lxc_init: add custom argument parser

src/lxc/Makefile.am

@@ -275,7 +275,7 @@ lxc_device_SOURCES = tools/lxc_device.c tools/arguments.c
 lxc_execute_SOURCES = tools/lxc_execute.c tools/arguments.c
 lxc_freeze_SOURCES = tools/lxc_freeze.c tools/arguments.c
 lxc_info_SOURCES = tools/lxc_info.c tools/arguments.c
-init_lxc_SOURCES = lxc_init.c tools/arguments.c
+init_lxc_SOURCES = lxc_init.c
 lxc_monitor_SOURCES = tools/lxc_monitor.c tools/arguments.c
 lxc_ls_SOURCES = tools/lxc_ls.c tools/arguments.c
 lxc_copy_SOURCES = tools/lxc_copy.c tools/arguments.c
@@ -303,8 +303,7 @@ endif
 if HAVE_STATIC_LIBCAP
 sbin_PROGRAMS += init.lxc.static
 
-init_lxc_static_SOURCES = lxc_init.c error.c log.c initutils.c caps.c \
-			  tools/arguments.c
+init_lxc_static_SOURCES = lxc_init.c error.c log.c initutils.c caps.c
 
 if !HAVE_GETLINE
 if HAVE_FGETLN

src/lxc/initutils.c

@@ -21,6 +21,8 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#include <sys/prctl.h>
+
 #include "initutils.h"
 #include "log.h"
 
@@ -296,3 +298,107 @@ FILE *fopen_cloexec(const char *path, const char *mode)
 	errno = saved_errno;
 	return ret;
 }
+
+/*
+ * Sets the process title to the specified title. Note that this may fail if
+ * the kernel doesn't support PR_SET_MM_MAP (kernels <3.18).
+ */
+int setproctitle(char *title)
+{
+	static char *proctitle = NULL;
+	char buf[2048], *tmp;
+	FILE *f;
+	int i, len, ret = 0;
+
+	/* We don't really need to know all of this stuff, but unfortunately
+	 * PR_SET_MM_MAP requires us to set it all at once, so we have to
+	 * figure it out anyway.
+	 */
+	unsigned long start_data, end_data, start_brk, start_code, end_code,
+			start_stack, arg_start, arg_end, env_start, env_end,
+			brk_val;
+	struct prctl_mm_map prctl_map;
+
+	f = fopen_cloexec("/proc/self/stat", "r");
+	if (!f) {
+		return -1;
+	}
+
+	tmp = fgets(buf, sizeof(buf), f);
+	fclose(f);
+	if (!tmp) {
+		return -1;
+	}
+
+	/* Skip the first 25 fields, column 26-28 are start_code, end_code,
+	 * and start_stack */
+	tmp = strchr(buf, ' ');
+	for (i = 0; i < 24; i++) {
+		if (!tmp)
+			return -1;
+		tmp = strchr(tmp+1, ' ');
+	}
+	if (!tmp)
+		return -1;
+
+	i = sscanf(tmp, "%lu %lu %lu", &start_code, &end_code, &start_stack);
+	if (i != 3)
+		return -1;
+
+	/* Skip the next 19 fields, column 45-51 are start_data to arg_end */
+	for (i = 0; i < 19; i++) {
+		if (!tmp)
+			return -1;
+		tmp = strchr(tmp+1, ' ');
+	}
+
+	if (!tmp)
+		return -1;
+
+	i = sscanf(tmp, "%lu %lu %lu %*u %*u %lu %lu",
+		&start_data,
+		&end_data,
+		&start_brk,
+		&env_start,
+		&env_end);
+	if (i != 5)
+		return -1;
+
+	/* Include the null byte here, because in the calculations below we
+	 * want to have room for it. */
+	len = strlen(title) + 1;
+
+	proctitle = realloc(proctitle, len);
+	if (!proctitle)
+		return -1;
+
+	arg_start = (unsigned long) proctitle;
+	arg_end = arg_start + len;
+
+	brk_val = syscall(__NR_brk, 0);
+
+	prctl_map = (struct prctl_mm_map) {
+		.start_code = start_code,
+		.end_code = end_code,
+		.start_stack = start_stack,
+		.start_data = start_data,
+		.end_data = end_data,
+		.start_brk = start_brk,
+		.brk = brk_val,
+		.arg_start = arg_start,
+		.arg_end = arg_end,
+		.env_start = env_start,
+		.env_end = env_end,
+		.auxv = NULL,
+		.auxv_size = 0,
+		.exe_fd = -1,
+	};
+
+	ret = prctl(PR_SET_MM, PR_SET_MM_MAP, (long) &prctl_map, sizeof(prctl_map), 0);
+	if (ret == 0)
+		strcpy((char*)arg_start, title);
+	else
+		INFO("setting cmdline failed - %s", strerror(errno));
+
+	return ret;
+}

src/lxc/initutils.h

@@ -25,17 +25,16 @@
 #define __LXC_INITUTILS_H
 
 #include <errno.h>
-#include <stdio.h>
+#include <fcntl.h>
+#include <inttypes.h>
 #include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mount.h>
 #include <sys/stat.h>
 #include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mount.h>
-#include <unistd.h>
-#include <string.h>
-#include <stdlib.h>
-#include <fcntl.h>
-
 
 #include "config.h"
 
@@ -44,11 +43,37 @@
 #define DEFAULT_ZFSROOT "lxc"
 #define DEFAULT_RBDPOOL "lxc"
 
