[v2,1/3] support: Add helpers to create paths longer than PATH_MAX
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Commit Message
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.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
---
support/temp_file.c | 173 +++++++++++++++++++++++++++++++++++++++++---
support/temp_file.h | 9 +++
2 files changed, 173 insertions(+), 9 deletions(-)
Comments
On 19/01/2022 13:51, Siddhesh Poyarekar via Libc-alpha wrote:
> 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.
>
> Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> ---
> support/temp_file.c | 173 +++++++++++++++++++++++++++++++++++++++++---
> support/temp_file.h | 9 +++
> 2 files changed, 173 insertions(+), 9 deletions(-)
>
> diff --git a/support/temp_file.c b/support/temp_file.c
> index e7bb8aadb9..59060e573f 100644
> --- a/support/temp_file.c
> +++ b/support/temp_file.c
> @@ -1,5 +1,6 @@
> /* Temporary file handling for tests.
> 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 +39,32 @@ 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;
> +static bool toolong_subdir_initialized;
> +
> +/* Return the maximum size of path on the target. */
> +static inline size_t
> +get_path_max (void)
> +{
> +#ifdef PATH_MAX
> + return PATH_MAX;
> +#else
> + size_t path_max = pathconf ("/", _PC_PATH_MAX);
> + return (path_max < 0 ? 1024
> + : path_max <= PTRDIFF_MAX ? path_max : PTRDIFF_MAX);
> +#endif
> +}
> +
> +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 +74,19 @@ 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 +118,8 @@ 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 +127,132 @@ 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_subdir_initialized (void)
> +{
> + if (!toolong_subdir_initialized)
> + FAIL_EXIT1 ("uninitialized toolong directory tree\n");
> +}
> +
> +static void
> +initialize_toolong_subdir (void)
> +{
> + size_t sz = NAME_MAX;
> + char testname[NAME_MAX];
> + int ret;
> +
> + if (toolong_subdir_initialized)
> + return;
> +
> + memset (testname, 'X', sz - 1);
> +
> + /* Explore the name limit on the file system. This should typically be
> + NAME_MAX, but it could be less on some fuse filesystems. */
> + do
> + {
> + struct stat statbuf;
> +
> + testname[sz - 1] = '\0';
> + ret = stat (testname, &statbuf);
> + }
> + while (ret != 0 && errno == ENAMETOOLONG && (sz = sz / 2) > 0);
> +
> + if (ret != 0 && errno == ENAMETOOLONG)
> + FAIL_EXIT1 ("stat (%s) failed with ENAMETOOLONG\n", testname);
> +
> + toolong_subdir = xmalloc (sz);
> + strcpy (toolong_subdir, testname);
> + toolong_subdir_initialized = true;
> +}
> +
> +char *
> +support_create_and_chdir_toolong_temp_directory (const char *basename)
> +{
> + size_t path_max = get_path_max ();
> +
> + char *base = create_temp_directory_internal (basename, true);
> +
> + xchdir (base);
> +
> + initialize_toolong_subdir ();
> +
> + 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 <= path_max / sz; i++)
> + {
> + xmkdir (toolong_subdir, S_IRWXU);
This still doesn't work on the trybot, which somehow fails with
ENAMETOOLONG even though stat() on that length worked in
initialize_toolong_subdir. I'm going to need to reproduce the
environment properly to figure out what's going on.
Siddhesh
> + xchdir (toolong_subdir);
> + }
> + return base;
> +}
>
> void
> -support_set_test_dir (const char *path)
> +support_chdir_toolong_temp_directory (const char *base)
> {
> - test_dir = path;
> + size_t path_max = get_path_max ();
> + ensure_toolong_subdir_initialized ();
> +
> + xchdir (base);
> +
> + size_t sz = strlen (toolong_subdir);
> + for (size_t i = 0; i <= path_max / sz; i++)
> + xchdir (toolong_subdir);
> +}
> +
> +/* Helper functions called by the test skeleton follow. */
> +
> +static void
> +remove_toolong_subdirs (const char *base)
> +{
> + size_t path_max = get_path_max ();
> +
> + ensure_toolong_subdir_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 <= path_max / sz; levels++)
> + if (chdir (toolong_subdir) != 0)
> + {
> + printf ("warning: toolong cleanup failed: chdir (\"%s\"): %m\n",
> + toolong_subdir);
> + return;
> + }
> +
> + /* 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 +267,9 @@ 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);
> @@ -133,6 +280,8 @@ support_delete_temp_files (void)
> free (temp_name_list);
> temp_name_list = next;
> }
> +
> + free (toolong_subdir);
> }
>
> void
> @@ -147,3 +296,9 @@ 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 50a443abe4..8459ddda72 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 */
On Wed, Jan 19, 2022 at 7:21 AM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
>
> On 19/01/2022 13:51, Siddhesh Poyarekar via Libc-alpha wrote:
> > 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.
Note that recentish linux kernel versions do not allow d_name 's
larger than kernel 's PATH_MAX definition, in that case getdents
returns EIO, this behavior is since kernel 5.5.
* Cristian Rodríguez:
> On Wed, Jan 19, 2022 at 7:21 AM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
>>
>> On 19/01/2022 13:51, Siddhesh Poyarekar via Libc-alpha wrote:
>> > 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.
