New upstream version 2017.4

libglnx/Makefile-libglnx.am

@@ -52,9 +52,18 @@ libglnx_la_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
 libglnx_la_LDFLAGS = -avoid-version -Bsymbolic-functions -export-symbols-regex "^glnx_" -no-undefined -export-dynamic 
 libglnx_la_LIBADD = $(libglnx_libs)
 
-TESTS += test-libglnx-xattrs
+libglnx_tests = test-libglnx-xattrs test-libglnx-fdio test-libglnx-errors
+TESTS += $(libglnx_tests)
 
-check_PROGRAMS += test-libglnx-xattrs
+check_PROGRAMS += $(libglnx_tests)
 test_libglnx_xattrs_SOURCES = $(libglnx_srcpath)/tests/test-libglnx-xattrs.c
 test_libglnx_xattrs_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
 test_libglnx_xattrs_LDADD = $(libglnx_libs) libglnx.la
+
+test_libglnx_fdio_SOURCES = $(libglnx_srcpath)/tests/test-libglnx-fdio.c
+test_libglnx_fdio_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
+test_libglnx_fdio_LDADD = $(libglnx_libs) libglnx.la
+
+test_libglnx_errors_SOURCES = $(libglnx_srcpath)/tests/test-libglnx-errors.c
+test_libglnx_errors_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
+test_libglnx_errors_LDADD = $(libglnx_libs) libglnx.la

libglnx/Makefile-libglnx.am.inc

@@ -52,9 +52,18 @@ libglnx_la_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
 libglnx_la_LDFLAGS = -avoid-version -Bsymbolic-functions -export-symbols-regex "^glnx_" -no-undefined -export-dynamic 
 libglnx_la_LIBADD = $(libglnx_libs)
 
-TESTS += test-libglnx-xattrs
+libglnx_tests = test-libglnx-xattrs test-libglnx-fdio test-libglnx-errors
+TESTS += $(libglnx_tests)
 
-check_PROGRAMS += test-libglnx-xattrs
+check_PROGRAMS += $(libglnx_tests)
 test_libglnx_xattrs_SOURCES = libglnx/tests/test-libglnx-xattrs.c
 test_libglnx_xattrs_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
 test_libglnx_xattrs_LDADD = $(libglnx_libs) libglnx.la
+
+test_libglnx_fdio_SOURCES = libglnx/tests/test-libglnx-fdio.c
+test_libglnx_fdio_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
+test_libglnx_fdio_LDADD = $(libglnx_libs) libglnx.la
+
+test_libglnx_errors_SOURCES = libglnx/tests/test-libglnx-errors.c
+test_libglnx_errors_CFLAGS = $(AM_CFLAGS) $(libglnx_cflags)
+test_libglnx_errors_LDADD = $(libglnx_libs) libglnx.la

libglnx/glnx-dirfd.c

@@ -68,8 +68,7 @@ glnx_opendirat (int             dfd,
   int ret = glnx_opendirat_with_errno (dfd, path, follow);
   if (ret == -1)
     {
-      glnx_set_prefix_error_from_errno (error, "%s", "openat");
-      return FALSE;
+      return glnx_throw_errno_prefix (error, "openat");
     }
   *out_fd = ret;
   return TRUE;
@@ -339,8 +338,7 @@ glnx_mkdtempat (int dfd,
           /* Any other error will apply also to other names we might
            *  try, and there are 2^32 or so of them, so give up now.
            */
-          glnx_set_prefix_error_from_errno (error, "%s", "mkdirat");
-          return FALSE;
+          return glnx_throw_errno_prefix (error, "mkdirat");
         }
 
       return TRUE;

libglnx/glnx-errors.c

@@ -24,30 +24,21 @@
 #include <glnx-errors.h>
 
 void
-glnx_real_set_prefix_error_from_errno (GError     **error,
-                                       gint         errsv,
-                                       const char  *format,
-                                       ...)
+glnx_real_set_prefix_error_from_errno_va (GError     **error,
+                                          gint         errsv,
+                                          const char  *format,
+                                          va_list      args)
 {
   if (!error)
     return;
-  else
-    {
-      GString *buf = g_string_new ("");
-      va_list args;
-    
-      va_start (args, format);
-      g_string_append_vprintf (buf, format, args);
-      va_end (args);
 
