Introduce --lxcpath cmdline option, and make default_lxc_path() return const char *

For the lxc-* C binaries, introduce a -P|--lxcpath command line option
to override the system default.

With this, I can

    lxc-create -t ubuntu -n r1
    lxc-create -t ubuntu -n r1 -P /home/ubuntu/lxcbase
    lxc-start -n r1 -d
    lxc-start -n r1 -d -P /home/ubuntu/lxcbase
    lxc-console -n r1 -d -P /home/ubuntu/lxcbase
    lxc-stop -n r1

all working with the right containers (module cgroup stuff).

To do:
    * lxc monitor needs to be made to handle cgroups.
      This is another very invasive one.  I started doing this as
      a part of this set, but that gets hairy, so I'm sending this
      separately.  Note that lxc-wait and lxc-monitor don't work
      without this, and there may be niggles in what I said works
      above - since start.c is doing lxc_monitor_send_state etc
      to the shared abstract unix domain socket.
    * Need to handle the cgroup conflicts.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>

doc/common_options.sgml.in

@@ -57,6 +57,15 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       </listitem>
     </varlistentry>
 
+    <varlistentry>
+      <term><option>-P, --lxcpath=<replaceable>PATH</replaceable></option></term>
+      <listitem>
+	<para>
+	  Use an alternate container path.  The default is @LXCPATH@.
+	</para>
+      </listitem>
+    </varlistentry>
+
     <varlistentry>
       <term><option>-o, --logfile=<replaceable>FILE</replaceable></option></term>
       <listitem>

src/lua-lxc/core.c

@@ -366,10 +366,9 @@ static int lxc_version_get(lua_State *L) {
 }
 
 static int lxc_default_config_path_get(lua_State *L) {
-    char *lxcpath = lxc_get_default_config_path();
+    const char *lxcpath = lxc_get_default_config_path();
 
     lua_pushstring(L, lxcpath);
-    free(lxcpath);
     return 1;
 }
 

src/lxc/arguments.c

@@ -32,6 +32,7 @@
 #include <unistd.h>
 
 #include "arguments.h"
+#include "utils.h"
 
 /*---------------------------------------------------------------------------*/
 static int build_shortopts(const struct option *a_options,
@@ -136,6 +137,7 @@ Common options :\n\
   -o, --logfile=FILE               Output log to FILE instead of stderr\n\
   -l, --logpriority=LEVEL          Set log priority to LEVEL\n\
   -q, --quiet                      Don't produce any output\n\
+  -P, --lxcpath=PATH               Use specified container path\n\
   -?, --help                       Give this help list\n\
       --usage                      Give a short usage message\n\
 \n\
@@ -154,6 +156,7 @@ extern int lxc_arguments_parse(struct lxc_arguments *args,
 	char shortopts[256];
 	int  ret = 0;
 
+	args->lxcpath = default_lxc_path();
 	ret = build_shortopts(args->options, shortopts, sizeof(shortopts));
 	if (ret < 0) {
 		lxc_error(args, "build_shortopts() failed : %s",
@@ -173,6 +176,7 @@ extern int lxc_arguments_parse(struct lxc_arguments *args,
 		case 'l':	args->log_priority = optarg; break;
 		case 'c':	args->console = optarg; break;
 		case 'q':	args->quiet = 1; break;
+		case 'P':	args->lxcpath = optarg; break;
 		case OPT_USAGE: print_usage(args->options, args);
 		case '?':	print_help(args, 1);
 		case 'h': 	print_help(args, 0);

src/lxc/arguments.h

@@ -47,6 +47,7 @@ struct lxc_arguments {
 	const char *console;
 	const char *console_log;
 	const char *pidfile;
+	const char *lxcpath;
 
 	/* for lxc-checkpoint/restart */
 	const char *statefile;
@@ -79,6 +80,7 @@ struct lxc_arguments {
 	{"quiet", no_argument,	0, 'q'}, \
 	{"logfile", required_argument, 0, 'o'}, \
 	{"logpriority", required_argument, 0, 'l'}, \
+	{"lxcpath", required_argument, 0, 'P'}, \
 	{0, 0, 0, 0}
 