>
> Note that recentish linux kernel versions do not allow d_name 's
> larger than kernel 's PATH_MAX definition, in that case getdents
> returns EIO, this behavior is since kernel 5.5.
NAME_MAX or PATH_MAX? d_name should be capped by NAME_MAX, but
historically it is not.
Thanks,
Florian
On 20/01/2022 20:17, Cristian Rodríguez wrote:
> On Wed, Jan 19, 2022 at 7:21 AM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
>>
>> On 19/01/2022 13:51, Siddhesh Poyarekar via Libc-alpha wrote:
>>> 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.
>
> Note that recentish linux kernel versions do not allow d_name 's
> larger than kernel 's PATH_MAX definition, in that case getdents
> returns EIO, this behavior is since kernel 5.5.
>
The d_name in these helpers is limited to _PC_NAME_MAX so AFAICT we
shouldn't run into issues with that.
Thanks,
Siddhesh
On Thu, Jan 20, 2022 at 11:56 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * Cristian Rodríguez:
>
> > On Wed, Jan 19, 2022 at 7:21 AM Siddhesh Poyarekar <siddhesh@gotplt.org> wrote:
> >>
> >> On 19/01/2022 13:51, Siddhesh Poyarekar via Libc-alpha wrote:
> >> > 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.
> >
> > Note that recentish linux kernel versions do not allow d_name 's
> > larger than kernel 's PATH_MAX definition, in that case getdents
> > returns EIO, this behavior is since kernel 5.5.
>
> NAME_MAX or PATH_MAX? d_name should be capped by NAME_MAX, but
> historically it is not.
PATH_MAX.. I wrote that correctly, see
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2c6b7bcd747201441923a0d3062577a8d1fbd8f8
@@ -1,5 +1,6 @@
/* Temporary file handling for tests.
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 +39,32 @@ 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;
+static bool toolong_subdir_initialized;
+
+/* Return the maximum size of path on the target. */
+static inline size_t
+get_path_max (void)
+{
+#ifdef PATH_MAX
+ return PATH_MAX;
+#else
+ size_t path_max = pathconf ("/", _PC_PATH_MAX);
+ return (path_max < 0 ? 1024
+ : path_max <= PTRDIFF_MAX ? path_max : PTRDIFF_MAX);
+#endif
+}
+
+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 +74,19 @@ 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 +118,8 @@ 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 +127,132 @@ 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_subdir_initialized (void)
+{
+ if (!toolong_subdir_initialized)
+ FAIL_EXIT1 ("uninitialized toolong directory tree\n");
+}
+
+static void
+initialize_toolong_subdir (void)
+{
+ size_t sz = NAME_MAX;
+ char testname[NAME_MAX];
+ int ret;
+
+ if (toolong_subdir_initialized)
+ return;
+
+ memset (testname, 'X', sz - 1);
+
+ /* Explore the name limit on the file system. This should typically be
+ NAME_MAX, but it could be less on some fuse filesystems. */
+ do
+ {
+ struct stat statbuf;
+
+ testname[sz - 1] = '\0';
+ ret = stat (testname, &statbuf);
+ }
+ while (ret != 0 && errno == ENAMETOOLONG && (sz = sz / 2) > 0);
+
+ if (ret != 0 && errno == ENAMETOOLONG)
+ FAIL_EXIT1 ("stat (%s) failed with ENAMETOOLONG\n", testname);
+
+ toolong_subdir = xmalloc (sz);
+ strcpy (toolong_subdir, testname);
+ toolong_subdir_initialized = true;
+}
+
+char *
+support_create_and_chdir_toolong_temp_directory (const char *basename)
+{
+ size_t path_max = get_path_max ();
+
+ char *base = create_temp_directory_internal (basename, true);
+
+ xchdir (base);
+
+ initialize_toolong_subdir ();
+
+ 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 <= path_max / sz; i++)
+ {
+ xmkdir (toolong_subdir, S_IRWXU);
+ xchdir (toolong_subdir);
+ }
+ return base;
+}
void
-support_set_test_dir (const char *path)
+support_chdir_toolong_temp_directory (const char *base)
{
- test_dir = path;
+ size_t path_max = get_path_max ();
+ ensure_toolong_subdir_initialized ();
+
+ xchdir (base);
+
+ size_t sz = strlen (toolong_subdir);
+ for (size_t i = 0; i <= path_max / sz; i++)
+ xchdir (toolong_subdir);
+}
+
+/* Helper functions called by the test skeleton follow. */
+
+static void
+remove_toolong_subdirs (const char *base)
+{
+ size_t path_max = get_path_max ();
+
+ ensure_toolong_subdir_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 <= path_max / sz; levels++)
+ if (chdir (toolong_subdir) != 0)
+ {
+ printf ("warning: toolong cleanup failed: chdir (\"%s\"): %m\n",
+ toolong_subdir);
+ return;
+ }
+
+ /* 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 +267,9 @@ 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);
@@ -133,6 +280,8 @@ support_delete_temp_files (void)
free (temp_name_list);
temp_name_list = next;
}
+
+ free (toolong_subdir);
}
void
@@ -147,3 +296,9 @@ support_print_temp_files (FILE *f)
fprintf (f, ")\n");
}
}
+
+void
+support_set_test_dir (const char *path)
+{
+ test_dir = path;
+}
@@ -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 */