diff mbox series

[v5] support: Add <support/readdir.h>

Message ID 871q1yfjlo.fsf@oldenburg.str.redhat.com
State New
Headers show
Series [v5] support: Add <support/readdir.h> | expand

Commit Message

Florian Weimer Sept. 5, 2024, 11:03 a.m. UTC
It allows to read directories using the six readdir variants
without writing type-specific code or using skeleton files
that are compiled four times.

The readdir_r subtest for support_readdir_expect_error revealed
bug 32124.

---
 support/Makefile              |   2 +
 support/readdir.h             |  85 +++++++++++
 support/support_readdir.c     | 318 ++++++++++++++++++++++++++++++++++++++++++
 support/tst-support_readdir.c |  70 ++++++++++
 4 files changed, 475 insertions(+)


base-commit: f169509ded534537eec9df00cfada6dbca908352

Comments

Joseph Myers Sept. 12, 2024, 3:51 p.m. UTC | #1
This introduces a testsuite build failure for Hurd ("'struct dirent64' has 
no member named 'd_off'").
diff mbox series

Patch

diff --git a/support/Makefile b/support/Makefile
index 93d32ae75f..84e2419775 100644
--- a/support/Makefile
+++ b/support/Makefile
@@ -78,6 +78,7 @@  libsupport-routines = \
   support_quote_blob \
   support_quote_blob_wide \
   support_quote_string \
+  support_readdir \
   support_readdir_check \
   support_readdir_r_check \
   support_record_failure \
@@ -332,6 +333,7 @@  tests = \
   tst-support_quote_blob \
   tst-support_quote_blob_wide \
   tst-support_quote_string \
+  tst-support_readdir \
   tst-support_record_failure \
   tst-test_compare \
   tst-test_compare_blob \
diff --git a/support/readdir.h b/support/readdir.h
new file mode 100644
index 0000000000..7d7c7650d4
--- /dev/null
+++ b/support/readdir.h
@@ -0,0 +1,85 @@ 
+/* Type-generic wrapper for readdir functions.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef SUPPORT_READDIR_H
+#define SUPPORT_READDIR_H
+
+#include <dirent.h>
+#include <stdbool.h>
+#include <stdint.h>
+
+__BEGIN_DECLS
+
+/* Definition independent of _FILE_OFFSET_BITS.  */
+struct support_dirent
+{
+  uint64_t d_ino;
+  uint64_t d_off;               /* 0 if d_off is not supported.  */
+  uint32_t d_type;
+  char *d_name;
+};
+
+/* Operation to be performed by support_readdir below.  */
+enum support_readdir_op
+  {
+    SUPPORT_READDIR,
+    SUPPORT_READDIR64,
+    SUPPORT_READDIR_R,
+    SUPPORT_READDIR64_R,
+    SUPPORT_READDIR64_COMPAT,
+    SUPPORT_READDIR64_R_COMPAT,
+  };
+
+/* Returns the last supported function.  May exclude
+   SUPPORT_READDIR64_R_COMPAT if not implemented.  */
+enum support_readdir_op support_readdir_op_last (void);
+
+/* Returns the name of the function that corresponds to the OP constant.  */
+const char *support_readdir_function (enum support_readdir_op op);
+
+/* Returns the d_ino field width for OP, in bits.  */
+unsigned int support_readdir_inode_width (enum support_readdir_op op);
+
+/* Returns the d_off field width for OP, in bits.  Zero if not present.  */
+unsigned int support_readdir_offset_width (enum support_readdir_op op);
+
+/* Returns true if OP is an _r variant with name length restrictions.  */
+bool support_readdir_r_variant (enum support_readdir_op op);
+
+/* First, free E->d_name and set the field to NULL.  Then call the
+   readdir variant as specified by OP.  If successfully, copy fields
+   to E, make a copy of the entry name using strdup, and write its
+   addres sto E->d_name.
+
+   Return true if an entry was read, or false if the end of the
+   directory stream was reached.  Terminates the process upon error.