 /* option keys for long only options */

src/lxc/commands.c

@@ -62,7 +62,7 @@ lxc_log_define(lxc_commands, lxc);
 static int fill_sock_name(char *path, int len, const char *name,
 			  const char *inpath)
 {
-	char *lxcpath = NULL;
+	const char *lxcpath = NULL;
 	int ret;
 
 	if (!inpath) {
@@ -73,8 +73,6 @@ static int fill_sock_name(char *path, int len, const char *name,
 		}
 	}
 	ret = snprintf(path, len, "%s/%s/command", lxcpath ? lxcpath : inpath, name);
-	if (lxcpath)
-		free(lxcpath);
 
 	if (ret < 0 || ret >= len) {
 		ERROR("Name too long");

src/lxc/conf.c

@@ -1519,7 +1519,7 @@ static int mount_entry_on_absolute_rootfs(struct mntent *mntent,
 	unsigned long mntflags;
 	char *mntdata;
 	int r, ret = 0, offset;
-	char *lxcpath;
+	const char *lxcpath;
 
 	if (parse_mntopts(mntent->mnt_opts, &mntflags, &mntdata) < 0) {
 		ERROR("failed to parse mount option '%s'", mntent->mnt_opts);
@@ -1535,7 +1535,6 @@ static int mount_entry_on_absolute_rootfs(struct mntent *mntent,
 	/* if rootfs->path is a blockdev path, allow container fstab to
 	 * use $lxcpath/CN/rootfs as the target prefix */
 	r = snprintf(path, MAXPATHLEN, "%s/%s/rootfs", lxcpath, lxc_name);
-	free(lxcpath);
 	if (r < 0 || r >= MAXPATHLEN)
 		goto skipvarlib;
 

src/lxc/lxc-create.in

@@ -20,9 +20,11 @@
 # License along with this library; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 
+. @DATADIR@/lxc/lxc.functions
+
 usage() {
     echo "usage: $(basename $0) -n NAME [-f CONFIG_FILE] [-t TEMPLATE] [FS_OPTIONS] --" >&2
-    echo "         [TEMPLATE_OPTIONS]" >&2
+    echo "         [-P lxcpath] [TEMPLATE_OPTIONS]" >&2
     echo >&2
     echo "where FS_OPTIONS is one of:" >&2
     echo "  -B none" >&2
@@ -42,6 +44,7 @@ help() {
     echo "  -f CONFIG_FILE     use an existing configuration file" >&2
     echo "  -t TEMPLATE        use an accessible template script" >&2
     echo "  -B BACKING_STORE   alter the container backing store (default: none)" >&2
+    echo "  --lxcpath path     specify an alternate container patch (default: $lxc_path)" >&2
     echo "  --lvname LV_NAME   specify the LVM logical volume name" >&2
     echo "                      (default: container name)" >&2
     echo "  --dir ROOTFS_DIR   specify path for custom rootfs directory location" >&2
@@ -73,7 +76,6 @@ optarg_check() {
     fi
 }
 
-. @DATADIR@/lxc/lxc.functions
 backingstore=_unset
 fstype=ext4
 fssize=500M
@@ -98,6 +100,11 @@ while [ $# -gt 0 ]; do
             lxc_config=$1
             shift
             ;;
+        -P|--lxcpath)
+            optarg_check $opt "$1"
+            lxc_path=$1
+            shift
+            ;;
         -t|--template)
             optarg_check $opt "$1"
             lxc_template=$1

src/lxc/lxc.h

@@ -171,9 +171,10 @@ extern int lxc_checkpoint(const char *name, int sfd, int flags);
  * @sfd: fd from which the container is restarted
  * @conf: lxc_conf structure.
  * @flags : restart flags (an ORed value)
+ * @lxcpath: container path
  * Returns 0 on success, < 0 otherwise
  */
-extern int lxc_restart(const char *, int, struct lxc_conf *, int);
+extern int lxc_restart(const char *, int, struct lxc_conf *, int, const char *);
 
 /*
  * Returns the version number of the library

src/lxc/lxc_attach.c

@@ -130,8 +130,6 @@ int main(int argc, char *argv[])
 	void *cgroup_data = NULL;
 	uid_t uid;
 	char *curdir;
-	/* TODO: add cmdline arg to set lxcpath */
-	const char *lxcpath = NULL;
 
 	ret = lxc_caps_init();
 	if (ret)
@@ -146,7 +144,7 @@ int main(int argc, char *argv[])
 	if (ret)
 		return ret;
 
