Replace lxc_execute by an intermediate lxc_init

src/lxc/Makefile.am

-INCLUDES= -I$(top_srcdir)/src -DLXCPATH="\"$(localstatedir)/lxc\""
+INCLUDES= -I$(top_srcdir)/src -DLXCPATH="\"$(localstatedir)/lxc\"" -DLXCBINDIR="\"$(bindir)\""
 lib_LTLIBRARIES = liblxc.la
 pkginclude_HEADERS = \
 		monitor.h \
@@ -17,7 +17,6 @@ liblxc_la_SOURCES = \
 	destroy.c \
 	start.c \
 	stop.c \
-	execute.c \
 	monitor.c monitor.h \
 	kill.c \
 	freezer.c \
@@ -46,6 +45,7 @@ bin_SCRIPTS = \
 	lxc-checkconfig
 
 bin_PROGRAMS = \
+	lxc-init \
 	lxc-create \
 	lxc-destroy \
 	lxc-stop \
@@ -63,6 +63,9 @@ bin_PROGRAMS = \
 	lxc-restart \
 	lxc-version
 
+lxc_init_SOURCES = lxc_init.c
+lxc_init_LDADD = liblxc.la
+
 lxc_create_SOURCES = lxc_create.c lxc_config.c lxc_config.h
 lxc_create_LDADD = liblxc.la
 

