fb0302ddbc
This is modelled after the existing ERRNO_IS_RESOURCES() and in particular ERRNO_IS_DISCONNECT(). It returns true for all transient network errors that should be handled like EAGAIN whenever we call accept() or accept4(). This is per documentation in the accept(2) man page that explicitly says to do so in the its "RETURN VALUE" section. The error list we cover is a bit more comprehensive, and based on existing code of ours. For example EINTR is included too (since we need that to cover cases where we call accept()/accept4() on a blocking socket), and of course ERRNO_IS_DISCONNECT() is a bit more comprehensive than the list in the man page too.
70 lines
2.4 KiB
C
70 lines
2.4 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#pragma once
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#include "macro.h"
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static inline void _reset_errno_(int *saved_errno) {
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if (*saved_errno < 0) /* Invalidated by UNPROTECT_ERRNO? */
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return;
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errno = *saved_errno;
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}
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#define PROTECT_ERRNO \
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_cleanup_(_reset_errno_) _unused_ int _saved_errno_ = errno
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#define UNPROTECT_ERRNO \
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do { \
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errno = _saved_errno_; \
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_saved_errno_ = -1; \
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} while (false)
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static inline int negative_errno(void) {
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/* This helper should be used to shut up gcc if you know 'errno' is
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* negative. Instead of "return -errno;", use "return negative_errno();"
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* It will suppress bogus gcc warnings in case it assumes 'errno' might
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* be 0 and thus the caller's error-handling might not be triggered. */
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assert_return(errno > 0, -EINVAL);
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return -errno;
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}
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/* Hint #1: ENETUNREACH happens if we try to connect to "non-existing" special IP addresses, such as ::5.
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*
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* Hint #2: The kernel sends e.g., EHOSTUNREACH or ENONET to userspace in some ICMP error cases. See the
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* icmp_err_convert[] in net/ipv4/icmp.c in the kernel sources */
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static inline bool ERRNO_IS_DISCONNECT(int r) {
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return IN_SET(abs(r),
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ECONNABORTED,
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ECONNREFUSED,
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ECONNRESET,
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EHOSTDOWN,
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EHOSTUNREACH,
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ENETDOWN,
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ENETRESET,
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ENETUNREACH,
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ENONET,
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ENOPROTOOPT,
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ENOTCONN,
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EPIPE,
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EPROTO,
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ESHUTDOWN);
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}
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/* Transient errors we might get on accept() that we should ignore. As per error handling comment in
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* the accept(2) man page. */
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static inline bool ERRNO_IS_ACCEPT_AGAIN(int r) {
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return ERRNO_IS_DISCONNECT(r) ||
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IN_SET(abs(r),
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EAGAIN,
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EINTR,
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EOPNOTSUPP);
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}
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/* Resource exhaustion, could be our fault or general system trouble */
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static inline bool ERRNO_IS_RESOURCE(int r) {
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return IN_SET(abs(r),
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EMFILE,
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ENFILE,
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ENOMEM);
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}
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