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cronie/anacron/runjob.c

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/*
Anacron - run commands periodically
Copyright (C) 1998 Itai Tzur <itzur@actcom.co.il>
Copyright (C) 1999 Sean 'Shaleh' Perry <shaleh@debian.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
The GNU General Public License can also be found in the file
`COPYING' that comes with the Anacron source distribution.
*/
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <pwd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <limits.h>
#include "global.h"
#include <langinfo.h>
static int
temp_file(job_rec *jr)
/* Open a temporary file and return its file descriptor */
{
char *dir;
char template[PATH_MAX+1];
int fdin = -1;
int fdout;
int len;
dir = getenv("TMPDIR");
if (dir == NULL || *dir == '\0')
dir = P_tmpdir;
len = snprintf(template, sizeof(template), "%s/$anacronXXXXXX", dir);
if (len < 0)
die_e("snprintf failed");
else if ((size_t) len >= sizeof(template))
die_e("TMPDIR too long");
fdout = mkstemp(template);
if (fdout == -1) die_e("Can't open temporary file for writing");
fdin = open(template, O_RDONLY, S_IRUSR | S_IWUSR);
if (fdin == -1) die_e("Can't open temporary file for reading");
if (unlink(template)) die_e("Can't unlink temporary file");
fcntl(fdout, F_SETFD, FD_CLOEXEC); /* set close-on-exec flag */
fcntl(fdin, F_SETFD, FD_CLOEXEC); /* set close-on-exec flag */
jr->input_fd = fdin;
jr->output_fd = fdout;
return fdout;
}
static off_t
file_size(int fd)
/* Return the size of temporary file fd */
{
struct stat st;
if (fstat(fd, &st)) die_e("Can't fstat temporary file");
return st.st_size;
}
static char *
username(void)
{
struct passwd *ps;
static char *user;
if (user)
return user;
ps = getpwuid(geteuid());
if (ps == NULL || ps->pw_name == NULL) die_e("getpwuid() error");
user = strdup(ps->pw_name);
if (user == NULL) die_e("memory allocation error");
return user;
}
static void
xputenv(const char *s)
{
char *name = NULL, *val = NULL;
char *eq_ptr;
size_t eq_index;
if (s == NULL) {
die_e("Invalid environment string");
}
eq_ptr = strchr(s, '=');
if (eq_ptr == NULL) {
die_e("Invalid environment string");
}
eq_index = (size_t) (eq_ptr - s);
name = malloc((eq_index + 1) * sizeof(char));
if (name == NULL) {
die_e("Not enough memory to set the environment");
}
val = malloc((strlen(s) - eq_index) * sizeof(char));
if (val == NULL) {
die_e("Not enough memory to set the environment");
}
strncpy(name, s, eq_index);
name[eq_index] = '\0';
strcpy(val, s + eq_index + 1);
if (setenv(name, val, 1)) {
die_e("Can't set the environment");
}
free(name);
free(val);
return;
}
static void
setup_env(const job_rec *jr)
/* Setup the environment for the job according to /etc/anacrontab */
{
env_rec *er;
er = first_env_rec;
if (er == NULL || jr->prev_env_rec == NULL) return;
xputenv(er->assign);
while (er != jr->prev_env_rec)
{
er = er->next;
xputenv(er->assign);
}
}
static void
run_job(const job_rec *jr)
/* This is called to start the job, after the fork */
{
/* setup stdout and stderr */
xclose(1);
xclose(2);
if (dup2(jr->output_fd, 1) != 1 || dup2(jr->output_fd, 2) != 2)
die_e("dup2() error"); /* dup2 also clears close-on-exec flag */
in_background = 0; /* now, errors will be mailed to the user */
if (chdir("/")) die_e("Can't chdir to '/'");
if (sigprocmask(SIG_SETMASK, &old_sigmask, NULL))
die_e("sigprocmask error");
xcloselog();
execl("/bin/sh", "/bin/sh", "-c", jr->command, (char *)NULL);
die_e("execl() error");
}
static void
xwrite(int fd, const char *string)
/* Write (using write()) the string "string" to temporary file "fd".
* Don't return on failure */
{
if (write(fd, string, strlen(string)) == -1)
die_e("Can't write to temporary file");
}
static int
xwait(pid_t pid , int *status)
/* Check if child process "pid" has finished. If it has, return 1 and its
* exit status in "*status". If not, return 0.