src/lxc/execute.c

-/*
- * lxc: linux Container library
- *
- * (C) Copyright IBM Corp. 2007, 2008
- *
- * Authors:
- * Daniel Lezcano <dlezcano at fr.ibm.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-#define _GNU_SOURCE
-#include <stdio.h>
-#undef _GNU_SOURCE
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <errno.h>
-#include <signal.h>
-#include <fcntl.h>
-#include <sys/types.h>
-#include <sys/param.h>
-#include <sys/prctl.h>
-#include <sys/wait.h>
-#include <sys/file.h>
-#include <sys/mount.h>
-
-#include <lxc/lxc.h>
-
-LXC_TTY_HANDLER(SIGINT);
-LXC_TTY_HANDLER(SIGQUIT);
-
-int lxc_execute(const char *name, int argc, char *argv[], 
-		lxc_callback_t preexec, void *data)
-{
-	char init[MAXPATHLEN];
-	char *val = NULL, *vinit = "[vinit]";
-	int fd, lock, sv[2], sync = 0, err = -1;
-	pid_t pid;
-	int clone_flags;
-
-	lock = lxc_get_lock(name);
-	if (!lock) {
-		lxc_log_error("'%s' is busy", name);
-		return -1;
-	}
-
-	if (lock < 0) {
-		lxc_log_error("failed to acquire lock on '%s':%s",
-			      name, strerror(-lock));
-		return -1;
-	}
-
-	if (lxc_setstate(name, STARTING)) {
-		lxc_log_error("failed to set state %s", lxc_state2str(STARTING));
-		goto out;
-	}
-
-	if (socketpair(AF_LOCAL, SOCK_STREAM, 0, sv)) {
-		lxc_log_syserror("failed to create communication socketpair");
-		goto err;
-	}
-
-	LXC_TTY_ADD_HANDLER(SIGINT);
-	LXC_TTY_ADD_HANDLER(SIGQUIT);
-
-	clone_flags = CLONE_NEWPID|CLONE_NEWIPC|CLONE_NEWNS;
-	if (conf_has_utsname(name))
-		clone_flags |= CLONE_NEWUTS;
-	if (conf_has_network(name))
-		clone_flags |= CLONE_NEWNET;
-
-	pid = fork_ns(clone_flags);
-	if (pid < 0) {
-		lxc_log_syserror("failed to fork into a new namespace");
-		goto err_fork_ns;
-	}
-
-	if (!pid) {
-
-		pid = fork();
-		if (pid < 0) {
-			lxc_log_syserror("failed to fork");
-			return 1;
-		}
-
-		if (!pid) {
-			close(sv[1]);
-			fcntl(sv[0], F_SETFD, FD_CLOEXEC);
-
-			if (write(sv[0], &sync, sizeof(sync)) < 0) {
-				lxc_log_syserror("failed to write socket");
-				exit(1);
-			}
-
-			if (read(sv[0], &sync, sizeof(sync)) < 0) {
-				lxc_log_syserror("failed to read socket");
-				exit(1);
-			}
-
-			if (lxc_setup(name)) {
-				lxc_log_error("failed to setup the container");
-				goto error;
-			}
-
-			if (mount("proc", "/proc", "proc", 0, NULL)) {
-				lxc_log_syserror("failed to mount '/proc'");
-				goto error;
-			}
-
-			if (clone_flags & CLONE_NEWNET)
-				if (mount("sysfs", "/sys", "sysfs", 0, NULL)) {
-					lxc_log_syserror("failed to mount '/sys'");
-					/* continue: non fatal error until sysfs not per
-					   namespace */
-				}
-
-			if (preexec)
-				if (preexec(name, argc, argv, data)) {
-					lxc_log_error("preexec callback has failed");
-					return -1;
-				}
-
-			execvp(argv[0], argv);
-			lxc_log_syserror("failed to exec %s", argv[0]);
-		error:
-			if (write(sv[0], &sync, sizeof(sync)) < 0)
-				lxc_log_syserror("failed to write the socket");
-			
-			exit(1);
-		}
-
-		setsid();
-		close(0);
-		close(1);
-		close(2);
-
-		if (prctl(PR_SET_NAME, vinit, 0, 0, 0))
-			lxc_log_syserror("failed to set process name");
-
-		close(sv[0]);
-		close(sv[1]);
-
-		for (;;) {
-			int status;
-			if (wait(&status) < 0) {
-				if (errno == ECHILD)
-					exit(0);
-				if (errno == EINTR)
-					continue;
-				lxc_log_syserror("failed to wait child");
-				exit(1);
-			}
-		}
-	}
-
-	close(sv[0]);
-	
-	if (read(sv[1], &sync, sizeof(sync)) < 0) {
-		lxc_log_syserror("failed to read the socket");
-		goto err_pipe_read;
-	}
-
-	if (lxc_link_nsgroup(name, pid))
-		lxc_log_warning("cgroupfs not found: cgroup disabled");
-
-	if (clone_flags & CLONE_NEWNET && conf_create_network(name, pid)) {
-		lxc_log_error("failed to create the configured network");
-		goto err_create_network;
-	}
-
-	if (write(sv[1], &sync, sizeof(sync)) < 0) {
-		lxc_log_syserror("failed to write the socket");
-		goto err_pipe_write;
-	}
-
-	err = read(sv[1], &sync, sizeof(sync));
-	if (err < 0) {
-		lxc_log_error("failed to read the socket");
-		goto err_pipe_read2;
-	}
-
-	if (err > 0) {
-		lxc_log_error("something went wrong with %d", pid);
-		/* TODO : check status etc ... */
-		waitpid(pid, NULL, 0);
-		goto err_child_failed;
-	}
-
-	snprintf(init, MAXPATHLEN, LXCPATH "/%s/init", name);
-		
-	fd = open(init, O_WRONLY|O_CREAT|O_TRUNC, S_IRUSR|S_IWUSR);
-	if (fd < 0) {
-		lxc_log_syserror("failed to open %s", init);
-		goto err_open;
-	}
-
-	if (!asprintf(&val, "%d", pid)) {
-		lxc_log_syserror("failed to allocate memory");
-		goto err_open;
-	}
-
-	if (write(fd, val, strlen(val)) < 0) {
-		lxc_log_syserror("failed to write init pid");
-		goto err_write;
-	}
-
-	if (lxc_setstate(name, RUNNING)) {
-		lxc_log_error("failed to set state to %s", lxc_state2str(RUNNING));
-		goto err_state_failed;
-	}
-
-wait_again:
-	if (waitpid(pid, NULL, 0) < 0) {
-		if (errno == EINTR) 
-			goto wait_again;
-		lxc_log_syserror("failed to wait the pid %d", pid);
-		goto err_waitpid_failed;
-	}
-
-	if (lxc_setstate(name, STOPPING))
-		lxc_log_error("failed to set state %s", lxc_state2str(STOPPING));
-
-	if (clone_flags & CLONE_NEWNET && conf_destroy_network(name))
-		lxc_log_error("failed to destroy the network");
-
-	err = 0;
-out:
-	if (lxc_setstate(name, STOPPED))
-		lxc_log_error("failed to set state %s", lxc_state2str(STOPPED));
-
-	lxc_unlink_nsgroup(name);
-	unlink(init);
-	free(val);
-	lxc_put_lock(lock);
-
-	return err;
-
-err_write:
-	close(fd);
-
-err_state_failed:
-err_child_failed:
-err_pipe_read2:
-err_pipe_write:
-	if (clone_flags & CLONE_NEWNET)
-		conf_destroy_network(name);
-err_create_network:
-err_pipe_read:
-err_open:
-err_waitpid_failed:
-	if (lxc_setstate(name, ABORTING))
-		lxc_log_error("failed to set state %s", lxc_state2str(STOPPED));
-
-	kill(pid, SIGKILL);
-err_fork_ns:
-	LXC_TTY_DEL_HANDLER(SIGQUIT);
-	LXC_TTY_DEL_HANDLER(SIGINT);
-	close(sv[0]);
-	close(sv[1]);
-err:
-	goto out;
-}

