fix all cases of strcpy on overlapping strings.

[oweals/busybox.git] / libbb / execable.c

diff --git a/libbb/execable.c b/libbb/execable.c
index cb56b91816513d2dd289a1ae0801d1405dfc70dd..5c7ac16a2c16465e99b1f9f3fc5f9b35e36709a0 100644 (file)
--- a/libbb/execable.c
+++ b/libbb/execable.c
@@ -13,21 +13,26 @@
  * return 1 if found;
  * return 0 otherwise;
  */
-int execable_file(const char *name)
+int FAST_FUNC execable_file(const char *name)
 {
        struct stat s;
        return (!access(name, X_OK) && !stat(name, &s) && S_ISREG(s.st_mode));
 }
 
-/* search $PATH for an executable file;
+/* search (*PATHp) for an executable file;
  * return allocated string containing full path if found;
- * return NULL otherwise;
+ *  PATHp points to the component after the one where it was found
+ *  (or NULL),
+ *  you may call find_execable 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/).
  */
-char *find_execable(const char *filename)
+char* FAST_FUNC find_execable(const char *filename, char **PATHp)
 {
-       char *path, *p, *n;
+       char *p, *n;
 
-       p = path = xstrdup(getenv("PATH") ? : "");
+       p = *PATHp;
        while (p) {
                n = strchr(p, ':');
                if (n)
@@ -35,24 +40,26 @@ char *find_execable(const char *filename)
                if (*p != '\0') { /* it's not a PATH="foo::bar" situation */
                        p = concat_path_file(p, filename);
                        if (execable_file(p)) {
-                               free(path);
+                               *PATHp = n;
                                return p;
                        }
                        free(p);
                }
                p = n;
-       }
-       free(path);
-       return NULL;
+       } /* on loop exit p == NULL */
+       return p;
 }
 
 /* search $PATH for an executable file;
  * return 1 if found;
  * return 0 otherwise;
  */
-int exists_execable(const char *filename)
+int FAST_FUNC exists_execable(const char *filename)
 {
-       char *ret = find_execable(filename);
+       char *path = xstrdup(getenv("PATH"));
+       char *tmp = path;
+       char *ret = find_execable(filename, &tmp);
+       free(path);
        if (ret) {
                free(ret);
                return 1;
@@ -60,3 +67,12 @@ int exists_execable(const char *filename)
        return 0;
 }
 
+#if ENABLE_FEATURE_PREFER_APPLETS
+/* just like the real execvp, but try to launch an applet named 'file' first
+ */
+int FAST_FUNC bb_execvp(const char *file, char *const argv[])
+{
+       return execvp(find_applet_by_name(file) >= 0 ? bb_busybox_exec_path : file,
+                                       argv);
+}
+#endif