create a new lxc_check_lock function

src/lxc/checkpoint.c

@@ -46,30 +46,25 @@ lxc_log_define(lxc_checkpoint, lxc);
 
 #define MAXPIDLEN 20
 
-int lxc_checkpoint(const char *name, const char *statefile, 
+int lxc_checkpoint(const char *name, const char *statefile,
 		unsigned long flags)
 {
 	char init[MAXPATHLEN];
 	char val[MAXPIDLEN];
-	int fd, lock, ret = -1;
+	int fd, ret = -1;
 	size_t pid;
 
-	lock = lxc_get_lock(name);
-	if (lock >= 0) {
-		lxc_put_lock(lock);
-		return -LXC_ERROR_ESRCH;
+	if (lxc_check_lock(name) < 0) {
+		return -1;
 	}
 
-	if (lock < 0 && lock != -LXC_ERROR_EBUSY)
-		return lock;
-
 	snprintf(init, MAXPATHLEN, LXCPATH "/%s/init", name);
 	fd = open(init, O_RDONLY);
 	if (fd < 0) {
 		SYSERROR("failed to open init file for %s", name);
 		goto out_close;
 	}
-	
+
 	if (read(fd, val, sizeof(val)) < 0) {
 		SYSERROR("failed to read %s", init);
 		goto out_close;

src/lxc/lock.c

@@ -33,7 +33,9 @@
 #include "error.h"
 #include <lxc/lxc.h>
 
-int lxc_get_lock(const char *name)
+lxc_log_define(lxc_lock, lxc);
+
+static int __lxc_get_lock(const char *name)
 {
 	char lock[MAXPATHLEN];
 	int fd, ret;
@@ -41,31 +43,37 @@ int lxc_get_lock(const char *name)
 	snprintf(lock, MAXPATHLEN, LXCPATH "/%s", name);
 
 	/* need to check access because of cap_dac_override */
-	if (access(lock, R_OK |W_OK | X_OK)) {
-		ret = errno;
-		goto out_err;
-	}
+	if (access(lock, R_OK |W_OK | X_OK))
+		return -errno;
 
 	fd = open(lock, O_RDONLY|O_DIRECTORY, S_IRUSR|S_IWUSR);
-	if (fd < 0) {
-		ret = errno;
-		goto out_err;
-	}
+	if (fd < 0)
+		return -errno;
 
         fcntl(fd, F_SETFD, FD_CLOEXEC);
 
 	if (flock(fd, LOCK_EX|LOCK_NB)) {
-		ret = errno;
+		ret = -errno;
 		close(fd);
-		goto out_err;
+		goto out;
 	}
 
 	ret = fd;
 out:
 	return ret;
+}
 
+int lxc_get_lock(const char *name)
+{
+	int ret;
+
+	ret = __lxc_get_lock(name);
+	if (ret < 0)
+		goto out_err;
+out:
+	return ret;
 out_err:
-	switch (ret) {
+	switch (-ret) {
 	case EWOULDBLOCK:
 		ret = -LXC_ERROR_EBUSY;
 		goto out;
@@ -81,6 +89,23 @@ out_err:
 	}
 }
 
+int lxc_check_lock(const char *name)
+{
+	int ret;
+
+	ret = __lxc_get_lock(name);
+	if (ret >= 0) {
+		ERROR("container '%s' is not active", name);
+		lxc_put_lock(ret);
+		return -1;
+	}
+	if (ret != -EWOULDBLOCK) {
+		ERROR("container '%s' : %s", name, strerror(-ret));
+		return -1;
+	}
+	return 0;
+}
+
 void lxc_put_lock(int lock)
 {
 	flock(lock, LOCK_UN);

src/lxc/lock.h

@@ -24,7 +24,7 @@
 #define _lock_h
 
 extern int lxc_get_lock(const char *name);
-
+extern int lxc_check_lock(const char *name);
 extern void lxc_put_lock(int lock);
 
 #endif

src/lxc/lxc_stop.c

@@ -65,10 +65,8 @@ int main(int argc, char *argv[])
 		return 1;
 
 	err = lxc_stop(name);
-	if (err) {
-		fprintf(stderr, "%s\n", lxc_strerror(err));
+	if (err)
 		return 1;
-	}
 
 	return 0;
 }

src/lxc/stop.c

@@ -42,17 +42,11 @@ int lxc_stop(const char *name)
 {
 	char init[MAXPATHLEN];
 	char val[MAXPIDLEN];
-	int fd, lock, ret = -LXC_ERROR_INTERNAL;
+	int fd, ret = -LXC_ERROR_INTERNAL;
 	size_t pid;
 
-	lock = lxc_get_lock(name);
-	if (lock >= 0) {
-		lxc_put_lock(lock);
-		return -LXC_ERROR_ESRCH;
-	}
-
-	if (lock < 0 && lock != -LXC_ERROR_EBUSY)
-		return lock;
+	if (lxc_check_lock(name) < 0)
+		return ret;
 
 	snprintf(init, MAXPATHLEN, LXCPATH "/%s/init", name);
 	fd = open(init, O_RDONLY);
@@ -60,7 +54,7 @@ int lxc_stop(const char *name)
 		SYSERROR("failed to open init file for %s", name);
 		goto out_close;
 	}
-	
+
 	if (read(fd, val, sizeof(val)) < 0) {
 		SYSERROR("failed to read %s", init);
 		goto out_close;