* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Reap any leftover children possibly holding file descriptors.
- * Children are identified by the open file descriptor.
- * PGID or SID may be set by the children on their own.
- * If we find a child by its file descriptor, we kill it will all its process
- * tree (grandchildren).
+ * Children are identified by the stale file descriptor or PGID / SID.
+ * Both can be missed but only the stale file descriptors are important for us.
+ * PGID / SID may be set by the children on their own.
+ * If we fine a candidate we kill it will all its process tree (grandchildren).
* The child process is run with `2>&1' redirection (due to forkpty(3)).
* 2007-07-10 Jan Kratochvil <jan.kratochvil@redhat.com>
*/
-#define _XOPEN_SOURCE 1
-#define _XOPEN_SOURCE_EXTENDED 1
-#define _BSD_SOURCE 1
+#define _GNU_SOURCE 1
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <assert.h>
#include <pty.h>
+#include <poll.h>
static const char *progname;
-static int signal_child_hit = 0;
+static volatile int signal_child_hit = 0;
static void signal_child (int signo)
{
}
static char childptyname[LINE_MAX];
+static pid_t child;
static int spawn (char **argv)
{
- pid_t child, child_got;
+ pid_t child_got;
int status, amaster, i;
- char buf[LINE_MAX];
- ssize_t buf_got;
struct sigaction act;
+ sigset_t sigset;
+
+ /* Never miss SIGCHLD. */
+ i = sigemptyset (&sigset);
+ assert (i == 0);
+ i = sigaddset (&sigset, SIGCHLD);
+ assert (i == 0);
+ i = sigprocmask (SIG_BLOCK, &sigset, NULL);
+ assert (i == 0);
+ i = sigemptyset (&sigset);
+ assert (i == 0);
/* We do not use signal(2) to be sure we have SA_RESTART unset. */
memset (&act, 0, sizeof (act));
act.sa_handler = signal_child;
i = sigemptyset (&act.sa_mask);
- if (i != 0)
- {
- perror ("sigemotyset(3)");
- exit (EXIT_FAILURE);
- }
+ assert (i == 0);
act.sa_flags = 0;
i = sigaction (SIGCHLD, &act, NULL);
- if (i != 0)
- {
- perror ("sigaction(2)");
- exit (EXIT_FAILURE);
- }
+ assert (i == 0);
child = forkpty (&amaster, childptyname, NULL, NULL);
switch (child)
perror ("forkpty(3)");
exit (EXIT_FAILURE);
case 0:
+ /* Do not setpgrp(2) in the parent process as the process-group
+ is shared for the whole sh(1) pipeline we could be a part
+ of. The process-group is set according to PID of the first
+ command in the pipeline.
+ We would rip even vi(1) in the case of:
+ ./orphanripper sh -c 'sleep 1&' | vi -
+ */
+ /* Do not setpgrp(2) as our pty would not be ours and we would
+ get `SIGSTOP' later, particularly after spawning gdb(1).