-      g_string_append (buf, ": ");
-      g_string_append (buf, g_strerror (errsv));
-    
-      g_set_error_literal (error,
-                           G_IO_ERROR,
-                           g_io_error_from_errno (errsv),
-                           buf->str);
-      g_string_free (buf, TRUE);
-      errno = errsv;
-    }
+  /* TODO - enhance GError to have a "set and take ownership" API */
+  g_autoptr(GString) buf = g_string_new ("");
+  g_string_append_vprintf (buf, format, args);
+  g_string_append (buf, ": ");
+  g_string_append (buf, g_strerror (errsv));
+  g_set_error_literal (error,
+                       G_IO_ERROR,
+                       g_io_error_from_errno (errsv),
+                       buf->str);
 }

libglnx/glnx-errors.h

@@ -25,25 +25,101 @@
 
 G_BEGIN_DECLS
 
+/* Set @error with G_IO_ERROR/G_IO_ERROR_FAILED.
+ *
+ * This function returns %FALSE so it can be used conveniently in a single
+ * statement:
+ *
+ * ``
+ *   if (strcmp (foo, "somevalue") != 0)
+ *     return glnx_throw (error, "key must be somevalue, not '%s'", foo);
+ * ```
+ */
+static inline gboolean G_GNUC_PRINTF (2,3)
+glnx_throw (GError **error, const char *fmt, ...)
+{
+  if (error == NULL)
+    return FALSE;
+
+  va_list args;
+  va_start (args, fmt);
+  GError *new = g_error_new_valist (G_IO_ERROR, G_IO_ERROR_FAILED, fmt, args);
+  va_end (args);
+  g_propagate_error (error, g_steal_pointer (&new));
+  return FALSE;
+}
+
+
+/* Set @error using the value of `g_strerror (errno)`.
+ *
+ * This function returns %FALSE so it can be used conveniently in a single
+ * statement:
+ *
+ * ``
+ *   if (unlinkat (fd, somepathname) < 0)
+ *     return glnx_throw_errno (error);
+ * ```
+ */
+static inline gboolean
+glnx_throw_errno (GError **error)
+{
+  /* Save the value of errno, in case one of the
+   * intermediate function calls happens to set it.
+   */
+  int errsv = errno;
+  g_set_error_literal (error, G_IO_ERROR,
+                       g_io_error_from_errno (errsv),
+                       g_strerror (errsv));
+  /* We also restore the value of errno, since that's
+   * what was done in a long-ago libgsystem commit
+   * https://git.gnome.org/browse/libgsystem/commit/?id=ed106741f7a0596dc8b960b31fdae671d31d666d
+   * but I certainly can't remember now why I did that.
+   */
+  errno = errsv;
+  return FALSE;
+}
+
+/* Implementation detail of glnx_throw_errno_prefix() */
+void glnx_real_set_prefix_error_from_errno_va (GError     **error,
+                                               gint         errsv,
+                                               const char  *format,
+                                               va_list      args) G_GNUC_PRINTF (3,0);
+
+/* Set @error using the value of `$prefix: g_strerror (errno)` where `$prefix`
+ * is computed via printf @fmt.
+ *
+ * This function returns %FALSE so it can be used conveniently in a single
+ * statement:
+ *
+ * ```
+ *   return glnx_throw_errno_prefix (error, "unlinking %s", pathname);
+ * ```
+ */
+static inline gboolean G_GNUC_PRINTF (2,3)
+glnx_throw_errno_prefix (GError **error, const char *fmt, ...)
+{
+  int errsv = errno;
+  va_list args;
+  va_start (args, fmt);
+  glnx_real_set_prefix_error_from_errno_va (error, errsv, fmt, args);
+  va_end (args);
+  /* See comment above about preserving errno */
+  errno = errsv;
+  return FALSE;
+}
+
+/* BEGIN LEGACY APIS */
+
 #define glnx_set_error_from_errno(error)                \
   do {                                                  \
-    int errsv = errno;                                  \
-    g_set_error_literal (error, G_IO_ERROR,             \
-                         g_io_error_from_errno (errsv), \
-                         g_strerror (errsv));           \
-    errno = errsv;                                      \
+    glnx_throw_errno (error);                           \
   } while (0);
 
