X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fsocket-util.c;h=cd0affca8e97c1557f66f4d1cbdbb49f38313c57;hb=5b5d1836ddfa1a83a9d3369c119eb4716831b8dd;hp=7f34ea2e939ea86b0e27e482b5ba4ab477e106a1;hpb=260aeca8609c2efda03772b7e4a6077369ae8b9c;p=sliver-openvswitch.git diff --git a/lib/socket-util.c b/lib/socket-util.c index 7f34ea2e9..cd0affca8 100644 --- a/lib/socket-util.c +++ b/lib/socket-util.c @@ -60,6 +60,10 @@ VLOG_DEFINE_THIS_MODULE(socket_util); #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); @@ -337,78 +341,161 @@ 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) +/* Attempts to shorten 'name' by opening a file descriptor for the directory + * part of the name and indirecting through /proc/self/fd//. + * On systems with Linux-like /proc, this works as long as 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) { - 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); + char *dir, *base; + int dirfd; + int len; + + if (!LINUX_DATAPATH) { + 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 /. This works on + * systems that support symlinks, as long as 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. 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. */ + * 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) + int *dirfdp, char linkname[MAX_UN_LEN + 1]) { - enum { MAX_UN_LEN = sizeof un->sun_path - 1 }; + char short_name[MAX_UN_LEN + 1]; *dirfdp = -1; + linkname[0] = '\0'; if (strlen(name) > MAX_UN_LEN) { - static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 1); - - if (LINUX_DATAPATH) { - /* '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//. */ - 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) { - free(base); - free(dir); - 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); + /* '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 " - "%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); + "%zu bytes", name, MAX_UN_LEN); + return error; } - return ENAMETOOLONG; - } else { - make_sockaddr_un__(name, un, un_len); - return 0; + 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); } } @@ -453,6 +540,7 @@ make_unix_socket(int style, bool nonblock, } if (bind_path) { + char linkname[MAX_UN_LEN + 1]; struct sockaddr_un un; socklen_t un_len; int dirfd; @@ -463,32 +551,31 @@ make_unix_socket(int style, bool nonblock, } fatal_signal_add_file_to_unlink(bind_path); - error = make_sockaddr_un(bind_path, &un, &un_len, &dirfd); + error = make_sockaddr_un(bind_path, &un, &un_len, &dirfd, linkname); if (!error) { error = bind_unix_socket(fd, (struct sockaddr *) &un, un_len); } - if (dirfd >= 0) { - close(dirfd); - } + 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); + error = make_sockaddr_un(connect_path, &un, &un_len, &dirfd, linkname); if (!error && connect(fd, (struct sockaddr*) &un, un_len) && errno != EINPROGRESS) { error = errno; } - if (dirfd >= 0) { - close(dirfd); - } + free_sockaddr_un(dirfd, linkname); + if (error) { goto error; }