From b5896ba9f6047e7031e2bdee0622d543e11a6734 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:46:30 +0200 Subject: Adding upstream version 3.4.23. Signed-off-by: Daniel Baumann --- src/util/sane_accept.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 src/util/sane_accept.c (limited to 'src/util/sane_accept.c') diff --git a/src/util/sane_accept.c b/src/util/sane_accept.c new file mode 100644 index 0000000..86e3d34 --- /dev/null +++ b/src/util/sane_accept.c @@ -0,0 +1,125 @@ +/*++ +/* NAME +/* sane_accept 3 +/* SUMMARY +/* sanitize accept() error returns +/* SYNOPSIS +/* #include +/* +/* int sane_accept(sock, buf, len) +/* int sock; +/* struct sockaddr *buf; +/* SOCKADDR_SIZE *len; +/* DESCRIPTION +/* sane_accept() implements the accept(2) socket call, and maps +/* known harmless error results to EAGAIN. +/* +/* If the buf and len arguments are not null, then additional +/* workarounds may be enabled that depend on the socket type. +/* BUGS +/* Bizarre systems may have other harmless error results. Such +/* systems encourage programmers to ignore error results, and +/* penalize programmers who code defensively. +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include "sys_defs.h" +#include +#include + +/* Utility library. */ + +#include "msg.h" +#include "sane_accept.h" + +/* sane_accept - sanitize accept() error returns */ + +int sane_accept(int sock, struct sockaddr *sa, SOCKADDR_SIZE *len) +{ + static int accept_ok_errors[] = { + EAGAIN, + ECONNREFUSED, + ECONNRESET, + EHOSTDOWN, + EHOSTUNREACH, + EINTR, + ENETDOWN, + ENETUNREACH, + ENOTCONN, + EWOULDBLOCK, + ENOBUFS, /* HPUX11 */ + ECONNABORTED, +#ifdef EPROTO + EPROTO, /* SunOS 5.5.1 */ +#endif + 0, + }; + int count; + int err; + int fd; + + /* + * XXX Solaris 2.4 accept() returns EPIPE when a UNIX-domain client has + * disconnected in the mean time. From then on, UNIX-domain sockets are + * hosed beyond recovery. There is no point treating this as a beneficial + * error result because the program would go into a tight loop. + * + * XXX Solaris 2.5.1 accept() returns EPROTO when a TCP client has + * disconnected in the mean time. Since there is no connection, it is + * safe to map the error code onto EAGAIN. + * + * XXX LINUX < 2.1 accept() wakes up before the three-way handshake is + * complete, so it can fail with ECONNRESET and other "false alarm" + * indications. + * + * XXX FreeBSD 4.2-STABLE accept() returns ECONNABORTED when a UNIX-domain + * client has disconnected in the mean time. The data that was sent with + * connect() write() close() is lost, even though the write() and close() + * reported successful completion. This was fixed shortly before FreeBSD + * 4.3. + * + * XXX HP-UX 11 returns ENOBUFS when the client has disconnected in the mean + * time. + */ + if ((fd = accept(sock, sa, len)) < 0) { + for (count = 0; (err = accept_ok_errors[count]) != 0; count++) { + if (errno == err) { + errno = EAGAIN; + break; + } + } + } + + /* + * XXX Solaris select() produces false read events, so that read() blocks + * forever on a blocking socket, and fails with EAGAIN on a non-blocking + * socket. Turning on keepalives will fix a blocking socket provided that + * the kernel's keepalive timer expires before the Postfix watchdog + * timer. + * + * XXX Work around NAT induced damage by sending a keepalive before an idle + * connection is expired. This requires that the kernel keepalive timer + * is set to a short time, like 100s. + */ + else if (sa && (sa->sa_family == AF_INET +#ifdef HAS_IPV6 + || sa->sa_family == AF_INET6 +#endif + )) { + int on = 1; + + (void) setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, + (void *) &on, sizeof(on)); + } + return (fd); +} -- cgit v1.2.3