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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>
129 lines
3.6 KiB
C
129 lines
3.6 KiB
C
/*
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* (C) Copyright 2000-2009
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* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
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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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* Definitions for Command Processor
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*/
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#ifndef __COMMAND_H
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#define __COMMAND_H
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#include <config.h>
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#ifndef NULL
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#define NULL 0
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#endif
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/* Default to a width of 8 characters for help message command width */
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#ifndef CONFIG_SYS_HELP_CMD_WIDTH
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#define CONFIG_SYS_HELP_CMD_WIDTH 8
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#endif
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#ifndef __ASSEMBLY__
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/*
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* Monitor Command Table
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*/
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struct cmd_tbl_s {
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char *name; /* Command Name */
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int maxargs; /* maximum number of arguments */
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int repeatable; /* autorepeat allowed? */
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/* Implementation function */
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int (*cmd)(struct cmd_tbl_s *, int, int, char * const []);
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char *usage; /* Usage message (short) */
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#ifdef CONFIG_SYS_LONGHELP
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char *help; /* Help message (long) */
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#endif
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#ifdef CONFIG_AUTO_COMPLETE
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/* do auto completion on the arguments */
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int (*complete)(int argc, char * const argv[], char last_char, int maxv, char *cmdv[]);
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#endif
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};
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typedef struct cmd_tbl_s cmd_tbl_t;
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extern cmd_tbl_t __u_boot_cmd_start;
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extern cmd_tbl_t __u_boot_cmd_end;
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/* common/command.c */
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int _do_help (cmd_tbl_t *cmd_start, int cmd_items, cmd_tbl_t * cmdtp, int
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flag, int argc, char * const argv[]);
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cmd_tbl_t *find_cmd(const char *cmd);
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cmd_tbl_t *find_cmd_tbl (const char *cmd, cmd_tbl_t *table, int table_len);
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extern int cmd_usage(cmd_tbl_t *cmdtp);
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#ifdef CONFIG_AUTO_COMPLETE
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extern void install_auto_complete(void);
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extern int cmd_auto_complete(const char *const prompt, char *buf, int *np, int *colp);
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#endif
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/*
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* Monitor Command
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*
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* All commands use a common argument format:
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*
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* void function (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
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*/
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typedef void command_t (cmd_tbl_t *, int, int, char *[]);
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#if defined(CONFIG_CMD_MEMORY) \
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|| defined(CONFIG_CMD_I2C) \
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|| defined(CONFIG_CMD_ITEST) \
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|| defined(CONFIG_CMD_PCI) \
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|| defined(CONFIG_CMD_PORTIO)
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#define CMD_DATA_SIZE
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extern int cmd_get_data_size(char* arg, int default_size);
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#endif
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#endif /* __ASSEMBLY__ */
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/*
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* Command Flags:
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*/
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#define CMD_FLAG_REPEAT 0x0001 /* repeat last command */
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#define CMD_FLAG_BOOTD 0x0002 /* command is from bootd */
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#define Struct_Section __attribute__ ((unused,section (".u_boot_cmd")))
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#ifdef CONFIG_SYS_LONGHELP
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#define U_BOOT_CMD(name,maxargs,rep,cmd,usage,help) \
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cmd_tbl_t __u_boot_cmd_##name Struct_Section = {#name, maxargs, rep, cmd, usage, help}
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#define U_BOOT_CMD_MKENT(name,maxargs,rep,cmd,usage,help) \
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{#name, maxargs, rep, cmd, usage, help}
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#else /* no long help info */
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#define U_BOOT_CMD(name,maxargs,rep,cmd,usage,help) \
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cmd_tbl_t __u_boot_cmd_##name Struct_Section = {#name, maxargs, rep, cmd, usage}
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#define U_BOOT_CMD_MKENT(name,maxargs,rep,cmd,usage,help) \
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{#name, maxargs, rep, cmd, usage}
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#endif /* CONFIG_SYS_LONGHELP */
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#endif /* __COMMAND_H */
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