[qemu-xen staging] linux-user: Use getcwd syscall directly

[patchbot@xxxxxxx]

commit 0f6bb1958f3aae0171996941df7fb7ea7536bb12
Author:     Andreas Schwab <schwab@xxxxxxx>
AuthorDate: Thu Jul 23 12:27:13 2020 +0200
Commit:     Laurent Vivier <laurent@xxxxxxxxx>
CommitDate: Mon Jul 27 22:05:34 2020 +0200

    linux-user: Use getcwd syscall directly
    
    The glibc getcwd function returns different errors than the getcwd
    syscall, which triggers an assertion failure in the glibc getcwd function
    when running under the emulation.
    
    When the syscall returns ENAMETOOLONG, the glibc wrapper uses a fallback
    implementation that potentially handles an unlimited path length, and
    returns with ERANGE if the provided buffer is too small.  The qemu
    emulation cannot distinguish the two cases, and thus always returns ERANGE.
    This is unexpected by the glibc wrapper.
    
    Signed-off-by: Andreas Schwab <schwab@xxxxxxx>
    Reviewed-by: Laurent Vivier <laurent@xxxxxxxxx>
    Message-Id: <mvmmu3qplvi.fsf@xxxxxxx>
    [lv: updated description]
    Signed-off-by: Laurent Vivier <laurent@xxxxxxxxx>
---
 linux-user/syscall.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index c1ebf7b8f3..945fc25279 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -388,14 +388,7 @@ static bitmask_transtbl fcntl_flags_tbl[] = {
   { 0, 0, 0, 0 }
 };
 
-static int sys_getcwd1(char *buf, size_t size)
-{
-  if (getcwd(buf, size) == NULL) {
-      /* getcwd() sets errno */
-      return (-1);
-  }
-  return strlen(buf)+1;
-}
+_syscall2(int, sys_getcwd1, char *, buf, size_t, size)
 
 #ifdef TARGET_NR_utimensat
 #if defined(__NR_utimensat)
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#staging