gutils: Split g_find_program_path() to make it more flexible and testable

Split g_find_program_path() in g_find_program_for_path() that supports
passing path arguments and providing a custom working directory.

Adding tests to cover the cases we were not doing before.

glib/gutils.c

@@ -275,7 +275,44 @@ gchar*
 g_find_program_in_path (const gchar *program)
 #endif
 {
-  const gchar *path, *p;
+  return g_find_program_for_path (program, NULL, NULL);
+}
+
+/**
+ * g_find_program_for_path:
+ * @program: (type filename): a program name in the GLib file name encoding
+ * @path: (type filename) (nullable): the current dir where to search program
+ * @working_dir: (type filename) (nullable): the working dir where to search
+ *   program
+ *
+ * Locates the first executable named @program in @path, in the
+ * same way that execvp() would locate it. Returns an allocated string
+ * with the absolute path name (taking in account the @working_dir), or
+ * %NULL if the program is not found in @path. If @program is already an
+ * absolute path, returns a copy of @program if @program exists and is
+ * executable, and %NULL otherwise.
+ *
+ * On Windows, if @path is %NULL, it looks for the file in the same way as
+ * CreateProcess()  would. This means first in the directory where the
+ * executing program was loaded from, then in the current directory, then in
+ * the Windows 32-bit system directory, then in the Windows directory, and
+ * finally in the directories in the `PATH` environment variable. If
+ * the program is found, the return value contains the full name
+ * including the type suffix.
+ *
+ * Returns: (type filename) (transfer full) (nullable): a newly-allocated
+ *   string with the absolute path, or %NULL
+ * Since: 2.76
+ **/
+char *
+g_find_program_for_path (const char *program,
+                         const char *path,
+                         const char *working_dir)
+{
+  const char *original_path = path;
+  const char *original_program = program;
+  char *program_path = NULL;
+  const gchar *p;
   gchar *name, *freeme;
 #ifdef G_OS_WIN32
   const gchar *path_copy;
@@ -290,20 +327,28 @@ g_find_program_in_path (const gchar *program)
 
   g_return_val_if_fail (program != NULL, NULL);
 
+  /* Use the working dir as program path if provided */
+  if (working_dir && !g_path_is_absolute (program))
+    {
+      program_path = g_build_filename (working_dir, program, NULL);
+      program = program_path;
+    }
+
   /* If it is an absolute path, or a relative path including subdirectories,
    * don't look in PATH.
    */
   if (g_path_is_absolute (program)
-      || strchr (program, G_DIR_SEPARATOR) != NULL
+      || strchr (original_program, G_DIR_SEPARATOR) != NULL
 #ifdef G_OS_WIN32
-      || strchr (program, '/') != NULL
+      || strchr (original_program, '/') != NULL
 #endif
       )
     {
       if (g_file_test (program, G_FILE_TEST_IS_EXECUTABLE) &&
 	  !g_file_test (program, G_FILE_TEST_IS_DIR))
         {
-          gchar *out = NULL, *cwd = NULL;
+          gchar *out = NULL;
+          char *cwd;
 
           if (g_path_is_absolute (program))
             return g_strdup (program);
@@ -311,13 +356,26 @@ g_find_program_in_path (const gchar *program)
           cwd = g_get_current_dir ();
           out = g_build_filename (cwd, program, NULL);
           g_free (cwd);
+          g_free (program_path);
+
           return g_steal_pointer (&out);
         }
       else
+        {
+          g_clear_pointer (&program_path, g_free);
+
+          if (g_path_is_absolute (original_program))
             return NULL;
         }
+    }
 
+  program = original_program;
+
+  if G_LIKELY (original_path == NULL)
     path = g_getenv ("PATH");
+  else
+    path = original_path;
+
 #if defined(G_OS_UNIX)
   if (path == NULL)
     {
@@ -334,6 +392,8 @@ g_find_program_in_path (const gchar *program)
       path = "/bin:/usr/bin:.";
     }
 #else
+  if G_LIKELY (original_path == NULL)
+    {
       n = GetModuleFileNameW (NULL, wfilename, MAXPATHLEN);
       if (n > 0 && n < MAXPATHLEN)
         filename = g_utf16_to_utf8 (wfilename, -1, NULL, NULL, NULL);
@@ -385,6 +445,12 @@ g_find_program_in_path (const gchar *program)
         }
 
       path_copy = path;
+    }
+  else
+    {
+      path_copy = g_strdup (path);
+    }
+
 #endif
   
   len = strlen (program) + 1;
@@ -401,6 +467,7 @@ g_find_program_in_path (const gchar *program)
   do
     {
       char *startp;
+      char *startp_path = NULL;
 
       path = p;
       p = my_strchrnul (path, G_SEARCHPATH_SEPARATOR);
@@ -413,6 +480,13 @@ g_find_program_in_path (const gchar *program)
       else
         startp = memcpy (name - (p - path), path, p - path);
 
