Add PANDA_PLUGIN_PATH

panda/python/core/pandare/panda.py

@@ -105,7 +105,11 @@ def __init__(self, arch="i386", mem="128M",
         self.catch_exceptions=catch_exceptions
         self.qlog = QEMU_Log_Manager(self)
         self.build_dir = None
-        self.plugin_path = plugin_path
+        prev_path = environ.get("PANDA_PLUGIN_PATH")
+        if plugin_path and prev_path:
+            environ["PANDA_PLUGIN_PATH"] = f"{plugin_path}:{prev_path}"
+        elif plugin_path:
+            environ["PANDA_PLUGIN_PATH"] = plugin_path
 
         self.serial_unconsumed_data = b''
 
@@ -259,19 +263,12 @@ def __init__(self, arch="i386", mem="128M",
         progress ("Panda args: [" + (" ".join(self.panda_args)) + "]")
     # /__init__
 
-    def get_plugin_path(self):
-        if self.plugin_path is None:
-            build_dir = self.get_build_dir()
-            rel_dir = pjoin(*[build_dir, self.arch_name+"-softmmu", "panda", "plugins"])
-
-            if build_dir == "/usr/local/bin/":
-                # Installed - use /usr/local/lib/panda/plugins
-                self.plugin_path = f"/usr/local/lib/panda/{self.arch_name}"
-            elif isdir(rel_dir):
-                self.plugin_path = rel_dir
-            else:
-                raise ValueError(f"Could not find plugin path. Build dir={build_dir}")
-        return self.plugin_path
+    def get_plugin_path(self, plugin_name):
+        plugin_name_ffi = self.ffi.new("char[]", bytes(plugin_name, "utf-8"))
+        plugin_path_ffi = self.libpanda.panda_plugin_path(plugin_name_ffi)
+        plugin_path = self.ffi.string(plugin_path_ffi).decode("utf-8")
+        # TODO: self.libpanda.g_free(plugin_path_ffi)
+        return plugin_path
 
     def get_build_dir(self):
         if self.build_dir is None:
@@ -946,7 +943,7 @@ def _load_plugin_library(self, name):
             libpanda_path_chr = self.ffi.new("char[]",bytes(self.libpanda_path, "UTF-8"))
             self.__did_load_libpanda = self.libpanda.panda_load_libpanda(libpanda_path_chr)
         if not name in self.plugins.keys():
-            plugin = pjoin(*[self.get_plugin_path(), f"panda_{name}.so"])
+            plugin = self.get_plugin_path(name)
             assert(isfile(plugin))
             self.plugins[name] = self.ffi.dlopen(plugin)
 

panda/src/callbacks.c

@@ -316,6 +316,7 @@ extern const char *qemu_file;
 //   - Relative to the QEMU binary
 //   - Relative to the standard install location (/usr/local/lib/panda/[arch]/)
 //   - Relative to the install prefix directory.
+//   - In the directories in the PANDA_PLUGIN_PATH environment variable.
 char* resolve_file_from_plugin_directory(const char* file_name_fmt, const char* name){
     char *plugin_path, *name_formatted;
     // makes "taint2" -> "panda_taint2"
@@ -357,7 +358,7 @@ char* resolve_file_from_plugin_directory(const char* file_name_fmt, const char*
         return plugin_path;
     }
 
-    // Finally, try relative to the installation path.
+    // Fourth, try relative to the installation path.
     plugin_path = attempt_normalize_path(
         g_strdup_printf("%s/%s/%s", CONFIG_PANDA_PLUGINDIR,
                         TARGET_NAME, name_formatted));
@@ -366,6 +367,20 @@ char* resolve_file_from_plugin_directory(const char* file_name_fmt, const char*
     }
     g_free(plugin_path);
 
+    // Finally, try the directories in PANDA_PLUGIN_PATH
+    gchar **panda_plugin_path = g_strsplit(g_getenv("PANDA_PLUGIN_PATH"), ":", -1);
+    for (gchar **dir = panda_plugin_path; *dir; dir++) {
+        gchar *plugin_path = attempt_normalize_path(g_strdup_printf(
+                                    "%s/%s/%s", *dir,
+                                    TARGET_NAME, name_formatted));
+        if (TRUE == g_file_test(plugin_path, G_FILE_TEST_EXISTS)) {
+            g_strfreev(panda_plugin_path);
+            return plugin_path;
+        }
+        g_free(plugin_path);
+    }
+    g_strfreev(panda_plugin_path);
+
     // Return null if plugin resolution failed.
     return NULL;
 }