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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 /board/inka4x0/inkadiag.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 'board/inka4x0/inkadiag.c')
-rw-r--r--board/inka4x0/inkadiag.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/board/inka4x0/inkadiag.c b/board/inka4x0/inkadiag.c
index 0a75abd..637bb5a 100644
--- a/board/inka4x0/inkadiag.c
+++ b/board/inka4x0/inkadiag.c
@@ -131,7 +131,7 @@ static void inka_digio_set_output(unsigned int state, int which)
}
static int do_inkadiag_io(cmd_tbl_t *cmdtp, int flag, int argc,
- char *argv[]) {
+ char * const argv[]) {
unsigned int state, val;
switch (argc) {
@@ -237,7 +237,7 @@ static int ser_getc(volatile struct mpc5xxx_psc *psc)
}
static int do_inkadiag_serial(cmd_tbl_t *cmdtp, int flag, int argc,
- char *argv[]) {
+ char * const argv[]) {
volatile struct NS16550 *uart;
volatile struct mpc5xxx_psc *psc;
unsigned int num, mode;
@@ -389,7 +389,7 @@ static void buzzer_turn_off(void)
}
static int do_inkadiag_buzzer(cmd_tbl_t *cmdtp, int flag, int argc,
- char *argv[]) {
+ char * const argv[]) {
unsigned int period, freq;
int prev, i;
@@ -435,7 +435,7 @@ static int do_inkadiag_buzzer(cmd_tbl_t *cmdtp, int flag, int argc,
return 0;
}
-static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
cmd_tbl_t cmd_inkadiag_sub[] = {
U_BOOT_CMD_MKENT(io, 1, 1, do_inkadiag_io, "read digital input",
@@ -450,10 +450,10 @@ cmd_tbl_t cmd_inkadiag_sub[] = {
};
static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag,
- int argc, char *argv[]) {
+ int argc, char * const argv[]) {
extern int _do_help (cmd_tbl_t *cmd_start, int cmd_items,
cmd_tbl_t *cmdtp, int flag,
- int argc, char *argv[]);
+ int argc, char * const argv[]);
/* do_help prints command name - we prepend inkadiag to our subcommands! */
#ifdef CONFIG_SYS_LONGHELP
puts ("inkadiag ");
@@ -463,7 +463,7 @@ static int do_inkadiag_help(cmd_tbl_t *cmdtp, int flag,
}
static int do_inkadiag(cmd_tbl_t *cmdtp, int flag, int argc,
- char *argv[]) {
+ char * const argv[]) {
cmd_tbl_t *c;
c = find_cmd_tbl(argv[1], &cmd_inkadiag_sub[0], ARRAY_SIZE(cmd_inkadiag_sub));