diff mbox series

[PULL,3/3] linux-user: Use getcwd syscall directly

Message ID 20200728123432.501354-4-laurent@vivier.eu
State New
Headers show
Series [PULL,1/3] linux-user: Ensure mmap_min_addr is non-zero | expand

Commit Message

Laurent Vivier July 28, 2020, 12:34 p.m. UTC 
From: Andreas Schwab <schwab@suse.de>

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@suse.de>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <mvmmu3qplvi.fsf@suse.de>
[lv: updated description]
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 linux-user/syscall.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)
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Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index c1ebf7b8f384..945fc252791c 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)