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socket-util: Refactor unix specific code to a new file.

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Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
This commit is contained in:
Gurucharan Shetty
2014-05-23 09:35:47 -07:00
parent 5d40fc5796
commit 7f1e1c7ffa
4 changed files with 420 additions and 402 deletions
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377
lib/socket-util.c
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@@ -26,14 +26,12 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <unistd.h>
#include "dynamic-string.h"
#include "fatal-signal.h"
#include "ovs-thread.h"
#include "packets.h"
#include "poll-loop.h"
@@ -49,23 +47,6 @@
VLOG_DEFINE_THIS_MODULE(socket_util);
/* #ifdefs make it a pain to maintain code: you have to try to build both ways.
* Thus, this file compiles all of the code regardless of the target, by
* writing "if (LINUX)" instead of "#ifdef __linux__". */
#ifdef __linux__
#define LINUX 1
#else
#define LINUX 0
#endif
#ifndef O_DIRECTORY
#define O_DIRECTORY 0
#endif
/* Maximum length of the sun_path member in a struct sockaddr_un, excluding
* space for a null terminator. */
#define MAX_UN_LEN (sizeof(((struct sockaddr_un *) 0)->sun_path) - 1)
static int getsockopt_int(int fd, int level, int option, const char *optname,
int *valuep);
@@ -277,43 +258,6 @@ check_connection_completion(int fd)
}
}
#ifndef _WIN32
/* Drain all the data currently in the receive queue of a datagram socket (and
* possibly additional data). There is no way to know how many packets are in
* the receive queue, but we do know that the total number of bytes queued does
* not exceed the receive buffer size, so we pull packets until none are left
* or we've read that many bytes. */
int
drain_rcvbuf(int fd)
{
int rcvbuf;
rcvbuf = get_socket_rcvbuf(fd);
if (rcvbuf < 0) {
return -rcvbuf;
}
while (rcvbuf > 0) {
/* In Linux, specifying MSG_TRUNC in the flags argument causes the
* datagram length to be returned, even if that is longer than the
* buffer provided. Thus, we can use a 1-byte buffer to discard the
* incoming datagram and still be able to account how many bytes were
* removed from the receive buffer.
*
* On other Unix-like OSes, MSG_TRUNC has no effect in the flags
* argument. */
char buffer[LINUX ? 1 : 2048];
ssize_t n_bytes = recv(fd, buffer, sizeof buffer,
MSG_TRUNC | MSG_DONTWAIT);
if (n_bytes <= 0 || n_bytes >= rcvbuf) {
break;
}
rcvbuf -= n_bytes;
}
return 0;
}
#endif
/* Returns the size of socket 'sock''s receive buffer (SO_RCVBUF), or a
* negative errno value if an error occurs. */
int
@@ -344,269 +288,6 @@ drain_fd(int fd, size_t n_packets)
}
}
#ifndef _WIN32
/* Attempts to shorten 'name' by opening a file descriptor for the directory
* part of the name and indirecting through /proc/self/fd/<dirfd>/<basename>.
* On systems with Linux-like /proc, this works as long as <basename> isn't too
* long.
*
* On success, returns 0 and stores the short name in 'short_name' and a
* directory file descriptor to eventually be closed in '*dirfpd'. */
static int
shorten_name_via_proc(const char *name, char short_name[MAX_UN_LEN + 1],
int *dirfdp)
{
char *dir, *base;
int dirfd;
int len;
if (!LINUX) {
return ENAMETOOLONG;
}
dir = dir_name(name);
dirfd = open(dir, O_DIRECTORY | O_RDONLY);
if (dirfd < 0) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
int error = errno;
VLOG_WARN_RL(&rl, "%s: open failed (%s)", dir, ovs_strerror(error));
free(dir);
return error;
}
free(dir);
base = base_name(name);
len = snprintf(short_name, MAX_UN_LEN + 1,
"/proc/self/fd/%d/%s", dirfd, base);
free(base);
if (len >= 0 && len <= MAX_UN_LEN) {
*dirfdp = dirfd;
return 0;
} else {
close(dirfd);
return ENAMETOOLONG;
}
}
/* Attempts to shorten 'name' by creating a symlink for the directory part of
* the name and indirecting through <symlink>/<basename>. This works on
* systems that support symlinks, as long as <basename> isn't too long.
