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core: add nm_utils_kill_child_async() and nm_utils_kill_child_sync() function

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Add utility function to kill and reap a child process.

https://bugzilla.gnome.org/show_bug.cgi?id=725660

Signed-off-by: Thomas Haller <thaller@redhat.com>
This commit is contained in:
Thomas Haller
2014-02-14 12:54:36 +01:00
parent c469e81f96
commit 1f8418541e
5 changed files with 783 additions and 1 deletions
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422
src/NetworkManagerUtils.c
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@@ -26,6 +26,8 @@
#include <unistd.h>
#include <stdlib.h>
#include <resolv.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "NetworkManagerUtils.h"
#include "nm-utils.h"
@@ -144,6 +146,426 @@ nm_spawn_process (const char *args)
return status;
}
/******************************************************************************************/
typedef struct {
pid_t pid;
guint64 log_domain;
union {
struct {
gint64 wait_start_us;
guint source_timeout_kill_id;
} async;
struct {
gboolean success;
int child_status;
} sync;
};
NMUtilsKillChildAsyncCb callback;
void *user_data;
char log_name[1]; /* variable-length object, must be last element!! */
} KillChildAsyncData;
#define LOG_NAME_FMT "kill child process '%s' (%ld)"
#define LOG_NAME_ARGS log_name,(long)pid
static KillChildAsyncData *
_kc_async_data_alloc (pid_t pid, guint64 log_domain, const char *log_name, NMUtilsKillChildAsyncCb callback, void *user_data)
{
KillChildAsyncData *data;
size_t log_name_len;
/* append the name at the end of our KillChildAsyncData. */
log_name_len = strlen (LOG_NAME_FMT) + 20 + strlen (log_name);
data = g_malloc (sizeof (KillChildAsyncData) - 1 + log_name_len);
g_snprintf (data->log_name, log_name_len, LOG_NAME_FMT, LOG_NAME_ARGS);
data->pid = pid;
data->user_data = user_data;
data->callback = callback;
data->log_domain = log_domain;
return data;
}
#define KC_EXIT_TO_STRING_BUF_SIZE 128
static const char *
_kc_exit_to_string (char *buf, int exit)
#define _kc_exit_to_string(buf, exit) ( G_STATIC_ASSERT_EXPR(sizeof (buf) == KC_EXIT_TO_STRING_BUF_SIZE && sizeof ((buf)[0]) == 1), _kc_exit_to_string (buf, exit) )
{
if (WIFEXITED (exit))
g_snprintf (buf, KC_EXIT_TO_STRING_BUF_SIZE, "normally with status %d", WEXITSTATUS (exit));
else if (WIFSIGNALED (exit))
g_snprintf (buf, KC_EXIT_TO_STRING_BUF_SIZE, "by signal %d", WTERMSIG (exit));
else
g_snprintf (buf, KC_EXIT_TO_STRING_BUF_SIZE, "with unexpected status %d", exit);
return buf;
}
static const char *
_kc_signal_to_string (int sig)
{
switch (sig) {
case 0: return "no signal (0)";
case SIGKILL: return "SIGKILL (" G_STRINGIFY (SIGKILL) ")";
case SIGTERM: return "SIGTERM (" G_STRINGIFY (SIGTERM) ")";
default:
return "Unexpected signal";
}
}
#define KC_WAITED_TO_STRING 100
static const char *
_kc_waited_to_string (char *buf, gint64 wait_start_us)
#define _kc_waited_to_string(buf, wait_start_us) ( G_STATIC_ASSERT_EXPR(sizeof (buf) == KC_WAITED_TO_STRING && sizeof ((buf)[0]) == 1), _kc_waited_to_string (buf, wait_start_us) )
{
g_snprintf (buf, KC_WAITED_TO_STRING, " (%ld usec elapsed)", (long) (nm_utils_get_monotonic_timestamp_us () - wait_start_us));
return buf;
}
static void
_kc_cb_watch_child (GPid pid, gint status, gpointer user_data)
{
KillChildAsyncData *data = user_data;
char buf_exit[KC_EXIT_TO_STRING_BUF_SIZE], buf_wait[KC_WAITED_TO_STRING];
if (data->async.source_timeout_kill_id)
g_source_remove (data->async.source_timeout_kill_id);
nm_log_dbg (data->log_domain, "%s: terminated %s%s",
data->log_name, _kc_exit_to_string (buf_exit, status),
_kc_waited_to_string (buf_wait, data->async.wait_start_us));
if (data->callback)
data->callback (pid, TRUE, status, data->user_data);
g_free (data);
}
static gboolean
_kc_cb_timeout_grace_period (void *user_data)
{
KillChildAsyncData *data = user_data;
int ret, errsv;
data->async.source_timeout_kill_id = 0;
if ((ret = kill (data->pid, SIGKILL)) != 0) {
errsv = errno;