-#define glnx_set_prefix_error_from_errno(error, format, args...)            \
-  do {                                                                  \
-    int errsv = errno;                                                  \
-    glnx_real_set_prefix_error_from_errno (error, errsv, format, args); \
-    errno = errsv;                                                      \
+#define glnx_set_prefix_error_from_errno(error, format, args...)  \
+  do {                                                            \
+    glnx_set_error_from_errno (error);                            \
+    g_prefix_error (error, format, args);                         \
   } while (0);
 
-void glnx_real_set_prefix_error_from_errno (GError     **error,
-                                            gint         errsv,
-                                            const char  *format,
-                                            ...) G_GNUC_PRINTF (3,4);
 
 G_END_DECLS

libglnx/glnx-fdio.c

@@ -54,11 +54,13 @@
             sizeof(type) <= 4 ? 10 :                                    \
             sizeof(type) <= 8 ? 20 : sizeof(int[-2*(sizeof(type) > 8)])))
 
-static gboolean
-rename_file_noreplace_at (int olddirfd, const char *oldpath,
-                          int newdirfd, const char *newpath,
-                          gboolean ignore_eexist,
-                          GError **error)
+
+/* An implementation of renameat2(..., RENAME_NOREPLACE)
+ * with fallback to a non-atomic version.
+ */
+int
+glnx_renameat2_noreplace (int olddirfd, const char *oldpath,
+                          int newdirfd, const char *newpath)
 {
 #ifndef ENABLE_WRPSEUDO_COMPAT
   if (renameat2 (olddirfd, oldpath, newdirfd, newpath, RENAME_NOREPLACE) < 0)
@@ -66,9 +68,35 @@ rename_file_noreplace_at (int olddirfd, const char *oldpath,
       if (errno == EINVAL || errno == ENOSYS)
         {
           /* Fall through */
-          ;
         }
-      else if (errno == EEXIST && ignore_eexist)
+      else
+        {
+          return -1;
+        }
+    }
+  else
+    return TRUE;
+#endif
+
+  if (linkat (olddirfd, oldpath, newdirfd, newpath, 0) < 0)
+    return -1;
+
+  if (unlinkat (olddirfd, oldpath, 0) < 0)
+    return -1;
+
+  return 0;
+}
+
+static gboolean
+rename_file_noreplace_at (int olddirfd, const char *oldpath,
+                          int newdirfd, const char *newpath,
+                          gboolean ignore_eexist,
+                          GError **error)
+{
+  if (glnx_renameat2_noreplace (olddirfd, oldpath,
+                                newdirfd, newpath) < 0)
+    {
+      if (errno == EEXIST && ignore_eexist)
         {
           (void) unlinkat (olddirfd, oldpath, 0);
           return TRUE;
@@ -79,29 +107,46 @@ rename_file_noreplace_at (int olddirfd, const char *oldpath,
           return FALSE;
         }
     }
-  else
-    return TRUE;
-#endif
+  return TRUE;
+}
 
-  if (linkat (olddirfd, oldpath, newdirfd, newpath, 0) < 0)
+/* An implementation of renameat2(..., RENAME_EXCHANGE)
+ * with fallback to a non-atomic version.
+ */
+int
+glnx_renameat2_exchange (int olddirfd, const char *oldpath,
+                         int newdirfd, const char *newpath)
+{
+#ifndef ENABLE_WRPSEUDO_COMPAT
+  if (renameat2 (olddirfd, oldpath, newdirfd, newpath, RENAME_EXCHANGE) == 0)
+    return 0;
+  else
     {
-      if (errno == EEXIST && ignore_eexist)
-        /* Fall through */
-        ;
+      if (errno == ENOSYS || errno == EINVAL)
+        {
+          /* Fall through */
+        }
       else
         {
-          glnx_set_error_from_errno (error);
-          return FALSE;
+          return -1;
         }
     }
-  
-  if (unlinkat (olddirfd, oldpath, 0) < 0)
-    {
-      glnx_set_error_from_errno (error);
-      return FALSE;
-    }
+#endif
 