src/lxc/lxc.h

@@ -48,9 +48,6 @@ extern "C" {
 
 struct lxc_mem_stat;
 
-typedef int (*lxc_callback_t)(const char *name, int argc, 
-			      char *argv[], void *data);
-
 /*
  * Create the container object. Creates the /lxc/<name> directory
  * and fills it with the files corresponding to the configuration
@@ -74,28 +71,10 @@ extern int lxc_destroy(const char *name);
 /*
  * Start the container previously created with lxc_create.
  * @name     : the name of the container
- * @argc     : the number of arguments of the command line
  * @argv     : an array of char * corresponding to the commande line
- * @prestart : hooks will be called just before the command execs
  * Returns 0 on sucess, < 0 otherwise
  */
-extern int lxc_start(const char *name, int argc, char *argv[], 
-		     lxc_callback_t prestart, void *data);
-
-/*
- * Create the container and start it directly, using the argc, argv 
- * parameter. This command is for application container.
- * At the end of the exec'ed command, the container will
- * automatically autodestroy.
- * @name    : the name of the container
- * @conf    : the configuration data
- * @argc    : the number of arguments of the command line
- * @argv    : an array of char * corresponding to the commande line
- * @preexec : hooks will be called just before the command execs
- * Returns 0 on success, < 0 otherwise
- */
-extern int lxc_execute(const char *name, int argc, char *argv[], 
-		       lxc_callback_t preexec, void *data);
+extern int lxc_start(const char *name, char *argv[]);
 
 /*
  * Stop the container previously started with lxc_start or lxc_exec

src/lxc/lxc_execute.c

@@ -20,6 +20,7 @@
  * License along with this library; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <errno.h>
 #include <libgen.h>
@@ -44,7 +45,7 @@ int main(int argc, char *argv[])
 {
 	char opt;
 	char *name = NULL, *file = NULL;
-	char **args;
+	static char **args;
 	char path[MAXPATHLEN];
 	int nbargs = 0;
 	int autodestroy = 0;
@@ -67,7 +68,6 @@ int main(int argc, char *argv[])
 	if (!name || !argv[optind] || !strlen(argv[optind]))
 		usage(argv[0]);
 
-	args = &argv[optind];
 	argc -= nbargs;
 	
 	if (lxc_config_init(&lxc_conf)) {
@@ -75,13 +75,9 @@ int main(int argc, char *argv[])
 		goto out;
 	}
 
-	if (file) {
-
-		if (lxc_config_read(file, &lxc_conf)) {
-			fprintf(stderr, "invalid configuration file\n");
-			goto out;
-		}
-
+	if (file && lxc_config_read(file, &lxc_conf)) {
+		fprintf(stderr, "invalid configuration file\n");
+		goto out;
 	}
 
 	snprintf(path, MAXPATHLEN, LXCPATH "/%s", name);
@@ -93,13 +89,27 @@ int main(int argc, char *argv[])
 		autodestroy = 1;
 	}
 