+ setsid(3) was already executed by forkpty(3) and it would fail if
+ executed again. */
+ if (getpid() != getpgrp ())
+ {
+ perror ("getpgrp(2)");
+ exit (EXIT_FAILURE);
+ }
execvp (argv[1], argv + 1);
perror ("execvp(2)");
exit (EXIT_FAILURE);
default:
break;
}
+ i = fcntl (amaster, F_SETFL, O_RDWR | O_NONBLOCK);
+ if (i != 0)
+ {
+ perror ("fcntl (amaster, F_SETFL, O_NONBLOCK)");
+ exit (EXIT_FAILURE);
+ }
for (;;)
{
- buf_got = read (amaster, buf, sizeof buf);
- if (buf_got == -1)
+ struct pollfd pollfd;
+ char buf[LINE_MAX];
+ ssize_t buf_got;
+
+ pollfd.fd = amaster;
+ pollfd.events = POLLIN;
+ i = ppoll (&pollfd, 1, NULL, &sigset);
+ assert (i == -1 || i == 1);
+ if (i == -1)
{
- assert (signal_child_hit != 0);
- assert (errno == EINTR || errno == EIO);
+ assert (errno == EINTR && signal_child_hit != 0);
+ break;
}
- if (buf_got <= 0)
+ /* i == 1 */
+ assert (pollfd.revents != 0);
+ if (pollfd.revents & POLLHUP)
break;
- if (write (STDOUT_FILENO, buf, buf_got) != buf_got)
+ if (pollfd.revents != POLLIN)
{
+ fprintf (stderr, "%s: ppoll(2): revents 0x%x\n", progname,
+ (unsigned) pollfd.revents);
+ exit (EXIT_FAILURE);
+ }
+ buf_got = read (amaster, buf, sizeof buf);
+ if (buf_got == 0)
+ break;
+ if (buf_got == -1)
+ {
+ perror ("read (amaster)");
+ exit (EXIT_FAILURE);
+ }
+ if (write (STDOUT_FILENO, buf, buf_got) != buf_got)
+ {
perror ("write(2)");
exit (EXIT_FAILURE);
}
}
+ /* WNOHANG still could fail. */
child_got = waitpid (child, &status, 0);
if (child != child_got)
{
dir = opendir (dirname);
if (dir == NULL)
{
- if (errno == EACCES)
- return 0;
+ if (errno == EACCES || errno == ENOENT)
+ return 0;
fprintf (stderr, "%s: opendir (\"%s\"): %m\n", progname, dirname);
exit (EXIT_FAILURE);
}
|| (dirent->d_type == DT_LNK && strspn (dirent->d_name, "0123456789")
!= strlen (dirent->d_name)))
{
- fprintf (stderr, "Unexpected entry \"%s\" on readdir (\"%s\"): %m\n",
- dirent->d_name, dirname);
+ /* There is a race, D_TYPE may be uninitialized if stat(2) fails. */
+ if (dirent->d_type != DT_UNKNOWN)
+ fprintf (stderr, "Unexpected entry \"%s\" (d_type %u)"
+ " on readdir (\"%s\"): %m\n",
+ dirent->d_name, (unsigned) dirent->d_type, dirname);
continue;
}
if (dirent->d_type == DT_DIR)
buf_len = readlink (linkname, buf, sizeof buf - 1);
if (buf_len <= 0 || buf_len >= sizeof buf - 1)
{
- fprintf (stderr, "Error reading link \"%s\": %m\n",
- linkname);
+ if (errno != ENOENT && errno != EACCES)
+ fprintf (stderr, "Error reading link \"%s\": %m\n",
+ linkname);
continue;
}
buf[buf_len] = 0;
while (errno = 0, fgets (line, sizeof line, f) == line)
{
if (strncmp (line, "PPid:\t", sizeof "PPid:\t" - 1) != 0)
- continue;
+ continue;
retval = atoi (line + sizeof "PPid:\t" - 1);
errno = 0;
break;
static void rip_pid_fs_scan (pid_t pid, void *data)
{
+ pid_t pgid;
+
/* Shouldn't happen. */
if (pid == getpid ())
return;
- if (fd_fs_scan (pid, rip_check) != 0)
+ /* Check both PGID and the stale file descriptors. */
+ pgid = getpgid (pid);
+ if (pgid == child
+ || fd_fs_scan (pid, rip_check) != 0)
killtree (pid);
}
const char *cmdline;
cmdline = read_cmdline (pid);
+ /* Avoid printing the message for already gone processes. */
if (kill (pid, 0) != 0 && errno == ESRCH)
return;
if (cmdline == NULL)
cmdline = "<error>";
fprintf (stderr, "%s: Killed -9 orphan PID %d: %s\n", progname, (int) pid, cmdline);
- if (kill (pid, SIGKILL)) {
- fprintf (stderr, "%s: kill (%d, SIGKILL): %m\n", progname,
- (int) pid);
- return;
- }
+ if (kill (pid, SIGKILL))
+ {
+ if (errno != ESRCH)
+ fprintf (stderr, "%s: kill (%d, SIGKILL): %m\n", progname, (int) pid);
+ return;
+ }
/* Do not waitpid(2) as it cannot be our direct descendant and it gets
cleaned up by init(8). */
#if 0
git://git.jankratochvil.net / nethome.git / commitdiff