-  return TRUE;
+  /* Fallback */
+  { const char *old_tmp_name = glnx_strjoina (oldpath, ".XXXXXX");
+
+    /* Move old out of the way */
+    if (renameat (olddirfd, oldpath, olddirfd, old_tmp_name) < 0)
+      return -1;
+    /* Now move new into its place */
+    if (renameat (newdirfd, newpath, olddirfd, oldpath) < 0)
+      return -1;
+    /* And finally old(tmp) into new */
+    if (renameat (olddirfd, old_tmp_name, newdirfd, newpath) < 0)
+      return -1;
+  }
+  return 0;
 }
 
 gboolean

libglnx/glnx-fdio.h

@@ -150,4 +150,10 @@ glnx_stream_fstat (GFileDescriptorBased *stream,
                    struct stat          *stbuf,
                    GError              **error);
 
+int glnx_renameat2_noreplace (int olddirfd, const char *oldpath,
+                              int newdirfd, const char *newpath);
+int glnx_renameat2_exchange (int olddirfd, const char *oldpath,
+                             int newdirfd, const char *newpath);
+
+
 G_END_DECLS

libglnx/glnx-missing.h

@@ -48,5 +48,8 @@
 #ifndef RENAME_NOREPLACE
 #define RENAME_NOREPLACE (1 << 0)
 #endif
+#ifndef RENAME_EXCHANGE
+#define RENAME_EXCHANGE (1 << 1)
+#endif
 
 #include "glnx-missing-syscall.h"

libglnx/tests/test-libglnx-errors.c

@@ -0,0 +1,79 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * This 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 of the License, or (at your option) any later version.
+ *
+ * This 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 this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+#include "libglnx.h"
+#include <glib.h>
+#include <stdlib.h>
+#include <gio/gio.h>
+#include <string.h>
+
+static void
+test_error_throw (void)
+{
+  g_autoptr(GError) error = NULL;
+
+  g_assert (!glnx_throw (&error, "foo: %s %d", "hello", 42));
+  g_assert_error (error, G_IO_ERROR, G_IO_ERROR_FAILED);
+  g_assert_cmpstr (error->message, ==, "foo: hello 42");
+}
+
+static void
+test_error_errno (void)
+{
+  g_autoptr(GError) error = NULL;
+  const char noent_path[] = "/enoent-this-should-not-exist";
+  int fd;
+
+  fd = open (noent_path, O_RDONLY);
+  if (fd < 0)
+    {
+      g_assert (!glnx_throw_errno (&error));
+      g_assert_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND);
+      g_clear_error (&error);
+    }
+  else
+    g_assert_cmpint (fd, ==, -1);
+
+  fd = open (noent_path, O_RDONLY);
+  if (fd < 0)
+    {
+      g_assert (!glnx_throw_errno_prefix (&error, "Failed to open %s", noent_path));
+      g_assert_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND);
+      g_assert (g_str_has_prefix (error->message, glnx_strjoina ("Failed to open ", noent_path)));
+      g_clear_error (&error);
+    }
+  else
+    g_assert_cmpint (fd, ==, -1);
+}
+
+int main (int argc, char **argv)
+{
+  int ret;
+
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/error-throw", test_error_throw);
+  g_test_add_func ("/error-errno", test_error_errno);
+
+  ret = g_test_run();
+
+  return ret;
+}

