diff options
author | Wolfgang Denk <wd@denx.de> | 2010-06-28 22:00:46 +0200 |
---|---|---|
committer | Wolfgang Denk <wd@denx.de> | 2010-07-04 23:55:42 +0200 |
commit | 54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch) | |
tree | 400f22f0a12ff0ae6c472bed6ac648befc1744a2 /arch/powerpc/cpu/mpc8xx | |
parent | b218ccb5435e64ac2318bb8b6c9594ef1cc724cd (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/powerpc/cpu/mpc8xx')
-rw-r--r-- | arch/powerpc/cpu/mpc8xx/bedbug_860.c | 4 | ||||
-rw-r--r-- | arch/powerpc/cpu/mpc8xx/cpu.c | 4 |
2 files changed, 4 insertions, 4 deletions
diff --git a/arch/powerpc/cpu/mpc8xx/bedbug_860.c b/arch/powerpc/cpu/mpc8xx/bedbug_860.c index 0308bbbf7a..9deda6c2a0 100644 --- a/arch/powerpc/cpu/mpc8xx/bedbug_860.c +++ b/arch/powerpc/cpu/mpc8xx/bedbug_860.c @@ -17,7 +17,7 @@ extern CPU_DEBUG_CTX bug_ctx; void bedbug860_init __P((void)); -void bedbug860_do_break __P((cmd_tbl_t*,int,int,char*[])); +void bedbug860_do_break __P((cmd_tbl_t*,int,int,char*const[])); void bedbug860_break_isr __P((struct pt_regs*)); int bedbug860_find_empty __P((void)); int bedbug860_set __P((int,unsigned long)); @@ -63,7 +63,7 @@ void bedbug860_init( void ) * ====================================================================== */ void bedbug860_do_break (cmd_tbl_t *cmdtp, int flag, int argc, - char *argv[]) + char * const argv[]) { long addr = 0; /* Address to break at */ int which_bp; /* Breakpoint number */ diff --git a/arch/powerpc/cpu/mpc8xx/cpu.c b/arch/powerpc/cpu/mpc8xx/cpu.c index 2eb848bd0e..142cfa5b98 100644 --- a/arch/powerpc/cpu/mpc8xx/cpu.c +++ b/arch/powerpc/cpu/mpc8xx/cpu.c @@ -478,7 +478,7 @@ void upmconfig (uint upm, uint * table, uint size) #ifndef CONFIG_LWMON -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[]) { ulong msr, addr; @@ -521,7 +521,7 @@ int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) * and thus too short to reset the external hardware. So we use the * watchdog to reset the board. */ -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[]) { /* prevent triggering the watchdog */ disable_interrupts (); |