path: root/arch/avr32
diff options
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 /arch/avr32
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 'arch/avr32')
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/avr32/cpu/cpu.c b/arch/avr32/cpu/cpu.c
index 904bfb227..e4489bb2e 100644
--- a/arch/avr32/cpu/cpu.c
+++ b/arch/avr32/cpu/cpu.c
@@ -76,7 +76,7 @@ void prepare_to_boot(void)
"sync 0" : : "r"(0) : "memory");
-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[])
/* This will reset the CPU core, caches, MMU and all internal busses */
__builtin_mtdr(8, 1 << 13); /* set DC:DBE */
diff --git a/arch/avr32/lib/bootm.c b/arch/avr32/lib/bootm.c
index 6a3172a9a..8a47cfeb4 100644
--- a/arch/avr32/lib/bootm.c
+++ b/arch/avr32/lib/bootm.c
@@ -171,7 +171,7 @@ static void setup_end_tag(struct tag *params)
params->hdr.size = 0;
-int do_bootm_linux(int flag, int argc, char *argv[], bootm_headers_t *images)
+int do_bootm_linux(int flag, int argc, char * const argv[], bootm_headers_t *images)
void (*theKernel)(int magic, void *tagtable);
struct tag *params, *params_start;