win32: move detection of file formats to stat(2)

Move the code to detect shell scripts and binary executables from
mingw_access to a separate function, has_exec_format.  Call this function
in do_lstat to decide whether to set the executable bits in the file mode.
This will slow down stat but has a couple of advantages:

- shell scripts are highlighted in ls output
- the test applet can use stat(2) to detect executable files

The new function is used to handle another corner case in spawnveq:
binary executables without the usual .exe extension are only run by
spawnve if the file name ends with '.'.

Two minor changes:

- file_is_win32_executable has been renamed add_win32_extension to
  clarify what it does
- a call to file_is_executable has been removed from find_command
  in ash as it resulted in unhelpful error messages.

1 files changed, 17 insertions, 3 deletions

diff --git a/win32/process.c b/win32/process.c
index da83d1c96..eda143e0e 100644
--- a/win32/process.c
+++ b/win32/process.c
@@ -192,6 +192,7 @@ static intptr_t
 spawnveq(int mode, const char *path, char *const *argv, char *const *env)
 {
         char **new_argv;
+        char *new_path = NULL;
         int i, argc = -1;
         intptr_t ret;
 
@@ -214,7 +215,7 @@ spawnveq(int mode, const char *path, char *const *argv, char *const *env)
                         p = strdup(new_argv[0]);
                 }
                 else {
-                        p = file_is_win32_executable(new_argv[0]);
+                        p = add_win32_extension(new_argv[0]);
                 }
 
                 if (p != NULL && has_bat_suffix(p)) {
@@ -231,12 +232,25 @@ spawnveq(int mode, const char *path, char *const *argv, char *const *env)
                 }
         }
 
-        ret = spawnve(mode, path, new_argv, env);
+        /*
+         * Another special case:  if a binary executable doesn't have an
+         * extension spawnve will only run it if the filename ends with a '.'.
+         */
+        if (!has_exe_suffix(path)) {
+                int len = strlen(path);
+
+                if (path[len-1] != '.' && has_exec_format(path)) {
+                        new_path = xasprintf("%s.", path);
+                }
+        }
+
+        ret = spawnve(mode, new_path ? new_path : path, new_argv, env);
 
         for (i = 0;i < argc;i++)
                 if (new_argv[i] != argv[i])
                         free(new_argv[i]);
         free(new_argv);
+        free(new_path);
 
         return ret;
 }
@@ -275,7 +289,7 @@ mingw_spawn_interpreter(int mode, const char *prog, char *const *argv, char *con
         memcpy(new_argv+nopts+2, argv+1, sizeof(*argv)*argc);
 
         if (file_is_executable(int_path) ||
-                        (fullpath=file_is_win32_executable(int_path)) != NULL) {
+                        (fullpath=add_win32_extension(int_path)) != NULL) {
                 new_argv[0] = fullpath ? fullpath : int_path;
                 ret = spawnveq(mode, new_argv[0], new_argv, envp);
         } else