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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/cm5200/fwupdate.c
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/cm5200/fwupdate.c')
-rw-r--r--board/cm5200/fwupdate.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/board/cm5200/fwupdate.c b/board/cm5200/fwupdate.c
index 5a27191..c1a4a19 100644
--- a/board/cm5200/fwupdate.c
+++ b/board/cm5200/fwupdate.c
@@ -35,9 +35,9 @@
#include "fwupdate.h"
-extern int do_bootm(cmd_tbl_t *, int, int, char *[]);
+extern int do_bootm(cmd_tbl_t *, int, int, char * const []);
extern long do_fat_read(const char *, void *, unsigned long, int);
-extern int do_fat_fsload(cmd_tbl_t *, int, int, char *[]);
+extern int do_fat_fsload(cmd_tbl_t *, int, int, char * const []);
static int load_rescue_image(ulong);
@@ -47,7 +47,7 @@ void cm5200_fwupdate(void)
char *rsargs;
char *tmp = NULL;
char ka[16];
- char *argv[3] = { "bootm", ka, NULL };
+ char * const argv[3] = { "bootm", ka, NULL };
/* Check if rescue system is disabled... */
if (getenv("norescue")) {
@@ -99,7 +99,7 @@ static int load_rescue_image(ulong addr)
char *tmp;
char dev[7];
char addr_str[16];
- char *argv[6] = { "fatload", "usb", dev, addr_str, nxri, NULL };
+ char * const argv[6] = { "fatload", "usb", dev, addr_str, nxri, NULL };
block_dev_desc_t *stor_dev = NULL;
cmd_tbl_t *bcmd;