Parse multiboot command line into argc/argv

Signed-off-by: Avi Kivity <avi@redhat.com>

Makefile

@@ -15,6 +15,7 @@ cflatobjs := \
 	lib/panic.o \
 	lib/printf.o \
 	lib/string.o
+cflatobjs += lib/argv.o
 
 #include architecure specific make rules
 include config-$(ARCH).mak

lib/argv.c

+#include "libcflat.h"
+
+int __argc;
+char *__argv[100];
+char *__args;
+char __args_copy[1000];
+
+static bool isblank(char p)
+{
+    return p == ' ' || p == '\t';
+}
+
+static char *skip_blanks(char *p)
+{
+    while (isblank(*p))
+        ++p;
+    return p;
+}
+
+void __setup_args(void)
+{
+    char *args = __args;
+    char **argv = __argv;
+    char *p = __args_copy;
+
+    while (*(args = skip_blanks(args)) != '\0') {
+        *argv++ = p;
+        while (*args != '\0' && !isblank(*args))
+            *p++ = *args++;
+        *p++ = '\0';
+    }
+    __argc = argv - __argv;
+}

x86/cstart.S

@@ -9,9 +9,15 @@ mb_flags = 0x0
 
 	# multiboot header
 	.long mb_magic, mb_flags, 0 - (mb_magic + mb_flags)
+mb_cmdline = 16
 
 .globl start
 start:
+	mov mb_cmdline(%ebx), %eax
+	mov %eax, __args
+	call __setup_args
+	pushl $__argv
+	pushl __argc
 	call main
 	push %eax
 	call exit

x86/cstart64.S

@@ -75,6 +75,8 @@ i = i + 1
 	.endr
 tss_end:
 
+mb_boot_info:	.quad 0
+
 .section .init
 
 .code32
@@ -84,6 +86,7 @@ mb_flags = 0x0
 
 	# multiboot header
 	.long mb_magic, mb_flags, 0 - (mb_magic + mb_flags)
+mb_cmdline = 16
 
 MSR_GS_BASE = 0xc0000101
 
@@ -96,6 +99,7 @@ MSR_GS_BASE = 0xc0000101
 
 .globl start
 start:
+	mov %ebx, mb_boot_info
 	mov $stacktop, %esp
 	setup_percpu_area
 	call prepare_64
@@ -179,6 +183,12 @@ start64:
 	call enable_apic
 	call smp_init
 	call enable_x2apic
+	mov mb_boot_info(%rip), %rax
+	mov mb_cmdline(%rax), %rax
+	mov %rax, __args(%rip)
+	call __setup_args
+	mov __argc(%rip), %edi
+	lea __argv(%rip), %rsi
 	call main
 	mov %eax, %edi
 	call exit