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>
diff --git a/common/cmd_sf.c b/common/cmd_sf.c
index d69ae6a..4826e9f 100644
--- a/common/cmd_sf.c
+++ b/common/cmd_sf.c
@@ -19,7 +19,7 @@
static struct spi_flash *flash;
-static int do_spi_flash_probe(int argc, char *argv[])
+static int do_spi_flash_probe(int argc, char * const argv[])
{
unsigned int bus = 0;
unsigned int cs;
@@ -75,7 +75,7 @@
return 1;
}
-static int do_spi_flash_read_write(int argc, char *argv[])
+static int do_spi_flash_read_write(int argc, char * const argv[])
{
unsigned long addr;
unsigned long offset;
@@ -122,7 +122,7 @@
return 1;
}
-static int do_spi_flash_erase(int argc, char *argv[])
+static int do_spi_flash_erase(int argc, char * const argv[])
{
unsigned long offset;
unsigned long len;
@@ -152,7 +152,7 @@
return 1;
}
-static int do_spi_flash(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+static int do_spi_flash(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
const char *cmd;
