[Xen-devel] [PATCH] kernel command line extension

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

In order to allow appending to the dom0 command line even with boot
loaders that only allow editing the kernel (i.e. Xen in our case)
command line, support a '--' separator option.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

Index: 2007-06-18/xen/arch/x86/setup.c
===================================================================
--- 2007-06-18.orig/xen/arch/x86/setup.c        2007-06-19 11:13:50.000000000 
+0200
+++ 2007-06-18/xen/arch/x86/setup.c     2007-06-19 11:26:17.000000000 +0200
@@ -405,7 +405,7 @@ void init_done(void)
 void __init __start_xen(unsigned long mbi_p)
 {
     char *memmap_type = NULL;
-    char __cmdline[] = "", *cmdline = __cmdline;
+    char __cmdline[] = "", *cmdline = __cmdline, *kextra;
     unsigned long _initrd_start = 0, _initrd_len = 0;
     unsigned int initrdidx = 1;
     char *_policy_start = NULL;
@@ -425,7 +425,7 @@ void __init __start_xen(multiboot_info_t
     /* Parse the command-line options. */
     if ( (mbi->flags & MBI_CMDLINE) && (mbi->cmdline != 0) )
         cmdline = __va(mbi->cmdline);
-    cmdline_parse(cmdline);
+    kextra = cmdline_parse(cmdline);
 
     parse_video_info();
 
@@ -1005,19 +1005,27 @@ void __init __start_xen(multiboot_info_t
 
     /* Grab the DOM0 command line. */
     cmdline = (char *)(mod[0].string ? __va(mod[0].string) : NULL);
-    if ( cmdline != NULL )
+    if ( cmdline != NULL || kextra != NULL )
     {
         static char dom0_cmdline[MAX_GUEST_CMDLINE];
 
-        /* Skip past the image name and copy to a local buffer. */
-        while ( *cmdline == ' ' ) cmdline++;
-        if ( (cmdline = strchr(cmdline, ' ')) != NULL )
+        if ( cmdline != NULL )
         {
+            /* Skip past the image name and copy to a local buffer. */
             while ( *cmdline == ' ' ) cmdline++;
-            safe_strcpy(dom0_cmdline, cmdline);
+            if ( (cmdline = strchr(cmdline, ' ')) != NULL )
+            {
+                while ( *cmdline == ' ' ) cmdline++;
+                safe_strcpy(dom0_cmdline, cmdline);
+            }
         }
+        else
+            dom0_cmdline[0] = '\0';
 
         /* Append any extra parameters. */
+        if ( kextra != NULL )
+            /* Note that kextra already includes a leading space. */
+            safe_strcat(dom0_cmdline, kextra);
         if ( skip_ioapic_setup && !strstr(dom0_cmdline, "noapic") )
             safe_strcat(dom0_cmdline, " noapic");
         if ( acpi_skip_timer_override &&
Index: 2007-06-18/xen/common/kernel.c
===================================================================
--- 2007-06-18.orig/xen/common/kernel.c 2007-06-18 12:03:19.000000000 +0200
+++ 2007-06-18/xen/common/kernel.c      2007-06-18 12:15:35.000000000 +0200
@@ -24,20 +24,20 @@
 
 int tainted;
 
-void cmdline_parse(char *cmdline)
+char *cmdline_parse(char *cmdline)
 {
     char opt[100], *optval, *q;
     const char *p = cmdline;
     struct kernel_param *param;
     
     if ( p == NULL )
-        return;
+        return (char *)p;
 
     /* Skip whitespace and the image name. */
     while ( *p == ' ' )
         p++;
     if ( (p = strchr(p, ' ')) == NULL )
-        return;
+        return (char *)p;
 
     for ( ; ; )
     {
@@ -57,6 +57,9 @@ void cmdline_parse(char *cmdline)
         }
         *q = '\0';
 
+        if ( strcmp(opt, "--") == 0 )
+            return (char *)p;
+
         /* Search for value part of a key=value option. */
         optval = strchr(opt, '=');
         if ( optval != NULL )
@@ -87,6 +90,8 @@ void cmdline_parse(char *cmdline)
             }
         }
     }
+
+    return NULL;
 }
 
 /**
Index: 2007-06-18/xen/include/xen/lib.h
===================================================================
--- 2007-06-18.orig/xen/include/xen/lib.h       2007-06-19 11:25:18.000000000 
+0200
+++ 2007-06-18/xen/include/xen/lib.h    2007-06-18 12:15:35.000000000 +0200
@@ -43,7 +43,7 @@ do {                                    
 
 struct domain;
 
-void cmdline_parse(char *cmdline);
+char *cmdline_parse(char *cmdline);
 
 /*#define DEBUG_TRACE_DUMP*/
 #ifdef DEBUG_TRACE_DUMP



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