-	init_pid = get_init_pid(my_args.name, lxcpath);
+	init_pid = get_init_pid(my_args.name, my_args.lxcpath);
 	if (init_pid < 0) {
 		ERROR("failed to get the init pid");
 		return -1;
@@ -176,7 +174,7 @@ int main(int argc, char *argv[])
 	 * by asking lxc-start
 	 */
 	if (namespace_flags == -1) {
-		namespace_flags = lxc_get_clone_flags(my_args.name, lxcpath);
+		namespace_flags = lxc_get_clone_flags(my_args.name, my_args.lxcpath);
 		/* call failed */
 		if (namespace_flags == -1) {
 			ERROR("failed to automatically determine the "

src/lxc/lxc_console.c

@@ -182,8 +182,6 @@ int main(int argc, char *argv[])
 	int err, std_in = 1;
 	struct lxc_epoll_descr descr;
 	struct termios newtios, oldtios;
-	/* TODO: add cmdline arg to specify lxcpath */
-	char *lxcpath = NULL;
 
 	err = lxc_arguments_parse(&my_args, argc, argv);
 	if (err)
@@ -200,7 +198,7 @@ int main(int argc, char *argv[])
 		return -1;
 	}
 
-	err = lxc_console(my_args.name, my_args.ttynum, &master, lxcpath);
+	err = lxc_console(my_args.name, my_args.ttynum, &master, my_args.lxcpath);
 	if (err)
 		goto out;
 

src/lxc/lxc_execute.c

@@ -109,14 +109,8 @@ int main(int argc, char *argv[])
 		rcfile = (char *)my_args.rcfile;
 	else {
 		int rc;
-		char *lxcpath = default_lxc_path();
-		if (!lxcpath) {
-			ERROR("Out of memory");
-			return -1;
-		}
 
-		rc = asprintf(&rcfile, "%s/%s/config", lxcpath, my_args.name);
-		free(lxcpath);
+		rc = asprintf(&rcfile, "%s/%s/config", my_args.lxcpath, my_args.name);
 		if (rc == -1) {
 			SYSERROR("failed to allocate memory");
 			return -1;
@@ -143,5 +137,5 @@ int main(int argc, char *argv[])
 	if (lxc_config_define_load(&defines, conf))
 		return -1;
 
-	return lxc_execute(my_args.name, my_args.argv, my_args.quiet, conf, NULL);
+	return lxc_execute(my_args.name, my_args.argv, my_args.quiet, conf, my_args.lxcpath);
 }

src/lxc/lxc_info.c

@@ -74,8 +74,6 @@ Options :\n\
 int main(int argc, char *argv[])
 {
 	int ret;
-	/* TODO: add lxcpath cmdline arg */
-	const char *lxcpath = NULL;
 
 	ret = lxc_arguments_parse(&my_args, argc, argv);
 	if (ret)
@@ -89,7 +87,7 @@ int main(int argc, char *argv[])
 		state = pid = true;
 
 	if (state || test_state) {
-		ret = lxc_getstate(my_args.name, lxcpath);
+		ret = lxc_getstate(my_args.name, my_args.lxcpath);
 		if (ret < 0)
 			return 1;
 		if (test_state)
@@ -99,7 +97,7 @@ int main(int argc, char *argv[])
 	}
 
 	if (pid)
-		printf("pid:%10d\n", get_init_pid(my_args.name, lxcpath));
+		printf("pid:%10d\n", get_init_pid(my_args.name, my_args.lxcpath));
 
 	return 0;
 }

src/lxc/lxc_kill.c

@@ -56,8 +56,6 @@ int main(int argc, char *argv[], char *envp[])
 	int ret;
 	pid_t pid;
 	int sig;
-	/* TODO: add lxcpath cmdline arg */
-	const char *lxcpath = NULL;
 
 	ret = lxc_arguments_parse(&my_args, argc, argv);
 	if (ret)
@@ -78,7 +76,7 @@ int main(int argc, char *argv[], char *envp[])
 	} else
 		sig=SIGKILL;
 
