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socket-util: Work around Unix domain socket path name limits on Linux.

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Many Open vSwitch tests fail on Debian's automatic build machines because
the builds occur in deeply nested directories with long names.  OVS tries
to bind and connect to Unix domain sockets using absolute path names, which
in combination with long directory names means that the socket's name
exceeds the limit for Unix domain socket names (108 bytes on Linux).

This commit works around the problem on Linux by indirecting through
/proc/self/fd/<dirfd>/<basename> when names exceed the maximum that can be
used directly.

Reported-by: Hector Oron <hector.oron@gmail.com>
Reported-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Reported-by: Roger Leigh <rleigh@codelibre.net>
Debian bug #602891.
Debian bug #602911.
This commit is contained in:
Ben Pfaff
2010-11-09 15:58:36 -08:00
parent e61c056cb9
commit 6e170b4c78
6 changed files with 199 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
AUTHORS
View File

@@ -43,6 +43,7 @@ Cedric Hobbs cedric@nicira.com
Derek Cormier derek.cormier@lab.ntt.co.jp
DK Moon dkmoon@nicira.com
Ghanem Bahri bahri.ghanem@gmail.com
Hector Oron hector.oron@gmail.com
Henrik Amren henrik@nicira.com
Jad Naous jnaous@gmail.com
Jan Medved jmedved@juniper.net
@@ -56,8 +57,10 @@ Paulo Cravero pcravero@as2594.net
Peter Balland peter@nicira.com
Ram Jothikumar rjothikumar@nicira.com
Rob Hoes rob.hoes@citrix.com
Roger Leigh rleigh@codelibre.net
Sajjad Lateef slateef@nicira.com
Sean Brady sbrady@gtfservices.com
Sebastian Andrzej Siewior sebastian@breakpoint.cc
Srini Seetharaman seethara@stanford.edu
Stephen Hemminger shemminger@vyatta.com
Takayuki HAMA t-hama@cb.jp.nec.com

107
lib/socket-util.c
View File

@@ -45,6 +45,10 @@ VLOG_DEFINE_THIS_MODULE(socket_util);
#define LINUX 0
#endif
#ifndef O_DIRECTORY
#define O_DIRECTORY 0
#endif
/* Sets 'fd' to non-blocking mode. Returns 0 if successful, otherwise a
* positive errno value. */
int
@@ -212,7 +216,7 @@ drain_fd(int fd, size_t n_packets)
/* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in
* '*un_len' the size of the sockaddr_un. */
static void
make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len)
make_sockaddr_un__(const char *name, struct sockaddr_un *un, socklen_t *un_len)
{
un->sun_family = AF_UNIX;
strncpy(un->sun_path, name, sizeof un->sun_path);
@@ -221,6 +225,68 @@ make_sockaddr_un(const char *name, struct sockaddr_un* un, socklen_t *un_len)
+ strlen (un->sun_path) + 1);
}
/* Stores in '*un' a sockaddr_un that refers to file 'name'. Stores in
* '*un_len' the size of the sockaddr_un.
*
* Returns 0 on success, otherwise a positive errno value. On success,
* '*dirfdp' is either -1 or a nonnegative file descriptor that the caller
* should close after using '*un' to bind or connect. On failure, '*dirfdp' is
* -1. */
static int
make_sockaddr_un(const char *name, struct sockaddr_un *un, socklen_t *un_len,
int *dirfdp)
{
enum { MAX_UN_LEN = sizeof un->sun_path - 1 };
*dirfdp = -1;
if (strlen(name) > MAX_UN_LEN) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
if (LINUX) {
/* 'name' is too long to fit in a sockaddr_un, but we have a
* workaround for that on Linux: shorten it by opening a file
* descriptor for the directory part of the name and indirecting
* through /proc/self/fd/<dirfd>/<basename>. */
char *dir, *base;
char *short_name;
int dirfd;
dir = dir_name(name);
base = base_name(name);
dirfd = open(dir, O_DIRECTORY | O_RDONLY);
if (dirfd < 0) {
return errno;
}
short_name = xasprintf("/proc/self/fd/%d/%s", dirfd, base);
free(dir);
free(base);
if (strlen(short_name) <= MAX_UN_LEN) {
make_sockaddr_un__(short_name, un, un_len);
free(short_name);
*dirfdp = dirfd;
return 0;
}
free(short_name);
close(dirfd);
VLOG_WARN_RL(&rl, "Unix socket name %s is longer than maximum "
"%d bytes (even shortened)", name, MAX_UN_LEN);
} else {
/* 'name' is too long and we have no workaround. */
VLOG_WARN_RL(&rl, "Unix socket name %s is longer than maximum "
"%d bytes", name, MAX_UN_LEN);
}
return ENAMETOOLONG;
} else {
make_sockaddr_un__(name, un, un_len);
return 0;
}
}
/* Creates a Unix domain socket in the given 'style' (either SOCK_DGRAM or
* SOCK_STREAM) that is bound to '*bind_path' (if 'bind_path' is non-null) and
* connected to '*connect_path' (if 'connect_path' is non-null). If 'nonblock'
@@ -247,9 +313,11 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED,
if (nonblock) {
int flags = fcntl(fd, F_GETFL, 0);
if (flags == -1) {
error = errno;
goto error;
}
if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) {
error = errno;
goto error;
}
}
@@ -257,13 +325,22 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED,
if (bind_path) {
struct sockaddr_un un;
socklen_t un_len;
make_sockaddr_un(bind_path, &un, &un_len);
if (unlink(un.sun_path) && errno != ENOENT) {
VLOG_WARN("unlinking \"%s\": %s\n", un.sun_path, strerror(errno));
int dirfd;
if (unlink(bind_path) && errno != ENOENT) {
VLOG_WARN("unlinking \"%s\": %s\n", bind_path, strerror(errno));
}
fatal_signal_add_file_to_unlink(bind_path);
if (bind(fd, (struct sockaddr*) &un, un_len)
|| fchmod(fd, S_IRWXU)) {
error = make_sockaddr_un(bind_path, &un, &un_len, &dirfd);
if (!error && (bind(fd, (struct sockaddr*) &un, un_len)
|| fchmod(fd, S_IRWXU))) {
error = errno;
}
if (dirfd >= 0) {
close(dirfd);
}
if (error) {
goto error;
}
}
@@ -271,9 +348,18 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED,
if (connect_path) {
struct sockaddr_un un;
socklen_t un_len;
make_sockaddr_un(connect_path, &un, &un_len);
if (connect(fd, (struct sockaddr*) &un, un_len)
int dirfd;
error = make_sockaddr_un(connect_path, &un, &un_len, &dirfd);
if (!error
&& connect(fd, (struct sockaddr*) &un, un_len)
&& errno != EINPROGRESS) {
error = errno;
}
if (dirfd >= 0) {
close(dirfd);
}
if (error) {
goto error;
}
}
@@ -282,6 +368,7 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED,
if (passcred) {
int enable = 1;
if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable))) {
error = errno;
goto error;
}
}
@@ -290,7 +377,9 @@ make_unix_socket(int style, bool nonblock, bool passcred OVS_UNUSED,
return fd;
error:
error = errno == EAGAIN ? EPROTO : errno;
if (error == EAGAIN) {
error = EPROTO;
}
if (bind_path) {
fatal_signal_remove_file_to_unlink(bind_path);
}

