Similar to previous patch, but introduce a new global big lock for
mon_fdsets. Take it where needed.
The monitor_fdset_get_fd() handling is a bit tricky: now we need to call
qemu_mutex_unlock() which might pollute errno, so we need to make sure
the correct errno be passed up to the callers.
Signed-off-by: Peter Xu <pet...@redhat.com>
---
monitor.c | 79 +++++++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 65 insertions(+), 14 deletions(-)
diff --git a/monitor.c b/monitor.c
index 696109acb4..84064a0b89 100644
--- a/monitor.c
+++ b/monitor.c
@@ -269,6 +269,9 @@ typedef struct QMPRequest QMPRequest;
/* Protects mon_list, monitor_event_state. */
static QemuMutex monitor_lock;
+/* Protects mon_fdsets */
+static QemuMutex mon_fdsets_lock;
+
static QTAILQ_HEAD(mon_list, Monitor) mon_list;
static QLIST_HEAD(mon_fdsets, MonFdset) mon_fdsets;
static int mon_refcount;
@@ -285,6 +288,16 @@ static QEMUClockType event_clock_type =
QEMU_CLOCK_REALTIME;
static void monitor_command_cb(void *opaque, const char *cmdline,
void *readline_opaque);
+/*
+ * This lock can be used very early, even during param parsing.
+ * Meanwhile it can also be used even at the end of main. Let's keep
+ * it initialized for the whole lifecycle of QEMU.
+ */
+static void __attribute__((constructor)) mon_fdsets_lock_init(void)
+{
+ qemu_mutex_init(&mon_fdsets_lock);
+}
+
/**
* Is @mon a QMP monitor?
*/
@@ -2314,9 +2327,11 @@ static void monitor_fdsets_cleanup(void)
MonFdset *mon_fdset;
MonFdset *mon_fdset_next;
+ qemu_mutex_lock(&mon_fdsets_lock);
QLIST_FOREACH_SAFE(mon_fdset, &mon_fdsets, next, mon_fdset_next) {
monitor_fdset_cleanup(mon_fdset);
}
+ qemu_mutex_unlock(&mon_fdsets_lock);
}
AddfdInfo *qmp_add_fd(bool has_fdset_id, int64_t fdset_id, bool has_opaque,
@@ -2351,6 +2366,7 @@ void qmp_remove_fd(int64_t fdset_id, bool has_fd, int64_t
fd, Error **errp)
MonFdsetFd *mon_fdset_fd;
char fd_str[60];
+ qemu_mutex_lock(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
if (mon_fdset->id != fdset_id) {
continue;
@@ -2370,10 +2386,12 @@ void qmp_remove_fd(int64_t fdset_id, bool has_fd,
int64_t fd, Error **errp)
goto error;
}
monitor_fdset_cleanup(mon_fdset);
+ qemu_mutex_unlock(&mon_fdsets_lock);
return;
}
error:
+ qemu_mutex_unlock(&mon_fdsets_lock);
if (has_fd) {
snprintf(fd_str, sizeof(fd_str), "fdset-id:%" PRId64 ", fd:%" PRId64,
fdset_id, fd);
@@ -2389,6 +2407,7 @@ FdsetInfoList *qmp_query_fdsets(Error **errp)
MonFdsetFd *mon_fdset_fd;
FdsetInfoList *fdset_list = NULL;
+ qemu_mutex_lock(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
FdsetInfoList *fdset_info = g_malloc0(sizeof(*fdset_info));
FdsetFdInfoList *fdsetfd_list = NULL;
@@ -2418,6 +2437,7 @@ FdsetInfoList *qmp_query_fdsets(Error **errp)
fdset_info->next = fdset_list;
fdset_list = fdset_info;
}
+ qemu_mutex_unlock(&mon_fdsets_lock);
return fdset_list;
}
@@ -2430,6 +2450,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool
has_fdset_id, int64_t fdset_id,
MonFdsetFd *mon_fdset_fd;
AddfdInfo *fdinfo;
+ qemu_mutex_lock(&mon_fdsets_lock);
if (has_fdset_id) {