-	pid = get_init_pid(my_args.name, lxcpath);
+	pid = get_init_pid(my_args.name, my_args.lxcpath);
 	if (pid < 0) {
 		ERROR("failed to get the init pid");
 		return -1;

src/lxc/lxc_restart.c

@@ -132,14 +132,8 @@ int main(int argc, char *argv[])
 		rcfile = (char *)my_args.rcfile;
 	else {
 		int rc;
-		char *lxcpath = default_lxc_path();
-		if (!lxcpath) {
-			ERROR("Out of memory");
-			return -1;
-		}
 
-		rc = asprintf(&rcfile, "%s/%s/config", lxcpath, my_args.name);
-		free(lxcpath);
+		rc = asprintf(&rcfile, "%s/%s/config", my_args.lxcpath, my_args.name);
 		if (rc == -1) {
 			SYSERROR("failed to allocate memory");
 			return -1;
@@ -178,7 +172,7 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	ret = lxc_restart(my_args.name, sfd, conf, my_args.flags);
+	ret = lxc_restart(my_args.name, sfd, conf, my_args.flags, my_args.lxcpath);
 
 	if (my_args.statefile)
 		close(sfd);

src/lxc/lxc_start.c

@@ -150,8 +150,6 @@ int main(int argc, char *argv[])
 		'\0',
 	};
 	FILE *pid_fp = NULL;
-	/* TODO: add cmdline arg to specify lxcpath */
-	char *lxcpath = NULL;
 
 	lxc_list_init(&defines);
 
@@ -175,14 +173,8 @@ int main(int argc, char *argv[])
 		rcfile = (char *)my_args.rcfile;
 	else {
 		int rc;
-		char *lxcpath = default_lxc_path();
-		if (!lxcpath) {
-			ERROR("Out of memory");
-			return -1;
-		}
 
-		rc = asprintf(&rcfile, "%s/%s/config", lxcpath, my_args.name);
-		free(lxcpath);
+		rc = asprintf(&rcfile, "%s/%s/config", my_args.lxcpath, my_args.name);
 		if (rc == -1) {
 			SYSERROR("failed to allocate memory");
 			return err;
@@ -260,7 +252,7 @@ int main(int argc, char *argv[])
 	if (my_args.close_all_fds)
 		conf->close_all_fds = 1;
 
-	err = lxc_start(my_args.name, args, conf, lxcpath);
+	err = lxc_start(my_args.name, args, conf, my_args.lxcpath);
 
 	/*
 	 * exec ourself, that requires to have all opened fd

src/lxc/lxc_stop.c

@@ -29,6 +29,7 @@
 #include <lxc/log.h>
 
 #include "arguments.h"
+#include "utils.h"
 
 static const struct option my_longopts[] = {
 	LXC_COMMON_OPTIONS
@@ -50,9 +51,6 @@ Options :\n\
 
 int main(int argc, char *argv[])
 {
-	/* TODO - make lxcpath a cmdline arg */
-	const char *lxcpath = NULL;
-
 	if (lxc_arguments_parse(&my_args, argc, argv))
 		return -1;
 
@@ -60,5 +58,5 @@ int main(int argc, char *argv[])
 			 my_args.progname, my_args.quiet))
 		return -1;
 
-	return lxc_stop(my_args.name, lxcpath);
+	return lxc_stop(my_args.name, my_args.lxcpath);
 }

src/lxc/lxc_wait.c

@@ -87,5 +87,5 @@ int main(int argc, char *argv[])
 			 my_args.progname, my_args.quiet))
 		return -1;
 
-	return lxc_wait(strdup(my_args.name), my_args.states, my_args.timeout);
+	return lxc_wait(strdup(my_args.name), my_args.states, my_args.timeout, my_args.lxcpath);
 }

src/lxc/lxccontainer.c

@@ -272,7 +272,7 @@ static bool lxcapi_wait(struct lxc_container *c, const char *state, int timeout)
 	if (!c)
 		return false;
 
-	ret = lxc_wait(c->name, state, timeout);
+	ret = lxc_wait(c->name, state, timeout, c->config_path);
 	return ret == 0;
 }
 
