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authorWolfgang Denk <wd@denx.de>2010-06-28 22:00:46 +0200
committerWolfgang Denk <wd@denx.de>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /board/eltec
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
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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 'board/eltec')
-rw-r--r--board/eltec/bab7xx/bab7xx.c2
-rw-r--r--board/eltec/elppc/elppc.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/board/eltec/bab7xx/bab7xx.c b/board/eltec/bab7xx/bab7xx.c
index 1f78f8d..f5c9777 100644
--- a/board/eltec/bab7xx/bab7xx.c
+++ b/board/eltec/bab7xx/bab7xx.c
@@ -184,7 +184,7 @@ void after_reloc (ulong dest_addr)
* do_reset is done here because in this case it is board specific, since the
* 7xx CPUs can only be reset by external HW (the RTC in this case).
*/
-void do_reset (cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[])
+void do_reset (cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
{
#if defined(CONFIG_RTC_MK48T59)
/* trigger watchdog immediately */
diff --git a/board/eltec/elppc/elppc.c b/board/eltec/elppc/elppc.c
index e73c712..cb9ab86 100644
--- a/board/eltec/elppc/elppc.c
+++ b/board/eltec/elppc/elppc.c
@@ -117,7 +117,7 @@ phys_size_t initdram (int board_type)
* Register PI in the MPC 107 (at offset 0x41090 of the Embedded Utilities
* Memory Block).
*/
-int do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char *argv[])
+int do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
{
out8 (MPC107_EUMB_PI, 1);
return (0);