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/* Copyright (c) 2007-2018 Dovecot authors, see the included COPYING file */
#include "lib.h"
#include "lib-signals.h"
#include "hash.h"
#include "child-wait.h"
#include <sys/wait.h>
struct child_wait {
unsigned int pid_count;
child_wait_callback_t *callback;
void *context;
};
static int child_wait_refcount = 0;
/* pid_t => wait */
static HASH_TABLE(void *, struct child_wait *) child_pids;
static void
sigchld_handler(const siginfo_t *si ATTR_UNUSED, void *context ATTR_UNUSED);
#undef child_wait_new_with_pid
struct child_wait *
child_wait_new_with_pid(pid_t pid, child_wait_callback_t *callback,
void *context)
{
struct child_wait *wait;
wait = i_new(struct child_wait, 1);
wait->callback = callback;
wait->context = context;
if (pid != (pid_t)-1)
child_wait_add_pid(wait, pid);
return wait;
}
void child_wait_free(struct child_wait **_wait)
{
struct child_wait *wait = *_wait;
struct hash_iterate_context *iter;
void *key;
struct child_wait *value;
*_wait = NULL;
if (wait->pid_count > 0) {
/* this should be rare, so iterating hash is fast enough */
iter = hash_table_iterate_init(child_pids);
while (hash_table_iterate(iter, child_pids, &key, &value)) {
if (value == wait) {
hash_table_remove(child_pids, key);
if (--wait->pid_count == 0)
break;
}
}
hash_table_iterate_deinit(&iter);
}
i_free(wait);
}
void child_wait_add_pid(struct child_wait *wait, pid_t pid)
{
wait->pid_count++;
hash_table_insert(child_pids, POINTER_CAST(pid), wait);
lib_signals_set_expected(SIGCHLD, TRUE, sigchld_handler, NULL);
}
void child_wait_remove_pid(struct child_wait *wait, pid_t pid)
{
wait->pid_count--;
hash_table_remove(child_pids, POINTER_CAST(pid));
if (hash_table_count(child_pids) == 0)
lib_signals_set_expected(SIGCHLD, FALSE, sigchld_handler, NULL);
}
static void
sigchld_handler(const siginfo_t *si ATTR_UNUSED, void *context ATTR_UNUSED)
{
struct child_wait_status status;
while ((status.pid = waitpid(-1, &status.status, WNOHANG)) > 0) {
status.wait = hash_table_lookup(child_pids,
POINTER_CAST(status.pid));
if (status.wait != NULL) {
child_wait_remove_pid(status.wait, status.pid);
status.wait->callback(&status, status.wait->context);
}
}
if (status.pid == -1 && errno != EINTR && errno != ECHILD)
i_error("waitpid() failed: %m");
}
void child_wait_switch_ioloop(void)
{
lib_signals_switch_ioloop(SIGCHLD, sigchld_handler, NULL);
}
void child_wait_init(void)
{
if (child_wait_refcount++ > 0) {
child_wait_switch_ioloop();
return;
}
hash_table_create_direct(&child_pids, default_pool, 0);
lib_signals_set_handler(SIGCHLD, LIBSIG_FLAGS_SAFE,
sigchld_handler, NULL);
}
void child_wait_deinit(void)
{
struct hash_iterate_context *iter;
void *key;
struct child_wait *value;
i_assert(child_wait_refcount > 0);
if (--child_wait_refcount > 0) {
child_wait_switch_ioloop();
return;
}
lib_signals_unset_handler(SIGCHLD, sigchld_handler, NULL);
iter = hash_table_iterate_init(child_pids);
while (hash_table_iterate(iter, child_pids, &key, &value))
i_free(value);
hash_table_iterate_deinit(&iter);
hash_table_destroy(&child_pids);
}
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