-	if (lxc_execute(name, argc, args, NULL, NULL)) {
+	/* lxc-init --mount-procfs -- .... */
+	args = malloc((argc + 3)*sizeof(*args));
+	if (!args) {
+		fprintf(stderr, "failed to allocate memory for '%s'\n", name);
+		goto out;
+	}
+
+	nbargs = 0;
+	args[nbargs++] = LXCBINDIR "/lxc-init";
+	args[nbargs++] = "--mount-procfs";
+	args[nbargs++] = "--";
+
+	for (opt = 0; opt < argc; opt++)
+		args[nbargs++] = argv[optind++];
+
+	if (lxc_start(name, args)) {
 		fprintf(stderr, "failed to execute '%s'\n", name);
 		goto out;
 	}
 
 	ret = 0;
-
 out:
 	if (autodestroy) {
 		if (lxc_destroy(name)) {

src/lxc/lxc_init.c

+/*
+ * lxc: linux Container library
+ *
+ * (C) Copyright IBM Corp. 2007, 2008
+ *
+ * Authors:
+ * Daniel Lezcano <dlezcano at fr.ibm.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/mount.h>
+#define _GNU_SOURCE
+#include <getopt.h>
+
+static int mount_sysfs;
+static int mount_procfs;
+
+static struct option options[] = {
+	{ "mount-sysfs", no_argument, &mount_sysfs, 1 },
+	{ "mount-procfs", no_argument, &mount_procfs, 1 },
+};
+
+int main(int argc, char *argv[])
+{
+	pid_t pid;
+
+	int nbargs = 0;
+	char **aargv;
+
+	while (1) {
+		int ret = getopt_long_only(argc, argv, "", options, NULL);
+		if (ret == -1)
+			break;
+		if (ret == '?')
+			exit(1);
+		nbargs++;
+	}
+
+	if (!argv[optind]) {
+		fprintf(stderr, "missing command to launch\n");
+		exit(1);
+	}
+
+	aargv = &argv[optind];
+	argc -= nbargs;
+
+	pid = fork();
+	
+	if (pid < 0)
+		exit(1);
+
+	if (!pid) {
+		
+		if (mount_sysfs && mount("sysfs", "/sys", "sysfs", 0, NULL)) {
+			fprintf(stderr, "failed to mount '/sys'\n");
+			exit(1);
+		}
+		
+		if (mount_procfs && mount("proc", "/proc", "proc", 0, NULL)) {
+			fprintf(stderr, "failed to mount '/proc'\n");
+			exit(1);
+		}
+
+		execvp(aargv[0], aargv);
+		fprintf(stderr, "failed to exec: %s\n", aargv[0]);
+		exit(1);
+	}
+
+	for (;;) {
+		int status;
+		if (wait(&status) < 0) {
+			if (errno == ECHILD)
+				exit(0);
+			if (errno == EINTR)
+				continue;
+			fprintf(stderr, "failed to wait child\n");
+			return 1;
+		}
+	}
+
+	return 0;
+}

src/lxc/lxc_start.c

@@ -64,7 +64,7 @@ int main(int argc, char *argv[])
 	args = &argv[optind];
 	argc -= nbargs;
 
-	if (lxc_start(name, argc, args, NULL, NULL)) {
+	if (lxc_start(name, args)) {
 		fprintf(stderr, "failed to start %s\n", name);
 		return 1;
 	}

src/lxc/start.c

@@ -43,8 +43,7 @@
 LXC_TTY_HANDLER(SIGINT);
 LXC_TTY_HANDLER(SIGQUIT);
 
-int lxc_start(const char *name, int argc, char *argv[], 
-	      lxc_callback_t prestart, void *data)
+int lxc_start(const char *name, char *argv[])
 {
 	char init[MAXPATHLEN];
 	char *val = NULL;
@@ -132,13 +131,6 @@ int lxc_start(const char *name, int argc, char *argv[],
 			goto out_child;
 		}
 
-		/* If a callback has been passed, call it before doing exec */
-		if (prestart)
-			if (prestart(name, argc, argv, data)) {
-				lxc_log_error("prestart callback has failed");
-				goto out_child;
-			}
-
 		if (prctl(PR_CAPBSET_DROP, CAP_SYS_BOOT, 0, 0, 0)) {
 			lxc_log_syserror("failed to remove CAP_SYS_BOOT capability");
 			goto out_child;