blob: 07e83e29c5995c5db059480be985d0ae2dfe2e73 [file] [log] [blame]
/*
* UNIX SOCK_STREAM protocol layer (uxst)
*
* Copyright 2000-2010 Willy Tarreau <w@1wt.eu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <time.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <haproxy/api.h>
#include <haproxy/connection.h>
#include <haproxy/errors.h>
#include <haproxy/fd.h>
#include <haproxy/global.h>
#include <haproxy/list.h>
#include <haproxy/listener.h>
#include <haproxy/log.h>
#include <haproxy/protocol.h>
#include <haproxy/sock.h>
#include <haproxy/sock_unix.h>
#include <haproxy/time.h>
#include <haproxy/tools.h>
#include <haproxy/version.h>
static int uxst_bind_listener(struct listener *listener, char *errmsg, int errlen);
static int uxst_connect_server(struct connection *conn, int flags);
static void uxst_add_listener(struct listener *listener, int port);
static int uxst_pause_listener(struct listener *l);
/* Note: must not be declared <const> as its list will be overwritten */
static struct protocol proto_unix = {
.name = "unix_stream",
.sock_domain = PF_UNIX,
.sock_type = SOCK_STREAM,
.sock_prot = 0,
.sock_family = AF_UNIX,
.sock_addrlen = sizeof(struct sockaddr_un),
.l3_addrlen = sizeof(((struct sockaddr_un*)0)->sun_path),/* path len */
.accept = &listener_accept,
.connect = &uxst_connect_server,
.bind = uxst_bind_listener,
.enable_all = enable_all_listeners,
.disable_all = disable_all_listeners,
.get_src = sock_get_src,
.get_dst = sock_get_dst,
.pause = uxst_pause_listener,
.add = uxst_add_listener,
.addrcmp = sock_unix_addrcmp,
.listeners = LIST_HEAD_INIT(proto_unix.listeners),
.nb_listeners = 0,
};
INITCALL1(STG_REGISTER, protocol_register, &proto_unix);
/********************************
* 1) low-level socket functions
********************************/
/********************************
* 2) listener-oriented functions
********************************/
/* This function creates a UNIX socket associated to the listener. It changes
* the state from ASSIGNED to LISTEN. The socket is NOT enabled for polling.
* The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL. It
* may return a warning or an error message in <errmsg> if the message is at
* most <errlen> bytes long (including '\0'). Note that <errmsg> may be NULL if
* <errlen> is also zero.
*/
static int uxst_bind_listener(struct listener *listener, char *errmsg, int errlen)
{
int fd;
char tempname[MAXPATHLEN];
char backname[MAXPATHLEN];
struct sockaddr_un addr;
const char *msg = NULL;
const char *path;
int maxpathlen;
int ext, ready;
socklen_t ready_len;
int err;
int ret;
err = ERR_NONE;
/* ensure we never return garbage */
if (errlen)
*errmsg = 0;
if (listener->state != LI_ASSIGNED)
return ERR_NONE; /* already bound */
if (listener->fd == -1)
listener->fd = sock_find_compatible_fd(listener);
path = ((struct sockaddr_un *)&listener->addr)->sun_path;
maxpathlen = MIN(MAXPATHLEN, sizeof(addr.sun_path));
/* if the listener already has an fd assigned, then we were offered the
* fd by an external process (most likely the parent), and we don't want
* to create a new socket. However we still want to set a few flags on
* the socket.
*/
fd = listener->fd;
ext = (fd >= 0);
if (ext)
goto fd_ready;
if (path[0]) {
ret = snprintf(tempname, maxpathlen, "%s.%d.tmp", path, pid);
if (ret < 0 || ret >= sizeof(addr.sun_path)) {
err |= ERR_FATAL | ERR_ALERT;
msg = "name too long for UNIX socket (limit usually 97)";
goto err_return;
}
ret = snprintf(backname, maxpathlen, "%s.%d.bak", path, pid);
if (ret < 0 || ret >= maxpathlen) {
err |= ERR_FATAL | ERR_ALERT;
msg = "name too long for UNIX socket (limit usually 97)";
goto err_return;
}
/* 2. clean existing orphaned entries */
if (unlink(tempname) < 0 && errno != ENOENT) {
err |= ERR_FATAL | ERR_ALERT;
msg = "error when trying to unlink previous UNIX socket";
goto err_return;
}
if (unlink(backname) < 0 && errno != ENOENT) {
err |= ERR_FATAL | ERR_ALERT;
msg = "error when trying to unlink previous UNIX socket";
goto err_return;
}
/* 3. backup existing socket */
if (link(path, backname) < 0 && errno != ENOENT) {
err |= ERR_FATAL | ERR_ALERT;
msg = "error when trying to preserve previous UNIX socket";
goto err_return;
}
/* Note: this test is redundant with the snprintf one above and
* will never trigger, it's just added as the only way to shut
* gcc's painfully dumb warning about possibly truncated output
* during strncpy(). Don't move it above or smart gcc will not
* see it!