*
* On success, returns 0 and stores the short name in 'short_name' and the
* symbolic link to eventually delete in 'linkname'. */
static int
shorten_name_via_symlink(const char *name, char short_name[MAX_UN_LEN + 1],
char linkname[MAX_UN_LEN + 1])
{
char *abs, *dir, *base;
const char *tmpdir;
int error;
int i;
abs = abs_file_name(NULL, name);
dir = dir_name(abs);
base = base_name(abs);
free(abs);
tmpdir = getenv("TMPDIR");
if (tmpdir == NULL) {
tmpdir = "/tmp";
}
for (i = 0; i < 1000; i++) {
int len;
len = snprintf(linkname, MAX_UN_LEN + 1,
"%s/ovs-un-c-%"PRIu32, tmpdir, random_uint32());
error = (len < 0 || len > MAX_UN_LEN ? ENAMETOOLONG
: symlink(dir, linkname) ? errno
: 0);
if (error != EEXIST) {
break;
}
}
if (!error) {
int len;
fatal_signal_add_file_to_unlink(linkname);
len = snprintf(short_name, MAX_UN_LEN + 1, "%s/%s", linkname, base);
if (len < 0 || len > MAX_UN_LEN) {
fatal_signal_unlink_file_now(linkname);
error = ENAMETOOLONG;
}
}
if (error) {
linkname[0] = '\0';
}
free(dir);
free(base);
return error;
}
/* 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.
*
* Uses '*dirfdp' and 'linkname' to store references to data when the caller no
* longer needs to use 'un'. On success, freeing these references with
* free_sockaddr_un() is mandatory to avoid a leak; on failure, freeing them is
* unnecessary but harmless. */
static int
make_sockaddr_un(const char *name, struct sockaddr_un *un, socklen_t *un_len,
int *dirfdp, char linkname[MAX_UN_LEN + 1])
{
char short_name[MAX_UN_LEN + 1];
*dirfdp = -1;
linkname[0] = '\0';
if (strlen(name) > MAX_UN_LEN) {
/* 'name' is too long to fit in a sockaddr_un. Try a workaround. */
int error = shorten_name_via_proc(name, short_name, dirfdp);
if (error == ENAMETOOLONG) {
error = shorten_name_via_symlink(name, short_name, linkname);
}
if (error) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1);
VLOG_WARN_RL(&rl, "Unix socket name %s is longer than maximum "
"%"PRIuSIZE" bytes", name, MAX_UN_LEN);
return error;
}
name = short_name;
}
un->sun_family = AF_UNIX;
ovs_strzcpy(un->sun_path, name, sizeof un->sun_path);
*un_len = (offsetof(struct sockaddr_un, sun_path)
+ strlen (un->sun_path) + 1);
return 0;
}
/* Clean up after make_sockaddr_un(). */
static void
free_sockaddr_un(int dirfd, const char *linkname)
{
if (dirfd >= 0) {
close(dirfd);
}
if (linkname[0]) {
fatal_signal_unlink_file_now(linkname);
}
}
/* Binds Unix domain socket 'fd' to a file with permissions 0700. */
static int
bind_unix_socket(int fd, struct sockaddr *sun, socklen_t sun_len)
{
/* According to _Unix Network Programming_, umask should affect bind(). */
mode_t old_umask = umask(0077);
int error = bind(fd, sun, sun_len) ? errno : 0;
umask(old_umask);
return error;
}
/* 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'
* is true, the socket is made non-blocking.
