On Mon, 15 Jul 2013 17:39:15 +0530, Mandeep Sandhu said:
#define push_root() \ recursive_mutex_lock(&context->id_lock); \ context->uid = current->fsuid; \ context->gid = current->fsgid; \ do { \ struct cred *new1 = prepare_creds(); \ //make changes to any member of this structure \ commit_creds(new1); \ } while(0);
Actually, this has 3 problems: 1) You have a call to mutex_loc() that doesn't get unlocked. This Is Bad. 2) If you're using the 'do { foo } while (0)' trick, you want to put the *whole thing* inside the { } (Hint - you can put local variable definitions inside the curlies as well). 3) Leave the ; off the 'while (0)' in the macro definition, because:
int main() { printf("in main\n"); pushme return 0; }
Somebody will forget and put a ; after pushme - and in some contexts, the additional ; will then cause issues.