From 3522d183bc926b922a5d4c7d96616264e8ca5cf8 Mon Sep 17 00:00:00 2001
From: Alexander Larsson <alexl@redhat.com>
Date: Mon, 2 Nov 2020 15:43:52 +0100
Subject: summaries: When regenerating summaries, ensure they get newer mtimes

The st_mtime field is all we can guarantee to keep, so whenever we
write a new summary file for a repo we ensure it is newer than the old
by checking if st_mtime is equal (or less) and if so, use the old
st_mtime plus one.

This means sometimes the generated summary files will be in the future but
that only happens in the corner case of multiple changes inside one
second, and in that particular case we need this change.

This fixes some issues I had with the mtime chacking in the tests due to
the python httpd handling If-Modified-Since based on st_mtime.
---
 common/flatpak-utils.c | 45 +++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 41 insertions(+), 4 deletions(-)

diff --git a/common/flatpak-utils.c b/common/flatpak-utils.c
index 089bdd81..8fc21c72 100644
--- a/common/flatpak-utils.c
+++ b/common/flatpak-utils.c
@@ -4008,18 +4008,31 @@ flatpak_repo_load_summary_index (OstreeRepo *repo,
 static gboolean
 flatpak_repo_save_compat_summary (OstreeRepo   *repo,
                                   GVariant     *summary,
+                                  time_t       *out_old_sig_mtime,
                                   GCancellable *cancellable,
                                   GError      **error)
 {
   int repo_dfd = ostree_repo_get_dfd (repo);
+  struct stat stbuf;
+  time_t old_sig_mtime = 0;
+  GLnxFileReplaceFlags flags;
+
+  flags = GLNX_FILE_REPLACE_INCREASING_MTIME;
+  if (ostree_repo_get_disable_fsync (repo))
+    flags |= GLNX_FILE_REPLACE_NODATASYNC;
+  else
+    flags |= GLNX_FILE_REPLACE_DATASYNC_NEW;
 
   if (!glnx_file_replace_contents_at (repo_dfd, "summary",
                                       g_variant_get_data (summary),
                                       g_variant_get_size (summary),
-                                      ostree_repo_get_disable_fsync (repo) ? GLNX_FILE_REPLACE_NODATASYNC : GLNX_FILE_REPLACE_DATASYNC_NEW,
+                                      flags,
                                       cancellable, error))
     return FALSE;
 
+  if (fstatat (repo_dfd, "summary.sig", &stbuf, AT_SYMLINK_NOFOLLOW) == 0)
+    old_sig_mtime = stbuf.st_mtime;
+
   if (unlinkat (repo_dfd, "summary.sig", 0) != 0 &&
       G_UNLIKELY (errno != ENOENT))
     {
@@ -4027,6 +4040,7 @@ flatpak_repo_save_compat_summary (OstreeRepo   *repo,
       return FALSE;
     }
 
+  *out_old_sig_mtime = old_sig_mtime;
   return TRUE;
 }
 
@@ -4038,6 +4052,7 @@ flatpak_repo_save_summary_index (OstreeRepo   *repo,
                                  GError      **error)
 {
   int repo_dfd = ostree_repo_get_dfd (repo);
+  GLnxFileReplaceFlags  flags;
 
   if (index == NULL)
     {
@@ -4057,10 +4072,16 @@ flatpak_repo_save_summary_index (OstreeRepo   *repo,
       return TRUE;
     }
 
+  flags = GLNX_FILE_REPLACE_INCREASING_MTIME;
+  if (ostree_repo_get_disable_fsync (repo))
+    flags |= GLNX_FILE_REPLACE_NODATASYNC;
+  else
+    flags |= GLNX_FILE_REPLACE_DATASYNC_NEW;
+
   if (!glnx_file_replace_contents_at (repo_dfd, "summary.idx",
                                       g_variant_get_data (index),
                                       g_variant_get_size (index),
-                                      ostree_repo_get_disable_fsync (repo) ? GLNX_FILE_REPLACE_NODATASYNC : GLNX_FILE_REPLACE_DATASYNC_NEW,
+                                      flags,
                                       cancellable, error))
     return FALSE;
 
@@ -4069,7 +4090,7 @@ flatpak_repo_save_summary_index (OstreeRepo   *repo,
       if (!glnx_file_replace_contents_at (repo_dfd, "summary.idx.sig",
                                           g_bytes_get_data (index_sig, NULL),
                                           g_bytes_get_size (index_sig),
-                                          ostree_repo_get_disable_fsync (repo) ? GLNX_FILE_REPLACE_NODATASYNC : GLNX_FILE_REPLACE_DATASYNC_NEW,
+                                          flags,
                                           cancellable, error))
         return FALSE;
     }
@@ -5722,6 +5743,7 @@ flatpak_repo_update (OstreeRepo   *repo,
   g_autoptr(GHashTable) digested_summaries = NULL;
   g_autoptr(GHashTable) digested_summary_cache = NULL;
   g_autoptr(GBytes) index_sig = NULL;
+  time_t old_compat_sig_mtime;
   GKeyFile *config;
   gboolean disable_index = (flags & FLATPAK_REPO_UPDATE_FLAG_DISABLE_INDEX) != 0;
 
@@ -5850,7 +5872,7 @@ flatpak_repo_update (OstreeRepo   *repo,
   if (!flatpak_repo_save_summary_index (repo, summary_index, index_sig, cancellable, error))
     return FALSE;
 
-  if (!flatpak_repo_save_compat_summary (repo, compat_summary, cancellable, error))
+  if (!flatpak_repo_save_compat_summary (repo, compat_summary, &old_compat_sig_mtime, cancellable, error))
     return FALSE;
 
   if (gpg_key_ids)
@@ -5861,6 +5883,21 @@ flatpak_repo_update (OstreeRepo   *repo,
                                                   cancellable,
                                                   error))
         return FALSE;
+
+
+      if (old_compat_sig_mtime != 0)
+        {
+          int repo_dfd = ostree_repo_get_dfd (repo);
+          struct stat stbuf;
+
+          /* Ensure we increase (in sec precision) */
+          if (fstatat (repo_dfd, "summary.sig", &stbuf, AT_SYMLINK_NOFOLLOW) == 0 &&
+              stbuf.st_mtime <= old_compat_sig_mtime)
+            {
+              struct timespec ts[2] = { {0, UTIME_OMIT}, {old_compat_sig_mtime + 1, 0} };
+              (void) utimensat (repo_dfd, "summary.sig", ts, AT_SYMLINK_NOFOLLOW);
+            }
+        }
     }
 
   if (!disable_index &&
-- 
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