Merge pull request #4149 from petris/lxc_multicall

tools: Provide multicall lxc binary

meson.build

@@ -141,6 +141,7 @@ want_pam_cgroup = get_option('pam-cgroup')
 want_mans = get_option('man')
 want_tests = get_option('tests')
 want_tools = get_option('tools')
+want_tools_multicall = get_option('tools-multicall')
 want_commands = get_option('commands')
 want_capabilities = get_option('capabilities')
 want_apparmor = get_option('apparmor')
@@ -793,7 +794,7 @@ subdir('hooks')
 if want_commands
     subdir('src/lxc/cmd')
 endif
-if want_tools
+if want_tools or want_tools_multicall
     subdir('src/lxc/tools')
 endif
 subdir('src/lxc/tools/include')

meson_options.txt

@@ -34,6 +34,9 @@ option('pam-cgroup', type: 'boolean', value: 'false',
 option('tools', type: 'boolean', value: 'true',
        description: 'build and install tools')
 
+option('tools-multicall', type: 'boolean', value: 'false',
+       description: 'build and install busybox style multicall binary')
+
 # was --{disable,enable}-commands in autotools
 option('commands', type: 'boolean', value: 'true',
        description: 'build and install commands')

src/lxc/tools/lxc_attach.c

@@ -271,7 +271,8 @@ static int lxc_attach_create_log_file(const char *log_file)
 	return fd;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_attach_main"))) main(int argc, char *argv[]);
+int lxc_attach_main(int argc, char *argv[])
 {
 	int ret = -1;
 	int wexit = 0;

src/lxc/tools/lxc_autostart.c

@@ -304,7 +304,8 @@ static int toss_list(struct lxc_list *c_groups_list)
 	return 1;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_autostart_main"))) main(int argc, char *argv[]);
+int lxc_autostart_main(int argc, char *argv[])
 {
 	int count = 0, failed = 0, i = 0, ret = 0;
 	struct lxc_list *cmd_group;

src/lxc/tools/lxc_cgroup.c

@@ -50,7 +50,8 @@ static int my_checker(const struct lxc_arguments *args)
 	return 0;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_cgroup_main"))) main(int argc, char *argv[]);
+int lxc_cgroup_main(int argc, char *argv[])
 {
 	char *state_object = NULL, *value = NULL;
 	struct lxc_container *c;

src/lxc/tools/lxc_checkpoint.c

@@ -246,7 +246,8 @@ static bool restore(struct lxc_container *c)
 	}
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_checkpoint_main"))) main(int argc, char *argv[]);
+int lxc_checkpoint_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_config.c

@@ -40,7 +40,8 @@ static void list_config_items(void)
 	exit(EXIT_SUCCESS);
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_config_main"))) main(int argc, char *argv[]);
+int lxc_config_main(int argc, char *argv[])
 {
 	struct lxc_config_items *i;
 	const char *value;

src/lxc/tools/lxc_console.c

@@ -77,7 +77,8 @@ static char etoc(const char *expr)
 	return 1 + ((c > 'Z') ? (c - 'a') : (c - 'Z'));
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_console_main"))) main(int argc, char *argv[]);
+int lxc_console_main(int argc, char *argv[])
 {
 	int ret;
 	struct lxc_container *c;

src/lxc/tools/lxc_copy.c

@@ -142,7 +142,8 @@ static int parse_mntsubopts(char *subopts, char *const *keys,
 static int parse_bind_mnt(char *mntstring, enum mnttype type);
 static int parse_ovl_mnt(char *mntstring, enum mnttype type);
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_copy_main"))) main(int argc, char *argv[]);
+int lxc_copy_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_create.c

@@ -190,7 +190,8 @@ static bool validate_bdev_args(struct lxc_arguments *args)
 	return true;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_create_main"))) main(int argc, char *argv[]);
+int lxc_create_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct bdev_specs spec;

src/lxc/tools/lxc_destroy.c

@@ -188,7 +188,8 @@ static bool do_destroy_with_snapshots(struct lxc_container *c)
 	return bret;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_destroy_main"))) main(int argc, char *argv[]);
+int lxc_destroy_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_device.c

@@ -78,7 +78,8 @@ static bool is_interface(const char *dev_name, pid_t pid)
 	return false;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_device_main"))) main(int argc, char *argv[]);
+int lxc_device_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_execute.c

