util: Pre-allocate buffer for ovs_lasterror_to_string().

[sliver-openvswitch.git] / lib / lockfile.c

diff --git a/lib/lockfile.c b/lib/lockfile.c
index 50a4e0c..779b74e 100644 (file)
--- a/lib/lockfile.c
+++ b/lib/lockfile.c
@@ -35,7 +35,6 @@
 VLOG_DEFINE_THIS_MODULE(lockfile);
 
 COVERAGE_DEFINE(lockfile_lock);
-COVERAGE_DEFINE(lockfile_timeout);
 COVERAGE_DEFINE(lockfile_error);
 COVERAGE_DEFINE(lockfile_unlock);
 
@@ -45,6 +44,7 @@ struct lockfile {
     dev_t device;
     ino_t inode;
     int fd;
+    HANDLE lock_handle;
 };
 
 /* Lock table.
@@ -53,14 +53,20 @@ struct lockfile {
  * descriptor for a file on which a process holds a lock drops *all* locks on
  * that file.  That means that we can't afford to open a lockfile more than
  * once. */
-static struct hmap lock_table = HMAP_INITIALIZER(&lock_table);
-
-/* Protects 'lock_table'. */
-static pthread_mutex_t lock_table_mutex = PTHREAD_MUTEX_INITIALIZER;
+static struct ovs_mutex lock_table_mutex = OVS_MUTEX_INITIALIZER;
+static struct hmap lock_table__ = HMAP_INITIALIZER(&lock_table__);
+static struct hmap *const lock_table OVS_GUARDED_BY(lock_table_mutex)
+    = &lock_table__;
 
 static void lockfile_unhash(struct lockfile *);
-static int lockfile_try_lock(const char *name, pid_t *pidp,
-                             struct lockfile **lockfilep);
+#ifdef _WIN32
+static int lockfile_try_lock_windows(const char *name, pid_t *pidp,
+                                     struct lockfile **lockfilep);
+static void lockfile_unlock_windows(struct lockfile * lockfile);
+#else
+static int lockfile_try_lock_posix(const char *name, pid_t *pidp,
+                                   struct lockfile **lockfilep);
+#endif
 
 /* Returns the name of the lockfile that would be created for locking a file
  * named 'filename_'.  The caller is responsible for freeing the returned name,
@@ -110,9 +116,13 @@ lockfile_lock(const char *file, struct lockfile **lockfilep)
 
     lock_name = lockfile_name(file);
 
-    xpthread_mutex_lock(&lock_table_mutex);
-    error = lockfile_try_lock(lock_name, &pid, lockfilep);
-    xpthread_mutex_unlock(&lock_table_mutex);
+    ovs_mutex_lock(&lock_table_mutex);
+#ifdef _WIN32
+    error = lockfile_try_lock_windows(lock_name, &pid, lockfilep);
+#else
+    error = lockfile_try_lock_posix(lock_name, &pid, lockfilep);
+#endif
+    ovs_mutex_unlock(&lock_table_mutex);
 
     if (error) {
         COVERAGE_INC(lockfile_error);
@@ -138,9 +148,13 @@ void
 lockfile_unlock(struct lockfile *lockfile)
 {
     if (lockfile) {
-        xpthread_mutex_lock(&lock_table_mutex);
+        ovs_mutex_lock(&lock_table_mutex);
+#ifdef _WIN32
+        lockfile_unlock_windows(lockfile);
+#else
         lockfile_unhash(lockfile);
-        xpthread_mutex_unlock(&lock_table_mutex);
+#endif
+        ovs_mutex_unlock(&lock_table_mutex);
 
         COVERAGE_INC(lockfile_unlock);
         free(lockfile->name);
@@ -156,12 +170,14 @@ lockfile_postfork(void)
 {
     struct lockfile *lockfile;
 
-    HMAP_FOR_EACH (lockfile, hmap_node, &lock_table) {
+    ovs_mutex_lock(&lock_table_mutex);
+    HMAP_FOR_EACH (lockfile, hmap_node, lock_table) {
         if (lockfile->fd >= 0) {
             VLOG_WARN("%s: child does not inherit lock", lockfile->name);
             lockfile_unhash(lockfile);
         }
     }
+    ovs_mutex_unlock(&lock_table_mutex);
 }
 \f
 static uint32_t
@@ -172,12 +188,12 @@ lockfile_hash(dev_t device, ino_t inode)
 }
 
 static struct lockfile *
-lockfile_find(dev_t device, ino_t inode)
+lockfile_find(dev_t device, ino_t inode) OVS_REQUIRES(&lock_table_mutex)
 {
     struct lockfile *lockfile;
 