+      /* Use the working dir as program path if provided */
+      if (working_dir && !g_path_is_absolute (startp))
+        {
+          startp_path = g_build_filename (working_dir, startp, NULL);
+          startp = startp_path;
+        }
+
       if (g_file_test (startp, G_FILE_TEST_IS_EXECUTABLE) &&
 	  !g_file_test (startp, G_FILE_TEST_IS_DIR))
         {
@@ -425,12 +499,15 @@ g_find_program_in_path (const gchar *program)
             ret = g_build_filename (cwd, startp, NULL);
             g_free (cwd);
           }
+          g_free (startp_path);
           g_free (freeme);
 #ifdef G_OS_WIN32
 	  g_free ((gchar *) path_copy);
 #endif
           return ret;
         }
+
+      g_free (startp_path);
     }
   while (*p++ != '\0');
   

glib/gutilsprivate.h

@@ -32,6 +32,11 @@ GLIB_AVAILABLE_IN_2_60
 void g_set_user_dirs (const gchar *first_dir_type,
                       ...) G_GNUC_NULL_TERMINATED;
 
+GLIB_AVAILABLE_IN_2_76
+char * g_find_program_for_path (const char *program,
+                                const char *path,
+                                const char *working_dir);
+
 /* Returns the smallest power of 2 greater than or equal to n,
  * or 0 if such power does not fit in a gsize
  */

glib/tests/utils.c

@@ -29,6 +29,8 @@
 
 #include "glib.h"
 #include "glib-private.h"
+#include "gutilsprivate.h"
+#include "glib/gstdio.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -485,6 +487,145 @@ test_find_program (void)
   g_assert (res == NULL);
 }
 
