objtool: Create backup on error and print args

Recreating objtool errors can be a manual process.  Kbuild removes the
object, so it has to be compiled or linked again before running objtool.
Then the objtool args need to be reversed engineered.

Make that all easier by automatically making a backup of the object file
on error, and print a modified version of the args which can be used to
recreate.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/7571e30636359b3e173ce6e122419452bb31882f.1741975349.git.jpoimboe@kernel.org

1 files changed, 0 insertions, 63 deletions

diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index 53cd881c6b95..1c73fb62fd57 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -20,64 +20,6 @@ bool help;
 
 static struct objtool_file file;
 
-static bool objtool_create_backup(const char *_objname)
-{
-	int len = strlen(_objname);
-	char *buf, *base, *name = malloc(len+6);
-	int s, d, l, t;
-
-	if (!name) {
-		perror("failed backup name malloc");
-		return false;
-	}
-
-	strcpy(name, _objname);
-	strcpy(name + len, ".orig");
-
-	d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644);
-	if (d < 0) {
-		perror("failed to create backup file");
-		return false;
-	}
-
-	s = open(_objname, O_RDONLY);
-	if (s < 0) {
-		perror("failed to open orig file");
-		return false;
-	}
-
-	buf = malloc(4096);
-	if (!buf) {
-		perror("failed backup data malloc");
-		return false;
-	}
-
-	while ((l = read(s, buf, 4096)) > 0) {
-		base = buf;
-		do {
-			t = write(d, base, l);
-			if (t < 0) {
-				perror("failed backup write");
-				return false;
-			}
-			base += t;
-			l -= t;
-		} while (l);
-	}
-
-	if (l < 0) {
-		perror("failed backup read");
-		return false;
-	}
-
-	free(name);
-	free(buf);
-	close(d);
-	close(s);
-
-	return true;
-}
-
 struct objtool_file *objtool_open_read(const char *filename)
 {
 	if (file.elf) {
@@ -89,11 +31,6 @@ struct objtool_file *objtool_open_read(const char *filename)
 	if (!file.elf)
 		return NULL;
 
-	if (opts.backup && !objtool_create_backup(objname)) {
-		WARN("can't create backup file");
-		return NULL;
-	}
-
 	hash_init(file.insn_hash);
 	INIT_LIST_HEAD(&file.retpoline_call_list);
 	INIT_LIST_HEAD(&file.return_thunk_list);