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Change how the mailer is waited for. Instead of having a SIGCHLD

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handler, use the double fork trick to orphan the child that opens
the pipe to sendmail.  Fixes a problem running su on some Linux distros.
This commit is contained in:
Todd C. Miller
2008-06-21 00:34:47 +00:00
parent c372928c38
commit 5756ddfbeb
4 changed files with 61 additions and 47 deletions
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79
logging.c
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@@ -425,8 +425,8 @@ send_mail(line)
{
FILE *mail;
char *p;
int pfd[2];
pid_t pid;
int pfd[2], status;
pid_t pid, rv;
sigaction_t sa, saved_sa_pipe;
#ifndef NO_ROOT_MAILER
static char *root_envp[] = {
@@ -443,19 +443,58 @@ send_mail(line)
if (!def_mailerpath || !def_mailto)
return;
/* Fork a child so we can be asyncronous. */
switch (pid = fork()) {
case -1:
/* Error. */
error(1, "cannot fork");
break;
case 0:
/* Child continues below. */
break;
default:
/* Parent waits and returns. */
do {
#ifdef sudo_waitpid
rv = sudo_waitpid(pid, &status, 0);
#else
rv = wait(&status);
#endif
} while (rv == -1 && errno == EINTR);
return;
}
/* Fork again and orphan the grandchild so parent can continue. */
switch (pid = fork()) {
case -1:
/* Error. */
warning("cannot fork");
_exit(1);
break;
case 0:
/* Grandchild continues below. */
break;
default:
/* Orphan grandchild. */
_exit(0);
}
/* Ignore SIGPIPE in case mailer exits prematurely (or is missing). */
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = SIG_IGN;
(void) sigaction(SIGPIPE, &sa, &saved_sa_pipe);
if (pipe(pfd) == -1)
error(1, "cannot open pipe");
if (pipe(pfd) == -1) {
warning("cannot open pipe");
_exit(1);
}
switch (pid = fork()) {
case -1:
/* Error. */
error(1, "cannot fork");
warning("cannot fork");
_exit(1);
break;
case 0:
{
@@ -463,7 +502,7 @@ send_mail(line)
char *mpath, *mflags;
int i;
/* Child, set stdin to output side of the pipe */
/* Great-grandchild, set stdin to output side of the pipe */
if (pfd[0] != STDIN_FILENO) {
(void) dup2(pfd[0], STDIN_FILENO);
(void) close(pfd[0]);
@@ -533,7 +572,13 @@ send_mail(line)
(void) fprintf(mail, "\n\n%s : %s : %s : %s\n\n", user_host,
get_timestr(), user_name, line);
fclose(mail);
do {
#ifdef sudo_waitpid
rv = sudo_waitpid(pid, &status, 0);
#else
rv = wait(&status);
#endif
} while (rv == -1 && errno == EINTR);
(void) sigaction(SIGPIPE, &saved_sa_pipe, NULL);
}
@@ -551,26 +596,6 @@ should_mail(status)
(def_mail_no_perms && !ISSET(status, VALIDATE_OK)));
}
/*
* SIGCHLD sig handler--wait for children as they die.
*/
RETSIGTYPE
reapchild(sig)
int sig;
{
int status, serrno = errno;
#ifdef sudo_waitpid
pid_t pid;
do {
pid = sudo_waitpid(-1, &status, WNOHANG);
} while (pid != 0 && (pid != -1 || errno == EINTR));
#else
(void) wait(&status);
#endif
errno = serrno;
}
/*
* Return an ascii string with the current date + time
* Uses strftime() if available, else falls back to ctime().