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/du440/du440.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) (limited to 'board/esd/du440') diff --git a/board/esd/du440/du440.c b/board/esd/du440/du440.c index 111cce5..ba3c97c 100644 --- a/board/esd/du440/du440.c +++ b/board/esd/du440/du440.c @@ -409,7 +409,7 @@ int dcf77_status(void) return mv; } -int do_dcf77(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_dcf77(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { int mv; u32 pin, pinold; @@ -490,7 +490,7 @@ int usbhub_init(void) return ret; } -int do_hubinit(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_hubinit(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { usbhub_init(); return 0; @@ -573,7 +573,7 @@ int boot_eeprom_write (unsigned dev_addr, return rcode; } -int do_setup_boot_eeprom(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_setup_boot_eeprom(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { ulong sdsdp[4]; @@ -673,7 +673,7 @@ 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; @@ -727,7 +727,7 @@ static int pld_interrupt(u32 arg) return rc; } -int do_waitpwrirq(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_waitpwrirq(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { got_pldirq = 0; @@ -795,7 +795,7 @@ int dvi_init(void) return ret; } -int do_dviinit(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_dviinit(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { dvi_init(); return 0; @@ -810,7 +810,7 @@ U_BOOT_CMD( * TODO: 'time' command might be useful for others as well. * Move to 'common' directory. */ -int do_time(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_time(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned long long start, end; char c, cmd[CONFIG_SYS_CBSIZE]; @@ -874,7 +874,7 @@ unsigned int prng(unsigned int max) return Y; } -int do_gfxdemo(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +int do_gfxdemo(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) { unsigned int color; unsigned int x, y, dx, dy; -- cgit v1.1