@@ -987,7 +987,7 @@ out:
 	return ret;
 }
 
-char *lxc_get_default_config_path(void)
+const char *lxc_get_default_config_path(void)
 {
 	return default_lxc_path();
 }
@@ -1006,7 +1006,7 @@ struct lxc_container *lxc_container_new(const char *name, const char *configpath
 	if (configpath)
 		c->config_path = strdup(configpath);
 	else
-		c->config_path = default_lxc_path();
+		c->config_path = strdup(default_lxc_path());
 
 	if (!c->config_path) {
 		fprintf(stderr, "Out of memory");

src/lxc/lxccontainer.h

@@ -86,7 +86,7 @@ struct lxc_container *lxc_container_new(const char *name, const char *configpath
 int lxc_container_get(struct lxc_container *c);
 int lxc_container_put(struct lxc_container *c);
 int lxc_get_wait_states(const char **states);
-char *lxc_get_default_config_path(void);
+const char *lxc_get_default_config_path(void);
 
 #if 0
 char ** lxc_get_valid_keys();

src/lxc/restart.c

@@ -64,14 +64,13 @@ static struct lxc_operations restart_ops = {
 	.post_start = post_restart
 };
 
-int lxc_restart(const char *name, int sfd, struct lxc_conf *conf, int flags)
+int lxc_restart(const char *name, int sfd, struct lxc_conf *conf, int flags,
+		const char *lxcpath)
 {
 	struct restart_args restart_arg = {
 		.sfd = sfd,
 		.flags = flags
 	};
-	/* TODO - make lxcpath a cmdline arg */
-	const char *lxcpath = NULL;
 
 	if (lxc_check_inherited(conf, sfd))
 		return -1;

src/lxc/state.c

@@ -191,13 +191,11 @@ static int fillwaitedstates(const char *strstates, int *states)
 	return 0;
 }
 
-extern int lxc_wait(const char *lxcname, const char *states, int timeout)
+extern int lxc_wait(const char *lxcname, const char *states, int timeout, const char *lxcpath)
 {
 	struct lxc_msg msg;
 	int state, ret;
 	int s[MAX_STATE] = { }, fd;
-	/* TODO: add cmdline arg to specify lxcpath */
-	char *lxcpath = NULL;
 
 	if (fillwaitedstates(states, s))
 		return -1;

src/lxc/state.h

@@ -33,6 +33,6 @@ extern lxc_state_t lxc_getstate(const char *name, const char *lxcpath);
 
 extern lxc_state_t lxc_str2state(const char *state);
 extern const char *lxc_state2str(lxc_state_t state);
-extern int lxc_wait(const char *lxcname, const char *states, int timeout);
+extern int lxc_wait(const char *lxcname, const char *states, int timeout, const char *lxcpath);
 
 #endif

src/lxc/utils.c

@@ -212,11 +212,16 @@ static char *copypath(char *p)
 	return retbuf;
 }
 
-char *default_lxc_path(void)
+char *default_lxcpath;
+
+const char *default_lxc_path(void)
 {
-	char buf[1024], *p, *retbuf;
+	char buf[1024], *p;
 	FILE *fin;
 
+	if (default_lxcpath)
+		return default_lxcpath;
+
 	fin = fopen(LXC_GLOBAL_CONF, "r");
 	if (fin) {
 		while (fgets(buf, 1024, fin)) {
@@ -232,20 +237,16 @@ char *default_lxc_path(void)
 			while (*p && (*p == ' ' || *p == '\t')) p++;
 			if (!*p)
 				continue;
-			retbuf = copypath(p);
+			default_lxcpath = copypath(p);
 			goto out;
 		}
 	}
 	/* we couldn't open the file, or didn't find a lxcpath
 	 * entry there.  Return @LXCPATH@ */
-	retbuf = malloc(strlen(LXCPATH)+1);
-	if (!retbuf)
-		goto out;
-	strcpy(retbuf, LXCPATH);
+	default_lxcpath = LXCPATH;
 
 out:
 	if (fin)
 		fclose(fin);
-	INFO("returning %s", (retbuf ? retbuf : "null"));
-	return retbuf;
+	return default_lxcpath;
 }

src/lxc/utils.h

@@ -31,6 +31,6 @@ extern int mkdir_p(const char *dir, mode_t mode);
  * Return a newly allocated buffer containing the default container
  * path.  Caller must free this buffer.
  */
-extern char *default_lxc_path(void);
+extern const char *default_lxc_path(void);
 
 #endif