1
tests/.gitignore vendored
View File

@@ -22,6 +22,7 @@
/test-timeval
/test-sha1
/test-type-props
/test-unix-socket
/test-uuid
/test-vconn
/testsuite

6
tests/automake.mk
View File

@@ -78,6 +78,7 @@ lcov_wrappers = \
tests/lcov/test-sha1 \
tests/lcov/test-timeval \
tests/lcov/test-type-props \
tests/lcov/test-unix-socket \
tests/lcov/test-uuid \
tests/lcov/test-vconn
@@ -127,6 +128,7 @@ valgrind_wrappers = \
tests/valgrind/test-sha1 \
tests/valgrind/test-timeval \
tests/valgrind/test-type-props \
tests/valgrind/test-unix-socket \
tests/valgrind/test-uuid \
tests/valgrind/test-vconn
@@ -214,6 +216,10 @@ noinst_PROGRAMS += tests/test-lockfile
tests_test_lockfile_SOURCES = tests/test-lockfile.c
tests_test_lockfile_LDADD = lib/libopenvswitch.a
noinst_PROGRAMS += tests/test-unix-socket
tests_test_unix_socket_SOURCES = tests/test-unix-socket.c
tests_test_unix_socket_LDADD = lib/libopenvswitch.a
noinst_PROGRAMS += tests/test-ovsdb
tests_test_ovsdb_SOURCES = \
tests/test-ovsdb.c \

27
tests/library.at
View File

@@ -38,3 +38,30 @@ AT_SETUP([test byte order conversion])
AT_KEYWORDS([byte order])
AT_CHECK([test-byte-order], [0], [ignore])
AT_CLEANUP
AT_SETUP([test unix socket -- short pathname])
AT_CHECK([test-unix-socket x])
AT_CLEANUP
dnl Unix sockets with long names are problematic because the name has to
dnl go in a fixed-length field in struct sockaddr_un. Generally the limit
dnl is about 100 bytes. On Linux, we work around this by indirecting through
dnl a directory fd using /proc/self/fd/<dirfd>. We do not have a workaround
dnl for other platforms, so we skip the test there.
AT_SETUP([test unix socket -- long pathname])
AT_CHECK([dnl
case `uname` in dnl (
*[[lL]]inux*)
exit 0
;; dnl (
*)
dnl Magic exit code to tell Autotest to skip this test.
exit 77
;;
esac
])
dnl Linux has a 108 byte limit; this is 150 bytes long.
mkdir 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
cd 012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789
AT_CHECK([test-unix-socket ../012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789/socket socket])
AT_CLEANUP

64
tests/test-unix-socket.c Normal file
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@@ -0,0 +1,64 @@
/*
* Copyright (c) 2010 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <config.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include "util.h"
#include "socket-util.h"
int
main(int argc, char *argv[])
{
const char *sockname1;
const char *sockname2;
int sock1, sock2;
set_program_name(argv[0]);
if (argc != 2 && argc != 3) {
ovs_fatal(0, "usage: %s SOCKETNAME1 [SOCKETNAME2]", argv[0]);
}
sockname1 = argv[1];
sockname2 = argc > 2 ? argv[2] : sockname1;
signal(SIGALRM, SIG_DFL);
alarm(5);
/* Create a listening socket under name 'sockname1'. */
sock1 = make_unix_socket(SOCK_STREAM, false, false, sockname1, NULL);
if (sock1 < 0) {
ovs_fatal(-sock1, "%s: bind failed", sockname1);
}
if (listen(sock1, 1)) {
ovs_fatal(errno, "%s: listen failed", sockname1);
}
/* Connect to 'sockname2' (which should be the same file, perhaps under a
* different name). */
sock2 = make_unix_socket(SOCK_STREAM, false, false, NULL, sockname2);
if (sock2 < 0) {
ovs_fatal(-sock2, "%s: connect failed", sockname2);
}
close(sock1);
close(sock2);
return 0;
}