From 29f363373fa252c720d34893b8283bedcda53a49 Mon Sep 17 00:00:00 2001 From: Andre Noll Date: Mon, 18 Jul 2016 23:35:48 +0200 Subject: [PATCH] Remove compatibility code for abstract unix domain sockets. Abstract sockets were introduced in paraslash-0.5.5 (2015-09-20). For backwards compatibility, create_local_socket() was modified to create an abtract socket *and* an ordinary pathname socket so that old audiod clients (which connect to the pathname socket) would still work. This patch breaks compatibility by going back to a single socket, either abstract (Linux) or pathname (all other systems), as determined in the first call to create_local_socket(). This allows to drop the "abstract" argument of init_unix_addr() and the "mode" argument of create_local_socket(). The code in net.c and the callers get quite a bit shorter since it has to deal with only a single file descriptor and one type of socket. --- afs.c | 11 +++-------- audiod.c | 59 +++++++++++++++++--------------------------------------- net.c | 59 ++++++++++++++++++++++++++++---------------------------- net.h | 2 +- 4 files changed, 52 insertions(+), 79 deletions(-) diff --git a/afs.c b/afs.c index 0946b6df..7f27b7dd 100644 --- a/afs.c +++ b/afs.c @@ -649,15 +649,10 @@ static int setup_command_socket_or_die(void) char *socket_name = conf.afs_socket_arg; unlink(socket_name); - ret = create_local_socket(socket_name, 0); + ret = create_local_socket(socket_name); if (ret < 0) { - ret = create_local_socket(socket_name, - S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IROTH); - if (ret < 0) { - PARA_EMERG_LOG("%s: %s\n", para_strerror(-ret), - socket_name); - exit(EXIT_FAILURE); - } + PARA_EMERG_LOG("%s: %s\n", para_strerror(-ret), socket_name); + exit(EXIT_FAILURE); } socket_fd = ret; PARA_INFO_LOG("listening on socket %s (fd %d)\n", socket_name, diff --git a/audiod.c b/audiod.c index db69cf14..254bcb8d 100644 --- a/audiod.c +++ b/audiod.c @@ -183,22 +183,9 @@ static uid_t *uid_whitelist; */ static struct status_task *stat_task = &status_task_struct; -/* - * The task for handling audiod commands. - * - * We need two listening sockets for backward compability: on Linux systems - * fd[0] is an abstract socket (more precisely, a socket bound to an address in - * the abstract namespace), and fd[1] is the usual pathname socket. On other - * systems, fd[0] is negative, and only the pathname socket is used. - * - * For 0.5.x we accept connections on both sockets to make sure that old - * para_audioc versions can still connect. New versions use only the abstract - * socket. Hence after v0.6.0 we can go back to a single socket, either an - * abstract one (Linux) or a pathname socket (all other systems). - */ struct command_task { - /** The local listening sockets. */ - int fd[2]; + /** The local listening socket. */ + int fd; /** the associated task structure */ struct task *task; }; @@ -1059,7 +1046,7 @@ static int parse_stream_args(void) } /* does not unlink socket on errors */ -static void init_local_sockets(struct command_task *ct) +static void init_local_socket(struct command_task *ct) { if (conf.socket_given) socket_name = para_strdup(conf.socket_arg); @@ -1072,12 +1059,10 @@ static void init_local_sockets(struct command_task *ct) PARA_NOTICE_LOG("local socket: %s\n", socket_name); if (conf.force_given) unlink(socket_name); - ct->fd[0] = create_local_socket(socket_name, 0); - ct->fd[1] = create_local_socket(socket_name, - S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH); - if (ct->fd[0] >= 0 || ct->fd[1] >= 0) + ct->fd = create_local_socket(socket_name); + if (ct->fd >= 0) return; - PARA_EMERG_LOG("%s\n", para_strerror(-ct->fd[1])); + PARA_EMERG_LOG("%s\n", para_strerror(-ct->fd)); exit(EXIT_FAILURE); } @@ -1104,16 +1089,12 @@ static int signal_post_select(struct sched *s, void *context) static void command_pre_select(struct sched *s, void *context) { struct command_task *ct = context; - int i; - - for (i = 0; i < 2; i++) - if (ct->fd[i] >= 0) - para_fd_set(ct->fd[i], &s->rfds, &s->max_fileno); + para_fd_set(ct->fd, &s->rfds, &s->max_fileno); } static int command_post_select(struct sched *s, void *context) { - int ret, i; + int ret; struct command_task *ct = context; static struct timeval last_status_dump; struct timeval tmp, delay; @@ -1122,19 +1103,15 @@ static int command_post_select(struct sched *s, void *context) ret = task_get_notification(ct->task); if (ret < 0) return ret; - for (i = 0; i < 2; i++) { - if (ct->fd[i] < 0) - continue; - ret = handle_connect(ct->fd[i], &s->rfds); - if (ret < 0) { - PARA_ERROR_LOG("%s\n", para_strerror(-ret)); - if (ret == -E_AUDIOD_TERM) { - task_notify_all(s, -ret); - return ret; - } - } else if (ret > 0) - force = true; - } + ret = handle_connect(ct->fd, &s->rfds); + if (ret < 0) { + PARA_ERROR_LOG("%s\n", para_strerror(-ret)); + if (ret == -E_AUDIOD_TERM) { + task_notify_all(s, -ret); + return ret; + } + } else if (ret > 0) + force = true; if (force == true) goto dump; @@ -1162,7 +1139,7 @@ dump: static void init_command_task(struct command_task *ct) { - init_local_sockets(ct); /* doesn't return on errors */ + init_local_socket(ct); /* doesn't return on errors */ ct->task = task_register(&(struct task_info) { .name = "command", diff --git a/net.c b/net.c index fa7cd4b8..023d78d0 100644 --- a/net.c +++ b/net.c @@ -818,25 +818,37 @@ int dccp_available_ccids(uint8_t **ccid_array) return nccids; } -/** - * Prepare a structure for \p AF_UNIX socket addresses. - * - * \param u Pointer to the struct to be prepared. - * \param name The socket pathname. +/* + * Prepare a structure for AF_UNIX socket addresses. * - * This just copies \a name to the sun_path component of \a u. + * This just copies name to the sun_path component of u, prepending a zero byte + * if abstract sockets are supported. * - * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer - * than \p UNIX_PATH_MAX. + * The first call to this function tries to bind a socket to the abstract name + * space. The result of this test is stored in a static variable. Subsequent + * calls read this variable and create abstract sockets on systems that support + * them. */ -static int init_unix_addr(struct sockaddr_un *u, const char *name, - bool abstract) +static int init_unix_addr(struct sockaddr_un *u, const char *name) { - if (strlen(name) + abstract >= UNIX_PATH_MAX) + static int use_abstract; + + if (strlen(name) + 1 >= UNIX_PATH_MAX) return -E_NAME_TOO_LONG; memset(u->sun_path, 0, UNIX_PATH_MAX); u->sun_family = PF_UNIX; - strcpy(u->sun_path + abstract, name); + if (use_abstract == 0) { /* executed only once */ + int fd = socket(PF_UNIX, SOCK_STREAM, 0); + memcpy(u->sun_path, "\0x\0", 3); + if (bind(fd, (struct sockaddr *)u, sizeof(*u)) == 0) + use_abstract = 1; /* yes */ + else + use_abstract = -1; /* no */ + close(fd); + PARA_NOTICE_LOG("%susing abstract socket namespace\n", + use_abstract == 1? "" : "not "); + } + strcpy(u->sun_path + (use_abstract == 1? 1 : 0), name); return 1; } @@ -844,28 +856,22 @@ static int init_unix_addr(struct sockaddr_un *u, const char *name, * Create a socket for local communication and listen on it. * * \param name The socket pathname. - * \param mode The desired permissions of the socket. * * This function creates a passive local socket for sequenced, reliable, * two-way, connection-based byte streams. The socket file descriptor is set to * nonblocking mode and listen(2) is called to prepare the socket for * accepting incoming connection requests. * - * If mode is zero, an abstract socket (a non-portable Linux extension) is - * created. In this case the socket name has no connection with filesystem - * pathnames. - * * \return The file descriptor on success, negative error code on failure. * * \sa socket(2), \sa bind(2), \sa chmod(2), listen(2), unix(7). */ -int create_local_socket(const char *name, mode_t mode) +int create_local_socket(const char *name) { struct sockaddr_un unix_addr; int fd, ret; - bool abstract = mode == 0; - ret = init_unix_addr(&unix_addr, name, abstract); + ret = init_unix_addr(&unix_addr, name); if (ret < 0) return ret; ret = socket(PF_UNIX, SOCK_STREAM, 0); @@ -880,7 +886,9 @@ int create_local_socket(const char *name, mode_t mode) ret = -ERRNO_TO_PARA_ERROR(errno); goto err; } - if (!abstract) { + if (unix_addr.sun_path[0] != 0) { /* pathname socket */ + mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP + | S_IROTH | S_IWOTH; ret = -E_CHMOD; if (chmod(name, mode) < 0) goto err; @@ -917,14 +925,7 @@ int connect_local_socket(const char *name) fd = socket(PF_UNIX, SOCK_STREAM, 0); if (fd < 0) return -ERRNO_TO_PARA_ERROR(errno); - /* first try (linux-only) abstract socket */ - ret = init_unix_addr(&unix_addr, name, true); - if (ret < 0) - goto err; - if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) != -1) - return fd; - /* next try pathname socket */ - ret = init_unix_addr(&unix_addr, name, false); + ret = init_unix_addr(&unix_addr, name); if (ret < 0) goto err; if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) != -1) diff --git a/net.h b/net.h index b2bb47c9..a70954a9 100644 --- a/net.h +++ b/net.h @@ -147,7 +147,7 @@ int recv_bin_buffer(int fd, char *buf, size_t size); int recv_buffer(int fd, char *buf, size_t size); int para_accept(int fd, fd_set *rfds, void *addr, socklen_t size, int *new_fd); -int create_local_socket(const char *name, mode_t mode); +int create_local_socket(const char *name); int connect_local_socket(const char *name); int recv_cred_buffer(int, char *, size_t); ssize_t send_cred_buffer(int, char*); -- 2.39.5