coredump: '% at the end' shouldn't bypass core_uses_pid logic

"goto end" should not bypass the "Backward compatibility with
core_uses_pid" code, move this label up.

While at it,

	- It is ugly to copy '|' into cn->corename and then inc
	  the pointer for argv_split().

	  Change format_corename() to increment pat_ptr instead.

	- Remove the dead "if (*pat_ptr == 0)" in format_corename(),
	  we already checked it is not zero.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Colin Walters <walters@verbum.org>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/coredump.c

@@ -165,13 +165,15 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 	cn->corename = NULL;
 	if (expand_corename(cn, core_name_size))
 		return -ENOMEM;
+	cn->corename[0] = '\0';
+
+	if (ispipe)
+		++pat_ptr;
 
 	/* Repeat as long as we have more pattern to process and more output
 	   space */
 	while (*pat_ptr) {
 		if (*pat_ptr != '%') {
-			if (*pat_ptr == 0)
-				goto out;
 			err = cn_printf(cn, "%c", *pat_ptr++);
 		} else {
 			switch (*++pat_ptr) {
@@ -240,6 +242,7 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 			return err;
 	}
 
+out:
 	/* Backward compatibility with core_uses_pid:
 	 *
 	 * If core_pattern does not include a %p (as is the default)
@@ -250,7 +253,6 @@ static int format_corename(struct core_name *cn, struct coredump_params *cprm)
 		if (err)
 			return err;
 	}
-out:
 	return ispipe;
 }
 
@@ -580,7 +582,7 @@ void do_coredump(siginfo_t *siginfo)
 			goto fail_dropcount;
 		}
 
-		helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL);
+		helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL);
 		if (!helper_argv) {
 			printk(KERN_WARNING "%s failed to allocate memory\n",
 			       __func__);
@@ -597,7 +599,7 @@ void do_coredump(siginfo_t *siginfo)
 
 		argv_free(helper_argv);
 		if (retval) {
-			printk(KERN_INFO "Core dump to %s pipe failed\n",
+			printk(KERN_INFO "Core dump to |%s pipe failed\n",
 			       cn.corename);
 			goto close_fail;
 		}