config: make M5_PATH a real search path

Although you can put a list of colon-separated directory names
in M5_PATH, the current code just takes the first one that
exists and assumes all files must live there.  This change
makes the code search the specified list of directories
for each individual binary or disk image that's requested.

The main motivation is that the x86/Alpha binaries and the
ARM binaries are in separate downloads, and thus naturally
end up in separate directories.  With this change, you can
have M5_PATH point to those two directories, then run any
FS regression test without changing M5_PATH.  Currently,
you either have to merge the two download directories
or change M5_PATH (or do something else I haven't figured out).

diff --git a/configs/common/SysPaths.py b/configs/common/SysPaths.py
index c61c9962e4509da4c3ff22bd6cae781fd8fc76c6..b13aff2182d4c4527babe4de6b352263ca737aaf 100644 (file)
--- a/configs/common/SysPaths.py
+++ b/configs/common/SysPaths.py
@@ -33,39 +33,46 @@ from os import environ as env
 config_path = os.path.dirname(os.path.abspath(__file__))
 config_root = os.path.dirname(config_path)
 
+def searchpath(path, file):
+    for p in path:
+        f = joinpath(p, file)
+        if os.path.exists(f):
+            return f
+    raise IOError, "Can't find file '%s' on path." % file
+
 def disk(file):
     system()
-    return joinpath(disk.dir, file)
+    return searchpath(disk.path, file)
 
 def binary(file):
     system()
-    return joinpath(binary.dir, file)
+    return searchpath(binary.path, file)
 
 def script(file):
     system()
-    return joinpath(script.dir, file)
+    return searchpath(script.path, file)
 
 def system():
-    if not system.dir:
+    if not system.path:
         try:
-                path = env['M5_PATH'].split(':')
+            path = env['M5_PATH'].split(':')
         except KeyError:
-                path = [ '/dist/m5/system', '/n/poolfs/z/dist/m5/system' ]
+            path = [ '/dist/m5/system', '/n/poolfs/z/dist/m5/system' ]
+
+        # filter out non-existent directories
+        system.path = filter(os.path.isdir, path)
 
-        for system.dir in path:
-            if os.path.isdir(system.dir):
-                break
-        else:
-            raise ImportError, "Can't find a path to system files."
+        if not system.path:
+            raise IOError, "Can't find a path to system files."
 
-    if not binary.dir:
-        binary.dir = joinpath(system.dir, 'binaries')
-    if not disk.dir:
-        disk.dir = joinpath(system.dir, 'disks')
-    if not script.dir:
-        script.dir = joinpath(config_root, 'boot')
+    if not binary.path:
+        binary.path = [joinpath(p, 'binaries') for p in system.path]
+    if not disk.path:
+        disk.path = [joinpath(p, 'disks') for p in system.path]
+    if not script.path:
+        script.path = [joinpath(config_root, 'boot')]
 
-system.dir = None
-binary.dir = None
-disk.dir = None
-script.dir = None
+system.path = None
+binary.path = None
+disk.path = None
+script.path = None