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https://github.com/brain-hackers/u-boot-brain
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![Wolfgang Denk](/assets/img/avatar_default.png)
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>
85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
/*
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* (C) Copyright 2003
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* Stefan Roese, esd gmbh germany, stefan.roese@esd-electronics.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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#include <common.h>
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#include <command.h>
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#include <pci.h>
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#include <pci_ids.h>
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#include <asm/4xx_pci.h>
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#if defined(CONFIG_CMD_BSP)
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/*
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* Set device number on pci board
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*/
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int do_setdevice(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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int idx = 1; /* start at 1 (skip device 0) */
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pci_dev_t bdf = 0;
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u32 addr;
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while (bdf >= 0) {
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if ((bdf = pci_find_device(PCI_VENDOR_ID_IBM, PCI_DEVICE_ID_IBM_405GP, idx++)) < 0) {
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break;
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}
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printf("Found device nr %d at %x!\n", idx-1, bdf);
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pci_read_config_dword(bdf, PCI_BASE_ADDRESS_1, &addr);
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addr &= ~0xf;
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*(u32 *)addr = (bdf & 0x0000f800) >> 11;
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printf("Wrote %x at %x!\n", (bdf & 0x0000f800) >> 11, addr);
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}
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return 0;
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}
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U_BOOT_CMD(
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setdevice, 1, 1, do_setdevice,
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"Set device number on pci adapter boards",
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""
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);
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/*
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* Get device number on pci board
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*/
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int do_getdevice(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
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{
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u32 device;
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char str[32];
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device = *(u32 *)0x0;
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device = 0x16 - device; /* calculate vxworks bp slot id */
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sprintf(str, "%d", device);
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setenv("slot", str);
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printf("Variabel slot set to %x\n", device);
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return 0;
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}
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U_BOOT_CMD(
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getdevice, 1, 1, do_getdevice,
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"Get device number and set slot env variable",
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""
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);
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#endif
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