From 3a3aea8eed5247c650befe2d5ca82e1b220b54c7 Mon Sep 17 00:00:00 2001
From: hpa <hpa>
Date: Fri, 17 Dec 2004 18:54:08 +0000
Subject: [PATCH] Actually parse argc/argv properly.

---
 dos/Makefile |  2 +-
 dos/argv.c   | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 dos/crt0.S   | 44 +++++++----------------------
 dos/malloc.c |  5 ++--
 4 files changed, 104 insertions(+), 37 deletions(-)
 create mode 100644 dos/argv.c

diff --git a/dos/Makefile b/dos/Makefile
index 3e8b531..135fe31 100644
--- a/dos/Makefile
+++ b/dos/Makefile
@@ -6,7 +6,7 @@ INCLUDES = -include code16.h -I. -I.. -I../libfat
 CFLAGS	 = -W -Wall -ffreestanding $(OPTFLAGS) $(INCLUDES)
 LDFLAGS	 = -T com16.ld
 
-SRCS     = syslinux.c conio.c skipatou.c atou.c malloc.c free.c \
+SRCS     = syslinux.c conio.c skipatou.c atou.c malloc.c free.c argv.c \
 	   ../syslxmod.c ../bootsect_bin.c ../ldlinux_bin.c \
            $(wildcard ../libfat/*.c)
 OBJS	 = crt0.o memcpy.o memset.o $(patsubst %.c,%.o,$(notdir $(SRCS)))
diff --git a/dos/argv.c b/dos/argv.c
new file mode 100644
index 0000000..62c3b04
--- /dev/null
+++ b/dos/argv.c
@@ -0,0 +1,90 @@
+#ident "$Id$"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2004 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *   
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *   
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * argv.c
+ *
+ * Parse a single C string into argc and argv (argc is return value.)
+ * memptr points to available memory.
+ */
+
+#include <inttypes.h>
+#include <stddef.h>
+
+#define ALIGN_UP(p,t)       ((t *)(((uintptr_t)(p) + (sizeof(t)-1)) & ~(sizeof(t)-1)))
+
+extern char _end[];	     /* Symbol created by linker */
+void *__mem_end = &_end;     /* Global variable for use by malloc() */
+
+int __parse_argv(char ***argv, const char *str)
+{
+  char *mem = __mem_end;
+  const char *p = str;
+  char *q = mem;
+  char *r;
+  char **arg;
+  int wasspace = 0;
+  int argc = 1;
+
+  /* First copy the string, turning whitespace runs into nulls */
+  for ( p = str ; ; p++ ) {
+    if ( *p <= ' ' ) {
+      if ( !wasspace ) {
+	wasspace = 1;
+	*q++ = '\0';
+      }
+    } else {
+      if ( wasspace ) {
+	argc++;
+	wasspace = 0;
+      }
+      *q++ = *p;
+    }
+
+    /* This test is AFTER we have processed the null byte;
+       we treat it as a whitespace character */
+    if ( ! *p )
+      break;
+  }
+  q--;				/* Point to final null */
+
+  /* Now create argv */
+  *argv = arg = ALIGN_UP(q,char *);
+  *arg++ = mem;			/* argv[0] */
+
+  for ( r = mem ; r < q ; r++ ) {
+    if ( *r == '\0' )
+      *arg++ = r+1;
+  }
+
+  *arg++ = NULL;		/* Null pointer at the end */
+  __mem_end = arg;		/* End of memory we used */
+
+  return argc;
+}
+
diff --git a/dos/crt0.S b/dos/crt0.S
index 38f6725..f567177 100644
--- a/dos/crt0.S
+++ b/dos/crt0.S
@@ -17,45 +17,21 @@ _start:
 	rep ; stosl
 
 	# Compute argc and argv
-	movzbw 0x80,%cx
-	movl $0x81,%esi
-	movw $argv,%di
-
-	xorl %eax,%eax		# Dummy argv[0]
-	stosl
-
-1:
-	# Skip any space or control character
-	jcxz 2f
-	lodsb
-	decw %cx
-	cmp $0x20,%al
-	ja 3f
-5:
-	movb $0,-1(%si)
-	jmp 1b
-
-3:
-	movl %esi,%eax
-	stosl
-4:
-	# Skip this word
-	jcxz 2f
-	lodsb
-	decw %cx
-	cmp $0x20,%al
-	ja 4b
-	jmp 5b
-2:
-	xorl %eax,%eax		# Final null argv entry
-	stosl	
+	xorl %edx,%edx
+	movzbw 80,%bx
+	movb %dl,81(%bx)	# Zero-terminate string
+	movb $81,%dl
+	pushl %eax		# Make space for argv
+	movl %esp,%eax
+	calll __parse_argv
+	pushl %eax		# argc
 
 	# Initialize malloc
 	calll __init_memory_arena
 
 	# Now call main...
-	movl $argv,%edx		# argv
-	xorl %eax,%eax		# dummy argc (we dont use it)
+	popl %eax		# argc
+	popl %edx		# argv
 	calll main
 
 	# Here %eax is the exit code, fall through into exit
diff --git a/dos/malloc.c b/dos/malloc.c
index 93a51bb..8d37b5d 100644
--- a/dos/malloc.c
+++ b/dos/malloc.c
@@ -29,13 +29,14 @@ static inline size_t sp(void)
   return sp;
 }
 
+extern void *__mem_end;
+
 void __init_memory_arena(void)
 {
-  extern char _end[];		/* Symbol created by the linker */
   struct free_arena_header *fp;
   size_t start, total_space;
 
-  start = (size_t)ARENA_ALIGN_UP(_end);
+  start = (size_t)ARENA_ALIGN_UP(__mem_end);
   total_space = sp() - start;
 
   fp = (struct free_arena_header *)start;
-- 
2.7.4