+   The caller is expected to free E->d_name if the function is not
+   called again for this E.
+
+   Note that this function assumes that E->d_name has been initialized
+   to NULL or has been allocated by a previous call to this function.  */
+bool support_readdir (DIR *stream, enum support_readdir_op op,
+                      struct support_dirent *e) __nonnull ((1, 3));
+
+/* Checks that the readdir operation OP fails with errno value EXPECTED.  */
+void support_readdir_expect_error (DIR *stream, enum support_readdir_op op,
+                                   int expected) __nonnull ((1));
+
+__END_DECLS
+
+#endif /* SUPPORT_READDIR_H */
diff --git a/support/support_readdir.c b/support/support_readdir.c
new file mode 100644
index 0000000000..10d808416f
--- /dev/null
+++ b/support/support_readdir.c
@@ -0,0 +1,318 @@ 
+/* Type-generic wrapper for readdir functions.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/readdir.h>
+
+#include <dlfcn.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xdirent.h>
+
+/* Copied from <olddirent.h>.  */
+struct __old_dirent64
+  {
+    __ino_t d_ino;
+    __off64_t d_off;
+    unsigned short int d_reclen;
+    unsigned char d_type;
+    char d_name[256];
+  };
+
+static struct __old_dirent64 *(*readdir64_compat) (DIR *);
+static int (*readdir64_r_compat) (DIR *, struct __old_dirent64 *,
+                                  struct __old_dirent64 **);
+
+static void __attribute__ ((constructor))
+init (void)
+{
+  /* These compat symbols exists on alpha, i386, m67k , powerpc, s390,
+     sparc. at the same GLIBC_2.1 version. */
+  readdir64_compat = dlvsym (RTLD_DEFAULT, "readdir64", "GLIBC_2.1");
+  readdir64_r_compat = dlvsym (RTLD_DEFAULT, "readdir64_r", "GLIBC_2.1");
+}
+
+enum support_readdir_op
+support_readdir_op_last (void)
+{
+  if (readdir64_r_compat != NULL)
+    {
+      TEST_VERIFY (readdir64_compat != NULL);
+      return SUPPORT_READDIR64_R_COMPAT;
+    }
+  else
+    return SUPPORT_READDIR64_R;
+}
+
+const char *
+support_readdir_function (enum support_readdir_op op)
+{
+  switch (op)
+    {
+      case SUPPORT_READDIR:
+        return "readdir";
+      case SUPPORT_READDIR64:
+        return "readdir64";
+      case SUPPORT_READDIR_R:
+        return "readdir_r";
+      case SUPPORT_READDIR64_R:
+        return "readdir64_r";
+      case SUPPORT_READDIR64_COMPAT:
+        return "readdir64@GBLIC_2.1";
+      case SUPPORT_READDIR64_R_COMPAT:
+        return "readdir64_r@GBLIC_2.1";
+    }
+  FAIL_EXIT1 ("invalid support_readdir_op constant: %d", op);
+}
+
+unsigned int
+support_readdir_inode_width (enum support_readdir_op op)
+{
+  switch (op)
+    {
+      case SUPPORT_READDIR:
+      case SUPPORT_READDIR_R:
+        return sizeof ((struct dirent) { 0, }.d_ino) * 8;
+      case SUPPORT_READDIR64:
+      case SUPPORT_READDIR64_R:
+        return sizeof ((struct dirent64) { 0, }.d_ino) * 8;
+      case SUPPORT_READDIR64_COMPAT:
+      case SUPPORT_READDIR64_R_COMPAT:
+        return sizeof ((struct __old_dirent64) { 0, }.d_ino) * 8;
+    }
+  FAIL_EXIT1 ("invalid support_readdir_op constant: %d", op);
+}
+
+unsigned int
+support_readdir_offset_width (enum support_readdir_op op)
+{
+#ifdef _DIRENT_HAVE_D_OFF
+  switch (op)
+    {
+    case SUPPORT_READDIR:
+    case SUPPORT_READDIR_R:
+      return sizeof ((struct dirent) { 0, }.d_off) * 8;
+    case SUPPORT_READDIR64:
+    case SUPPORT_READDIR64_R:
+      return sizeof ((struct dirent64) { 0, }.d_off) * 8;
+    case SUPPORT_READDIR64_COMPAT:
+    case SUPPORT_READDIR64_R_COMPAT:
+      return sizeof ((struct __old_dirent64) { 0, }.d_off) * 8;
+    }
+#else
+  switch (op)
+    {
+    case SUPPORT_READDIR:
+    case SUPPORT_READDIR_R:
+    case SUPPORT_READDIR64:
+    case SUPPORT_READDIR64_R:
+    case SUPPORT_READDIR64_COMPAT:
+    case SUPPORT_READDIR64_R_COMPAT:
+      return 0;
+    }
+#endif
+  FAIL_EXIT1 ("invalid support_readdir_op constant: %d", op);
+}
+
+bool
+support_readdir_r_variant (enum support_readdir_op op)
+{
+  switch (op)
+    {
+      case SUPPORT_READDIR:
+      case SUPPORT_READDIR64:
+      case SUPPORT_READDIR64_COMPAT:
+        return false;
+      case SUPPORT_READDIR_R:
+      case SUPPORT_READDIR64_R:
+      case SUPPORT_READDIR64_R_COMPAT:
+        return true;
+    }
+  FAIL_EXIT1 ("invalid support_readdir_op constant: %d", op);
+}
+
+static bool
+copy_dirent (struct support_dirent *dst, struct dirent *src)
+{
+  if (src == NULL)
+    return false;
+  dst->d_ino = src->d_ino;
+#ifdef _DIRENT_HAVE_D_OFF
+  dst->d_off = src->d_off;
+#else
+  dst->d_off = 0;
+#endif
+  dst->d_type = src->d_type;
+  dst->d_name = xstrdup (src->d_name);
+  return true;
+}
+
+static bool
+copy_dirent64 (struct support_dirent *dst, struct dirent64 *src)
+{
+  if (src == NULL)
+    return false;
+  dst->d_ino = src->d_ino;
+#ifdef _DIRENT_HAVE_D_OFF
+  dst->d_off = src->d_off;
+#else
+  dst->d_off = 0;
+#endif
+  dst->d_type = src->d_type;
+  dst->d_name = xstrdup (src->d_name);
+  return true;
+}
+
+static bool
+copy_old_dirent64 (struct support_dirent *dst, struct __old_dirent64 *src)
+{
+  if (src == NULL)
+    return false;
+  dst->d_ino = src->d_ino;
+#ifdef _DIRENT_HAVE_D_OFF
+  dst->d_off = src->d_off;
+#else
+  dst->d_off = 0;
+#endif
+  dst->d_type = src->d_type;
+  dst->d_name = xstrdup (src->d_name);
+  return true;
+}
+
+bool
+support_readdir (DIR *stream, enum support_readdir_op op,
+                 struct support_dirent *e)
+{
+  free (e->d_name);
+  e->d_name = NULL;
+  switch (op)
+    {
+    case SUPPORT_READDIR:
+      return copy_dirent (e, xreaddir (stream));
+    case SUPPORT_READDIR64:
+      return copy_dirent64 (e, xreaddir64 (stream));
+
+      /* The functions readdir_r, readdir64_r were deprecated in glibc 2.24.  */
+      DIAG_PUSH_NEEDS_COMMENT;
+      DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wdeprecated-declarations");
+
+    case SUPPORT_READDIR_R:
+      {
+        struct dirent buf;
+        if (!xreaddir_r (stream, &buf))
+          return false;
+        return copy_dirent (e, &buf);
+      }
+    case SUPPORT_READDIR64_R:
+      {
+        struct dirent64 buf;
+        if (!xreaddir64_r (stream, &buf))
+          return false;
+        return copy_dirent64 (e, &buf);
+      }
+
+      DIAG_POP_NEEDS_COMMENT;
+
+    case SUPPORT_READDIR64_COMPAT:
+      if (readdir64_compat == NULL)
+        FAIL_EXIT1 ("readdir64 compat function not implemented");
+      return copy_old_dirent64 (e, readdir64_compat (stream));
+
+    case SUPPORT_READDIR64_R_COMPAT:
+      {
+        if (readdir64_r_compat == NULL)
+          FAIL_EXIT1 ("readdir64_r compat function not implemented");
+        struct __old_dirent64 buf;
+        struct __old_dirent64 *e1;
+        int ret = readdir64_r_compat (stream, &buf, &e1);
+        if (ret != 0)
+          {
+            errno = ret;
+            FAIL ("readdir64_r@GLIBC_2.1: %m");
+            return false;
+          }
+        if (e1 == NULL)
+          return false;
+        return copy_old_dirent64 (e, e1);
+      }
+    }
+  FAIL_EXIT1 ("support_readdir: invalid op argument %d", (int) op);