+static void
+test_find_program_for_path (void)
+{
+  GError *error = NULL;
+  /* Using .cmd extension to make windows to consider it an executable */
+  const char *command_to_find = "just-an-exe-file.cmd";
+  char *path;
+  char *exe_path;
+  char *found_path;
+  char *old_cwd;
+  char *tmp;
+
+  tmp = g_dir_make_tmp ("find_program_for_path_XXXXXXX", &error);
+  g_assert_no_error (error);
+
+  path = g_build_filename (tmp, "sub-path", NULL);
+  g_mkdir (path, 0700);
+  g_assert_true (g_file_test (path, G_FILE_TEST_IS_DIR));
+
+  exe_path = g_build_filename (path, command_to_find, NULL);
+  g_file_set_contents (exe_path, "", -1, &error);
+  g_assert_no_error (error);
+  g_assert_true (g_file_test (exe_path, G_FILE_TEST_EXISTS));
+
+#ifdef G_OS_UNIX
+  g_assert_no_errno (g_chmod (exe_path, 0500));
+#endif
+  g_assert_true (g_file_test (exe_path, G_FILE_TEST_IS_EXECUTABLE));
+
+  g_assert_null (g_find_program_in_path (command_to_find));
+  g_assert_null (g_find_program_for_path (command_to_find, NULL, NULL));
+
+  found_path = g_find_program_for_path (command_to_find, path, NULL);
+#ifdef __APPLE__
+  g_assert_nonnull (found_path);
+  g_assert_true (g_str_has_suffix (found_path, exe_path));
+#else
+  g_assert_cmpstr (exe_path, ==, found_path);
+#endif
+  g_clear_pointer (&found_path, g_free);
+
+  found_path = g_find_program_for_path (command_to_find, path, path);
+#ifdef __APPLE__
+  g_assert_nonnull (found_path);
+  g_assert_true (g_str_has_suffix (found_path, exe_path));
+#else
+  g_assert_cmpstr (exe_path, ==, found_path);
+#endif
+  g_clear_pointer (&found_path, g_free);
+
+  found_path = g_find_program_for_path (command_to_find, NULL, path);
+#ifdef __APPLE__
+  g_assert_nonnull (found_path);
+  g_assert_true (g_str_has_suffix (found_path, exe_path));
+#else
+  g_assert_cmpstr (exe_path, ==, found_path);
+#endif
+  g_clear_pointer (&found_path, g_free);
+
+  found_path = g_find_program_for_path (command_to_find, "::", path);
+#ifdef __APPLE__
+  g_assert_nonnull (found_path);
+  g_assert_true (g_str_has_suffix (found_path, exe_path));
+#else
+  g_assert_cmpstr (exe_path, ==, found_path);
+#endif
+  g_clear_pointer (&found_path, g_free);
+
+  old_cwd = g_get_current_dir ();
+  g_chdir (path);
+  found_path =
+    g_find_program_for_path (command_to_find,
+      G_SEARCHPATH_SEPARATOR_S G_SEARCHPATH_SEPARATOR_S, NULL);
+  g_chdir (old_cwd);
+  g_clear_pointer (&old_cwd, g_free);
+#ifdef __APPLE__
+  g_assert_nonnull (found_path);
+  g_assert_true (g_str_has_suffix (found_path, exe_path));
+#else
+  g_assert_cmpstr (exe_path, ==, found_path);
+#endif
+  g_clear_pointer (&found_path, g_free);
+
+  old_cwd = g_get_current_dir ();
+  g_chdir (tmp);
+  found_path =
+    g_find_program_for_path (command_to_find,
+      G_SEARCHPATH_SEPARATOR_S G_SEARCHPATH_SEPARATOR_S, "sub-path");
+  g_chdir (old_cwd);
+  g_clear_pointer (&old_cwd, g_free);
+#ifdef __APPLE__
+  g_assert_nonnull (found_path);
+  g_assert_true (g_str_has_suffix (found_path, exe_path));
+#else
+  g_assert_cmpstr (exe_path, ==, found_path);
+#endif
+  g_clear_pointer (&found_path, g_free);
+
+  g_assert_null (
+    g_find_program_for_path (command_to_find,
+      G_SEARCHPATH_SEPARATOR_S G_SEARCHPATH_SEPARATOR_S, "other-sub-path"));
+
+  found_path = g_find_program_for_path (command_to_find,
+    G_SEARCHPATH_SEPARATOR_S "sub-path" G_SEARCHPATH_SEPARATOR_S, tmp);
+#ifdef __APPLE__
+  g_assert_nonnull (found_path);
+  g_assert_true (g_str_has_suffix (found_path, exe_path));
+#else
+  g_assert_cmpstr (exe_path, ==, found_path);
+#endif
+  g_clear_pointer (&found_path, g_free);
+
+  g_assert_null (g_find_program_for_path (command_to_find,
+    G_SEARCHPATH_SEPARATOR_S "other-sub-path" G_SEARCHPATH_SEPARATOR_S, tmp));
+
+#ifdef G_OS_UNIX
+  found_path = g_find_program_for_path ("sh", NULL, tmp);
+  g_assert_nonnull (found_path);
+  g_clear_pointer (&found_path, g_free);
+
+  old_cwd = g_get_current_dir ();
+  g_chdir ("/");
+  found_path = g_find_program_for_path ("sh", "sbin:bin:usr/bin:usr/sbin", NULL);
+  g_chdir (old_cwd);
+  g_clear_pointer (&old_cwd, g_free);
+  g_assert_nonnull (found_path);
+  g_clear_pointer (&found_path, g_free);
+
+  found_path = g_find_program_for_path ("sh", "sbin:bin:usr/bin:usr/sbin", "/");
+  g_assert_nonnull (found_path);
+  g_clear_pointer (&found_path, g_free);
+#endif /* G_OS_UNIX */
+
+  g_clear_pointer (&exe_path, g_free);
+  g_clear_pointer (&path, g_free);
+  g_clear_pointer (&tmp, g_free);
+  g_clear_error (&error);
+}
+
 static void
 test_debug (void)
 {
@@ -1149,6 +1290,7 @@ main (int   argc,
   g_test_add_func ("/utils/bits", test_bits);
   g_test_add_func ("/utils/swap", test_swap);
   g_test_add_func ("/utils/find-program", test_find_program);
+  g_test_add_func ("/utils/find-program-for-path", test_find_program_for_path);
   g_test_add_func ("/utils/debug", test_debug);
   g_test_add_func ("/utils/codeset", test_codeset);
   g_test_add_func ("/utils/codeset2", test_codeset2);