Initial add of libappdir-wrapper.c ...

icculus · Jun 9, 2009 · e6ca2cc · e6ca2cc
1 parent 45ba188
commit e6ca2cc
Showing 1 changed file with 65 additions and 0 deletions.
diff --git a/libappdir-wrapper.c b/libappdir-wrapper.c
@@ -0,0 +1,65 @@
+/*
+ * To use this:
+ *  LD_PRELOAD=libappdir-wrapper.so ./my-badly-behaved-app
+ */
+
+#include <limits.h>
+#include <sqlite3.h>
+
+#define DB_FNAME "/etc/libappdir/legacymappings.sqlite3"
+
+static int map_file(const char *path, char *newpath, size_t len)
+{
+    int mapping = 0;
+    int failure = 1;
+    const char *sql = NULL;
+
+    sqlite3 *db = NULL;
+    const int rc = sqlite3_open_v2(DB_FNAME, &db, SQLITE_OPEN_READONLY, NULL);
+    if (rc != SQLITE_OK)
+    {
+        logError("Couldn't open " DB_FNAME ": sqlite3 error is %d", rc);
+        return 0;
+    } /* if */
+
+    sqlite3_stmt *stmt = NULL;
+    void *tail = NULL;
+    sql = "select remapped from mappings where original=?1 limit 1";
+    if (sqlite3_prepare_v2(db, sql, -1, &stmt, &tail) != SQLITE_OK)
+        goto done_map_file;
+
+    const int pathlen = (int) strlen(path);
+    if (sqlite3_bind_text(stmt, 1, path, pathlen, SQLITE_STATIC) != SQLITE_OK)
+        goto done_map_file;
+
+    const int step = sqlite3_step(stmt);
+    if (step == SQLITE_DONE)  /* no mapping, but this isn't an error. */
+        failure = 0;
+    has_mapping = (step == SQLITE_ROW);
+    if (!has_mapping)
+        goto done_map_file;
+
+    failure = 0;
+
+    const char *remapped = (const char *) sqlite3_column_text(stmt, 0);
+    if (snprintf(newpath, len, "%s", remapped) >= len)
+    {
+        logError("buffer too small for remapping");
+        has_mapping = 0;
+    } /* if */
+
+done_map_file:
+    if (failure)
+        logError("sqlite3 error: %s", db ? sqlite3_errmsg(db) : "???");
+    if (stmt != NULL)
+        sqlite3_finalize(stmt);
+    if (db != NULL)
+        sqlite3_close(db);
+
+    return has_mapping;
+} /* map_file */
+
+
+
+/* end of libappdir-wrapper.c ... */
+