From 5ee749cd25f221c382fa4b9545cff62eefcb10cf Mon Sep 17 00:00:00 2001 From: Philip Withnall Date: Wed, 1 Aug 2018 15:14:19 +0100 Subject: service: Allow opening corrupt GVDB files when writing If a GVDB file cannot be opened due to being corrupt, move it out of the way, warn, and open a new blank database instead. This prevents the situation where a corrupt database stops the entire desktop session from loading. Note that the dconf_gvdb_utils_read_file() code path is only taken inside DConfWriter. The DConf engine sources (such as dconf-engine-source-system.c) open the GVDB tables separately, and already all handle errors gracefully. Signed-off-by: Philip Withnall https://gitlab.gnome.org/GNOME/glib/issues/1454 --- service/dconf-gvdb-utils.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/service/dconf-gvdb-utils.c b/service/dconf-gvdb-utils.c index 099a9f3..fdd90e2 100644 --- a/service/dconf-gvdb-utils.c +++ b/service/dconf-gvdb-utils.c @@ -26,6 +26,9 @@ #include "../gvdb/gvdb-builder.h" #include "../gvdb/gvdb-reader.h" +#include +#include +#include #include DConfChangeset * @@ -57,7 +60,36 @@ dconf_gvdb_utils_read_file (const gchar *filename, /* Otherwise, we should report errors to prevent ourselves from * overwriting the database in other situations... */ - if (my_error) + if (g_error_matches (my_error, G_FILE_ERROR, G_FILE_ERROR_INVAL)) + { + /* Move the database to a backup file, warn and continue with a new + * database. The alternative is erroring out and exiting the daemon, + * which leaves the user’s session essentially unusable. + * + * The code to find an unused backup filename is racy, but this is an + * error handling path. Who cares. */ + g_autofree gchar *backup_filename = NULL; + guint i; + + for (i = 0; + i < G_MAXUINT && + (backup_filename == NULL || g_file_test (backup_filename, G_FILE_TEST_EXISTS)); + i++) + { + g_free (backup_filename); + backup_filename = g_strdup_printf ("%s~%u", filename, i); + } + + if (g_rename (filename, backup_filename) != 0) + g_warning ("Error renaming corrupt database from ‘%s’ to ‘%s’: %s", + filename, backup_filename, g_strerror (errno)); + else + g_warning ("Database ‘%s’ was corrupt: moved it to ‘%s’ and created an empty replacement", + filename, backup_filename); + + g_clear_error (&my_error); + } + else if (my_error) { g_propagate_prefixed_error (error, my_error, "Cannot open dconf database: "); return NULL; -- cgit v1.2.1