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>
64 lines
1.2 KiB
C
64 lines
1.2 KiB
C
/*
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* U-boot - boot.c - misc boot helper functions
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*
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* Copyright (c) 2005-2008 Analog Devices Inc.
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*
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* (C) Copyright 2000-2004
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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*
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* Licensed under the GPL-2 or later.
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*/
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#include <common.h>
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#include <command.h>
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#include <image.h>
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#include <asm/blackfin.h>
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#ifdef SHARED_RESOURCES
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extern void swap_to(int device_id);
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#endif
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static char *make_command_line(void)
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{
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char *dest = (char *)CONFIG_LINUX_CMDLINE_ADDR;
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char *bootargs = getenv("bootargs");
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if (bootargs == NULL)
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return NULL;
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strncpy(dest, bootargs, CONFIG_LINUX_CMDLINE_SIZE);
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dest[CONFIG_LINUX_CMDLINE_SIZE - 1] = 0;
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return dest;
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}
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extern ulong bfin_poweron_retx;
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int do_bootm_linux(int flag, int argc, char * const argv[], bootm_headers_t *images)
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{
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int (*appl) (char *cmdline);
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char *cmdline;
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if ((flag != 0) && (flag != BOOTM_STATE_OS_GO))
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return 1;
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#ifdef SHARED_RESOURCES
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swap_to(FLASH);
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#endif
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appl = (int (*)(char *))images->ep;
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printf("Starting Kernel at = %p\n", appl);
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cmdline = make_command_line();
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icache_disable();
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dcache_disable();
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asm __volatile__(
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"RETX = %[retx];"
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"CALL (%0);"
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:
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: "p"(appl), "q0"(cmdline), [retx] "d"(bfin_poweron_retx)
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);
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/* does not return */
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return 1;
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}
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