@@ -128,7 +128,8 @@ static bool set_argv(struct lxc_container *c, struct lxc_arguments *args)
 	return true;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_execute_main"))) main(int argc, char *argv[]);
+int lxc_execute_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_freeze.c

@@ -36,7 +36,8 @@ Options :\n\
 	.log_file     = "none",
 };
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_freeze_main"))) main(int argc, char *argv[]);
+int lxc_freeze_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_info.c

@@ -388,7 +388,8 @@ static int print_info(const char *name, const char *lxcpath)
 	return 0;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_info_main"))) main(int argc, char *argv[]);
+int lxc_info_main(int argc, char *argv[])
 {
 	int ret = EXIT_FAILURE;
 	struct lxc_log log;

src/lxc/tools/lxc_ls.c

@@ -188,7 +188,8 @@ Options :\n\
 	.ls_nesting = 0,
 };
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_ls_main"))) main(int argc, char *argv[]);
+int lxc_ls_main(int argc, char *argv[])
 {
 	int ret = EXIT_FAILURE;
 	struct lxc_log log;

src/lxc/tools/lxc_monitor.c

@@ -216,7 +216,8 @@ static int lxc_tool_monitord_spawn(const char *lxcpath)
 	_exit(EXIT_FAILURE);
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_monitor_main"))) main(int argc, char *argv[]);
+int lxc_monitor_main(int argc, char *argv[])
 {
 	char *regexp;
 	struct lxc_msg msg;

src/lxc/tools/lxc_multicall.c

@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <string.h>
+#include <stdio.h>
+
+#define PREFIX "lxc-"
+
+int lxc_attach_main(int argc, char *argv[]);
+int lxc_autostart_main(int argc, char *argv[]);
+int lxc_cgroup_main(int argc, char *argv[]);
+int lxc_checkpoint_main(int argc, char *argv[]);
+int lxc_config_main(int argc, char *argv[]);
+int lxc_console_main(int argc, char *argv[]);
+int lxc_copy_main(int argc, char *argv[]);
+int lxc_create_main(int argc, char *argv[]);
+int lxc_destroy_main(int argc, char *argv[]);
+int lxc_device_main(int argc, char *argv[]);
+int lxc_execute_main(int argc, char *argv[]);
+int lxc_freeze_main(int argc, char *argv[]);
+int lxc_info_main(int argc, char *argv[]);
+int lxc_ls_main(int argc, char *argv[]);
+int lxc_monitor_main(int argc, char *argv[]);
+int lxc_snapshot_main(int argc, char *argv[]);
+int lxc_start_main(int argc, char *argv[]);
+int lxc_stop_main(int argc, char *argv[]);
+int lxc_top_main(int argc, char *argv[]);
+int lxc_unfreeze_main(int argc, char *argv[]);
+int lxc_unshare_main(int argc, char *argv[]);
+int lxc_wait_main(int argc, char *argv[]);
+
+static const struct {
+	const char *cmd;
+	int (*main)(int argc, char *argv[]);
+} applets[] = {
+	{ "attach", lxc_attach_main },
+	{ "autostart", lxc_autostart_main },
+	{ "cgroup", lxc_cgroup_main },
+	{ "checkpoint", lxc_checkpoint_main },
+	{ "config", lxc_config_main },
+	{ "console", lxc_console_main },
+	{ "copy", lxc_copy_main },
+	{ "create", lxc_create_main },
+	{ "destroy", lxc_destroy_main },
+	{ "device", lxc_device_main },
+	{ "execute", lxc_execute_main },
+	{ "freeze", lxc_freeze_main },
+	{ "info", lxc_info_main },
+	{ "ls", lxc_ls_main },
+	{ "monitor", lxc_monitor_main },
+	{ "snapshot", lxc_snapshot_main },
+	{ "start", lxc_start_main },
+	{ "stop", lxc_stop_main },
+	{ "top", lxc_top_main },
+	{ "unfreeze", lxc_unfreeze_main },
+	{ "unshare", lxc_unshare_main },
+	{ "wait", lxc_wait_main }
+};
+
+const int applets_nmemb = (int)(sizeof(applets)/sizeof(applets[0]));
+
+int main(int argc, char *argv[])
+{
+	const char *cmd;
+	int i;
+
+	if (argc < 1)
+		goto err0;
+
+	cmd = strrchr(argv[0], '/');
+	cmd = cmd ? cmd + 1 : argv[0];
+
+
+	if (!strcmp(cmd, "lxc")) {
+		if (argc < 2)
+			goto err0;
+		cmd = argv[1];
+		argc -= 1;
+		argv += 1;
+		if (!strcmp(cmd, "-h") || !strcmp(cmd, "--help"))
+			goto err0;
+	} else if (!strncmp(cmd, PREFIX, strlen(PREFIX))) {
+		cmd += strlen(PREFIX);
+	} else {
+		goto err0;
+	}
+
+	for (i = 0; i < applets_nmemb; i++) {
+		if (!strcmp(applets[i].cmd, cmd))
+			return applets[i].main(argc, argv);
+	}
+
+	fprintf(stderr, "Unsupported command '%s'\n", cmd);
+	goto err1;
+
+err0:	fprintf(stderr, "This is a multi-call binary, argv[0] is expected to be\n"
+			"  a name of the requested command prefixed with '%s'\n"
+			"or\n"
+			"  'lxc' and the command should be the 1st argument.\n\n"
+			"For example calling this program as '%sls' or 'lxc' "
+			"with the argument 'ls' lists containers.\n\n",
+			PREFIX, PREFIX);
+err1:	fprintf(stderr, "Known commands:\n");
+	for (i = 0; i < applets_nmemb; i++) {
+		fprintf(stderr, "%s ", applets[i].cmd);
+	}
+	putc('\n', stderr);
+	return 1;
+}

