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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 /arch/powerpc/cpu/mpc8220
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
downloadu-boot-linaro-stable-54841ab50c20d6fa6c9cc3eb826989da3a22d934.tar.gz
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/powerpc/cpu/mpc8220')
-rw-r--r--arch/powerpc/cpu/mpc8220/cpu.c2
-rw-r--r--arch/powerpc/cpu/mpc8220/interrupts.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/cpu/mpc8220/cpu.c b/arch/powerpc/cpu/mpc8220/cpu.c
index 563cfe053..64e0526e8 100644
--- a/arch/powerpc/cpu/mpc8220/cpu.c
+++ b/arch/powerpc/cpu/mpc8220/cpu.c
@@ -52,7 +52,7 @@ int checkcpu (void)
/* ------------------------------------------------------------------------- */
-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[])
{
volatile gptmr8220_t *gptmr = (volatile gptmr8220_t *) MMAP_GPTMR;
ulong msr;
diff --git a/arch/powerpc/cpu/mpc8220/interrupts.c b/arch/powerpc/cpu/mpc8220/interrupts.c
index 78e99179c..9544d85b5 100644
--- a/arch/powerpc/cpu/mpc8220/interrupts.c
+++ b/arch/powerpc/cpu/mpc8220/interrupts.c
@@ -74,7 +74,7 @@ void irq_free_handler (int vec)
/****************************************************************************/
void
-do_irqinfo (cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char *argv[])
+do_irqinfo (cmd_tbl_t * cmdtp, bd_t * bd, int flag, int argc, char * const argv[])
{
puts ("IRQ related functions are unimplemented currently.\n");
}