utils: add key-value offset support to get_cmdline_val()

Add offset support of key-value pairs to get_cmdline_val() for getting
multiple values of the same keys.

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

utils/utils.c

@@ -163,10 +163,10 @@ char *get_active_console(char *out, int len)
 	return NULL;
 }
 
-char* get_cmdline_val(const char* name, char* out, int len)
+char *get_cmdline_val_offset(const char *name, char *out, int len, int offset)
 {
 	char line[CMDLINE_SIZE + 1], *c, *sptr;
-	int fd = open("/proc/cmdline", O_RDONLY);
+	int i, fd = open("/proc/cmdline", O_RDONLY);
 	ssize_t r = read(fd, line, sizeof(line) - 1);
 	close(fd);
 
@@ -175,7 +175,7 @@ char* get_cmdline_val(const char* name, char* out, int len)
 
 	line[r] = 0;
 
-	for (c = strtok_r(line, " \t\n", &sptr); c;
+	for (i = 0, c = strtok_r(line, " \t\n", &sptr); c;
 			c = strtok_r(NULL, " \t\n", &sptr)) {
 		char *sep = strchr(c, '=');
 		if (sep == NULL)
@@ -185,6 +185,8 @@ char* get_cmdline_val(const char* name, char* out, int len)
 		if (strncmp(name, c, klen) || name[klen] != 0)
 			continue;
 
+		if (i++ < offset)
+			continue;
 		strncpy(out, &sep[1], len);
 		out[len-1] = 0;
 		return out;

utils/utils.h

@@ -51,9 +51,12 @@ int blobmsg_list_fill(struct blobmsg_list *list, void *data, int len, bool array
 void blobmsg_list_free(struct blobmsg_list *list);
 bool blobmsg_list_equal(struct blobmsg_list *l1, struct blobmsg_list *l2);
 void blobmsg_list_move(struct blobmsg_list *list, struct blobmsg_list *src);
-char *get_cmdline_val(const char *name, char *out, int len);
+char *get_cmdline_val_offset(const char *name, char *out, int len, int offset);
 char *get_active_console(char *out, int len);
 
+#define get_cmdline_val(name, out, len) \
+	get_cmdline_val_offset(name, out, len, 0)
+
 int patch_fd(const char *device, int fd, int flags);
 int patch_stdio(const char *device);