+}
+
+void
+support_readdir_expect_error (DIR *stream, enum support_readdir_op op,
+                              int expected)
+{
+  switch (op)
+    {
+    case SUPPORT_READDIR:
+      errno = 0;
+      TEST_VERIFY (readdir (stream) == NULL);
+      TEST_COMPARE (errno, expected);
+      return;
+    case SUPPORT_READDIR64:
+      errno = 0;
+      TEST_VERIFY (readdir64 (stream) == NULL);
+      TEST_COMPARE (errno, expected);
+      return;
+
+      /* The functions readdir_r, readdir64_r were deprecated in glibc 2.24.  */
+      DIAG_PUSH_NEEDS_COMMENT;
+      DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wdeprecated-declarations");
+
+    case SUPPORT_READDIR_R:
+      {
+        struct dirent buf;
+        struct dirent *e;
+        errno = readdir_r (stream, &buf, &e);
+        TEST_COMPARE (errno, expected);;
+      }
+      return;
+    case SUPPORT_READDIR64_R:
+      {
+        struct dirent64 buf;
+        struct dirent64 *e;
+        errno = readdir64_r (stream, &buf, &e);
+        TEST_COMPARE (errno, expected);;
+      }
+      return;
+
+      DIAG_POP_NEEDS_COMMENT;
+
+    case SUPPORT_READDIR64_COMPAT:
+      if (readdir64_compat == NULL)
+        FAIL_EXIT1 ("readdir64_r compat function not implemented");
+      errno = 0;
+      TEST_VERIFY (readdir64_compat (stream) == NULL);
+      TEST_COMPARE (errno, expected);
+      return;
+    case SUPPORT_READDIR64_R_COMPAT:
+      {
+        if (readdir64_r_compat == NULL)
+          FAIL_EXIT1 ("readdir64_r compat function not implemented");
+        struct __old_dirent64 buf;
+        struct __old_dirent64 *e;
+        errno = readdir64_r_compat (stream, &buf, &e);
+        TEST_COMPARE (errno, expected);
+      }
+      return;
+    }
+  FAIL_EXIT1 ("support_readdir_expect_error: invalid op argument %d",
+              (int) op);
+}
diff --git a/support/tst-support_readdir.c b/support/tst-support_readdir.c
new file mode 100644
index 0000000000..c0639571c7
--- /dev/null
+++ b/support/tst-support_readdir.c
@@ -0,0 +1,70 @@ 
+/* Test the support_readdir function.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <support/readdir.h>
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/xdirent.h>
+#include <support/xunistd.h>
+
+static int
+do_test (void)
+{
+  DIR *reference_stream = xopendir (".");
+  struct dirent64 *reference = xreaddir64 (reference_stream);
+
+  for (enum support_readdir_op op = 0; op <= support_readdir_op_last (); ++op)
+    {
+      DIR *stream = xopendir (".");
+      struct support_dirent e;
+      memset (&e, 0xcc, sizeof (e));
+      e.d_name = NULL;
+      TEST_VERIFY (support_readdir (stream, op, &e));
+      TEST_COMPARE (e.d_ino, reference->d_ino);
+      if (support_readdir_offset_width (op) != 0)
+        TEST_COMPARE (e.d_off, reference->d_off);
+      else
+        TEST_COMPARE (e.d_off, 0);
+      TEST_COMPARE (e.d_type, reference->d_type);
+      TEST_COMPARE_STRING (e.d_name, reference->d_name);
+      free (e.d_name);
+      xclosedir (stream);
+    }
+
+  xclosedir (reference_stream);
+
+  /* Error injection test.  */
+  int devnull = xopen ("/dev/null", O_RDONLY, 0);
+  for (enum support_readdir_op op = 0; op <= support_readdir_op_last (); ++op)
+    {
+      DIR *stream = xopendir (".");
+      /* A descriptor incompatible with readdir.  */
+      xdup2 (devnull, dirfd (stream));
+      errno = -1;
+      support_readdir_expect_error (stream, op, ENOTDIR);
+      xclosedir (stream);
+    }
+  xclose (devnull);
+
+  return 0;
+}
+
+#include <support/test-driver.c>