chiark / gitweb /
util: unify SO_PEERCRED/SO_PEERSEC invocations
[elogind.git] / src / libsystemd-bus / bus-socket.c
index fed1971ec79ad588ae8c9e6c0849213772999afe..0c4b6af447297fbe8f1e348f096df36d879f37d9 100644 (file)
 #include "missing.h"
 #include "strv.h"
 #include "utf8.h"
+#include "sd-daemon.h"
 
 #include "sd-bus.h"
 #include "bus-socket.h"
 #include "bus-internal.h"
 #include "bus-message.h"
 
+#define SNDBUF_SIZE (8*1024*1024)
+
 static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) {
 
         while (size > 0) {
@@ -57,6 +60,65 @@ static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) {
         }
 }
 
+static int append_iovec(sd_bus_message *m, const void *p, size_t sz) {
+        assert(m);
+        assert(p);
+        assert(sz > 0);
+
+        m->iovec[m->n_iovec].iov_base = (void*) p;
+        m->iovec[m->n_iovec].iov_len = sz;
+        m->n_iovec++;
+
+        return 0;
+}
+
+static int bus_message_setup_iovec(sd_bus_message *m) {
+        struct bus_body_part *part;
+        unsigned n, i;
+        int r;
+
+        assert(m);
+        assert(m->sealed);
+
+        if (m->n_iovec > 0)
+                return 0;
+
+        assert(!m->iovec);
+
+        n = 1 + m->n_body_parts;
+        if (n < ELEMENTSOF(m->iovec_fixed))
+                m->iovec = m->iovec_fixed;
+        else {
+                m->iovec = new(struct iovec, n);
+                if (!m->iovec) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+        }
+
+        r = append_iovec(m, m->header, BUS_MESSAGE_BODY_BEGIN(m));
+        if (r < 0)
+                goto fail;
+
+        MESSAGE_FOREACH_PART(part, i, m)  {
+                r = bus_body_part_map(part);
+                if (r < 0)
+                        goto fail;
+
+                r = append_iovec(m, part->data, part->size);
+                if (r < 0)
+                        goto fail;
+        }
+
+        assert(n == m->n_iovec);
+
+        return 0;
+
+fail:
+        m->poisoned = true;
+        return r;
+}
+
 bool bus_socket_auth_needs_write(sd_bus *b) {
 
         unsigned i;
@@ -75,7 +137,6 @@ bool bus_socket_auth_needs_write(sd_bus *b) {
 }
 
 static int bus_socket_write_auth(sd_bus *b) {
-        struct msghdr mh;
         ssize_t k;
 
         assert(b);
@@ -84,16 +145,26 @@ static int bus_socket_write_auth(sd_bus *b) {
         if (!bus_socket_auth_needs_write(b))
                 return 0;
 
-        zero(mh);
-        mh.msg_iov = b->auth_iovec + b->auth_index;
-        mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
+        if (b->prefer_writev)
+                k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
+        else {
+                struct msghdr mh;
+                zero(mh);
+
+                mh.msg_iov = b->auth_iovec + b->auth_index;
+                mh.msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index;
+
+                k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+                if (k < 0 && errno == ENOTSOCK) {
+                        b->prefer_writev = true;
+                        k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
+                }
+        }
 
-        k = sendmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
         if (k < 0)
                 return errno == EAGAIN ? 0 : -errno;
 
         iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k);
-
         return 1;
 }
 
@@ -112,7 +183,7 @@ static int bus_socket_auth_verify_client(sd_bus *b) {
         if (!e)
                 return 0;
 
-        if (b->negotiate_fds) {
+        if (b->hello_flags & KDBUS_HELLO_ACCEPT_FD) {
                 f = memmem(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2);
                 if (!f)
                         return 0;
@@ -225,7 +296,7 @@ static int verify_external_token(sd_bus *b, const char *p, size_t l) {
          * the owner of this bus wanted authentication he should have
          * checked SO_PEERCRED before even creating the bus object. */
 
