alsactl: Fix the file locking routines (for the state management)

3 files changed, 46 insertions, 20 deletions

diff --git a/alsactl/alsactl.h b/alsactl/alsactl.h
index 76e8c36..bd9bf23 100644
--- a/alsactl/alsactl.h
+++ b/alsactl/alsactl.h
@@ -25,7 +25,8 @@ void dbg_(const char *fcn, long line, const char *fmt, ...);
 #endif	
 
 int init(const char *file, const char *cardname);
-int state_lock(const char *file, int lock, int timeout);
+int state_lock(const char *file, int timeout);
+int state_unlock(int fd, const char *file);
 int save_state(const char *file, const char *cardname);
 int load_state(const char *file, const char *initfile, const char *cardname,
 	       int do_init);
diff --git a/alsactl/lock.c b/alsactl/lock.c
index 6f85f20..9d7efcc 100644
--- a/alsactl/lock.c
+++ b/alsactl/lock.c
@@ -30,7 +30,7 @@
 #include <sys/stat.h>
 #include "alsactl.h"
 
-static int state_lock_(const char *file, int lock, int timeout)
+static int state_lock_(const char *file, int lock, int timeout, int _fd)
 {
 	int fd = -1, err = 0;
 	struct flock lck;
@@ -50,9 +50,14 @@ static int state_lock_(const char *file, int lock, int timeout)
 		snprintf(lcktxt, sizeof(lcktxt), "%10li\n", (long)getpid());
 	} else {
 		snprintf(lcktxt, sizeof(lcktxt), "%10s\n", "");
+		fd = _fd;
 	}
 	while (fd < 0 && timeout-- > 0) {
 		fd = open(nfile, O_RDWR);
+		if (!lock && fd < 0) {
+			err = -EIO;
+			goto out;
+		}
 		if (fd < 0) {
 			fd = open(nfile, O_RDWR|O_CREAT|O_EXCL, 0644);
 			if (fd < 0) {
@@ -74,12 +79,12 @@ static int state_lock_(const char *file, int lock, int timeout)
 		err = -errno;
 		goto out;
 	}
-	if (st.st_size != 11) {
+	if (st.st_size != 11 || !lock) {
 		if (write(fd, lcktxt, 11) != 11) {
 			err = -EIO;
 			goto out;
 		}
-		if (lseek(fd, 0, SEEK_SET)) {
+		if (lock && lseek(fd, 0, SEEK_SET)) {
 			err = -errno;
 			goto out;
 		}
@@ -96,21 +101,37 @@ static int state_lock_(const char *file, int lock, int timeout)
 		err = -EBUSY;
 		goto out;
 	}
-	if (write(fd, lcktxt, 11) != 11) {
-		err = -EIO;
-		goto out;
+	if (lock) {
+		if (write(fd, lcktxt, 11) != 11) {
+			err = -EIO;
+			goto out;
+		}
+		return fd;
 	}
+	err = 0;
+
 out:
+	if (fd >= 0)
+		close(fd);
+	return err;
+}
+
+int state_lock(const char *file, int timeout)
+{
+	int err;
+
+	err = state_lock_(file, 1, timeout, -1);
+	if (err < 0)
+		error("file %s lock error: %s", file, strerror(-err));
 	return err;
 }
 
-int state_lock(const char *file, int lock, int timeout)
+int state_unlock(int _fd, const char *file)
 {
 	int err;
 
-	err = state_lock_(file, lock, timeout);
+	err = state_lock_(file, 0, 10, _fd);
 	if (err < 0)
-		error("file %s %slock error: %s", file,
-				lock ? "" : "un", strerror(-err));
+		error("file %s unlock error: %s", file, strerror(-err));
 	return err;
 }
diff --git a/alsactl/state.c b/alsactl/state.c
index e0c6f2e..0c89703 100644
--- a/alsactl/state.c
+++ b/alsactl/state.c
@@ -1544,6 +1544,7 @@ int save_state(const char *file, const char *cardname)
 	snd_output_t *out;
 	int stdio;
 	char *nfile = NULL;
+	int lock_fd = -EINVAL;
 
 	err = snd_config_top(&config);
 	if (err < 0) {
@@ -1555,12 +1556,16 @@ int save_state(const char *file, const char *cardname)
 		nfile = malloc(strlen(file) + 5);
 		if (nfile == NULL) {
 			error("No enough memory...");
+			err = -ENOMEM;
 			goto out;
 		}
 		strcpy(nfile, file);
 		strcat(nfile, ".new");
-		if (state_lock(file, 1, 10) != 0)
+		lock_fd = state_lock(file, 10);
+		if (lock_fd < 0) {
+			err = lock_fd;
 			goto out;
+		}
 	}
 	if (!stdio && (err = snd_input_stdio_open(&in, file, "r")) >= 0) {
 		err = snd_config_load(config, in);
@@ -1632,8 +1637,8 @@ int save_state(const char *file, const char *cardname)
 			error("rename failed: %s (%s)", strerror(-err), file);
 	}
 out:
-	if (!stdio)
-		state_lock(file, 0, 10);
+	if (!stdio && lock_fd >= 0)
+		state_unlock(lock_fd, file);
 	free(nfile);
 	snd_config_delete(config);
 	snd_config_update_free_global();
@@ -1646,7 +1651,7 @@ int load_state(const char *file, const char *initfile, const char *cardname,
 	int err, finalerr = 0;
 	snd_config_t *config;
 	snd_input_t *in;
-	int stdio, locked = 0;
+	int stdio, lock_fd = -EINVAL;
 
 	err = snd_config_top(&config);
 	if (err < 0) {
@@ -1657,15 +1662,14 @@ int load_state(const char *file, const char *initfile, const char *cardname,
 	if (stdio) {
 		err = snd_input_stdio_attach(&in, stdin, 0);
 	} else {
-		err = state_lock(file, 1, 10);
-		locked = err >= 0;
-		err = err >= 0 ? snd_input_stdio_open(&in, file, "r") : err;
+		lock_fd = state_lock(file, 10);
+		err = lock_fd >= 0 ? snd_input_stdio_open(&in, file, "r") : lock_fd;
 	}
 	if (err >= 0) {
 		err = snd_config_load(config, in);
 		snd_input_close(in);
-		if (locked)
-			state_lock(file, 0, 10);
+		if (lock_fd >= 0)
+			state_unlock(lock_fd, file);
 		if (err < 0) {
 			error("snd_config_load error: %s", snd_strerror(err));
 			goto out;