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/*
* UNIX SOCK_STREAM protocol layer (uxst)
*
* Copyright 2000-2009 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/param.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/memory.h>
#include <common/mini-clist.h>
#include <common/standard.h>
#include <common/ticks.h>
#include <common/time.h>
#include <common/version.h>
#include <types/global.h>
#include <proto/acl.h>
#include <proto/backend.h>
#include <proto/buffers.h>
#include <proto/fd.h>
#include <proto/log.h>
#include <proto/protocols.h>
#include <proto/proto_uxst.h>
#include <proto/queue.h>
#include <proto/session.h>
#include <proto/stream_interface.h>
#include <proto/stream_sock.h>
#include <proto/task.h>
#ifndef MAXPATHLEN
#define MAXPATHLEN 128
#endif
static int uxst_bind_listeners(struct protocol *proto);
static int uxst_unbind_listeners(struct protocol *proto);
/* 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 */
.read = &stream_sock_read,
.write = &stream_sock_write,
.bind_all = uxst_bind_listeners,
.unbind_all = uxst_unbind_listeners,
.enable_all = enable_all_listeners,
.disable_all = disable_all_listeners,
.listeners = LIST_HEAD_INIT(proto_unix.listeners),
.nb_listeners = 0,
};
/********************************
* 1) low-level socket functions
********************************/
/* This function creates a named PF_UNIX stream socket at address <path>. Note
* that the path cannot be NULL nor empty. <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.
* It returns the assigned file descriptor, or -1 in the event of an error.
*/
static int create_uxst_socket(const char *path, uid_t uid, gid_t gid, mode_t mode)
{
char tempname[MAXPATHLEN];
char backname[MAXPATHLEN];
struct sockaddr_un addr;
int ret, sock;
/* 1. create socket names */
if (!path[0]) {
Alert("Invalid name for a UNIX socket. Aborting.\n");
goto err_return;
}
ret = snprintf(tempname, MAXPATHLEN, "%s.%d.tmp", path, pid);
if (ret < 0 || ret >= MAXPATHLEN) {
Alert("name too long for UNIX socket. Aborting.\n");
goto err_return;
}
ret = snprintf(backname, MAXPATHLEN, "%s.%d.bak", path, pid);
if (ret < 0 || ret >= MAXPATHLEN) {
Alert("name too long for UNIX socket. Aborting.\n");
goto err_return;
}
/* 2. clean existing orphaned entries */
if (unlink(tempname) < 0 && errno != ENOENT) {
Alert("error when trying to unlink previous UNIX socket. Aborting.\n");
goto err_return;
}
if (unlink(backname) < 0 && errno != ENOENT) {
Alert("error when trying to unlink previous UNIX socket. Aborting.\n");
goto err_return;
}
/* 3. backup existing socket */
if (link(path, backname) < 0 && errno != ENOENT) {
Alert("error when trying to preserve previous UNIX socket. Aborting.\n");
goto err_return;
}
/* 4. prepare new socket */
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path, tempname, sizeof(addr.sun_path));
addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
sock = socket(PF_UNIX, SOCK_STREAM, 0);
if (sock < 0) {
Alert("cannot create socket for UNIX listener. Aborting.\n");
goto err_unlink_back;
}
if (sock >= global.maxsock) {
Alert("socket(): not enough free sockets for UNIX listener. Raise -n argument. Aborting.\n");
goto err_unlink_temp;
}
if (fcntl(sock, F_SETFL, O_NONBLOCK) == -1) {
Alert("cannot make UNIX socket non-blocking. Aborting.\n");
goto err_unlink_temp;
}
if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
/* note that bind() creates the socket <tempname> on the file system */
Alert("cannot bind socket for UNIX listener. Aborting.\n");
goto err_unlink_temp;
}
if (((uid != -1 || gid != -1) && (chown(tempname, uid, gid) == -1)) ||
(mode != 0 && chmod(tempname, mode) == -1)) {
Alert("cannot change UNIX socket ownership. Aborting.\n");
goto err_unlink_temp;
}
if (listen(sock, 0) < 0) {
Alert("cannot listen to socket for UNIX listener. Aborting.\n");
goto err_unlink_temp;
}
/* 5. install.
* 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.
*/
if (rename(tempname, path) < 0) {
Alert("cannot switch final and temporary sockets for UNIX listener. Aborting.\n");
goto err_rename;
}
/* 6. cleanup */
unlink(backname); /* no need to keep this one either */
return sock;
err_rename:
ret = rename(backname, path);
if (ret < 0 && errno == ENOENT)
unlink(path);
err_unlink_temp:
unlink(tempname);
close(sock);
err_unlink_back:
unlink(backname);
err_return:
return -1;
}
/* Tries to destroy the UNIX stream socket <path>. The socket must not be used
* anymore. It practises best effort, and no error is returned.
