exec: kill bprm->tcomm[], simplify the "basename" logic
Starting from commit c4ad8f98bef7 ("execve: use 'struct filename *' for
executable name passing") bprm->filename can not go away after
flush_old_exec(), so we do not need to save the binary name in
bprm->tcomm[] added by 96e02d158678 ("exec: fix use-after-free bug in
setup_new_exec()").
And there was never need for filename_to_taskname-like code, we can
simply do set_task_comm(kbasename(filename).
This patch has to change set_task_comm() and trace_task_rename() to
accept "const char *", but I think this change is also good.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/exec.c b/fs/exec.c
index b60ccf9..9e81c63 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1046,7 +1046,7 @@
* so that a new one can be started
*/
-void set_task_comm(struct task_struct *tsk, char *buf)
+void set_task_comm(struct task_struct *tsk, const char *buf)
{
task_lock(tsk);
trace_task_rename(tsk, buf);
@@ -1055,21 +1055,6 @@
perf_event_comm(tsk);
}
-static void filename_to_taskname(char *tcomm, const char *fn, unsigned int len)
-{
- int i, ch;
-
- /* Copies the binary name from after last slash */
- for (i = 0; (ch = *(fn++)) != '\0';) {
- if (ch == '/')
- i = 0; /* overwrite what we wrote */
- else
- if (i < len - 1)
- tcomm[i++] = ch;
- }
- tcomm[i] = '\0';
-}
-
int flush_old_exec(struct linux_binprm * bprm)
{
int retval;
@@ -1083,8 +1068,6 @@
goto out;
set_mm_exe_file(bprm->mm, bprm->file);
-
- filename_to_taskname(bprm->tcomm, bprm->filename, sizeof(bprm->tcomm));
/*
* Release all of the old mmap stuff
*/
@@ -1127,7 +1110,7 @@
else
set_dumpable(current->mm, suid_dumpable);
- set_task_comm(current, bprm->tcomm);
+ set_task_comm(current, kbasename(bprm->filename));
/* Set the new mm task size. We have to do that late because it may
* depend on TIF_32BIT which is only updated in flush_thread() on