[patch] cmdline.c rewrite

[Andrew Clausen <clausen@melbourne.sgi.com>]

Hi all,

This patch is mainly a cleanup.  There is only one change (improvement!)
in the semantics:

Some kernel parameters are auto-generated.   eg: root= (always has been
broken).  Anyway, the old version of cmdline.c added these auto-generated
parameters unconditionally.  Now, it old adds them if there's no
collision with old parameters.  Is that Right?

Cheers,
Andrew


Index: cmdline.c
===================================================================
RCS file: /home/cvs/linux/arch/mips/arc/cmdline.c,v
retrieving revision 1.5.2.3
diff -u -r1.5.2.3 cmdline.c
--- cmdline.c   5 Aug 2002 23:53:30 -0000       1.5.2.3
+++ cmdline.c   24 Jan 2003 06:43:57 -0000
@@ -6,6 +6,8 @@
  * cmdline.c: Kernel command line creation using ARCS argc/argv.
  *
  * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
+ * Copyright (C) 2003 Silicon Graphics, Inc.
+ *     modifications by Andrew Clausen (clausen@gnu.org)
  */
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -16,96 +18,76 @@
 
 #undef DEBUG_CMDLINE
 
-char arcs_cmdline[CL_SIZE];
+char arcs_cmdline[CL_SIZE]; /* initialized to empty */
+static int __initdata arg_count = 0;
 
 char * __init prom_getcmdline(void)
 {
-       return &(arcs_cmdline[0]);
+       return arcs_cmdline;
 }
 
-static char *ignored[] = {
+static void __init append_translated_arg(const char* match, const char* trans)
+{
+       int len = strlen(match);
+       int i;
+
+       /* don't repeat arguments, like "root=X root=Y", unless the
+        * replacement string "trans" is empty, in which case the user is
+        * getting exactly what they asked for.
+        */
+       if (strlen(trans) > 0 && strstr(arcs_cmdline, trans))
+               return;
+
+       for (i = 1; i < prom_argc; i++) {
+               if (!strncmp(prom_argv(i), match, len)) {
+                       if (arg_count++)
+                               strcat(arcs_cmdline, " ");
+                       strcat(arcs_cmdline, trans);
+                       strcat(arcs_cmdline, prom_argv(i) + len);
+                       return;
+               }
+       }
+}
+
+static char __initdata *ignored_args[] = {
        "ConsoleIn=",
        "ConsoleOut=",
        "SystemPartition=",
        "OSLoader=",
        "OSLoadPartition=",
        "OSLoadFilename=",
-       "OSLoadOptions="
-};
-#define NENTS(foo) ((sizeof((foo)) / (sizeof((foo[0])))))
-
-static char *used_arc[][2] = {
-       { "OSLoadPartition=", "root=" },
-       { "OSLoadOptions=", "" }
+       "OSLoadOptions=",
+       NULL
 };
 
-static char * __init move_firmware_args(char* cp)
+static int __init is_arg_useful(const char* arg)
 {
-       char *s;
-       int actr, i;
-
-       actr = 1; /* Always ignore argv[0] */
-
-       while (actr < prom_argc) {
-               for(i = 0; i < NENTS(used_arc); i++) {
-                       int len = strlen(used_arc[i][0]);
-
-                       if (!strncmp(prom_argv(actr), used_arc[i][0], len)) {
-                       /* Ok, we want it. First append the replacement... */
-                               strcat(cp, used_arc[i][1]);
-                               cp += strlen(used_arc[i][1]);
-                               /* ... and now the argument */
-                               s = strstr(prom_argv(actr), "=");
-                               if (s) {
-                                       s++;
-                                       strcpy(cp, s);
-                                       cp += strlen(s);
-                               }
-                               *cp++ = ' ';
-                               break;
-                       }
-               }
-               actr++;
+       int i;
+       for (i = 0; ignored_args[i] != NULL; i++) {
+               if (!strncmp(arg, ignored_args[i], strlen(ignored_args[i]) - 1))
+                       return 0;
        }
-
-       return cp;
+       return 1;
 }
 
-
-void __init prom_init_cmdline(void)
+static void __init append_untranslated_args(void)
 {
-       char *cp;
-       int actr, i;
-
-       actr = 1; /* Always ignore argv[0] */
-
-       cp = &(arcs_cmdline[0]);
-       /*
-        * Move ARC variables to the beginning to make sure they can be
-        * overridden by later arguments.
-        */
-       cp = move_firmware_args(cp);
-
-       while (actr < prom_argc) {
-               for (i = 0; i < NENTS(ignored); i++) {
-                       int len = strlen(ignored[i]);
-
-                       if (!strncmp(prom_argv(actr), ignored[i], len))
-                               goto pic_cont;
+       int i;
+       for (i = 1; i < prom_argc; i++) {
+               if (is_arg_useful(prom_argv(i))) {
+                       if (arg_count++)
+                               strcat(arcs_cmdline, " ");
+                       strcat(arcs_cmdline, prom_argv(i));
                }
-               /* Ok, we want it. */
-               strcpy(cp, prom_argv(actr));
-               cp += strlen(prom_argv(actr));
-               *cp++ = ' ';
-
-       pic_cont:
-               actr++;
        }
-       if (cp != &(arcs_cmdline[0])) /* get rid of trailing space */
-               --cp;
-       *cp = '\0';
+}
 
+void __init prom_init_cmdline(void)
+{
+       append_translated_arg("OSLoadOptions=", "");
+       append_translated_arg("OSLoadPartition=", "root=");
+       append_untranslated_args();
 #ifdef DEBUG_CMDLINE
-       prom_printf("prom_init_cmdline: %s\n", &(arcs_cmdline[0]));
+       prom_printf("prom_init_cmdline: \"%s\"\n", arcs_cmdline);
 #endif
 }