path: root/api
diff options
authorWolfgang Denk2010-06-28 15:00:46 -0500
committerWolfgang Denk2010-07-04 16:55:42 -0500
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /api
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
Make sure that argv[] argument pointers are not modified.
The hush shell dynamically allocates (and re-allocates) memory for the argument strings in the "char *argv[]" argument vector passed to commands. Any code that modifies these pointers will cause serious corruption of the malloc data structures and crash U-Boot, so make sure the compiler can check that no such modifications are being done by changing the code into "char * const argv[]". This modification is the result of debugging a strange crash caused after adding a new command, which used the following argument processing code which has been working perfectly fine in all Unix systems since version 6 - but not so in U-Boot: int main (int argc, char **argv) { while (--argc > 0 && **++argv == '-') { /* ====> */ while (*++*argv) { switch (**argv) { case 'd': debug++; break; ... default: usage (); } } } ... } The line marked "====>" will corrupt the malloc data structures and usually cause U-Boot to crash when the next command gets executed by the shell. With the modification, the compiler will prevent this with an error: increment of read-only location '*argv' N.B.: The code above can be trivially rewritten like this: while (--argc > 0 && **++argv == '-') { char *arg = *argv; while (*++arg) { switch (*arg) { ... Signed-off-by: Wolfgang Denk <wd@denx.de> Acked-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'api')
1 files changed, 1 insertions, 1 deletions
diff --git a/api/api.c b/api/api.c
index 385a7e3cdc..190ee6ad6c 100644
--- a/api/api.c
+++ b/api/api.c
@@ -37,7 +37,7 @@
37#undef DEBUG 37#undef DEBUG
38 38
39/* U-Boot routines needed */ 39/* U-Boot routines needed */
40extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]); 40extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
41 41
42/***************************************************************************** 42/*****************************************************************************
43 * 43 *