src/lxc/tools/lxc_snapshot.c

@@ -61,7 +61,8 @@ static int do_snapshot_restore(struct lxc_container *c,
 static int do_snapshot_task(struct lxc_container *c, enum task task);
 static void print_file(char *path);
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_snapshot_main"))) main(int argc, char *argv[]);
+int lxc_snapshot_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_start.c

@@ -149,7 +149,8 @@ static int ensure_path(char **confpath, const char *path)
 	return 0;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_start_main"))) main(int argc, char *argv[]);
+int lxc_start_main(int argc, char *argv[])
 {
 	const char *lxcpath;
 	char *const *args;

src/lxc/tools/lxc_stop.c

@@ -81,7 +81,8 @@ static int my_parser(struct lxc_arguments *args, int c, char *arg)
 	return 0;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_stop_main"))) main(int argc, char *argv[]);
+int lxc_stop_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_top.c

@@ -564,7 +564,8 @@ static int stdin_handler(int fd, uint32_t events, void *data,
 	return LXC_MAINLOOP_CLOSE;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_top_main"))) main(int argc, char *argv[]);
+int lxc_top_main(int argc, char *argv[])
 {
 	struct lxc_async_descr descr;
 	int ret, ct_print_cnt;

src/lxc/tools/lxc_unfreeze.c

@@ -36,7 +36,8 @@ Options :\n\
 	.log_file     = "none",
 };
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_unfreeze_main"))) main(int argc, char *argv[]);
+int lxc_unfreeze_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/lxc_unshare.c

@@ -280,7 +280,8 @@ static void free_ifname_list(void)
 	}
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_unshare_main"))) main(int argc, char *argv[]);
+int lxc_unshare_main(int argc, char *argv[])
 {
 	int ret;
 	pid_t pid;

src/lxc/tools/lxc_wait.c

@@ -72,7 +72,8 @@ static int my_checker(const struct lxc_arguments *args)
 	return 0;
 }
 
-int main(int argc, char *argv[])
+int __attribute__((weak, alias("lxc_wait_main"))) main(int argc, char *argv[]);
+int lxc_wait_main(int argc, char *argv[])
 {
 	struct lxc_container *c;
 	struct lxc_log log;

src/lxc/tools/meson.build

@@ -2,224 +2,41 @@
 
 tools_common_sources = liblxc_sources + files('arguments.c', 'arguments.h') + include_sources + netns_ifaddrs_sources
 
