1 files changed, 30 insertions, 0 deletions
diff --git a/libc/arch-x86/bionic/vfork.S b/libc/arch-x86/bionic/vfork.S
new file mode 100644
index 0000000..53910ab
--- /dev/null
+++ b/libc/arch-x86/bionic/vfork.S
@@ -0,0 +1,30 @@
+#include <sys/linux-syscalls.h>
+
+#ifndef __NR_vfork
+#define __NR_vfork  190
+#endif
+
+
+    .text
+    .type vfork, @function
+    .globl vfork
+    .align 4
+
+/* Get rid of the stack modifications (popl/ret) after vfork() success.
+ * vfork is VERY sneaky. One has to be very careful about what can be done
+ * between a successful vfork and a a subsequent execve()
+ */
+
+vfork:
+    /* grab the return address */
+    popl    %ecx
+    movl    $__NR_vfork, %eax
+    int     $0x80
+    cmpl    $-129, %eax
+    jb      1f
+    negl    %eax
+    pushl   %eax
+    call    __set_errno
+    orl     $-1, %eax
+1:
+    jmp     *%ecx