/* ESRCH means, process does not exist or is already a zombie. */
if (errsv != ESRCH) {
nm_log_err (LOGD_CORE | data->log_domain, "%s: kill(SIGKILL) returned unexpected return value %d: (%s, %d)",
data->log_name, ret, strerror (errsv), errsv);
}
} else {
nm_log_dbg (data->log_domain, "%s: process not terminated after %ld usec. Sending SIGKILL signal",
data->log_name, (long) (nm_utils_get_monotonic_timestamp_us () - data->async.wait_start_us));
}
return G_SOURCE_REMOVE;
}
static gboolean
_kc_invoke_callback_idle (gpointer user_data)
{
KillChildAsyncData *data = user_data;
if (data->sync.success) {
char buf_exit[KC_EXIT_TO_STRING_BUF_SIZE];
nm_log_dbg (data->log_domain, "%s: invoke callback: terminated %s",
data->log_name, _kc_exit_to_string (buf_exit, data->sync.child_status));
} else
nm_log_dbg (data->log_domain, "%s: invoke callback: killing child failed", data->log_name);
data->callback (data->pid, data->sync.success, data->sync.child_status, data->user_data);
g_free (data);
return G_SOURCE_REMOVE;
}
static void
_kc_invoke_callback (pid_t pid, guint64 log_domain, const char *log_name, NMUtilsKillChildAsyncCb callback, void *user_data, gboolean success, int child_status)
{
KillChildAsyncData *data;
if (!callback)
return;
data = _kc_async_data_alloc (pid, log_domain, log_name, callback, user_data);
data->sync.success = success;
data->sync.child_status = child_status;
g_idle_add (_kc_invoke_callback_idle, data);
}
/* nm_utils_kill_child_async:
* @pid: the process id of the process to kill
* @sig: signal to send initially. Set to 0 to send not signal.
* @log_domain: the logging domain used for logging (LOGD_NONE to suppress logging)
* @log_name: (allow-none): for logging, the name of the processes to kill
* @wait_before_kill_msec: Waittime in milliseconds before sending %SIGKILL signal. Set this value
* to zero, not to send %SIGKILL. If @sig is already %SIGKILL, this parameter is ignored.
* @callback: (allow-none): callback after the child terminated. This function will always
* be invoked asynchronously.
* @user_data: passed on to callback
*
* Uses g_child_watch_add(), so note the glib comment: if you obtain pid from g_spawn_async() or
* g_spawn_async_with_pipes() you will need to pass %G_SPAWN_DO_NOT_REAP_CHILD as flag to the spawn
* function for the child watching to work.
* Also note, that you must g_source_remove() any other child watchers for @pid because glib
* supports only one watcher per child.
**/
void
nm_utils_kill_child_async (pid_t pid, int sig, guint64 log_domain,
const char *log_name, guint32 wait_before_kill_msec,
NMUtilsKillChildAsyncCb callback, void *user_data)
{
int status = 0, errsv;
pid_t ret;
KillChildAsyncData *data;
char buf_exit[KC_EXIT_TO_STRING_BUF_SIZE];
g_return_if_fail (pid > 0);
g_return_if_fail (log_name != NULL);
/* let's see if the child already terminated... */
ret = waitpid (pid, &status, WNOHANG);
if (ret > 0) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": process %ld already terminated %s",
LOG_NAME_ARGS, (long) ret, _kc_exit_to_string (buf_exit, status));
_kc_invoke_callback (pid, log_domain, log_name, callback, user_data, TRUE, status);
return;
} else if (ret != 0) {
errsv = errno;
/* ECHILD means, the process is not a child/does not exist or it has SIGCHILD blocked. */
if (errsv != ECHILD) {
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": unexpected error while waitpid: %s (%d)",
LOG_NAME_ARGS, strerror (errsv), errsv);
_kc_invoke_callback (pid, log_domain, log_name, callback, user_data, FALSE, -1);
return;
}
}
/* send the first signal. */
if (kill (pid, sig) != 0) {
errsv = errno;
/* ESRCH means, process does not exist or is already a zombie. */
if (errsv != ESRCH) {
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": unexpected error sending %s: %s (%d)",
LOG_NAME_ARGS, _kc_signal_to_string (sig), strerror (errsv), errsv);
_kc_invoke_callback (pid, log_domain, log_name, callback, user_data, FALSE, -1);
return;
}
/* let's try again with waitpid, probably there was a race... */
ret = waitpid (pid, &status, 0);
