Cleanup brk/sbrk

1 files changed, 38 insertions, 22 deletions

diff --git a/libc/sysdeps/linux/i386/brk.c b/libc/sysdeps/linux/i386/brk.c
index 9e06d0acc..eca0e8326 100644
--- a/libc/sysdeps/linux/i386/brk.c
+++ b/libc/sysdeps/linux/i386/brk.c
@@ -1,32 +1,48 @@
-/* From libc-5.3.12 */
+/* brk system call for Linux/i386.
+   Copyright (C) 1995, 1996, 2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
 
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <errno.h>
 #include <unistd.h>
 #include <sys/syscall.h>
-#include <errno.h>
 
-extern void * ___brk_addr;
 
-extern int __init_brk ();
+/* This must be initialized data because commons can't have aliases.  */
+void *___brk_addr = 0;
 
-int brk(void * end_data_seg)
+int brk (void *addr)
 {
-    if (__init_brk () == 0)
+    void *__unbounded newbrk, *__unbounded scratch;
+
+    asm ("movl %%ebx, %1\n"	/* Save %ebx in scratch register.  */
+	    "movl %3, %%ebx\n"	/* Put ADDR in %ebx to be syscall arg.  */
+	    "int $0x80 # %2\n"	/* Perform the system call.  */
+	    "movl %1, %%ebx\n"	/* Restore %ebx from scratch register.  */
+	    : "=a" (newbrk), "=r" (scratch)
+	    : "0" (__NR_brk), "g" (__ptrvalue (addr)));
+
+    ___brk_addr = newbrk;
+
+    if (newbrk < addr)
     {
-#if defined(__PIC__) || defined (__pic__)
-	__asm__ volatile ("pushl %%ebx\n\t"
-			  "movl %%ecx,%%ebx\n\t"
-			  "int $0x80\n\t"
-			  "popl %%ebx"
-		:"=a" (___brk_addr)
-		:"0" (__NR_brk),"c" (end_data_seg));
-#else
-	__asm__ volatile ("int $0x80"
-		:"=a" (___brk_addr)
-		:"0" (__NR_brk),"b" (end_data_seg));
-#endif
-	if (___brk_addr == end_data_seg)
-		return 0;
-	__set_errno(ENOMEM);
+	__set_errno (ENOMEM);
+	return -1;
     }
-    return -1;
+
+    return 0;
 }