path: root/board/mpl/mip405
diff options
authorWolfgang Denk <>2010-06-28 22:00:46 +0200
committerWolfgang Denk <>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /board/mpl/mip405
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 <> Acked-by: Mike Frysinger <>
Diffstat (limited to 'board/mpl/mip405')
1 files changed, 2 insertions, 2 deletions
diff --git a/board/mpl/mip405/cmd_mip405.c b/board/mpl/mip405/cmd_mip405.c
index cd93a7ca0b..8ddb54db1c 100644
--- a/board/mpl/mip405/cmd_mip405.c
+++ b/board/mpl/mip405/cmd_mip405.c
@@ -30,12 +30,12 @@
extern void print_mip405_info(void);
-extern int do_mplcommon(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+extern int do_mplcommon(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
/* ------------------------------------------------------------------------- */
-int do_mip405(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_mip405(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
ulong led_on;
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