commit 062ff490c1467059f6cd64bb9c3d85f6cc6cf97a

Author: Siddhesh Poyarekar <siddhesh@sourceware.org>

Date:   Tue Jan 18 13:29:36 2022 +0530

    support: Add helpers to create paths longer than PATH_MAX

    Add new helpers support_create_and_chdir_toolong_temp_directory and

    support_chdir_toolong_temp_directory to create and descend into

    directory trees longer than PATH_MAX.

    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

    Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

    (cherry picked from commit fb7bff12e81c677a6622f724edd4d4987dd9d971)

diff --git a/support/temp_file.c b/support/temp_file.c

index c6df641876285bb2..e41128c2d43fe903 100644

--- a/support/temp_file.c

+++ b/support/temp_file.c

@@ -1,5 +1,6 @@

 /* Temporary file handling for tests.

-   Copyright (C) 1998-2021 Free Software Foundation, Inc.

+   Copyright (C) 1998-2022 Free Software Foundation, Inc.

+   Copyright The GNU Tools Authors.

    This file is part of the GNU C Library.

    The GNU C Library is free software; you can redistribute it and/or

@@ -20,15 +21,17 @@

    some 32-bit platforms. */

 #define _FILE_OFFSET_BITS 64

+#include <support/check.h>

 #include <support/temp_file.h>

 #include <support/temp_file-internal.h>

 #include <support/support.h>

+#include <errno.h>

 #include <paths.h>

 #include <stdio.h>

 #include <stdlib.h>

 #include <string.h>

-#include <unistd.h>

+#include <xunistd.h>

 /* List of temporary files.  */

 static struct temp_name_list

@@ -36,14 +39,20 @@ static struct temp_name_list

   struct temp_name_list *next;

   char *name;

   pid_t owner;

+  bool toolong;

 } *temp_name_list;

 /* Location of the temporary files.  Set by the test skeleton via

    support_set_test_dir.  The string is not be freed.  */

 static const char *test_dir = _PATH_TMP;

-void

-add_temp_file (const char *name)

+/* Name of subdirectories in a too long temporary directory tree.  */

+static char toolong_subdir[NAME_MAX + 1];

+static bool toolong_initialized;

+static size_t toolong_path_max;

+

+static void

+add_temp_file_internal (const char *name, bool toolong)

 {

   struct temp_name_list *newp

     = (struct temp_name_list *) xcalloc (sizeof (*newp), 1);

@@ -53,12 +62,19 @@ add_temp_file (const char *name)

       newp->name = newname;

       newp->next = temp_name_list;

       newp->owner = getpid ();

+      newp->toolong = toolong;

       temp_name_list = newp;

     }

   else

     free (newp);

 }

+void

+add_temp_file (const char *name)

+{

+  add_temp_file_internal (name, false);

+}

+

 int

 create_temp_file_in_dir (const char *base, const char *dir, char **filename)

 {

@@ -90,8 +106,8 @@ create_temp_file (const char *base, char **filename)

   return create_temp_file_in_dir (base, test_dir, filename);

 }

-char *

-support_create_temp_directory (const char *base)

+static char *

+create_temp_directory_internal (const char *base, bool toolong)

 {

   char *path = xasprintf ("%s/%sXXXXXX", test_dir, base);

   if (mkdtemp (path) == NULL)

@@ -99,16 +115,132 @@ support_create_temp_directory (const char *base)

       printf ("error: mkdtemp (\"%s\"): %m", path);

       exit (1);

     }

-  add_temp_file (path);

+  add_temp_file_internal (path, toolong);

   return path;

 }

-/* Helper functions called by the test skeleton follow.  */

+char *

+support_create_temp_directory (const char *base)

+{

+  return create_temp_directory_internal (base, false);

+}

+

+static void

+ensure_toolong_initialized (void)

+{

+  if (!toolong_initialized)

+    FAIL_EXIT1 ("uninitialized toolong directory tree\n");

+}

+

+static void

+initialize_toolong (const char *base)

+{

+  long name_max = pathconf (base, _PC_NAME_MAX);

+  name_max = (name_max < 0 ? 64

+	      : (name_max < sizeof (toolong_subdir) ? name_max

+		 : sizeof (toolong_subdir) - 1));

+

+  long path_max = pathconf (base, _PC_PATH_MAX);

+  path_max = (path_max < 0 ? 1024

+	      : path_max <= PTRDIFF_MAX ? path_max : PTRDIFF_MAX);

+

+  /* Sanity check to ensure that the test does not create temporary directories

+     in different filesystems because this API doesn't support it.  */

+  if (toolong_initialized)

