Add return error status in the different functions

From: Daniel Lezcano <dlezcano@fr.ibm.com>

Add the most known error to the different API to be followed up by the
caller, so we can later show a better message to the user when something
goes wrong. The error catching is coarse grain right now but will be improved,
step by step.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

src/lxc/cgroup.c

@@ -36,6 +36,7 @@
 #include <netinet/in.h>
 #include <net/if.h>
 
+#include "error.h"
 #include <lxc/lxc.h>
 
 #define MTAB "/etc/mtab"
@@ -98,7 +99,7 @@ int lxc_unlink_nsgroup(const char *name)
 
 int lxc_cgroup_set(const char *name, const char *subsystem, const char *value)
 {
-	int fd, ret = -1;;
+	int fd, ret = -LXC_ERROR_INTERNAL;;
 	char path[MAXPATHLEN];
 
         snprintf(path, MAXPATHLEN, LXCPATH "/%s/nsgroup/%s", name, subsystem);
@@ -119,7 +120,7 @@ out:
 int lxc_cgroup_get(const char *name, const char *subsystem,  
 		   char *value, size_t len)
 {
-	int fd, ret = -1;;
+	int fd, ret = -LXC_ERROR_INTERNAL;
 	char path[MAXPATHLEN];
 
         snprintf(path, MAXPATHLEN, LXCPATH "/%s/nsgroup/%s", name, subsystem);

src/lxc/create.c

@@ -30,6 +30,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
+#include "error.h"
 #include <lxc/lxc.h>
 
 static int dir_filter(const struct dirent *dirent)
@@ -93,17 +94,17 @@ static int remove_lxc_directory(const char *dirname)
 
 int lxc_create(const char *name, struct lxc_conf *conf)
 {
-	int lock, err = -1;
+	int lock, err = -LXC_ERROR_INTERNAL;
 
 	if (create_lxc_directory(name)) {
 		lxc_log_error("failed to create %s directory", name);
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 	}
 
 	lock = lxc_get_lock(name);
 	if (!lock) {
 		lxc_log_error("'%s' is busy", name);
-		goto err;
+		return -LXC_ERROR_ALREADY_EXISTS;
 	}
 
 	if (lock < 0) {

src/lxc/destroy.c

@@ -29,6 +29,7 @@
 #include <errno.h>
 #include <sys/param.h>
 
+#include "error.h"
 #include <lxc/lxc.h>
 
 static int remove_lxc_directory(const char *dirname)
@@ -47,13 +48,13 @@ static int remove_lxc_directory(const char *dirname)
 
 int lxc_destroy(const char *name)
 {
-	int ret = -1, lock;
+	int lock, ret = -LXC_ERROR_INTERNAL;
 	char path[MAXPATHLEN];
 
 	lock = lxc_get_lock(name);
 	if (!lock) {
 		lxc_log_error("'%s' is busy", name);
-		goto out;
+		return -LXC_ERROR_BUSY;
 	}
 
 	if (lock < 0) {

src/lxc/error.c

@@ -27,6 +27,7 @@
 
 static char *catalogue[] = {
 	[LXC_ERROR_EMPTY] = "The container is not running",
+	[LXC_ERROR_ALREADY_EXISTS] = "The container already exists",
 	[LXC_ERROR_BUSY] = "The container is busy",
 	[LXC_ERROR_NOT_FOUND] = "The container was not found",
 	[LXC_ERROR_PERMISSION_DENIED] = "Permission denied",
@@ -43,6 +44,8 @@ static char *catalogue[] = {
 	[LXC_ERROR_SETUP_UTSNAME] = "Failed to setup the utsname",
 	[LXC_ERROR_SETUP_NETWORK] = "Failed to setup the network",
 	[LXC_ERROR_SETUP_ROOTFS] = "Failed to setup the root fs",
+
+	[LXC_ERROR_INTERNAL] = "Internal system error",
 };
 
 const char *const lxc_strerror(int error)

src/lxc/error.h

@@ -20,12 +20,13 @@
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
-#ifndef __lxc_h
+#ifndef __lxc_error_h
-#define __lxc_h
+#define __lxc_error_h
 
 typedef enum {
 	LXC_ERROR_EMPTY,
 	LXC_ERROR_BUSY,
+	LXC_ERROR_ALREADY_EXISTS,
 	LXC_ERROR_NOT_FOUND,
 	LXC_ERROR_PERMISSION_DENIED,
 	LXC_ERROR_WRONG_COMMAND,
@@ -42,6 +43,8 @@ typedef enum {
 	LXC_ERROR_SETUP_NETWORK,
 	LXC_ERROR_SETUP_ROOTFS,
 
