ubi tools: ubiupdatevol supports "-" input and actually respects -s SIZE

Decided to not make any flash applets NOEXEC.
Minor robustifications here and there. Better error messages. Save on strings:

function                                             old     new   delta
ubi_tools_main                                      1235    1288     +53
ubi_get_volid_by_name                                125     133      +8
ubirename_main                                       198     204      +6
get_num_from_file                                     90      94      +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 71/0)               Total: 71 bytes
   text	   data	    bss	    dec	    hex	filename
 915696	    485	   6880	 923061	  e15b5	busybox_old
 915670	    485	   6880	 923035	  e159b	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/miscutils/ubirename.c b/miscutils/ubirename.c
index 786c4b9fa..ecc8fe137 100644
--- a/miscutils/ubirename.c
+++ b/miscutils/ubirename.c
@@ -14,6 +14,7 @@
 //config:	Utility to rename UBI volumes
 
 //applet:IF_UBIRENAME(APPLET(ubirename, BB_DIR_USR_SBIN, BB_SUID_DROP))
+/* not NOEXEC: if flash operation stalls, use less memory in "hung" process */
 
 //kbuild:lib-$(CONFIG_UBIRENAME) += ubirename.o
 
@@ -80,9 +81,12 @@ int ubirename_main(int argc, char **argv)
 	argv += 2;
 	while (argv[0]) {
 		rnvol->ents[n].vol_id = ubi_get_volid_by_name(ubi_devnum, argv[0]);
-		rnvol->ents[n].name_len = strlen(argv[1]);
+
+		/* strnlen avoids overflow of 16-bit field (paranoia) */
+		rnvol->ents[n].name_len = strnlen(argv[1], sizeof(rnvol->ents[n].name));
 		if (rnvol->ents[n].name_len >= sizeof(rnvol->ents[n].name))
 			bb_error_msg_and_die("new name '%s' is too long", argv[1]);
+
 		strcpy(rnvol->ents[n].name, argv[1]);
 		n++;
 		argv += 2;