+#ifndef PR_SET_MM
+#define PR_SET_MM 35
+#endif
+
+#ifndef PR_SET_MM_MAP
+#define PR_SET_MM_MAP 14
+
+struct prctl_mm_map {
+	uint64_t start_code;
+	uint64_t end_code;
+	uint64_t start_data;
+	uint64_t end_data;
+	uint64_t start_brk;
+	uint64_t brk;
+	uint64_t start_stack;
+	uint64_t arg_start;
+	uint64_t arg_end;
+	uint64_t env_start;
+	uint64_t env_end;
+	uint64_t *auxv;
+	uint32_t auxv_size;
+	uint32_t exe_fd;
+};
+#endif
+
 extern void lxc_setup_fs(void);
 extern const char *lxc_global_config_value(const char *option_name);
 
 /* open a file with O_CLOEXEC */
 extern void remove_trailing_slashes(char *p);
-FILE *fopen_cloexec(const char *path, const char *mode);
+extern FILE *fopen_cloexec(const char *path, const char *mode);
+extern int setproctitle(char *title);
 
 #endif /* __LXC_INITUTILS_H */

src/lxc/utils.c

@@ -50,31 +50,6 @@
 #include "parse.h"
 #include "utils.h"
 
-#ifndef PR_SET_MM
-#define PR_SET_MM 35
-#endif
-
-#ifndef PR_SET_MM_MAP
-#define PR_SET_MM_MAP 14
-
-struct prctl_mm_map {
-        uint64_t   start_code;
-        uint64_t   end_code;
-        uint64_t   start_data;
-        uint64_t   end_data;
-        uint64_t   start_brk;
-        uint64_t   brk;
-        uint64_t   start_stack;
-        uint64_t   arg_start;
-        uint64_t   arg_end;
-        uint64_t   env_start;
-        uint64_t   env_end;
-        uint64_t   *auxv;
-        uint32_t   auxv_size;
-        uint32_t   exe_fd;
-};
-#endif
-
 #ifndef O_PATH
 #define O_PATH      010000000
 #endif
@@ -1372,110 +1347,6 @@ char *get_template_path(const char *t)
 }
 
 /*
- * Sets the process title to the specified title. Note that this may fail if
- * the kernel doesn't support PR_SET_MM_MAP (kernels <3.18).
- */
-int setproctitle(char *title)
-{
-	static char *proctitle = NULL;
-	char buf[2048], *tmp;
-	FILE *f;
-	int i, len, ret = 0;
-
-	/* We don't really need to know all of this stuff, but unfortunately
-	 * PR_SET_MM_MAP requires us to set it all at once, so we have to
-	 * figure it out anyway.
-	 */
-	unsigned long start_data, end_data, start_brk, start_code, end_code,
-			start_stack, arg_start, arg_end, env_start, env_end,
-			brk_val;
-	struct prctl_mm_map prctl_map;
-
-	f = fopen_cloexec("/proc/self/stat", "r");
-	if (!f) {
-		return -1;
-	}
-
-	tmp = fgets(buf, sizeof(buf), f);
-	fclose(f);
-	if (!tmp) {
-		return -1;
-	}
-
-	/* Skip the first 25 fields, column 26-28 are start_code, end_code,
-	 * and start_stack */
-	tmp = strchr(buf, ' ');
-	for (i = 0; i < 24; i++) {
-		if (!tmp)
-			return -1;
-		tmp = strchr(tmp+1, ' ');
-	}
-	if (!tmp)
-		return -1;
-
-	i = sscanf(tmp, "%lu %lu %lu", &start_code, &end_code, &start_stack);
-	if (i != 3)
-		return -1;
-
-	/* Skip the next 19 fields, column 45-51 are start_data to arg_end */
-	for (i = 0; i < 19; i++) {
-		if (!tmp)
-			return -1;
-		tmp = strchr(tmp+1, ' ');
-	}
-
-	if (!tmp)
-		return -1;
-
-	i = sscanf(tmp, "%lu %lu %lu %*u %*u %lu %lu",
-		&start_data,
-		&end_data,
-		&start_brk,
-		&env_start,
-		&env_end);
-	if (i != 5)
-		return -1;
-
-	/* Include the null byte here, because in the calculations below we
-	 * want to have room for it. */
-	len = strlen(title) + 1;
-
-	proctitle = realloc(proctitle, len);
-	if (!proctitle)
-		return -1;
-
-	arg_start = (unsigned long) proctitle;
-	arg_end = arg_start + len;
-
-	brk_val = syscall(__NR_brk, 0);
-
-	prctl_map = (struct prctl_mm_map) {
-		.start_code = start_code,
-		.end_code = end_code,
-		.start_stack = start_stack,
-		.start_data = start_data,
-		.end_data = end_data,
-		.start_brk = start_brk,
-		.brk = brk_val,
-		.arg_start = arg_start,
-		.arg_end = arg_end,
-		.env_start = env_start,
-		.env_end = env_end,
-		.auxv = NULL,
-		.auxv_size = 0,
-		.exe_fd = -1,
-	};
-
-	ret = prctl(PR_SET_MM, PR_SET_MM_MAP, (long) &prctl_map, sizeof(prctl_map), 0);
-	if (ret == 0)
-		strcpy((char*)arg_start, title);
-	else
-		INFO("setting cmdline failed - %s", strerror(errno));
-
-	return ret;
-}
-
-/*
  * @path:    a pathname where / replaced with '\0'.
  * @offsetp: pointer to int showing which path segment was last seen.
  *           Updated on return to reflect the next segment.

src/lxc/utils.h

@@ -450,7 +450,6 @@ extern int print_to_file(const char *file, const char *content);
 extern bool switch_to_ns(pid_t pid, const char *ns);
 extern int is_dir(const char *path);
 extern char *get_template_path(const char *t);
-extern int setproctitle(char *title);
 extern int safe_mount(const char *src, const char *dest, const char *fstype,
 		      unsigned long flags, const void *data,
 		      const char *rootfs);