Commit ba584f1d authored Mar 05, 2019 by Andreas Schwab Committed by Laurent Vivier Mar 07, 2019

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 <schwab@suse.de>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <mvm5zsxz2we.fsf@suse.de>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

parent 14c8a3a1

linux-user/syscall.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -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;