Don't pre-allocate argument vector for command lines

Signed-off-by: David Oberhollenzer <david.oberhollenzer@tele2.at>

initd/runlst.c

@@ -18,6 +18,7 @@
 #include <sys/wait.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <string.h>
 #include <stdio.h>
 #include <fcntl.h>
 
@@ -55,6 +56,20 @@ static int child_setup(const char *ctty)
 	return 0;
 }
 
+static NORETURN void argv_exec(exec_t *e)
+{
+	char **argv = alloca(e->argc + 1), *ptr;
+	int i;
+
+	for (ptr = e->args, i = 0; i < e->argc; ++i, ptr += strlen(ptr) + 1)
+		argv[i] = ptr;
+
+	argv[i] = NULL;
+	execve(argv[0], argv, environ);
+	perror(argv[0]);
+	exit(EXIT_FAILURE);
+}
+
 int runlst_wait(exec_t *list, const char *ctty)
 {
 	pid_t ret, pid;
@@ -66,9 +81,7 @@ int runlst_wait(exec_t *list, const char *ctty)
 		if (pid == 0) {
 			if (child_setup(ctty))
 				exit(EXIT_FAILURE);
-			execve(list->argv[0], list->argv, environ);
+			argv_exec(list);
-			perror(list->argv[0]);
-			exit(EXIT_FAILURE);
 		}
 
 		if (pid == -1) {
@@ -101,9 +114,7 @@ pid_t runlst(exec_t *list, const char *ctty)
 		if (list->next != NULL)
 			exit(runlst_wait(list, NULL));
 
-		execve(list->argv[0], list->argv, environ);
+		argv_exec(list);
-		perror(list->argv[0]);
-		exit(EXIT_FAILURE);
 	}
 
 	if (pid == -1)

lib/include/service.h

@@ -46,8 +46,8 @@ enum {
 
 typedef struct exec_t {
 	struct exec_t *next;
-	char **argv;		/* NULL terminated argument vector */
+	int argc;		/* number of elements in argument vector */
-	char buffer[];		/* backing store for argv */
+	char args[];		/* argument vectot string blob */
 } exec_t;
 
 typedef struct service_t {

lib/include/util.h

@@ -112,18 +112,6 @@ int unescape(char *src);
 */
 int pack_argv(char *str);
 
-/*
-	Split a space seperated string into a sequence of null-terminated
-	strings. Return a NULL terminated array of strings pointing to the
-	start of each sub string.
-
-	It basically runs pack_argv on 'str' and then constructs the argv
-	vector from that, with each entry pointing into 'str'.
-
-	The returned array must be freed with free().
-*/
-char **split_argv(char *str);
-
 /*
 	Search through an array of enum_map_t entries to resolve a string to
 	a numeric value. The end of the map is indicated by a sentinel entry

lib/src/delsvc.c

@@ -30,7 +30,6 @@ void delsvc(service_t *svc)
 		e = svc->exec;
 		svc->exec = e->next;
 
-		free(e->argv);
 		free(e);
 	}
 

lib/src/rdsvc.c

@@ -38,26 +38,6 @@ static int try_unescape(char *arg, rdline_t *rd)
 	return 0;
 }
 
-static char **try_split_argv(char *str, rdline_t *rd)
-{
-	char **argv = split_argv(str);
-
-	if (argv == NULL) {
-		switch (errno) {
-		case EINVAL:
-			fprintf(stderr, "%s: %zu: malformed string constant\n",
-				rd->filename, rd->lineno);
-			break;
-		default:
-			fprintf(stderr, "%s: %zu: %s\n",
-				rd->filename, rd->lineno, strerror(errno));
-			break;
-		}
-	}
-
-	return argv;
-}
-
 static char *try_strdup(const char *str, rdline_t *rd)
 {
 	char *out = strdup(str);
@@ -96,11 +76,12 @@ static int svc_exec(service_t *svc, char *arg, rdline_t *rd)
 		return -1;
 	}
 
-	strcpy(e->buffer, arg);
+	strcpy(e->args, arg);
 
-	e->argv = try_split_argv(e->buffer, rd);
+	e->argc = pack_argv(e->args);
-	if (e->argv == NULL) {
+	if (e->argc < 0) {
-		free(e);
+		fprintf(stderr, "%s: %zu: malformed string constant\n",
+				rd->filename, rd->lineno);
 		return -1;
 	}
 

lib/src/split_argv.c

@@ -80,25 +80,3 @@ fail_str:
 	errno = EINVAL;
 	return -1;
 }
-
-char **split_argv(char *str)
-{
-	char **argv = NULL;
-	int i, count;
-
-	count = pack_argv(str);
-	if (count <= 0)
-		return NULL;
-
-	argv = malloc(sizeof(argv[0]) * (count + 1));
-	if (argv == NULL)
-		return NULL;
-
-	for (i = 0; i < count; ++i) {
-		argv[i] = str;
-		str += strlen(str) + 1;
-	}
-
-	argv[i] = NULL;
-	return argv;
-}