add a service to reap zombies, use it in SLIRP
SLIRP -smb support wants to fork a process and forget about reaping it.
To please it, add a generic service to register a process id and let
QEMU reap it. In the future it could be enhanced to pass a status,
but this would be unused.
With this in place, the SIGCHLD signal handler would not stomp on pclose
anymore.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/iohandler.c b/iohandler.c
index 2e30fe3..2b82421 100644
--- a/iohandler.c
+++ b/iohandler.c
@@ -27,6 +27,10 @@
#include "qemu-char.h"
#include "qemu-queue.h"
+#ifndef _WIN32
+#include <sys/wait.h>
+#endif
+
typedef struct IOHandlerRecord {
int fd;
IOCanReadHandler *fd_read_poll;
@@ -127,3 +131,63 @@
}
}
}
+
+/* reaping of zombies. right now we're not passing the status to
+ anyone, but it would be possible to add a callback. */
+#ifndef _WIN32
+typedef struct ChildProcessRecord {
+ int pid;
+ QLIST_ENTRY(ChildProcessRecord) next;
+} ChildProcessRecord;
+
+static QLIST_HEAD(, ChildProcessRecord) child_watches =
+ QLIST_HEAD_INITIALIZER(child_watches);
+
+static QEMUBH *sigchld_bh;
+
+static void sigchld_handler(int signal)
+{
+ qemu_bh_schedule(sigchld_bh);
+}
+
+static void sigchld_bh_handler(void *opaque)
+{
+ ChildProcessRecord *rec, *next;
+
+ QLIST_FOREACH_SAFE(rec, &child_watches, next, next) {
+ if (waitpid(rec->pid, NULL, WNOHANG) == rec->pid) {
+ QLIST_REMOVE(rec, next);
+ qemu_free(rec);
+ }
+ }
+}
+
+static void qemu_init_child_watch(void)
+{
+ struct sigaction act;
+ sigchld_bh = qemu_bh_new(sigchld_bh_handler, NULL);
+
+ act.sa_handler = sigchld_handler;
+ act.sa_flags = SA_NOCLDSTOP;
+ sigaction(SIGCHLD, &act, NULL);
+}
+
+int qemu_add_child_watch(pid_t pid)
+{
+ ChildProcessRecord *rec;
+
+ if (!sigchld_bh) {
+ qemu_init_child_watch();
+ }
+
+ QLIST_FOREACH(rec, &child_watches, next) {
+ if (rec->pid == pid) {
+ return 1;
+ }
+ }
+ rec = qemu_mallocz(sizeof(ChildProcessRecord));
+ rec->pid = pid;
+ QLIST_INSERT_HEAD(&child_watches, rec, next);
+ return 0;
+}
+#endif
diff --git a/os-posix.c b/os-posix.c
index eb49e2f..3204197 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -67,11 +67,6 @@
qemu_system_killed(info->si_signo, info->si_pid);
}
-static void sigchld_handler(int signal)
-{
- waitpid(-1, NULL, WNOHANG);
-}
-
void os_setup_signal_handling(void)
{
struct sigaction act;
@@ -82,10 +77,6 @@
sigaction(SIGINT, &act, NULL);
sigaction(SIGHUP, &act, NULL);
sigaction(SIGTERM, &act, NULL);
-
- act.sa_handler = sigchld_handler;
- act.sa_flags = SA_NOCLDSTOP;
- sigaction(SIGCHLD, &act, NULL);
}
/* Find a likely location for support files using the location of the binary.
diff --git a/qemu-common.h b/qemu-common.h
index 665c893..8ecb488 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -214,6 +214,7 @@
void qemu_set_cloexec(int fd);
#ifndef _WIN32
+int qemu_add_child_watch(pid_t pid);
int qemu_eventfd(int pipefd[2]);
int qemu_pipe(int pipefd[2]);
#endif
diff --git a/slirp/misc.c b/slirp/misc.c
index 19dbec4..08eba6a 100644
--- a/slirp/misc.c
+++ b/slirp/misc.c
@@ -119,6 +119,7 @@
char *bptr;
const char *curarg;
int c, i, ret;
+ pid_t pid;
DEBUG_CALL("fork_exec");
DEBUG_ARG("so = %lx", (long)so);
@@ -142,7 +143,8 @@
}
}
- switch(fork()) {
+ pid = fork();
+ switch(pid) {
case -1:
lprint("Error: fork failed: %s\n", strerror(errno));
close(s);
@@ -206,6 +208,7 @@
exit(1);
default:
+ qemu_add_child_watch(pid);
if (do_pty == 2) {
close(s);
so->s = master;