+    {

+      if (name_max != strlen (toolong_subdir))

+	FAIL_UNSUPPORTED ("name_max: Temporary directories in different"

+			  " filesystems not supported yet\n");

+      if (path_max != toolong_path_max)

+	FAIL_UNSUPPORTED ("path_max: Temporary directories in different"

+			  " filesystems not supported yet\n");

+      return;

+    }

+

+  toolong_path_max = path_max;

+

+  size_t len = name_max;

+  memset (toolong_subdir, 'X', len);

+  toolong_initialized = true;

+}

+

+char *

+support_create_and_chdir_toolong_temp_directory (const char *basename)

+{

+  char *base = create_temp_directory_internal (basename, true);

+  xchdir (base);

+

+  initialize_toolong (base);

+

+  size_t sz = strlen (toolong_subdir);

+

+  /* Create directories and descend into them so that the final path is larger

+     than PATH_MAX.  */

+  for (size_t i = 0; i <= toolong_path_max / sz; i++)

+    {

+      int ret = mkdir (toolong_subdir, S_IRWXU);

+      if (ret != 0 && errno == ENAMETOOLONG)

+	FAIL_UNSUPPORTED ("Filesystem does not support creating too long "

+			  "directory trees\n");

+      else if (ret != 0)

+	FAIL_EXIT1 ("Failed to create directory tree: %m\n");

+      xchdir (toolong_subdir);

+    }

+  return base;

+}

 void

-support_set_test_dir (const char *path)

+support_chdir_toolong_temp_directory (const char *base)

 {

-  test_dir = path;

+  ensure_toolong_initialized ();

+

+  xchdir (base);

+

+  size_t sz = strlen (toolong_subdir);

+  for (size_t i = 0; i <= toolong_path_max / sz; i++)

+    xchdir (toolong_subdir);

+}

+

+/* Helper functions called by the test skeleton follow.  */

+

+static void

+remove_toolong_subdirs (const char *base)

+{

+  ensure_toolong_initialized ();

+

+  if (chdir (base) != 0)

+    {

+      printf ("warning: toolong cleanup base failed: chdir (\"%s\"): %m\n",

+	      base);

+      return;

+    }

+

+  /* Descend.  */

+  int levels = 0;

+  size_t sz = strlen (toolong_subdir);

+  for (levels = 0; levels <= toolong_path_max / sz; levels++)

+    if (chdir (toolong_subdir) != 0)

+      {

+	printf ("warning: toolong cleanup failed: chdir (\"%s\"): %m\n",

+		toolong_subdir);

+	break;

+      }

+

+  /* Ascend and remove.  */

+  while (--levels >= 0)

+    {

+      if (chdir ("..") != 0)

+	{

+	  printf ("warning: toolong cleanup failed: chdir (\"..\"): %m\n");

+	  return;

+	}

+      if (remove (toolong_subdir) != 0)

+	{

+	  printf ("warning: could not remove subdirectory: %s: %m\n",

+		  toolong_subdir);

+	  return;

+	}

+    }

 }

 void

@@ -123,6 +255,9 @@ support_delete_temp_files (void)

 	 around, to prevent PID reuse.)  */

       if (temp_name_list->owner == pid)

 	{

+	  if (temp_name_list->toolong)

+	    remove_toolong_subdirs (temp_name_list->name);

+

 	  if (remove (temp_name_list->name) != 0)

 	    printf ("warning: could not remove temporary file: %s: %m\n",

 		    temp_name_list->name);

@@ -147,3 +282,9 @@ support_print_temp_files (FILE *f)

       fprintf (f, ")\n");

     }

 }

+

+void

+support_set_test_dir (const char *path)

+{

+  test_dir = path;

+}

diff --git a/support/temp_file.h b/support/temp_file.h

index f3a7fb6f9ca44d19..a22964c6fa11abd2 100644

--- a/support/temp_file.h

+++ b/support/temp_file.h

@@ -44,6 +44,15 @@ int create_temp_file_in_dir (const char *base, const char *dir,

    returns.  The caller should free this string.  */

 char *support_create_temp_directory (const char *base);

+/* Create a temporary directory tree that is longer than PATH_MAX and schedule

+   it for deletion.  BASENAME is used as a prefix for the unique directory

+   name, which the function returns.  The caller should free this string.  */

+char *support_create_and_chdir_toolong_temp_directory (const char *basename);

+

+/* Change into the innermost directory of the directory tree BASE, which was

+   created using support_create_and_chdir_toolong_temp_directory.  */

+void support_chdir_toolong_temp_directory (const char *base);

+

 __END_DECLS

 #endif /* SUPPORT_TEMP_FILE_H */