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, 10 insertions, 8 deletions

diff --git a/libbb/executable.c b/libbb/executable.c
index 325dd0107..29d2a2c85 100644
--- a/libbb/executable.c
+++ b/libbb/executable.c
@@ -25,7 +25,8 @@ int FAST_FUNC file_is_executable(const char *name)
  *  you may call find_executable again with this PATHp to continue
  *  (if it's not NULL).
  * return NULL otherwise; (PATHp is undefined)
- * in all cases (*PATHp) contents will be trashed (s/:/NUL/).
+ * in all cases (*PATHp) contents are temporarily modified
+ * but are restored on return (s/:/NUL/ and back).
  */
 char* FAST_FUNC find_executable(const char *filename, char **PATHp)
 {
@@ -41,14 +42,17 @@ char* FAST_FUNC find_executable(const char *filename, char **PATHp)
 
 	p = *PATHp;
 	while (p) {
+		int ex;
+
 		n = strchr(p, ':');
-		if (n)
-			*n++ = '\0';
+		if (n) *n = '\0';
 		p = concat_path_file(
 			p[0] ? p : ".", /* handle "::" case */
 			filename
 		);
-		if (file_is_executable(p)) {
+		ex = file_is_executable(p);
+		if (n) *n++ = ':';
+		if (ex) {
 			*PATHp = n;
 			return p;
 		}
@@ -64,10 +68,8 @@ char* FAST_FUNC find_executable(const char *filename, char **PATHp)
  */
 int FAST_FUNC executable_exists(const char *filename)
 {
-	char *path = xstrdup(getenv("PATH"));
-	char *tmp = path;
-	char *ret = find_executable(filename, &tmp);
-	free(path);
+	char *path = getenv("PATH");
+	char *ret = find_executable(filename, &path);
 	free(ret);
 	return ret != NULL;
 }