From ba584f1de30e58b0d93cd81bd437271b894eefbf Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Tue, 5 Mar 2019 17:45:05 +0100 Subject: [PATCH] linux-user: don't short-circuit read with zero length A zero-length read still needs to do the usual checks, thus it may return errors like EBADF. This makes the read syscall emulation consistent with the pread64 syscall emulation. Signed-off-by: Andreas Schwab Reviewed-by: Laurent Vivier Message-Id: Signed-off-by: Laurent Vivier --- linux-user/syscall.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 5f72209deb..9f7eb7d7a8 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -7009,8 +7009,8 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1, _exit(arg1); return 0; /* avoid warning */ case TARGET_NR_read: - if (arg3 == 0) { - return 0; + if (arg2 == 0 && arg3 == 0) { + return get_errno(safe_read(arg1, 0, 0)); } else { if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0))) return -TARGET_EFAULT;