if (ret > 0) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": process %ld already terminated %s",
LOG_NAME_ARGS, (long) ret, _kc_exit_to_string (buf_exit, status));
_kc_invoke_callback (pid, log_domain, log_name, callback, user_data, TRUE, status);
} else {
errsv = errno;
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": failed due to unexpected return value %ld by waitpid (%s, %d) after sending %s",
LOG_NAME_ARGS, (long) ret, strerror (errsv), errsv, _kc_signal_to_string (sig));
_kc_invoke_callback (pid, log_domain, log_name, callback, user_data, FALSE, -1);
}
return;
}
data = _kc_async_data_alloc (pid, log_domain, log_name, callback, user_data);
data->async.wait_start_us = nm_utils_get_monotonic_timestamp_us ();
if (sig != SIGKILL && wait_before_kill_msec > 0) {
data->async.source_timeout_kill_id = g_timeout_add (wait_before_kill_msec, _kc_cb_timeout_grace_period, data);
nm_log_dbg (log_domain, "%s: wait for process to terminate after sending %s (send SIGKILL in %ld milliseconds)...",
data->log_name, _kc_signal_to_string (sig), (long) wait_before_kill_msec);
} else {
data->async.source_timeout_kill_id = 0;
nm_log_dbg (log_domain, "%s: wait for process to terminate after sending %s...",
data->log_name, _kc_signal_to_string (sig));
}
g_child_watch_add (pid, _kc_cb_watch_child, data);
}
/* nm_utils_kill_child_sync:
* @pid: process id to kill
* @sig: signal to sent initially. If 0, no signal is sent. If %SIGKILL, the
* second %SIGKILL signal is not sent after @wait_before_kill_msec milliseconds.
* @log_domain: log debug information for this domain. Errors and warnings are logged both
* as %LOGD_CORE and @log_domain.
* @log_name: (allow-none): name of the process to kill for logging.
* @child_status: (out) (allow-none): return the exit status of the child, if no error occured.
* @wait_before_kill_msec: Waittime in milliseconds before sending %SIGKILL signal. Set this value
* to zero, not to send %SIGKILL. If @sig is already %SIGKILL, this parameter has not effect.
* @sleep_duration_msec: the synchronous function sleeps repeatedly waiting for the child to terminate.
* Set to zero, to use the default (meaning 20 wakeups per seconds).
*
* Kill a child process synchronously and wait. The function first checks if the child already terminated
* and if it did, return the exit status. Otherwise send one @sig signal. @sig will always be
* sent unless the child already exited. If the child does not exit within @wait_before_kill_msec milliseconds,
* the function will send %SIGKILL and waits for the child indefinitly. If @wait_before_kill_msec is zero, no
* %SIGKILL signal will be sent.
**/
gboolean
nm_utils_kill_child_sync (pid_t pid, int sig, guint64 log_domain, const char *log_name,
int *child_status, guint32 wait_before_kill_msec,
guint32 sleep_duration_msec)
{
int status = 0, errsv;
pid_t ret;
gboolean success = FALSE;
gboolean was_waiting = FALSE, send_kill = FALSE;
char buf_exit[KC_EXIT_TO_STRING_BUF_SIZE];
char buf_wait[KC_WAITED_TO_STRING];
gint64 wait_start_us;
g_return_val_if_fail (pid > 0, FALSE);
g_return_val_if_fail (log_name != NULL, FALSE);
/* check if the child process already terminated... */
ret = waitpid (pid, &status, WNOHANG);
if (ret > 0) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": process %ld already terminated %s",
LOG_NAME_ARGS, (long) ret, _kc_exit_to_string (buf_exit, status));
success = TRUE;
goto out;
} else if (ret != 0) {
errsv = errno;
/* ECHILD means, the process is not a child/does not exist or it has SIGCHILD blocked. */
if (errsv != ECHILD) {
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": unexpected error while waitpid: %s (%d)",
LOG_NAME_ARGS, strerror (errsv), errsv);
goto out;
}
}
/* send first signal @sig */
if (kill (pid, sig) != 0) {
errsv = errno;
/* ESRCH means, process does not exist or is already a zombie. */
if (errsv != ESRCH) {
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": failed to send %s: %s (%d)",
LOG_NAME_ARGS, _kc_signal_to_string (sig), strerror (errsv), errsv);
} else {
/* let's try again with waitpid, probably there was a race... */
