path: root/include/bedbug
diff options
authorWolfgang Denk <>2010-06-28 22:00:46 +0200
committerWolfgang Denk <>2010-07-04 23:55:42 +0200
commit54841ab50c20d6fa6c9cc3eb826989da3a22d934 (patch)
tree400f22f0a12ff0ae6c472bed6ac648befc1744a2 /include/bedbug
parentb218ccb5435e64ac2318bb8b6c9594ef1cc724cd (diff)
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 <> Acked-by: Mike Frysinger <>
Diffstat (limited to 'include/bedbug')
1 files changed, 1 insertions, 1 deletions
diff --git a/include/bedbug/type.h b/include/bedbug/type.h
index 38ee9ded73..b7b447b1fe 100644
--- a/include/bedbug/type.h
+++ b/include/bedbug/type.h
@@ -15,7 +15,7 @@ typedef struct {
int current_bp;
struct pt_regs *regs;
- void (*do_break) (cmd_tbl_t *, int, int, char *[]);
+ void (*do_break) (cmd_tbl_t *, int, int, char * const []);
void (*break_isr) (struct pt_regs *);
int (*find_empty) (void);
int (*set) (int, unsigned long);
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