     HMAP_FOR_EACH_WITH_HASH (lockfile, hmap_node,
-                             lockfile_hash(device, inode), &lock_table) {
+                             lockfile_hash(device, inode), lock_table) {
         if (lockfile->device == device && lockfile->inode == inode) {
             return lockfile;
         }
@@ -186,17 +202,18 @@ lockfile_find(dev_t device, ino_t inode)
 }
 
 static void
-lockfile_unhash(struct lockfile *lockfile)
+lockfile_unhash(struct lockfile *lockfile) OVS_REQUIRES(&lock_table_mutex)
 {
     if (lockfile->fd >= 0) {
         close(lockfile->fd);
         lockfile->fd = -1;
-        hmap_remove(&lock_table, &lockfile->hmap_node);
+        hmap_remove(lock_table, &lockfile->hmap_node);
     }
 }
 
 static struct lockfile *
 lockfile_register(const char *name, dev_t device, ino_t inode, int fd)
+    OVS_REQUIRES(&lock_table_mutex)
 {
     struct lockfile *lockfile;
 
@@ -211,13 +228,82 @@ lockfile_register(const char *name, dev_t device, ino_t inode, int fd)
     lockfile->device = device;
     lockfile->inode = inode;
     lockfile->fd = fd;
-    hmap_insert(&lock_table, &lockfile->hmap_node,
+    hmap_insert(lock_table, &lockfile->hmap_node,
                 lockfile_hash(device, inode));
     return lockfile;
 }
 
+#ifdef _WIN32
+static void
+lockfile_unlock_windows(struct lockfile *lockfile)
+    OVS_REQUIRES(&lock_table_mutex)
+{
+    if (lockfile->fd >= 0) {
+        OVERLAPPED overl;
+        overl.hEvent = 0;
+        overl.Offset = 0;
+        overl.OffsetHigh = 0;
+        UnlockFileEx(lockfile->lock_handle, 0, 1, 0, &overl);
+
+        close(lockfile->fd);
+        lockfile->fd = -1;
+    }
+}
+
 static int
-lockfile_try_lock(const char *name, pid_t *pidp, struct lockfile **lockfilep)
+lockfile_try_lock_windows(const char *name, pid_t *pidp,
+                          struct lockfile **lockfilep)
+    OVS_REQUIRES(&lock_table_mutex)
+{
+    HANDLE lock_handle;
+    BOOL retval;
+    OVERLAPPED overl;
+    struct lockfile *lockfile;
+    int fd;
+
+    *pidp = 0;
+
+    fd = open(name, O_RDWR | O_CREAT, 0600);
+    if (fd < 0) {
+        VLOG_WARN("%s: failed to open lock file: %s",
+                   name, ovs_strerror(errno));
+        return errno;
+    }
+
+    lock_handle = (HANDLE)_get_osfhandle(fd);
+    if (lock_handle < 0) {
+        VLOG_WARN("%s: failed to get the file handle: %s",
+                   name, ovs_strerror(errno));
+        return errno;
+    }
+
+    /* Lock the file 'name' for the region that includes just the first
+     * byte. */
+    overl.hEvent = 0;
+    overl.Offset = 0;
+    overl.OffsetHigh = 0;
+    retval = LockFileEx(lock_handle, LOCKFILE_EXCLUSIVE_LOCK
+                        | LOCKFILE_FAIL_IMMEDIATELY, 0, 1, 0, &overl);
+    if (!retval) {
+        VLOG_WARN("Failed to lock file : %s", ovs_lasterror_to_string());
+        return EEXIST;
+    }
+
+    lockfile = xmalloc(sizeof *lockfile);
+    lockfile->name = xstrdup(name);
+    lockfile->fd = fd;
+    lockfile->lock_handle = lock_handle;
+
+    *lockfilep = lockfile;
+    return 0;
+}
+#endif
+
+#ifndef _WIN32
+static int
+lockfile_try_lock_posix(const char *name, pid_t *pidp,
+                        struct lockfile **lockfilep)
+    OVS_REQUIRES(&lock_table_mutex)
 {
     struct flock l;
     struct stat s;
@@ -273,4 +359,4 @@ lockfile_try_lock(const char *name, pid_t *pidp, struct lockfile **lockfilep)
     }
     return error;
 }
-
+#endif