*/
{
pid_t r;
r = waitpid(pid, status, WNOHANG);
if (r == -1) die_e("waitpid() error");
if (r == 0) return 0;
return 1;
}
static void
launch_mailer(job_rec *jr)
{
pid_t pid;
struct stat buf;
if (jr->mailto == NULL)
{
explain("Empty MAILTO set, not mailing output");
return;
}
/* Check that we have a way of sending mail. */
if(stat(SENDMAIL, &buf))
{
complain("Can't find sendmail at %s, not mailing output", SENDMAIL);
return;
}
pid = xfork();
if (pid == 0)
{
/* child */
in_background = 1;
/* set stdin to the job's output */
xclose(STDIN_FILENO);
if (dup2(jr->input_fd, STDIN_FILENO) != 0) die_e("Can't dup2()");
if (lseek(STDIN_FILENO, 0, SEEK_SET) != 0) die_e("Can't lseek()");
if (sigprocmask(SIG_SETMASK, &old_sigmask, NULL))
die_e("sigprocmask error");
xcloselog();
/* Ensure stdout/stderr are sane before exec-ing sendmail */
xclose(STDOUT_FILENO); xopen(STDOUT_FILENO, "/dev/null", O_WRONLY);
xclose(STDERR_FILENO); xopen(STDERR_FILENO, "/dev/null", O_WRONLY);
xclose(jr->output_fd);
/* Ensure stdin is not appendable ... ? */
/* fdflags = fcntl(0, F_GETFL); fdflags &= ~O_APPEND; */
/* fcntl(0, F_SETFL, fdflags ); */
/* Here, I basically mirrored the way /usr/sbin/sendmail is called
* by cron on a Debian system, except for the "-oem" and "-or0s"
* options, which don't seem to be appropriate here.
* Hopefully, this will keep all the MTAs happy. */
execl(SENDMAIL, SENDMAIL, "-FAnacron", "-odi",
jr->mailto, (char *)NULL);
die_e("Can't exec " SENDMAIL);
}
/* parent */
/* record mailer pid */
jr->mailer_pid = pid;
running_mailers++;
}
static void
tend_mailer(job_rec *jr, int status)
{
if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
complain("Tried to mail output of job `%s', "
"but mailer process (" SENDMAIL ") exited with status %d",
jr->ident, WEXITSTATUS(status));
else if (!WIFEXITED(status) && WIFSIGNALED(status))
complain("Tried to mail output of job `%s', "
"but mailer process (" SENDMAIL ") got signal %d",
jr->ident, WTERMSIG(status));
else if (!WIFEXITED(status) && !WIFSIGNALED(status))
complain("Tried to mail output of job `%s', "
"but mailer process (" SENDMAIL ") terminated abnormally"
, jr->ident);
jr->mailer_pid = 0;
running_mailers--;
}
void
launch_job(job_rec *jr)
{
pid_t pid;
int fd;
char hostname[512];
char *mailto;
char *mailfrom;
/* get hostname */
if (gethostname(hostname, 512)) {
strcpy (hostname,"unknown machine");
}
setup_env(jr);
/* Get the destination email address if set, or current user otherwise */
mailto = getenv("MAILTO");
if (mailto == NULL)
mailto = username();
/* Get the source email address if set, or current user otherwise */
mailfrom = getenv("MAILFROM");
if (mailfrom == NULL)
mailfrom = username();
/* create temporary file for stdout and stderr of the job */
temp_file(jr); fd = jr->output_fd;
/* write mail header */
xwrite(fd, "From: ");
xwrite(fd, "Anacron <");
xwrite(fd, mailfrom);
xwrite(fd, ">\n");
xwrite(fd, "To: ");
xwrite(fd, mailto);
xwrite(fd, "\n");
xwrite(fd, "MIME-Version: 1.0\n");
xwrite(fd, "Content-Type: text/plain; charset=\"");
xwrite(fd, nl_langinfo(CODESET));
xwrite(fd, "\"\n");
xwrite(fd, "Subject: Anacron job '");
xwrite(fd, jr->ident);
xwrite(fd, "' on ");
xwrite(fd, hostname);
xwrite(fd, "\n\n");
if (*mailto == '\0')
jr->mailto = NULL;
else
/* ugly but works without strdup() */
jr->mailto = mailto;
jr->mail_header_size = file_size(fd);
pid = xfork();
if (pid == 0)
{
/* child */
in_background = 1;
run_job(jr);
/* execution never gets here */
}
/* parent */
explain("Job `%s' started", jr->ident);
jr->job_pid = pid;
running_jobs++;
}
static void
tend_job(job_rec *jr, int status)
/* Take care of a finished job */
{
int mail_output;
const char *m;
update_timestamp(jr);
unlock(jr);
if (file_size(jr->output_fd) > jr->mail_header_size) mail_output = 1;
else mail_output = 0;
m = mail_output ? " (produced output)" : "";
if (WIFEXITED(status) && WEXITSTATUS(status) == 0)
explain("Job `%s' terminated%s", jr->ident, m);
else if (WIFEXITED(status))
explain("Job `%s' terminated (exit status: %d)%s",
jr->ident, WEXITSTATUS(status), m);
else if (WIFSIGNALED(status))
complain("Job `%s' terminated due to signal %d%s",
jr->ident, WTERMSIG(status), m);
else /* is this possible? */
complain("Job `%s' terminated abnormally%s", jr->ident, m);
jr->job_pid = 0;
running_jobs--;
if (mail_output) launch_mailer(jr);
xclose(jr->output_fd);
xclose(jr->input_fd);
}
void
tend_children(void)
/* This is called whenever we get a SIGCHLD.
* Takes care of zombie children.
*/
{
int j;
int status;
j = 0;
while (j < njobs)
{
if (job_array[j]->mailer_pid != 0 &&
xwait(job_array[j]->mailer_pid, &status))
tend_mailer(job_array[j], status);
if (job_array[j]->job_pid != 0 &&
xwait(job_array[j]->job_pid, &status))
tend_job(job_array[j], status);
j++;
}
}
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