*/
if (strlen(tempname) >= sizeof(addr.sun_path)) {
err |= ERR_FATAL | ERR_ALERT;
msg = "name too long for UNIX socket (limit usually 97)";
goto err_return;
}
strncpy(addr.sun_path, tempname, sizeof(addr.sun_path) - 1);
addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
}
else {
/* first char is zero, it's an abstract socket whose address
* is defined by all the bytes past this zero.
*/
memcpy(addr.sun_path, path, sizeof(addr.sun_path));
}
addr.sun_family = AF_UNIX;
fd = socket(PF_UNIX, SOCK_STREAM, 0);
if (fd < 0) {
err |= ERR_FATAL | ERR_ALERT;
msg = "cannot create UNIX socket";
goto err_unlink_back;
}
fd_ready:
if (fd >= global.maxsock) {
err |= ERR_FATAL | ERR_ALERT;
msg = "socket(): not enough free sockets, raise -n argument";
goto err_unlink_temp;
}
if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
err |= ERR_FATAL | ERR_ALERT;
msg = "cannot make UNIX socket non-blocking";
goto err_unlink_temp;
}
if (!ext && bind(fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
/* note that bind() creates the socket <tempname> on the file system */
if (errno == EADDRINUSE) {
/* the old process might still own it, let's retry */
err |= ERR_RETRYABLE | ERR_ALERT;
msg = "cannot listen to socket";
}
else {
err |= ERR_FATAL | ERR_ALERT;
msg = "cannot bind UNIX socket";
}
goto err_unlink_temp;
}
/* <uid> and <gid> different of -1 will be used to change the socket owner.
* If <mode> is not 0, it will be used to restrict access to the socket.
* While it is known not to be portable on every OS, it's still useful
* where it works. We also don't change permissions on abstract sockets.
*/
if (!ext && path[0] &&
(((listener->bind_conf->ux.uid != -1 || listener->bind_conf->ux.gid != -1) &&
(chown(tempname, listener->bind_conf->ux.uid, listener->bind_conf->ux.gid) == -1)) ||
(listener->bind_conf->ux.mode != 0 && chmod(tempname, listener->bind_conf->ux.mode) == -1))) {
err |= ERR_FATAL | ERR_ALERT;
msg = "cannot change UNIX socket ownership";
goto err_unlink_temp;
}
ready = 0;
ready_len = sizeof(ready);
if (getsockopt(fd, SOL_SOCKET, SO_ACCEPTCONN, &ready, &ready_len) == -1)
ready = 0;
if (!(ext && ready) && /* only listen if not already done by external process */
listen(fd, listener_backlog(listener)) < 0) {
err |= ERR_FATAL | ERR_ALERT;
msg = "cannot listen to UNIX socket";
goto err_unlink_temp;
}
/* Point of no return: we are ready, we'll switch the sockets. We don't
* fear losing the socket <path> because we have a copy of it in
* backname. Abstract sockets are not renamed.
