which: fix TODO with NOFORK+malloc_failure misbehaving

function                                             old     new   delta
find_executable                                       86     104     +18
which_main                                           202     194      -8
executable_exists                                     66      51     -15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 18/-23)             Total: -5 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/debianutils/which.c b/debianutils/which.c
index 3bd54ac..02f77a2 100644
--- a/debianutils/which.c
+++ b/debianutils/which.c
@@ -30,12 +30,15 @@
 int which_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int which_main(int argc UNUSED_PARAM, char **argv)
 {
-	const char *env_path;
+	char *env_path;
 	int status = 0;
+	/* This sizeof(): bb_default_root_path is shorter than BB_PATH_ROOT_PATH */
+	char buf[sizeof(BB_PATH_ROOT_PATH)];
 
 	env_path = getenv("PATH");
 	if (!env_path)
-		env_path = bb_default_root_path;
+		/* env_path must be writable, and must not alloc, so... */
+		env_path = strcpy(buf, bb_default_root_path);
 
 	getopt32(argv, "^" "a" "\0" "-1"/*at least one arg*/);
 	argv += optind;
@@ -51,20 +54,17 @@ int which_main(int argc UNUSED_PARAM, char **argv)
 			}
 		} else {
 			char *path;
-			char *tmp;
 			char *p;
 
-			path = tmp = xstrdup(env_path);
-//NOFORK FIXME: nested xmallocs (one is inside find_executable())
-//can leak memory on failure
-			while ((p = find_executable(*argv, &tmp)) != NULL) {
+			path = env_path;
+			/* NOFORK NB: xmalloc inside find_executable(), must have no allocs above! */
+			while ((p = find_executable(*argv, &path)) != NULL) {
 				missing = 0;
 				puts(p);
 				free(p);
 				if (!option_mask32) /* -a not set */
 					break;
 			}
-			free(path);
 		}
 		status |= missing;
 	} while (*++argv);