From 54841ab50c20d6fa6c9cc3eb826989da3a22d934 Mon Sep 17 00:00:00 2001 From: Wolfgang Denk Date: Mon, 28 Jun 2010 22:00:46 +0200 Subject: 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 Acked-by: Mike Frysinger --- board/tqc/tqm5200/cmd_stk52xx.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'board/tqc/tqm5200/cmd_stk52xx.c') diff --git a/board/tqc/tqm5200/cmd_stk52xx.c b/board/tqc/tqm5200/cmd_stk52xx.c index e309beb..0db7050 100644 --- a/board/tqc/tqm5200/cmd_stk52xx.c +++ b/board/tqc/tqm5200/cmd_stk52xx.c @@ -301,7 +301,7 @@ static int i2s_squarewave(unsigned long duration, unsigned int freq, return 0; } -static int cmd_sound(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int cmd_sound(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned long reg, val, duration; char *tmp; @@ -419,7 +419,7 @@ static int cmd_sound(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return 1; } -static int cmd_wav(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int cmd_wav(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned long length, addr; unsigned char volume; @@ -484,7 +484,7 @@ static int cmd_wav(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) return rcode; } -static int cmd_beep(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +static int cmd_beep(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned char volume; unsigned int channel; @@ -581,7 +581,7 @@ void led_init(void) * return 1 if led number unknown * return 0 else */ -int do_led(char *argv[]) +int do_led(char * const argv[]) { struct mpc5xxx_gpio *gpio = (struct mpc5xxx_gpio *)MPC5XXX_GPIO; struct mpc5xxx_gpt_0_7 *gpt = (struct mpc5xxx_gpt_0_7 *)MPC5XXX_GPT; @@ -892,7 +892,7 @@ int can_init(void) * return 1 on CAN failure * return 0 if no failure */ -int do_can(char *argv[]) +int do_can(char * const argv[]) { int i; struct mpc5xxx_mscan *can1 = @@ -994,7 +994,7 @@ int do_can(char *argv[]) * return 3 on rts/cts failure * return 0 if no failure */ -int do_rs232(char *argv[]) +int do_rs232(char * const argv[]) { int error_status = 0; struct mpc5xxx_gpio *gpio = (struct mpc5xxx_gpio *)MPC5XXX_GPIO; @@ -1123,7 +1123,7 @@ static void sm501_backlight (unsigned int state) } #endif /* !CONFIG_FO300 & !CONFIG_TQM5200S */ -int cmd_fkt(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int cmd_fkt(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { int rcode; -- cgit v1.1