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/*
* 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 <pwd.h>
#include <grp.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 <common/compat.h>
#include <common/config.h>
#include <common/debug.h>
#include <common/errors.h>
#include <common/mini-clist.h>
#include <common/standard.h>
#include <common/time.h>
#include <common/version.h>
#include <types/global.h>
#include <proto/connection.h>
#include <proto/fd.h>
#include <proto/listener.h>
#include <proto/log.h>
#include <proto/protocol.h>
#include <proto/proto_uxst.h>
#include <proto/task.h>
static int uxst_bind_listener(struct listener *listener, char *errmsg, int errlen);
static int uxst_bind_listeners(struct protocol *proto, char *errmsg, int errlen);
static int uxst_unbind_listeners(struct protocol *proto);
static int uxst_connect_server(struct connection *conn, int data, int delack);
/* 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,
.bind_all = uxst_bind_listeners,
.unbind_all = uxst_unbind_listeners,
.enable_all = enable_all_listeners,
.disable_all = disable_all_listeners,
.get_src = uxst_get_src,
.get_dst = uxst_get_dst,
.pause = uxst_pause_listener,
.listeners = LIST_HEAD_INIT(proto_unix.listeners),
.nb_listeners = 0,
};
/********************************
* 1) low-level socket functions
********************************/
/*
* Retrieves the source address for the socket <fd>, with <dir> indicating
* if we're a listener (=0) or an initiator (!=0). It returns 0 in case of
* success, -1 in case of error. The socket's source address is stored in
* <sa> for <salen> bytes.
*/
int uxst_get_src(int fd, struct sockaddr *sa, socklen_t salen, int dir)
{
if (dir)
return getsockname(fd, sa, &salen);
else
return getpeername(fd, sa, &salen);
}
/*
* Retrieves the original destination address for the socket <fd>, with <dir>
* indicating if we're a listener (=0) or an initiator (!=0). It returns 0 in
* case of success, -1 in case of error. The socket's source address is stored
* in <sa> for <salen> bytes.
*/
int uxst_get_dst(int fd, struct sockaddr *sa, socklen_t salen, int dir)
{
if (dir)
return getpeername(fd, sa, &salen);
else
return getsockname(fd, sa, &salen);
}
/********************************
* 2) listener-oriented functions
********************************/
static int uxst_find_compatible_fd(struct listener *l)
{
struct xfer_sock_list *xfer_sock = xfer_sock_list;
int ret = -1;
while (xfer_sock) {
struct sockaddr_un *un1 = (void *)&l->addr;
struct sockaddr_un *un2 = (void *)&xfer_sock->addr;
/*
* The bound socket's path as returned by getsockaddr
* will be the temporary name <sockname>.XXXXX.tmp,
* so we can't just compare the two names
*/
if (xfer_sock->addr.ss_family == AF_UNIX &&
strncmp(un1->sun_path, un2->sun_path,
strlen(un1->sun_path)) == 0) {
char *after_sockname = un2->sun_path +
strlen(un1->sun_path);
/* Make a reasonnable effort to check that
* it is indeed a haproxy-generated temporary
* name, it's not perfect, but probably good enough.
*/
if (after_sockname[0] == '.') {
after_sockname++;
while (after_sockname[0] >= '0' &&
after_sockname[0] <= '9')
after_sockname++;
if (!strcmp(after_sockname, ".tmp"))
break;
}
}
xfer_sock = xfer_sock->next;
}
if (xfer_sock != NULL) {
ret = xfer_sock->fd;
if (xfer_sock == xfer_sock_list)
xfer_sock_list = xfer_sock->next;
if (xfer_sock->prev)
xfer_sock->prev->next = xfer_sock->next;
if (xfer_sock->next)
xfer_sock->next->prev = xfer_sock->next->prev;
free(xfer_sock);
}
return ret;
}
/* 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 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 = uxst_find_compatible_fd(listener);
path = ((struct sockaddr_un *)&listener->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 >= MAXPATHLEN) {
err |= ERR_FATAL | ERR_ALERT;
msg = "name too long for UNIX socket";
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";
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;
}
strncpy(addr.sun_path, tempname, sizeof(addr.sun_path));
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->backlog : listener->maxconn) < 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 loosing 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;
/* the function for the accept() event */
fd_insert(fd);
fdtab[fd].iocb = listener->proto->accept;
fdtab[fd].owner = listener; /* reference the listener instead of a task */
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;
}
/* This function closes the UNIX sockets for the specified listener.
* The listener enters the LI_ASSIGNED state. It always returns ERR_NONE.
*/
static int uxst_unbind_listener(struct listener *listener)
{
if (listener->state > LI_ASSIGNED) {
unbind_listener(listener);
}
return ERR_NONE;
}
/* Add a listener to the list of unix stream listeners. The listener's state
* is automatically updated from LI_INIT to LI_ASSIGNED. The number of
* listeners is updated. This is the function to use to add a new listener.
*/
void uxst_add_listener(struct listener *listener)
{
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.
*/
int uxst_pause_listener(struct listener *l)
{
if (((struct sockaddr_un *)&l->addr)->sun_path[0])
return 1;
unbind_listener(l);
return 0;
}
/*
* This function initiates a UNIX connection establishment to the target assigned
* to connection <conn> using (si->{target,addr.to}). 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.
