mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-10 23:24:38 +00:00
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>
146 lines
3.6 KiB
C
146 lines
3.6 KiB
C
/*
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* (C) Copyright 2002
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* Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* SPI Read/Write Utilities
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*/
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#include <common.h>
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#include <command.h>
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#include <spi.h>
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/*-----------------------------------------------------------------------
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* Definitions
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*/
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#ifndef MAX_SPI_BYTES
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# define MAX_SPI_BYTES 32 /* Maximum number of bytes we can handle */
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#endif
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#ifndef CONFIG_DEFAULT_SPI_BUS
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# define CONFIG_DEFAULT_SPI_BUS 0
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#endif
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#ifndef CONFIG_DEFAULT_SPI_MODE
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# define CONFIG_DEFAULT_SPI_MODE SPI_MODE_0
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#endif
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/*
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* Values from last command.
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*/
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static unsigned int device;
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static int bitlen;
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static uchar dout[MAX_SPI_BYTES];
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static uchar din[MAX_SPI_BYTES];
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/*
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* SPI read/write
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*
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* Syntax:
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* spi {dev} {num_bits} {dout}
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* {dev} is the device number for controlling chip select (see TBD)
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* {num_bits} is the number of bits to send & receive (base 10)
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* {dout} is a hexadecimal string of data to send
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* The command prints out the hexadecimal string received via SPI.
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*/
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int do_spi (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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struct spi_slave *slave;
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char *cp = 0;
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uchar tmp;
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int j;
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int rcode = 0;
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/*
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* We use the last specified parameters, unless new ones are
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* entered.
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*/
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if ((flag & CMD_FLAG_REPEAT) == 0)
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{
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if (argc >= 2)
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device = simple_strtoul(argv[1], NULL, 10);
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if (argc >= 3)
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bitlen = simple_strtoul(argv[2], NULL, 10);
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if (argc >= 4) {
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cp = argv[3];
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for(j = 0; *cp; j++, cp++) {
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tmp = *cp - '0';
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if(tmp > 9)
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tmp -= ('A' - '0') - 10;
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if(tmp > 15)
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tmp -= ('a' - 'A');
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if(tmp > 15) {
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printf("Hex conversion error on %c, giving up.\n", *cp);
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return 1;
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}
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if((j % 2) == 0)
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dout[j / 2] = (tmp << 4);
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else
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dout[j / 2] |= tmp;
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}
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}
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}
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if ((bitlen < 0) || (bitlen > (MAX_SPI_BYTES * 8))) {
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printf("Invalid bitlen %d, giving up.\n", bitlen);
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return 1;
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}
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/* FIXME: Make these parameters run-time configurable */
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slave = spi_setup_slave(CONFIG_DEFAULT_SPI_BUS, device, 1000000,
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CONFIG_DEFAULT_SPI_MODE);
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if (!slave) {
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printf("Invalid device %d, giving up.\n", device);
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return 1;
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}
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debug ("spi chipsel = %08X\n", device);
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spi_claim_bus(slave);
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if(spi_xfer(slave, bitlen, dout, din,
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SPI_XFER_BEGIN | SPI_XFER_END) != 0) {
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printf("Error with the SPI transaction.\n");
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rcode = 1;
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} else {
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for(j = 0; j < ((bitlen + 7) / 8); j++) {
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printf("%02X", din[j]);
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}
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printf("\n");
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}
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spi_release_bus(slave);
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spi_free_slave(slave);
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return rcode;
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}
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/***************************************************/
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U_BOOT_CMD(
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sspi, 5, 1, do_spi,
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"SPI utility commands",
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"<device> <bit_len> <dout> - Send <bit_len> bits from <dout> out the SPI\n"
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"<device> - Identifies the chip select of the device\n"
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"<bit_len> - Number of bits to send (base 10)\n"
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"<dout> - Hexadecimal string that gets sent"
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);
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