From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42635) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fLi2u-0003Wb-T4 for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fLi2t-000060-Em for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:12 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:34352 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fLi2t-00005q-9g for qemu-devel@nongnu.org; Thu, 24 May 2018 00:40:11 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DF6F140BC049 for ; Thu, 24 May 2018 04:40:10 +0000 (UTC) From: Peter Xu Date: Thu, 24 May 2018 12:39:52 +0800 Message-Id: <20180524043952.11245-5-peterx@redhat.com> In-Reply-To: <20180524043952.11245-1-peterx@redhat.com> References: <20180524043952.11245-1-peterx@redhat.com> Subject: [Qemu-devel] [PATCH v7 4/4] monitor: add lock to protect mon_fdsets List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Eric Blake , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Markus Armbruster , Stefan Hajnoczi , "Dr . David Alan Gilbert" , peterx@redhat.com 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. To make things simpler, we let monitor_fdset_get_fd() return the -errno directly when error happens, then in qemu_open() we translate it back into errno. Signed-off-by: Peter Xu --- monitor.c | 70 +++++++++++++++++++++++++++++++++++++++++----------- util/osdep.c | 3 ++- 2 files changed, 58 insertions(+), 15 deletions(-) diff --git a/monitor.c b/monitor.c index f01589f945..6266ff65c4 100644 --- a/monitor.c +++ b/monitor.c @@ -271,6 +271,9 @@ 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; @@ -287,6 +290,16 @@ 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? */ @@ -2316,9 +2329,11 @@ 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, @@ -2353,6 +2368,7 @@ 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; @@ -2372,10 +2388,12 @@ 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); @@ -2391,6 +2409,7 @@ 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; @@ -2420,6 +2439,7 @@ FdsetInfoList *qmp_query_fdsets(Error **errp) fdset_info->next = fdset_list; fdset_list = fdset_info; } + qemu_mutex_unlock(&mon_fdsets_lock); return fdset_list; } @@ -2432,6 +2452,7 @@ 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 */ @@ -2452,6 +2473,7 @@ 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 */ @@ -2502,16 +2524,21 @@ 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 + return -ENOENT; +#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; @@ -2519,49 +2546,60 @@ 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); + 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) { @@ -2570,14 +2608,18 @@ 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) diff --git a/util/osdep.c b/util/osdep.c index a73de0e1ba..ea51d500b6 100644 --- a/util/osdep.c +++ b/util/osdep.c @@ -302,7 +302,8 @@ int qemu_open(const char *name, int flags, ...) } fd = monitor_fdset_get_fd(fdset_id, flags); - if (fd == -1) { + if (fd < 0) { + errno = -fd; return -1; } -- 2.17.0