*/
if (!ext && path[0] && rename(tempname, path) < 0) {
err |= ERR_FATAL | ERR_ALERT;
msg = "cannot switch final and temporary UNIX sockets";
goto err_rename;
}
/* Cleanup: only unlink if we didn't inherit the fd from the parent */
if (!ext && path[0])
unlink(backname);
/* the socket is now listening */
listener->fd = fd;
listener->state = LI_LISTEN;
fd_insert(fd, listener, listener->proto->accept,
thread_mask(listener->bind_conf->bind_thread) & all_threads_mask);
/* for now, all regularly bound UNIX listeners are exportable */
if (!(listener->options & LI_O_INHERITED))
fdtab[fd].exported = 1;
return err;
err_rename:
ret = rename(backname, path);
if (ret < 0 && errno == ENOENT)
unlink(path);
err_unlink_temp:
if (!ext && path[0])
unlink(tempname);
close(fd);
err_unlink_back:
if (!ext && path[0])
unlink(backname);
err_return:
if (msg && errlen) {
if (!ext)
snprintf(errmsg, errlen, "%s [%s]", msg, path);
else
snprintf(errmsg, errlen, "%s [fd %d]", msg, fd);
}
return err;
}
/* Add <listener> to the list of unix stream listeners (port is ignored). The
* listener's state is automatically updated from LI_INIT to LI_ASSIGNED.
* The number of listeners for the protocol is updated.
*
* Must be called with proto_lock held.
*
*/
static void uxst_add_listener(struct listener *listener, int port)
{
if (listener->state != LI_INIT)
return;
listener->state = LI_ASSIGNED;
listener->proto = &proto_unix;
LIST_ADDQ(&proto_unix.listeners, &listener->proto_list);
proto_unix.nb_listeners++;
}
/* Pause a listener. Returns < 0 in case of failure, 0 if the listener
* was totally stopped, or > 0 if correctly paused. Nothing is done for
* plain unix sockets since currently it's the new process which handles
* the renaming. Abstract sockets are completely unbound.
*/
static int uxst_pause_listener(struct listener *l)
{
if (((struct sockaddr_un *)&l->addr)->sun_path[0])
return 1;
/* Listener's lock already held. Call lockless version of
* unbind_listener. */
do_unbind_listener(l, 1);
return 0;
}
/*
* This function initiates a UNIX connection establishment to the target assigned
* to connection <conn> using (si->{target,dst}). The source address is ignored
* and will be selected by the system. conn->target may point either to a valid
* server or to a backend, depending on conn->target. Only OBJ_TYPE_PROXY and
* OBJ_TYPE_SERVER are supported. The <data> parameter is a boolean indicating
* whether there are data waiting for being sent or not, in order to adjust data
* write polling and on some platforms. The <delack> argument is ignored.
*
* Note that a pending send_proxy message accounts for data.
*
* It can return one of :
* - SF_ERR_NONE if everything's OK
* - SF_ERR_SRVTO if there are no more servers
* - SF_ERR_SRVCL if the connection was refused by the server
* - SF_ERR_PRXCOND if the connection has been limited by the proxy (maxconn)
* - SF_ERR_RESOURCE if a system resource is lacking (eg: fd limits, ports, ...)
* - SF_ERR_INTERNAL for any other purely internal errors
* Additionally, in the case of SF_ERR_RESOURCE, an emergency log will be emitted.
*
* The connection's fd is inserted only when SF_ERR_NONE is returned, otherwise
* it's invalid and the caller has nothing to do.
*/
static int uxst_connect_server(struct connection *conn, int flags)
{
int fd;
struct server *srv;
struct proxy *be;
switch (obj_type(conn->target)) {
case OBJ_TYPE_PROXY:
be = objt_proxy(conn->target);
srv = NULL;
break;
case OBJ_TYPE_SERVER:
srv = objt_server(conn->target);
be = srv->proxy;
break;
default:
conn->flags |= CO_FL_ERROR;
return SF_ERR_INTERNAL;
}
if ((fd = conn->handle.fd = socket(PF_UNIX, SOCK_STREAM, 0)) == -1) {
qfprintf(stderr, "Cannot get a server socket.\n");
if (errno == ENFILE) {
conn->err_code = CO_ER_SYS_FDLIM;
send_log(be, LOG_EMERG,
"Proxy %s reached system FD limit (maxsock=%d). Please check system tunables.\n",
be->id, global.maxsock);
}
else if (errno == EMFILE) {
conn->err_code = CO_ER_PROC_FDLIM;
send_log(be, LOG_EMERG,
"Proxy %s reached process FD limit (maxsock=%d). Please check 'ulimit-n' and restart.\n",
be->id, global.maxsock);
}
else if (errno == ENOBUFS || errno == ENOMEM) {
conn->err_code = CO_ER_SYS_MEMLIM;
send_log(be, LOG_EMERG,
"Proxy %s reached system memory limit (maxsock=%d). Please check system tunables.\n",
be->id, global.maxsock);
}
else if (errno == EAFNOSUPPORT || errno == EPROTONOSUPPORT) {
conn->err_code = CO_ER_NOPROTO;
}
else
conn->err_code = CO_ER_SOCK_ERR;
/* this is a resource error */
conn->flags |= CO_FL_ERROR;
return SF_ERR_RESOURCE;
}
if (fd >= global.maxsock) {
/* do not log anything there, it's a normal condition when this option
* is used to serialize connections to a server !
