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/amcc/taishan/showinfo.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'board/amcc/taishan/showinfo.c') diff --git a/board/amcc/taishan/showinfo.c b/board/amcc/taishan/showinfo.c index a9a80e5..587fe74 100644 --- a/board/amcc/taishan/showinfo.c +++ b/board/amcc/taishan/showinfo.c @@ -161,7 +161,7 @@ void show_xbridge_info(void) printf("PCIL0_XSTS = %#010lx\n", in32r(PCIL0_STS)); } -int do_show_xbridge_info(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_show_xbridge_info(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { show_xbridge_info(); return 0; @@ -215,7 +215,7 @@ void show_pcix_device_info(void) } int do_show_pcix_device_info(cmd_tbl_t * cmdtp, int flag, int argc, - char *argv[]) + char * const argv[]) { show_pcix_device_info(); return 0; @@ -226,7 +226,7 @@ U_BOOT_CMD(xdevinfo, 1, 1, do_show_pcix_device_info, extern void show_reset_reg(void); -int do_show_reset_reg_info(cmd_tbl_t * cmdtp, int flag, int argc, char *argv[]) +int do_show_reset_reg_info(cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[]) { show_reset_reg(); return 0; -- cgit v1.1