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authorWolfgang Denk <wd@denx.de>2010-06-28 22:00:46 +0200
committerWolfgang Denk <wd@denx.de>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /arch/blackfin/cpu
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
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Make sure that argv[] argument pointers are not modified.
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>
Diffstat (limited to 'arch/blackfin/cpu')
-rw-r--r--arch/blackfin/cpu/bootrom-asm-offsets.c.in2
-rw-r--r--arch/blackfin/cpu/reset.c2
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/blackfin/cpu/bootrom-asm-offsets.c.in b/arch/blackfin/cpu/bootrom-asm-offsets.c.in
index 3146e46..64c2f24 100644
--- a/arch/blackfin/cpu/bootrom-asm-offsets.c.in
+++ b/arch/blackfin/cpu/bootrom-asm-offsets.c.in
@@ -9,4 +9,4 @@
#define _DEFINE(sym, val) asm volatile("\n->" #sym " %0 " #val : : "i" (val))
#define DEFINE(s, m) _DEFINE(offset_##s##_##m, offsetof(s, m))
-int main(int argc, char *argv[])
+int main(int argc, char * const argv[])
diff --git a/arch/blackfin/cpu/reset.c b/arch/blackfin/cpu/reset.c
index e3be740..164afde 100644
--- a/arch/blackfin/cpu/reset.c
+++ b/arch/blackfin/cpu/reset.c
@@ -99,7 +99,7 @@ void bfin_reset_or_hang(void)
#endif
}
-int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
{
bfin_reset_trampoline();
return 0;