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
/* Break if match found or match impossible due to ordering by ID
*/
@@ -2450,6 +2471,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool
has_fdset_id, int64_t fdset_id,
if (fdset_id < 0) {
error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "fdset-id",
"a non-negative value");
+ qemu_mutex_unlock(&mon_fdsets_lock);
return NULL;
}
/* Use specified fdset ID */
@@ -2500,16 +2522,22 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool
has_fdset_id, int64_t fdset_id,
fdinfo->fdset_id = mon_fdset->id;
fdinfo->fd = mon_fdset_fd->fd;
+ qemu_mutex_unlock(&mon_fdsets_lock);
return fdinfo;
}
int monitor_fdset_get_fd(int64_t fdset_id, int flags)
{
-#ifndef _WIN32
+#ifdef _WIN32
+ errno = ENOENT;
+ return -1;
+#else
MonFdset *mon_fdset;
MonFdsetFd *mon_fdset_fd;
int mon_fd_flags;
+ int ret = -ENOENT;
+ qemu_mutex_lock(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
if (mon_fdset->id != fdset_id) {
continue;
@@ -2517,49 +2545,68 @@ int monitor_fdset_get_fd(int64_t fdset_id, int flags)
QLIST_FOREACH(mon_fdset_fd, &mon_fdset->fds, next) {
mon_fd_flags = fcntl(mon_fdset_fd->fd, F_GETFL);
if (mon_fd_flags == -1) {
- return -1;
+ ret = -errno;
+ goto out;
}
if ((flags & O_ACCMODE) == (mon_fd_flags & O_ACCMODE)) {
- return mon_fdset_fd->fd;
+ ret = mon_fdset_fd->fd;
+ goto out;
}
}
- errno = EACCES;
- return -1;
+ ret = -EACCES;
+ break;
+ }
+out:
+ qemu_mutex_unlock(&mon_fdsets_lock);
+ /*
+ * qemu_mutex_unlock might pollute errno, so we translate the
+ * "ret" value into errno if error happened.
+ */
+ if (ret < 0) {
+ errno = -ret;
+ ret = -1;
}
+ return ret;
#endif
-
- errno = ENOENT;
- return -1;
}
int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd)
{
MonFdset *mon_fdset;
MonFdsetFd *mon_fdset_fd_dup;
+ int ret = -1;
+ qemu_mutex_lock(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
if (mon_fdset->id != fdset_id) {
continue;
}
QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) {
if (mon_fdset_fd_dup->fd == dup_fd) {
- return -1;
+ ret = -1;
+ goto out;
}
}
mon_fdset_fd_dup = g_malloc0(sizeof(*mon_fdset_fd_dup));
mon_fdset_fd_dup->fd = dup_fd;
QLIST_INSERT_HEAD(&mon_fdset->dup_fds, mon_fdset_fd_dup, next);
- return 0;
+ ret = 0;
+ break;
}
- return -1;
+
+out:
+ qemu_mutex_unlock(&mon_fdsets_lock);
+ return ret;
}
static int monitor_fdset_dup_fd_find_remove(int dup_fd, bool remove)
{
MonFdset *mon_fdset;
MonFdsetFd *mon_fdset_fd_dup;
+ int ret = -1;
+ qemu_mutex_lock(&mon_fdsets_lock);
QLIST_FOREACH(mon_fdset, &mon_fdsets, next) {
QLIST_FOREACH(mon_fdset_fd_dup, &mon_fdset->dup_fds, next) {
if (mon_fdset_fd_dup->fd == dup_fd) {
@@ -2568,14 +2615,18 @@ static int monitor_fdset_dup_fd_find_remove(int dup_fd,
bool remove)
if (QLIST_EMPTY(&mon_fdset->dup_fds)) {
monitor_fdset_cleanup(mon_fdset);
}
- return -1;
+ ret = -1;
+ goto out;
} else {
- return mon_fdset->id;
+ ret = mon_fdset->id;
+ goto out;
}
}
}
}
- return -1;
+out:
+ qemu_mutex_unlock(&mon_fdsets_lock);
+ return ret;
}
int monitor_fdset_dup_fd_find(int dup_fd)
--
2.17.0