-tools_lxc_attach_sources = files(
-    'lxc_attach.c') + tools_common_sources
-
-tools_lxc_autostart_sources = files(
-    'lxc_autostart.c') + tools_common_sources
-
-tools_lxc_cgroup_sources = files(
-    'lxc_cgroup.c') + tools_common_sources
-
-tools_lxc_checkpoint_sources = files(
-    'lxc_checkpoint.c') + tools_common_sources
-
-tools_lxc_config_sources = files(
-    'lxc_config.c') + tools_common_sources
-
-tools_lxc_console_sources = files(
-    'lxc_console.c') + tools_common_sources
-
-tools_lxc_copy_sources = files(
-    'lxc_copy.c') + tools_common_sources
-
-tools_lxc_create_sources = files(
-    'lxc_create.c') + tools_common_sources
-
-tools_lxc_destroy_sources = files(
-    'lxc_destroy.c') + tools_common_sources
-
-tools_lxc_device_sources = files(
-    'lxc_device.c') + tools_common_sources
-
-tools_lxc_execute_sources = files(
-    'lxc_execute.c') + tools_common_sources
-
-tools_lxc_freeze_sources = files(
-    'lxc_freeze.c') + tools_common_sources
-
-tools_lxc_info_sources = files(
-    'lxc_info.c') + tools_common_sources
-
-tools_lxc_ls_sources = files(
-    'lxc_ls.c') + tools_common_sources
-
-tools_lxc_monitor_sources = files(
-    'lxc_monitor.c') + tools_common_sources
-
-tools_lxc_snapshot_sources = files(
-    'lxc_snapshot.c') + tools_common_sources
-
-tools_lxc_start_sources = files(
-    'lxc_start.c') + tools_common_sources
-
-tools_lxc_stop_sources = files(
-    'lxc_stop.c') + tools_common_sources
-
-tools_lxc_top_sources = files(
-    'lxc_top.c') + tools_common_sources
-
-tools_lxc_unfreeze_sources = files(
-    'lxc_unfreeze.c') + tools_common_sources
-
-tools_lxc_unshare_sources = files(
-    'lxc_unshare.c') + tools_common_sources
-
-tools_lxc_wait_sources = files(
-    'lxc_wait.c') + tools_common_sources
+tools_commands = ['attach', 'autostart', 'cgroup', 'checkpoint', 'config',
+    'console', 'copy', 'create', 'destroy', 'device', 'execute', 'freeze',
+    'info', 'ls', 'monitor', 'snapshot', 'start', 'stop', 'top', 'unfreeze',
+    'unshare', 'wait']
 
 if want_tools
-    public_programs += executable(
-        'lxc-attach',
-        tools_lxc_attach_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-autostart',
-        tools_lxc_autostart_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-       'lxc-cgroup',
-        tools_lxc_cgroup_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-       'lxc-checkpoint',
-        tools_lxc_checkpoint_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-config',
-        tools_lxc_config_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-console',
-        tools_lxc_console_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-copy',
-        tools_lxc_copy_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-create',
-        tools_lxc_create_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-destroy',
-        tools_lxc_destroy_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-device',
-        tools_lxc_device_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-execute',
-        tools_lxc_execute_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-freeze',
-        tools_lxc_freeze_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-info',
-        tools_lxc_info_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-ls',
-        tools_lxc_ls_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-monitor',
-        tools_lxc_monitor_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-snapshot',
-        tools_lxc_snapshot_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-start',
-        tools_lxc_start_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-stop',
-        tools_lxc_stop_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-top',
-        tools_lxc_top_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-unfreeze',
-        tools_lxc_unfreeze_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-unshare',
-        tools_lxc_unshare_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
-
-    public_programs += executable(
-        'lxc-wait',
-        tools_lxc_wait_sources,
-        include_directories: liblxc_includes,
-        dependencies: liblxc_dep,
-        install: true)
+    foreach cmd : tools_commands 
+        public_programs += executable(
+            'lxc-' + cmd,
+            files('lxc_' + cmd + '.c') + tools_common_sources,
+            include_directories: liblxc_includes,
+            dependencies: liblxc_dep,
+            install: true)
+    endforeach
+endif
+
+if want_tools_multicall
+    tools_all_sources = files('lxc_multicall.c') + tools_common_sources
+    foreach cmd : tools_commands
+        tools_all_sources += files('lxc_' + cmd + '.c')
+    endforeach
+
+    public_programs += executable(
+        'lxc',
+        tools_all_sources,
+        include_directories: liblxc_includes,
+        dependencies: liblxc_dep,
+        install: true)
+
+    if want_tools == false
+        foreach cmd : tools_commands
+            public_programs += install_symlink(
+                'lxc-' + cmd,
+                pointing_to: 'lxc',
+                install_dir: get_option('bindir'))
+        endforeach
+    endif
 endif