*/
static void destroy_uxst_socket(const char *path)
{
struct sockaddr_un addr;
int sock, ret;
/* We might have been chrooted, so we may not be able to access the
* socket. In order to avoid bothering the other end, we connect with a
* wrong protocol, namely SOCK_DGRAM. The return code from connect()
* is enough to know if the socket is still live or not. If it's live
* in mode SOCK_STREAM, we get EPROTOTYPE or anything else but not
* ECONNREFUSED. In this case, we do not touch it because it's used
* by some other process.
*/
sock = socket(PF_UNIX, SOCK_DGRAM, 0);
if (sock < 0)
return;
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path, path, sizeof(addr.sun_path));
addr.sun_path[sizeof(addr.sun_path) - 1] = 0;
ret = connect(sock, (struct sockaddr *)&addr, sizeof(addr));
if (ret < 0 && errno == ECONNREFUSED) {
/* Connect failed: the socket still exists but is not used
* anymore. Let's remove this socket now.
*/
unlink(path);
}
close(sock);
}
/********************************
* 2) listener-oriented functions
********************************/
/* This function creates the 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.
*/
static int uxst_bind_listener(struct listener *listener)
{
int fd;
if (listener->state != LI_ASSIGNED)
return ERR_NONE; /* already bound */
fd = create_uxst_socket(((struct sockaddr_un *)&listener->addr)->sun_path,
listener->perm.ux.uid,
listener->perm.ux.gid,
listener->perm.ux.mode);
if (fd == -1)
return ERR_FATAL;
/* the socket is now listening */
listener->fd = fd;
listener->state = LI_LISTEN;
/* the function for the accept() event */
fd_insert(fd);
fdtab[fd].cb[DIR_RD].f = listener->accept;
fdtab[fd].cb[DIR_WR].f = NULL; /* never called */
fdtab[fd].cb[DIR_RD].b = fdtab[fd].cb[DIR_WR].b = NULL;
fdtab[fd].owner = listener; /* reference the listener instead of a task */
fdtab[fd].state = FD_STLISTEN;
fdtab[fd].peeraddr = NULL;
fdtab[fd].peerlen = 0;
return ERR_NONE;
}
/* 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_READY)
EV_FD_CLR(listener->fd, DIR_RD);
if (listener->state >= LI_LISTEN) {
fd_delete(listener->fd);
listener->state = LI_ASSIGNED;
destroy_uxst_socket(((struct sockaddr_un *)&listener->addr)->sun_path);
}
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++;
}
/********************************
* 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)
{
struct listener *listener;
int err = ERR_NONE;
list_for_each_entry(listener, &proto->listeners, proto_list) {
err |= uxst_bind_listener(listener);
if (err != ERR_NONE)
continue;
}
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;
}
/********************************
* 4) high-level functions
********************************/
/*
* This function is called on a read event from a listen socket, corresponding
* to an accept. It tries to accept as many connections as possible.
* It returns 0. Since we use UNIX sockets on the local system for monitoring
* purposes and other related things, we do not need to output as many messages
* as with TCP which can fall under attack.
*/
int uxst_event_accept(int fd) {
struct listener *l = fdtab[fd].owner;
struct session *s;
struct task *t;
int cfd;
int max_accept;
if (global.nbproc > 1)
max_accept = 8; /* let other processes catch some connections too */
else
max_accept = -1;
while (max_accept--) {
struct sockaddr_storage addr;
socklen_t laddr = sizeof(addr);
if ((cfd = accept(fd, (struct sockaddr *)&addr, &laddr)) == -1) {
switch (errno) {
case EAGAIN:
case EINTR:
case ECONNABORTED:
return 0; /* nothing more to accept */
case ENFILE:
/* Process reached system FD limit. Check system tunables. */
return 0;
case EMFILE:
/* Process reached process FD limit. Check 'ulimit-n'. */
return 0;
case ENOBUFS:
case ENOMEM:
/* Process reached system memory limit. Check system tunables. */
return 0;
default:
return 0;
}
}
if (l->nbconn >= l->maxconn || actconn >= global.maxconn) {
/* too many connections, we shoot this one and return.
* FIXME: it would be better to simply switch the listener's
* state to LI_FULL and disable the FD. We could re-enable
* it upon fd_delete(), but this requires all protocols to
* be switched.
