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/* crontab 1.2 - user crontab manipulation Author: Kees J. Bot
* 12 Jan 1997
*/
#define nil ((void*)0)
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <pwd.h>
#include <sys/stat.h>
#include "misc.h"
#include "tab.h"
static int opentab(int uid, char *file, int how)
/* Open a crontab file under the given uid. How is 'r' or 'w'. Return
* the result of open(2).
*/
{
uid_t safe_uid;
int flags, r, err;
switch (how) {
case 'r': flags= O_RDONLY; break;
case 'w': flags= O_WRONLY | O_CREAT | O_TRUNC; break;
default: errno= EINVAL; return -1;
}
safe_uid= geteuid();
seteuid(uid);
r= open(file, flags, 0666);
err= errno;
seteuid(safe_uid);
errno= err;
return r;
}
static void copytab(int fd_in, char *file_in, int fd_out, char *file_out)
/* Copy one open file to another. Complain and exit on errors. */
{
ssize_t r, w;
char buf[1024];
while ((r= read(fd_in, buf, sizeof(buf))) > 0) {
w= 0;
while (w < r) {
if ((r= write(fd_out, buf+w, r-w)) <= 0) {
fprintf(stderr,
"%s: Write error on %s: %s\n",
prog_name,
file_out,
r == 0 ? "End of file"
: strerror(errno));
exit(1);
}
w+= r;
}
}
if (r < 0) {
fprintf(stderr, "%s: Read error on %s: %s\n",
prog_name, file_in, strerror(errno));
exit(1);
}
}
static void usage(void)
{
fprintf(stderr,
"Usage: %s -c [user] file # Change crontab\n"
" %s -l [user] # List crontab\n"
" %s -r [user] # Remove crontab\n"
" %s -p # Tell cron to reload\n",
prog_name, prog_name, prog_name, prog_name);
exit(1);
}
int main(int argc, char **argv)
{
int i;
int cflag, lflag, rflag, pflag;
uid_t uid;
char *user, *file;
struct passwd *pw;
static char SPOOLDIR[]= "/usr/spool/crontabs";
char tabfile[sizeof(SPOOLDIR) + NAME_MAX];
prog_name= strrchr(argv[0], '/');
if (prog_name == nil) prog_name= argv[0]; else prog_name++;
cflag= lflag= rflag= pflag= 0;
i= 1;
while (i < argc && argv[i][0] == '-') {
char *opt= argv[i++] + 1;
if (opt[0] == '-' && opt[1] == 0) break; /* -- */
while (*opt != 0) switch (*opt++) {
case 'c': cflag= 1; break;
case 'l': lflag= 1; break;
case 'r': rflag= 1; break;
case 'p': pflag= 1; break;
default: usage();
}
}
if (cflag + lflag + rflag + pflag != 1) usage();
user= file= nil;
if (!pflag && i < argc) user= argv[i++];
if (cflag) {
if (user == nil) usage();
if (i < argc) {
file= argv[i++];
} else {
file= user;
user= nil;
}
}
if (i != argc) usage();
if (geteuid() != 0) {
fprintf(stderr, "%s: No root privileges?\n", prog_name);
}
uid= getuid();
if (user == nil) {
if ((pw= getpwuid(uid)) == nil) {
fprintf(stderr,
"%s: Don't know who you (uid %lu) are!\n",
prog_name, (unsigned long) uid);
exit(1);
}
} else {
if ((pw= getpwnam(user)) == nil) {
fprintf(stderr,
"%s: Don't know who you (%s) are!\n",
prog_name, user);
exit(1);
}
}
if (uid != 0 && pw->pw_uid != uid) {
fprintf(stderr,
"%s: Only root can change the crontabs of others!\n",
prog_name);
exit(1);
}
user= pw->pw_name;
uid= pw->pw_uid;
seteuid(uid);
umask(0077);
selectlog(STDERR);
sprintf(tabfile, "%s/%s", SPOOLDIR, user);
if (lflag) {
int fd;
if ((fd= opentab(0, tabfile, 'r')) < 0) {
fprintf(stderr, "%s: Can't open %s: %s\n",
prog_name, tabfile, strerror(errno));
exit(1);
}
copytab(fd, tabfile, 1, "stdout");
close(fd);
}
if (rflag) {
seteuid(0);
if (unlink(tabfile) < 0) {
fprintf(stderr, "%s: Can't remove %s: %s\n",
prog_name, tabfile, strerror(errno));
exit(1);
}
seteuid(uid);
printf("Crontab of %s removed\n", user);
pflag= 1;
}
/* Initialize current Time */
time(&now);
if (cflag) {
int fd1, fd2;
if ((fd1= opentab(uid, file, 'r')) < 0) {
fprintf(stderr, "%s: Can't open %s: %s\n",
prog_name, file, strerror(errno));
exit(1);
}
/* Try to parse the new crontab file. If the parsing
* succeeds then 'crontabs' will be non-null.
*/
tab_parse(file, user);
tab_purge();
if (crontabs == nil) exit(1);
if ((fd2= opentab(0, tabfile, 'w')) < 0) {
fprintf(stderr, "%s: Can't open %s: %s\n",
prog_name, tabfile, strerror(errno));
exit(1);
}
copytab(fd1, file, fd2, tabfile);
close(fd1);
close(fd2);
printf("New crontab for %s installed\n", user);
pflag= 1;
}
if (pflag) {
/* Alert cron to the new situation. */
FILE *fp;
seteuid(0);
if ((fp= fopen(PIDFILE, "r")) != NULL) {
unsigned long pid;
int c;
pid= 0;
while ((c= fgetc(fp)) != EOF && c != '\n') {
if ((unsigned) (c - '0') >= 10) {
pid= 0; break;
}
pid= 10*pid + (c - '0');
if (pid >= 30000) { pid= 0; break; }
}
if (pid > 1 && kill((pid_t) pid, SIGHUP) == 0) {
pflag= 0;
}
}
seteuid(uid);
if (pflag) {
fprintf(stderr,
"%s: Alerting cron has failed; cron still running?\n",
prog_name);
exit(1);
}
printf("Cron signalled to reload tables\n");
}
return 0;
}
/*
* $PchId: crontab.c,v 1.4 2000/07/17 18:54:50 philip Exp $
*/
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