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authorWolfgang Denk <wd@denx.de>2010-06-28 22:00:46 +0200
committerWolfgang Denk <wd@denx.de>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /common/hush.c
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
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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 'common/hush.c')
-rw-r--r--common/hush.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/common/hush.c b/common/hush.c
index 9eea90f..8a74d22 100644
--- a/common/hush.c
+++ b/common/hush.c
@@ -94,7 +94,7 @@
#include <hush.h>
#include <command.h> /* find_cmd */
/*cmd_boot.c*/
-extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]); /* do_bootd */
+extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]); /* do_bootd */
#endif
#ifndef __U_BOOT__
#include <ctype.h> /* isalpha, isdigit */
@@ -1024,7 +1024,7 @@ static void get_user_input(struct in_str *i)
#ifdef CONFIG_BOOT_RETRY_TIME
# ifdef CONFIG_RESET_TO_RETRY
- extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+ extern int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
# else
# error "This currently only works with CONFIG_RESET_TO_RETRY enabled"
# endif
@@ -1681,7 +1681,7 @@ static int run_pipe_real(struct pipe *pi)
} else {
int rcode;
#if defined(CONFIG_CMD_BOOTD)
- extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+ extern int do_bootd (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
/* avoid "bootd" recursion */
if (cmdtp->cmd == do_bootd) {
@@ -3351,7 +3351,7 @@ static void setup_job_control(void)
tcsetpgrp(shell_terminal, shell_pgrp);
}
-int hush_main(int argc, char **argv)
+int hush_main(int argc, char * const *argv)
{
int opt;
FILE *input;
@@ -3588,7 +3588,7 @@ static char * make_string(char ** inp)
}
#ifdef __U_BOOT__
-int do_showvar (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_showvar (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
int i, k;
int rcode = 0;