mirror of
https://source.denx.de/u-boot/u-boot.git
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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>
57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
#ifndef __EXPORTS_H__
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#define __EXPORTS_H__
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#ifndef __ASSEMBLY__
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#include <common.h>
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/* These are declarations of exported functions available in C code */
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unsigned long get_version(void);
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int getc(void);
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int tstc(void);
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void putc(const char);
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void puts(const char*);
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int printf(const char* fmt, ...);
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void install_hdlr(int, interrupt_handler_t*, void*);
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void free_hdlr(int);
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void *malloc(size_t);
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void free(void*);
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void __udelay(unsigned long);
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unsigned long get_timer(unsigned long);
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int vprintf(const char *, va_list);
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void do_reset (void);
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unsigned long simple_strtoul(const char *cp,char **endp,unsigned int base);
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char *getenv (char *name);
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int setenv (char *varname, char *varvalue);
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long simple_strtol(const char *cp,char **endp,unsigned int base);
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int strcmp(const char * cs,const char * ct);
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int ustrtoul(const char *cp, char **endp, unsigned int base);
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#ifdef CONFIG_HAS_UID
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void forceenv (char *varname, char *varvalue);
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#endif
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#if defined(CONFIG_CMD_I2C)
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int i2c_write (uchar, uint, int , uchar* , int);
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int i2c_read (uchar, uint, int , uchar* , int);
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#endif
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#include <spi.h>
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void app_startup(char * const *);
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#endif /* ifndef __ASSEMBLY__ */
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enum {
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#define EXPORT_FUNC(x) XF_ ## x ,
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#include <_exports.h>
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#undef EXPORT_FUNC
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XF_MAX
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};
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#define XF_VERSION 6
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#if defined(CONFIG_I386)
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extern gd_t *global_data;
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#endif
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#endif /* __EXPORTS_H__ */
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