ret = waitpid (pid, &status, 0);
if (ret > 0) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": process %ld already terminated %s",
LOG_NAME_ARGS, (long) ret, _kc_exit_to_string (buf_exit, status));
success = TRUE;
} else {
errsv = errno;
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": failed due to unexpected return value %ld by waitpid (%s, %d) after sending %s",
LOG_NAME_ARGS, (long) ret, strerror (errsv), errsv, _kc_signal_to_string (sig));
}
}
goto out;
}
wait_start_us = nm_utils_get_monotonic_timestamp_us ();
/* wait for the process to terminated... */
if (sig != SIGKILL) {
gint64 wait_until, now;
gulong sleep_time, sleep_duration_usec;
int loop_count = 0;
sleep_duration_usec = (sleep_duration_msec <= 0) ? (G_USEC_PER_SEC / 20) : MIN (G_MAXULONG, ((gint64) sleep_duration_msec) * 1000L);
wait_until = wait_before_kill_msec <= 0 ? 0 : wait_start_us + (((gint64) wait_before_kill_msec) * 1000L);
while (TRUE) {
ret = waitpid (pid, &status, WNOHANG);
if (ret > 0) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": after sending %s, process %ld exited %s%s",
LOG_NAME_ARGS, _kc_signal_to_string (sig), (long) ret, _kc_exit_to_string (buf_exit, status),
was_waiting ? _kc_waited_to_string (buf_wait, wait_start_us) : "");
success = TRUE;
goto out;
}
if (ret == -1) {
errsv = errno;
/* ECHILD means, the process is not a child/does not exist or it has SIGCHILD blocked. */
if (errsv != ECHILD) {
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": after sending %s, waitpid failed with %s (%d)%s",
LOG_NAME_ARGS, _kc_signal_to_string (sig), strerror (errsv), errsv,
was_waiting ? _kc_waited_to_string (buf_wait, wait_start_us) : "");
goto out;
}
}
if (!wait_until)
break;
now = nm_utils_get_monotonic_timestamp_us ();
if (now >= wait_until)
break;
if (!was_waiting) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": waiting up to %ld milliseconds for process to terminate normally after sending %s...",
LOG_NAME_ARGS, (long) MAX (wait_before_kill_msec, 0), _kc_signal_to_string (sig));
was_waiting = TRUE;
}
sleep_time = MIN (wait_until - now, sleep_duration_usec);
if (loop_count < 20) {
/* At the beginning we expect the process to die fast.
* Limit the sleep time, the limit doubles with every iteration. */
sleep_time = MIN (sleep_time, (((guint64) 1) << loop_count++) * G_USEC_PER_SEC / 2000);
}
g_usleep (sleep_time);
}
/* send SIGKILL, if called with @wait_before_kill_msec > 0 */
if (wait_until) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": sending SIGKILL...", LOG_NAME_ARGS);
send_kill = TRUE;
if (kill (pid, SIGKILL) != 0) {
errsv = errno;
/* ESRCH means, process does not exist or is already a zombie. */
if (errsv != ESRCH) {
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": failed to send SIGKILL (after sending %s), %s (%d)",
LOG_NAME_ARGS, _kc_signal_to_string (sig), strerror (errsv), errsv);
goto out;
}
}
}
}
if (!was_waiting) {
nm_log_dbg (log_domain, LOG_NAME_FMT ": waiting for process to terminate after sending %s%s...",
LOG_NAME_ARGS, _kc_signal_to_string (sig), send_kill ? " and SIGKILL" : "");
}
/* block until the child terminates. */
while ((ret = waitpid (pid, &status, 0)) <= 0) {
errsv = errno;
if (errsv != EINTR) {
nm_log_err (LOGD_CORE | log_domain, LOG_NAME_FMT ": after sending %s%s, waitpid failed with %s (%d)%s",
LOG_NAME_ARGS, _kc_signal_to_string (sig), send_kill ? " and SIGKILL" : "", strerror (errsv), errsv,
_kc_waited_to_string (buf_wait, wait_start_us));
goto out;
}
}
nm_log_dbg (log_domain, LOG_NAME_FMT ": after sending %s%s, process %ld exited %s%s",
LOG_NAME_ARGS, _kc_signal_to_string (sig), send_kill ? " and SIGKILL" : "", (long) ret,
_kc_exit_to_string (buf_exit, status), _kc_waited_to_string (buf_wait, wait_start_us));
success = TRUE;
out:
if (child_status)
*child_status = success ? status : -1;
return success;
}
#undef LOG_NAME_FMT
#undef LOG_NAME_ARGS
/******************************************************************************************/
gboolean
nm_match_spec_string (const GSList *specs, const char *match)
{