From 5fb8bb955e2b762e0d462d0acd0924cb842f88ab Mon Sep 17 00:00:00 2001
From: Colin Walters <walters@verbum.org>
Date: Tue, 21 Oct 2014 14:34:04 -0400
Subject: [PATCH] repo: When writing to a non-root owned repo, chown() objects
 to match

Some package systems need to be run as root, so the process linking to
libostree may also be root.  However, it's reasonable to have the
target repository be owned by a uid other than root.

This patch makes it Just Work by chowning the file content to match.

Note this only operates on archive-z2 repositories, because you can't
usefully serve bare repositories via HTTP.

https://bugzilla.gnome.org/show_bug.cgi?id=738954
---
 src/libostree/ostree-repo-commit.c  | 16 ++++++++++++++++
 src/libostree/ostree-repo-private.h |  3 +++
 src/libostree/ostree-repo.c         | 17 +++++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/src/libostree/ostree-repo-commit.c b/src/libostree/ostree-repo-commit.c
index 68cff05d..f76dcd66 100644
--- a/src/libostree/ostree-repo-commit.c
+++ b/src/libostree/ostree-repo-commit.c
@@ -72,6 +72,22 @@ commit_loose_object_trusted (OstreeRepo        *self,
 {
   gboolean ret = FALSE;
 
+  /* We may be writing as root to a non-root-owned repository; if so,
+   * automatically inherit the non-root ownership.
+   */
+  if (self->mode == OSTREE_REPO_MODE_ARCHIVE_Z2
+      && self->target_owner_uid != -1) 
+    {
+      if (G_UNLIKELY (fchownat (self->tmp_dir_fd, temp_filename,
+                                self->target_owner_uid,
+                                self->target_owner_gid,
+                                AT_SYMLINK_NOFOLLOW) == -1))
+        {
+          ot_util_set_error_from_errno (error, errno);
+          goto out;
+        }
+    }
+
   /* Special handling for symlinks in bare repositories */
   if (is_symlink && self->mode == OSTREE_REPO_MODE_BARE)
     {
diff --git a/src/libostree/ostree-repo-private.h b/src/libostree/ostree-repo-private.h
index ad512f98..e893c4f8 100644
--- a/src/libostree/ostree-repo-private.h
+++ b/src/libostree/ostree-repo-private.h
@@ -65,6 +65,9 @@ struct OstreeRepo {
   GHashTable *updated_uncompressed_dirs;
   GHashTable *object_sizes;
 
+  uid_t target_owner_uid;
+  gid_t target_owner_gid;
+
   GKeyFile *config;
   OstreeRepoMode mode;
   gboolean enable_uncompressed_cache;
diff --git a/src/libostree/ostree-repo.c b/src/libostree/ostree-repo.c
index 4887e8d1..98617552 100644
--- a/src/libostree/ostree-repo.c
+++ b/src/libostree/ostree-repo.c
@@ -819,6 +819,7 @@ ostree_repo_open (OstreeRepo    *self,
 {
   gboolean ret = FALSE;
   gboolean is_archive;
+  struct stat stbuf;
   gs_free char *version = NULL;
   gs_free char *mode = NULL;
   gs_free char *parent_repo_path = NULL;
@@ -836,6 +837,22 @@ ostree_repo_open (OstreeRepo    *self,
 
   self->writable = faccessat (AT_FDCWD, gs_file_get_path_cached (self->objects_dir), W_OK, 0) == 0;
 
+  if (fstat (self->objects_dir_fd, &stbuf) != 0)
+    {
+      ot_util_set_error_from_errno (error, errno);
+      goto out;
+    }
+
+  if (stbuf.st_uid != getuid () || stbuf.st_gid != getgid ())
+    {
+      self->target_owner_uid = stbuf.st_uid;
+      self->target_owner_gid = stbuf.st_gid;
+    }
+  else
+    {
+      self->target_owner_uid = self->target_owner_gid = -1;
+    }
+
   self->config = g_key_file_new ();
   if (!g_key_file_load_from_file (self->config, gs_file_get_path_cached (self->config_file), 0, error))
     {