*/
ha_alert("socket(): not enough free sockets. Raise -n argument. Giving up.\n");
close(fd);
conn->err_code = CO_ER_CONF_FDLIM;
conn->flags |= CO_FL_ERROR;
return SF_ERR_PRXCOND; /* it is a configuration limit */
}
if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
qfprintf(stderr,"Cannot set client socket to non blocking mode.\n");
close(fd);
conn->err_code = CO_ER_SOCK_ERR;
conn->flags |= CO_FL_ERROR;
return SF_ERR_INTERNAL;
}
if (master == 1 && (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1)) {
ha_alert("Cannot set CLOEXEC on client socket.\n");
close(fd);
conn->err_code = CO_ER_SOCK_ERR;
conn->flags |= CO_FL_ERROR;
return SF_ERR_INTERNAL;
}
/* if a send_proxy is there, there are data */
if (conn->send_proxy_ofs)
flags |= CONNECT_HAS_DATA;
if (global.tune.server_sndbuf)
setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &global.tune.server_sndbuf, sizeof(global.tune.server_sndbuf));
if (global.tune.server_rcvbuf)
setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &global.tune.server_rcvbuf, sizeof(global.tune.server_rcvbuf));
if (connect(fd, (struct sockaddr *)conn->dst, get_addr_len(conn->dst)) == -1) {
if (errno == EINPROGRESS || errno == EALREADY) {
conn->flags |= CO_FL_WAIT_L4_CONN;
}
else if (errno == EISCONN) {
conn->flags &= ~CO_FL_WAIT_L4_CONN;
}
else if (errno == EAGAIN || errno == EADDRINUSE || errno == EADDRNOTAVAIL) {
char *msg;
if (errno == EAGAIN || errno == EADDRNOTAVAIL) {
msg = "can't connect to destination unix socket, check backlog size on the server";
conn->err_code = CO_ER_FREE_PORTS;
}
else {
msg = "local address already in use";
conn->err_code = CO_ER_ADDR_INUSE;
}
qfprintf(stderr,"Connect() failed for backend %s: %s.\n", be->id, msg);
close(fd);
send_log(be, LOG_ERR, "Connect() failed for backend %s: %s.\n", be->id, msg);
conn->flags |= CO_FL_ERROR;
return SF_ERR_RESOURCE;
}
else if (errno == ETIMEDOUT) {
close(fd);
conn->err_code = CO_ER_SOCK_ERR;
conn->flags |= CO_FL_ERROR;
return SF_ERR_SRVTO;
}
else { // (errno == ECONNREFUSED || errno == ENETUNREACH || errno == EACCES || errno == EPERM)
close(fd);
conn->err_code = CO_ER_SOCK_ERR;
conn->flags |= CO_FL_ERROR;
return SF_ERR_SRVCL;
}
}
else {
/* connect() already succeeded, which is quite usual for unix
* sockets. Let's avoid a second connect() probe to complete it.
*/
conn->flags &= ~CO_FL_WAIT_L4_CONN;
}
conn->flags |= CO_FL_ADDR_TO_SET;
/* Prepare to send a few handshakes related to the on-wire protocol. */
if (conn->send_proxy_ofs)
conn->flags |= CO_FL_SEND_PROXY;
conn_ctrl_init(conn); /* registers the FD */
fdtab[fd].linger_risk = 0; /* no need to disable lingering */
if (conn->flags & CO_FL_WAIT_L4_CONN) {
fd_want_send(fd);
fd_cant_send(fd);
fd_cant_recv(fd);
}
if (conn_xprt_init(conn) < 0) {
conn_full_close(conn);
conn->flags |= CO_FL_ERROR;
return SF_ERR_RESOURCE;
}
return SF_ERR_NONE; /* connection is OK */
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/