-1);
}
}
}
return(pas->pw_uid);
}
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