*
* Returns the socket's fd if successful, otherwise a negative errno value. */
int
make_unix_socket(int style, bool nonblock,
const char *bind_path, const char *connect_path)
{
int error;
int fd;
fd = socket(PF_UNIX, style, 0);
if (fd < 0) {
return -errno;
}
/* Set nonblocking mode right away, if we want it. This prevents blocking
* in connect(), if connect_path != NULL. (In turn, that's a corner case:
* it will only happen if style is SOCK_STREAM or SOCK_SEQPACKET, and only
* if a backlog of un-accepted connections has built up in the kernel.) */
if (nonblock) {
error = set_nonblocking(fd);
if (error) {
goto error;
}
}
if (bind_path) {
char linkname[MAX_UN_LEN + 1];
struct sockaddr_un un;
socklen_t un_len;
int dirfd;
if (unlink(bind_path) && errno != ENOENT) {
VLOG_WARN("unlinking \"%s\": %s\n",
bind_path, ovs_strerror(errno));
}
fatal_signal_add_file_to_unlink(bind_path);
error = make_sockaddr_un(bind_path, &un, &un_len, &dirfd, linkname);
if (!error) {
error = bind_unix_socket(fd, (struct sockaddr *) &un, un_len);
}
free_sockaddr_un(dirfd, linkname);
if (error) {
goto error;
}
}
if (connect_path) {
char linkname[MAX_UN_LEN + 1];
struct sockaddr_un un;
socklen_t un_len;
int dirfd;
error = make_sockaddr_un(connect_path, &un, &un_len, &dirfd, linkname);
if (!error
&& connect(fd, (struct sockaddr*) &un, un_len)
&& errno != EINPROGRESS) {
error = errno;
}
free_sockaddr_un(dirfd, linkname);
if (error) {
goto error;
}
}
return fd;
error:
if (error == EAGAIN) {
error = EPROTO;
}
if (bind_path) {
fatal_signal_unlink_file_now(bind_path);
}
close(fd);
return -error;
}
int
get_unix_name_len(socklen_t sun_len)
{
return (sun_len >= offsetof(struct sockaddr_un, sun_path)
? sun_len - offsetof(struct sockaddr_un, sun_path)
: 0);
}
#endif /* _WIN32 */
ovs_be32
guess_netmask(ovs_be32 ip_)
{
@@ -1057,24 +738,6 @@ get_mtime(const char *file_name, struct timespec *mtime)
}
}
#ifndef _WIN32
void
xpipe(int fds[2])
{
if (pipe(fds)) {
VLOG_FATAL("failed to create pipe (%s)", ovs_strerror(errno));
}
}
void
xpipe_nonblocking(int fds[2])
{
xpipe(fds);
xset_nonblocking(fds[0]);
xset_nonblocking(fds[1]);
}
#endif
static int
getsockopt_int(int fd, int level, int option, const char *optname, int *valuep)
{
@@ -1241,46 +904,6 @@ describe_fd(int fd)
return ds_steal_cstr(&string);
}
#ifndef _WIN32
/* Calls ioctl() on an AF_INET sock, passing the specified 'command' and
* 'arg'. Returns 0 if successful, otherwise a positive errno value. */
int
af_inet_ioctl(unsigned long int command, const void *arg)
{
static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
static int sock;
if (ovsthread_once_start(&once)) {
sock = socket(AF_INET, SOCK_DGRAM, 0);
if (sock < 0) {
int error = sock_errno();
VLOG_ERR("failed to create inet socket: %s", sock_strerror(error));
sock = -error;
}
ovsthread_once_done(&once);
}
return (sock < 0 ? -sock
: ioctl(sock, command, arg) == -1 ? errno
: 0);
}
int
af_inet_ifreq_ioctl(const char *name, struct ifreq *ifr, unsigned long int cmd,
const char *cmd_name)
{
int error;
ovs_strzcpy(ifr->ifr_name, name, sizeof ifr->ifr_name);
error = af_inet_ioctl(cmd, ifr);
if (error) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
VLOG_DBG_RL(&rl, "%s: ioctl(%s) failed: %s", name, cmd_name,
ovs_strerror(error));
}
return error;
}
#endif
/* sockaddr_storage helpers. */