*/
goto out_close;
}
if ((s = pool_alloc2(pool2_session)) == NULL) {
Alert("out of memory in uxst_event_accept().\n");
goto out_close;
}
LIST_ADDQ(&sessions, &s->list);
LIST_INIT(&s->back_refs);
s->flags = 0;
s->term_trace = 0;
if ((t = task_new()) == NULL) {
Alert("out of memory in uxst_event_accept().\n");
goto out_free_session;
}
s->cli_addr = addr;
/* FIXME: should be checked earlier */
if (cfd >= global.maxsock) {
Alert("accept(): not enough free sockets. Raise -n argument. Giving up.\n");
goto out_free_task;
}
if (fcntl(cfd, F_SETFL, O_NONBLOCK) == -1) {
Alert("accept(): cannot set the socket in non blocking mode. Giving up\n");
goto out_free_task;
}
t->process = l->handler;
t->context = s;
t->nice = l->nice;
s->task = t;
s->listener = l;
s->fe = s->be = l->private;
s->ana_state = 0;
s->req = s->rep = NULL; /* will be allocated later */
s->si[0].state = s->si[0].prev_state = SI_ST_EST;
s->si[0].err_type = SI_ET_NONE;
s->si[0].err_loc = NULL;
s->si[0].owner = t;
s->si[0].update = stream_sock_data_finish;
s->si[0].shutr = stream_sock_shutr;
s->si[0].shutw = stream_sock_shutw;
s->si[0].chk_rcv = stream_sock_chk_rcv;
s->si[0].chk_snd = stream_sock_chk_snd;
s->si[0].connect = NULL;
s->si[0].fd = cfd;
s->si[0].flags = SI_FL_NONE;
s->si[0].exp = TICK_ETERNITY;
s->si[1].state = s->si[1].prev_state = SI_ST_INI;
s->si[1].err_type = SI_ET_NONE;
s->si[1].err_loc = NULL;
s->si[1].owner = t;
s->si[1].update = stream_sock_data_finish;
s->si[1].shutr = stream_sock_shutr;
s->si[1].shutw = stream_sock_shutw;
s->si[1].chk_rcv = stream_sock_chk_rcv;
s->si[1].chk_snd = stream_sock_chk_snd;
s->si[1].connect = NULL;
s->si[1].exp = TICK_ETERNITY;
s->si[1].fd = -1; /* just to help with debugging */
s->si[1].flags = SI_FL_NONE;
s->srv = s->prev_srv = s->srv_conn = NULL;
s->pend_pos = NULL;
memset(&s->logs, 0, sizeof(s->logs));
memset(&s->txn, 0, sizeof(s->txn));
s->logs.tv_accept = now; /* corrected date for internal use */
s->data_state = DATA_ST_INIT;
s->data_source = DATA_SRC_NONE;
s->uniq_id = totalconn;
if ((s->req = pool_alloc2(pool2_buffer)) == NULL)
goto out_free_task;
s->req->size = global.tune.bufsize;
buffer_init(s->req);
s->req->prod = &s->si[0];
s->req->cons = &s->si[1];
s->si[0].ib = s->si[1].ob = s->req;
s->req->flags |= BF_READ_ATTACHED; /* the producer is already connected */
s->req->flags |= BF_READ_DONTWAIT; /* we plan to read small requests */
s->req->analysers = l->analysers;
s->req->wto = TICK_ETERNITY;
s->req->cto = TICK_ETERNITY;
s->req->rto = TICK_ETERNITY;
if ((s->rep = pool_alloc2(pool2_buffer)) == NULL)
goto out_free_req;
s->rep->size = global.tune.bufsize;
buffer_init(s->rep);
s->rep->prod = &s->si[1];
s->rep->cons = &s->si[0];
s->si[0].ob = s->si[1].ib = s->rep;
s->rep->rto = TICK_ETERNITY;
s->rep->cto = TICK_ETERNITY;
s->rep->wto = TICK_ETERNITY;
s->req->rex = TICK_ETERNITY;
s->req->wex = TICK_ETERNITY;
s->req->analyse_exp = TICK_ETERNITY;
s->rep->rex = TICK_ETERNITY;
s->rep->wex = TICK_ETERNITY;
s->rep->analyse_exp = TICK_ETERNITY;
t->expire = TICK_ETERNITY;
if (l->timeout) {
s->req->rto = *l->timeout;
s->rep->wto = *l->timeout;
}
fd_insert(cfd);
fdtab[cfd].owner = &s->si[0];
fdtab[cfd].state = FD_STREADY;
fdtab[cfd].cb[DIR_RD].f = l->proto->read;
fdtab[cfd].cb[DIR_RD].b = s->req;
fdtab[cfd].cb[DIR_WR].f = l->proto->write;
fdtab[cfd].cb[DIR_WR].b = s->rep;
fdtab[cfd].peeraddr = (struct sockaddr *)&s->cli_addr;
fdtab[cfd].peerlen = sizeof(s->cli_addr);
EV_FD_SET(cfd, DIR_RD);
task_wakeup(t, TASK_WOKEN_INIT);
l->nbconn++; /* warning! right now, it's up to the handler to decrease this */
if (l->nbconn >= l->maxconn) {
EV_FD_CLR(l->fd, DIR_RD);
l->state = LI_FULL;
}
actconn++;
totalconn++;
}
return 0;
out_free_req:
pool_free2(pool2_buffer, s->req);
out_free_task:
task_free(t);
out_free_session:
LIST_DEL(&s->list);
pool_free2(pool2_session, s);
out_close:
close(cfd);
return 0;
}
__attribute__((constructor))
static void __uxst_protocol_init(void)
{
protocol_register(&proto_unix);
}
/*
* Local variables:
* c-indent-level: 8
* c-basic-offset: 8
* End:
*/