*/
int uxst_connect_server(struct connection *conn, int data, int delack)
{
int fd;
struct server *srv;
struct proxy *be;
conn->flags = 0;
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 at %d. Please check system tunables.\n",
be->id, maxfd);
}
else if (errno == EMFILE) {
conn->err_code = CO_ER_PROC_FDLIM;
send_log(be, LOG_EMERG,
"Proxy %s reached process FD limit at %d. Please check 'ulimit-n' and restart.\n",
be->id, maxfd);
}
else if (errno == ENOBUFS || errno == ENOMEM) {
conn->err_code = CO_ER_SYS_MEMLIM;
send_log(be, LOG_EMERG,
"Proxy %s reached system memory limit at %d sockets. Please check system tunables.\n",
be->id, maxfd);
}
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 !
*/
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 a send_proxy is there, there are data */
data |= conn->send_proxy_ofs;
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->addr.to, get_addr_len(&conn->addr.to)) == -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_xprt_init(conn) < 0) {
conn_force_close(conn);
conn->flags |= CO_FL_ERROR;
return SF_ERR_RESOURCE;
}
if (conn->flags & (CO_FL_HANDSHAKE | CO_FL_WAIT_L4_CONN)) {
conn_sock_want_send(conn); /* for connect status, proxy protocol or SSL */
}
else {
/* If there's no more handshake, we need to notify the data
* layer when the connection is already OK otherwise we'll have
* no other opportunity to do it later (eg: health checks).
*/
data = 1;
}
if (data)
conn_data_want_send(conn); /* prepare to send data if any */
return SF_ERR_NONE; /* connection is OK */
}
/********************************
* 3) protocol-oriented functions
********************************/
/* This function creates all UNIX sockets bound to the protocol entry <proto>.
* It is intended to be used as the protocol's bind_all() function.
* The sockets will be registered but not added to any fd_set, in order not to
* loose them across the fork(). A call to uxst_enable_listeners() is needed
* to complete initialization.
*
* The return value is composed from ERR_NONE, ERR_RETRYABLE and ERR_FATAL.
*/
static int uxst_bind_listeners(struct protocol *proto, char *errmsg, int errlen)
{
struct listener *listener;
int err = ERR_NONE;
list_for_each_entry(listener, &proto->listeners, proto_list) {
err |= uxst_bind_listener(listener, errmsg, errlen);
if (err & ERR_ABORT)
break;
}
return err;
}
/* This function stops all listening UNIX sockets bound to the protocol
* <proto>. It does not detaches them from the protocol.
* It always returns ERR_NONE.
*/
static int uxst_unbind_listeners(struct protocol *proto)
{
struct listener *listener;
list_for_each_entry(listener, &proto->listeners, proto_list)
uxst_unbind_listener(listener);
return ERR_NONE;
}
/* parse the "mode" bind keyword */
static int bind_parse_mode(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
{
if (!*args[cur_arg + 1]) {
memprintf(err, "'%s' : missing mode (octal integer expected)", args[cur_arg]);
return ERR_ALERT | ERR_FATAL;
}
conf->ux.mode = strtol(args[cur_arg + 1], NULL, 8);
return 0;
}
/* parse the "gid" bind keyword */
static int bind_parse_gid(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
{
if (!*args[cur_arg + 1]) {
memprintf(err, "'%s' : missing value", args[cur_arg]);
return ERR_ALERT | ERR_FATAL;
}
conf->ux.gid = atol(args[cur_arg + 1]);
return 0;
}
/* parse the "group" bind keyword */
static int bind_parse_group(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
{
struct group *group;
if (!*args[cur_arg + 1]) {
memprintf(err, "'%s' : missing group name", args[cur_arg]);
return ERR_ALERT | ERR_FATAL;
}
group = getgrnam(args[cur_arg + 1]);
if (!group) {
memprintf(err, "'%s' : unknown group name '%s'", args[cur_arg], args[cur_arg + 1]);
return ERR_ALERT | ERR_FATAL;
}
conf->ux.gid = group->gr_gid;
return 0;
}
/* parse the "uid" bind keyword */
static int bind_parse_uid(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
{
if (!*args[cur_arg + 1]) {
memprintf(err, "'%s' : missing value", args[cur_arg]);
return ERR_ALERT | ERR_FATAL;
}
conf->ux.uid = atol(args[cur_arg + 1]);
return 0;
}
/* parse the "user" bind keyword */
static int bind_parse_user(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
{
struct passwd *user;
if (!*args[cur_arg + 1]) {
memprintf(err, "'%s' : missing user name", args[cur_arg]);
return ERR_ALERT | ERR_FATAL;
}
user = getpwnam(args[cur_arg + 1]);
if (!user) {
memprintf(err, "'%s' : unknown user name '%s'", args[cur_arg], args[cur_arg + 1]);
return ERR_ALERT | ERR_FATAL;
}
conf->ux.uid = user->pw_uid;
return 0;
}
/* Note: must not be declared <const> as its list will be overwritten.
* Please take care of keeping this list alphabetically sorted, doing so helps
* all code contributors.
* Optional keywords are also declared with a NULL ->parse() function so that
* the config parser can report an appropriate error when a known keyword was
* not enabled.
*/
static struct bind_kw_list bind_kws = { "UNIX", { }, {
{ "gid", bind_parse_gid, 1 }, /* set the socket's gid */
{ "group", bind_parse_group, 1 }, /* set the socket's gid from the group name */
{ "mode", bind_parse_mode, 1 }, /* set the socket's mode (eg: 0644)*/
{ "uid", bind_parse_uid, 1 }, /* set the socket's uid */
{ "user", bind_parse_user, 1 }, /* set the socket's uid from the user name */
{ NULL, NULL, 0 },
}};
/********************************
* 4) high-level functions
********************************/
__attribute__((constructor))
static void __uxst_protocol_init(void)
{
protocol_register(&proto_unix);
bind_register_keywords(&bind_kws);
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/