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/esd/pmc405de/pmc405de.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'board/esd/pmc405de') diff --git a/board/esd/pmc405de/pmc405de.c b/board/esd/pmc405de/pmc405de.c index 3725ece394..b84e08ad72 100644 --- a/board/esd/pmc405de/pmc405de.c +++ b/board/esd/pmc405de/pmc405de.c @@ -374,7 +374,7 @@ int eeprom_write_enable(unsigned dev_addr, int state) return state; } -int do_eep_wren(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_eep_wren(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { int query = argc == 1; int state = 0; @@ -417,7 +417,7 @@ U_BOOT_CMD(eepwren, 2, 0, do_eep_wren, #include extern env_t *env_ptr; -int do_painit(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_painit(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { u32 pram, nextbase, base; char *v; @@ -477,7 +477,7 @@ U_BOOT_CMD( ); #endif /* CONFIG_PRAM */ -int do_selfreset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_selfreset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { struct ppc4xx_gpio *gpio0 = (struct ppc4xx_gpio *)GPIO_BASE; setbits_be32(&gpio0->tcr, CONFIG_SYS_GPIO_SELFRST_N); @@ -489,7 +489,7 @@ U_BOOT_CMD( "" ); -int do_resetout(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_resetout(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { struct pmc405de_cpld *cpld = (struct pmc405de_cpld *)CONFIG_SYS_CPLD_BASE; -- cgit v1.2.1