libglnx/tests/test-libglnx-fdio.c

@@ -0,0 +1,155 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * This 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 of the License, or (at your option) any later version.
+ *
+ * This 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 this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+#include "libglnx.h"
+#include <glib.h>
+#include <stdlib.h>
+#include <gio/gio.h>
+#include <err.h>
+#include <string.h>
+
+static gboolean
+renameat_test_setup (int *out_srcfd, int *out_destfd,
+                     GError **error)
+{
+  glnx_fd_close int srcfd = -1;
+  glnx_fd_close int destfd = -1;
+
+  (void) glnx_shutil_rm_rf_at (AT_FDCWD, "srcdir", NULL, NULL);
+  if (mkdir ("srcdir", 0755) < 0)
+    err (1, "mkdir");
+  if (!glnx_opendirat (AT_FDCWD, "srcdir", TRUE, &srcfd, error))
+    return FALSE;
+  (void) glnx_shutil_rm_rf_at (AT_FDCWD, "destdir", NULL, NULL);
+  if (mkdir ("destdir", 0755) < 0)
+    err (1, "mkdir");
+  if (!glnx_opendirat (AT_FDCWD, "destdir", TRUE, &destfd, error))
+    return FALSE;
+
+  if (!glnx_file_replace_contents_at (srcfd, "foo", (guint8*)"foo contents", strlen ("foo contents"),
+                                      GLNX_FILE_REPLACE_NODATASYNC, NULL, error))
+    return FALSE;
+  if (!glnx_file_replace_contents_at (destfd, "bar", (guint8*)"bar contents", strlen ("bar contents"),
+                                      GLNX_FILE_REPLACE_NODATASYNC, NULL, error))
+    return FALSE;
+
+  *out_srcfd = srcfd; srcfd = -1;
+  *out_destfd = destfd; destfd = -1;
+  return TRUE;
+}
+
+static void
+test_renameat2_noreplace (void)
+{
+  g_autoptr(GError) local_error = NULL;
+  GError **error = &local_error;
+  glnx_fd_close int srcfd = -1;
+  glnx_fd_close int destfd = -1;
+  struct stat stbuf;
+
+  if (!renameat_test_setup (&srcfd, &destfd, error))
+    goto out;
+
+  if (glnx_renameat2_noreplace (srcfd, "foo", destfd, "bar") == 0)
+    g_assert_not_reached ();
+  else
+    {
+      g_assert_cmpint (errno, ==, EEXIST);
+    }
+
+  if (glnx_renameat2_noreplace (srcfd, "foo", destfd, "baz") < 0)
+    {
+      glnx_set_error_from_errno (error);
+      goto out;
+    }
+  if (fstatat (destfd, "bar", &stbuf, AT_SYMLINK_NOFOLLOW) < 0)
+    {
+      glnx_set_error_from_errno (error);
+      goto out;
+    }
+
+  if (fstatat (srcfd, "foo", &stbuf, AT_SYMLINK_NOFOLLOW) == 0)
+    g_assert_not_reached ();
+  else
+    g_assert_cmpint (errno, ==, ENOENT);
+
+ out:
+  g_assert_no_error (local_error);
+}
+
+static void
+test_renameat2_exchange (void)
+{
+  g_autoptr(GError) local_error = NULL;
+  GError **error = &local_error;
+  glnx_fd_close int srcfd = -1;
+  glnx_fd_close int destfd = -1;
+  struct stat stbuf;
+
+  if (!renameat_test_setup (&srcfd, &destfd, error))
+    goto out;
+
+  if (glnx_renameat2_exchange (AT_FDCWD, "srcdir", AT_FDCWD, "destdir") < 0)
+    {
+      glnx_set_error_from_errno (error);
+      goto out;
+    }
+
+  /* Ensure the dir fds are the same */
+  if (fstatat (srcfd, "foo", &stbuf, AT_SYMLINK_NOFOLLOW) < 0)
+    {
+      glnx_set_error_from_errno (error);
+      goto out;
+    }
+  if (fstatat (destfd, "bar", &stbuf, AT_SYMLINK_NOFOLLOW) < 0)
+    {
+      glnx_set_error_from_errno (error);
+      goto out;
+    }
+  /* But the dirs should be swapped */
+  if (fstatat (AT_FDCWD, "destdir/foo", &stbuf, AT_SYMLINK_NOFOLLOW) < 0)
+    {
+      glnx_set_error_from_errno (error);
+      goto out;
+    }
+  if (fstatat (AT_FDCWD, "srcdir/bar", &stbuf, AT_SYMLINK_NOFOLLOW) < 0)
+    {
+      glnx_set_error_from_errno (error);
+      goto out;
+    }
+
+ out:
+  g_assert_no_error (local_error);
+}
+
+int main (int argc, char **argv)
+{
+  int ret;
+
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/renameat2-noreplace", test_renameat2_noreplace);
+  g_test_add_func ("/renameat2-exchange", test_renameat2_exchange);
+
+  ret = g_test_run();
+
+  return ret;
+}