mirror of
https://github.com/AsahiLinux/u-boot
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54841ab50c
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>
37 lines
616 B
C
37 lines
616 B
C
/*
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* Command for accessing DataFlash.
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*
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* Copyright (C) 2008 Atmel Corporation
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*/
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#include <common.h>
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#include <df.h>
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static int do_df(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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const char *cmd;
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/* need at least two arguments */
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if (argc < 2)
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goto usage;
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cmd = argv[1];
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if (strcmp(cmd, "init") == 0) {
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df_init(0, 0, 1000000);
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return 0;
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}
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if (strcmp(cmd, "info") == 0) {
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df_show_info();
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return 0;
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}
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usage:
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cmd_usage(cmdtp);
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return 1;
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}
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U_BOOT_CMD(
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sf, 2, 1, do_serial_flash,
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"Serial flash sub-system",
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"probe [bus:]cs - init flash device on given SPI bus and CS")
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