+	LXC_ERROR_INTERNAL,
+
 	LXC_LAST_ERROR,
 } lxc_error_t;
 

src/lxc/freezer.c

@@ -31,6 +31,7 @@
 #include <sys/types.h>
 #include <sys/param.h>
 
+#include "error.h"
 #include <lxc/lxc.h>
 
 static int freeze_unfreeze(const char *name, int freeze)
@@ -58,10 +59,10 @@ static int freeze_unfreeze(const char *name, int freeze)
 int lxc_freeze(const char *name)
 {
 	if (freeze_unfreeze(name, 1))
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 
 	if (lxc_setstate(name, FROZEN))
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 
 	return 0;
 }
@@ -69,10 +70,10 @@ int lxc_freeze(const char *name)
 int lxc_unfreeze(const char *name)
 {
 	if (freeze_unfreeze(name, 0))
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 
 	if (lxc_setstate(name, RUNNING))
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 
 	return 0;
 }

src/lxc/monitor.c

@@ -36,6 +36,7 @@
 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>
 
+#include "error.h"
 #include <lxc/lxc.h>
 
 #ifndef UNIX_PATH_MAX
@@ -151,7 +152,7 @@ int lxc_monitor_open(void)
 	fd = socket(PF_NETLINK, SOCK_RAW, 0);
 	if (fd < 0) {
 		lxc_log_syserror("failed to create notification socket");
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 	}
 
 	memset(&addr, 0, sizeof(addr));
@@ -180,7 +181,7 @@ int lxc_monitor_read(int fd, struct lxc_msg *msg)
 		       (struct sockaddr *)&from, &len);
 	if (ret < 0) {
 		lxc_log_syserror("failed to received state");
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 	}
 
 	return ret;

src/lxc/start.c

@@ -38,6 +38,8 @@
 #include <sys/capability.h>
 #include <sys/wait.h>
 
+#include "error.h"
+
 #include <lxc/lxc.h>
 
 LXC_TTY_HANDLER(SIGINT);
@@ -48,20 +50,20 @@ int lxc_start(const char *name, char *argv[])
 	char init[MAXPATHLEN];
 	char *val = NULL;
 	char ttyname[MAXPATHLEN];
-	int fd, lock, sv[2], sync = 0, err = -1;
+	int fd, lock, sv[2], sync = 0, err = -LXC_ERROR_INTERNAL;
 	pid_t pid;
 	int clone_flags;
 
 	lock = lxc_get_lock(name);
 	if (!lock) {
 		lxc_log_error("'%s' is busy", name);
-		return -1;
+		return -LXC_ERROR_BUSY;
 	}
 
 	if (lock < 0) {
 		lxc_log_error("failed to acquire lock on '%s':%s",
 			      name, strerror(-lock));
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 	}
 
 	/* Begin the set the state to STARTING*/

src/lxc/stop.c

@@ -31,6 +31,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
+#include "error.h"
 #include <lxc/lxc.h>
 
 #define MAXPIDLEN 20
@@ -39,20 +40,20 @@ int lxc_stop(const char *name)
 {
 	char init[MAXPATHLEN];
 	char val[MAXPIDLEN];
-	int fd, lock, ret = -1;
+	int fd, lock, ret = -LXC_ERROR_INTERNAL;
 	size_t pid;
 
 	lock = lxc_get_lock(name);
 	if (lock > 0) {
 		lxc_log_error("'%s' is not running", name);
 		lxc_put_lock(lock);
-		return -1;
+		return -LXC_ERROR_EMPTY;
 	}
 
 	if (lock < 0) {
 		lxc_log_error("failed to acquire the lock on '%s':%s", 
 			      name, strerror(-lock));
-		return -1;
+		return -LXC_ERROR_INTERNAL;
 	}
 
 	snprintf(init, MAXPATHLEN, LXCPATH "/%s/init", name);