-        if (!b->ucred_valid)
+        if (!b->anonymous_auth && !b->ucred_valid)
                 return 0;
 
         if (l <= 0)
@@ -248,7 +319,9 @@ static int verify_external_token(sd_bus *b, const char *p, size_t l) {
         if (r < 0)
                 return 0;
 
-        if (u != b->ucred.uid)
+        /* We ignore the passed value if anonymous authentication is
+         * on anyway. */
+        if (!b->anonymous_auth && u != b->ucred.uid)
                 return 0;
 
         return 1;
@@ -301,13 +374,16 @@ static int bus_socket_auth_verify_server(sd_bus *b) {
 
         assert(b);
 
-        if (b->rbuffer_size < 3)
+        if (b->rbuffer_size < 1)
                 return 0;
 
         /* First char must be a NUL byte */
         if (*(char*) b->rbuffer != 0)
                 return -EIO;
 
+        if (b->rbuffer_size < 3)
+                return 0;
+
         /* Begin with the first line */
         if (b->auth_rbegin <= 0)
                 b->auth_rbegin = 1;
@@ -390,7 +466,7 @@ static int bus_socket_auth_verify_server(sd_bus *b) {
                                         r = bus_socket_auth_write_ok(b);
                         }
                 } else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) {
-                        if (b->auth == _BUS_AUTH_INVALID || !b->negotiate_fds)
+                        if (b->auth == _BUS_AUTH_INVALID || !(b->hello_flags & KDBUS_HELLO_ACCEPT_FD))
                                 r = bus_socket_auth_write(b, "ERROR\r\n");
                         else {
                                 b->can_fds = true;
@@ -431,6 +507,7 @@ static int bus_socket_read_auth(sd_bus *b) {
                             CMSG_SPACE(NAME_MAX)]; /*selinux label */
         } control;
         struct cmsghdr *cmsg;
+        bool handle_cmsg = false;
 
         assert(b);
         assert(b->state == BUS_AUTHENTICATING);
@@ -439,7 +516,7 @@ static int bus_socket_read_auth(sd_bus *b) {
         if (r != 0)
                 return r;
 
-        n = MAX(256, b->rbuffer_size * 2);
+        n = MAX(256u, b->rbuffer_size * 2);
 
         if (n > BUS_AUTH_SIZE_MAX)
                 n = BUS_AUTH_SIZE_MAX;
@@ -457,13 +534,22 @@ static int bus_socket_read_auth(sd_bus *b) {
         iov.iov_base = (uint8_t*) b->rbuffer + b->rbuffer_size;
         iov.iov_len = n - b->rbuffer_size;
 
-        zero(mh);
-        mh.msg_iov = &iov;
-        mh.msg_iovlen = 1;
-        mh.msg_control = &control;
-        mh.msg_controllen = sizeof(control);
-
-        k = recvmsg(b->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
+        if (b->prefer_readv)
+                k = readv(b->input_fd, &iov, 1);
+        else {
+                zero(mh);
+                mh.msg_iov = &iov;
+                mh.msg_iovlen = 1;
+                mh.msg_control = &control;
+                mh.msg_controllen = sizeof(control);
+
+                k = recvmsg(b->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
+                if (k < 0 && errno == ENOTSOCK) {
+                        b->prefer_readv = true;
+                        k = readv(b->input_fd, &iov, 1);
+                } else
+                        handle_cmsg = true;
+        }
         if (k < 0)
                 return errno == EAGAIN ? 0 : -errno;
         if (k == 0)
@@ -471,32 +557,41 @@ static int bus_socket_read_auth(sd_bus *b) {
 
         b->rbuffer_size += k;
 
-        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
-                if (cmsg->cmsg_level == SOL_SOCKET &&
-                    cmsg->cmsg_type == SCM_RIGHTS) {
-                        int j;
+        if (handle_cmsg) {
+                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+                        if (cmsg->cmsg_level == SOL_SOCKET &&
+                            cmsg->cmsg_type == SCM_RIGHTS) {
+                                int j;
+
+                                /* Whut? We received fds during the auth
+                                 * protocol? Somebody is playing games with
+                                 * us. Close them all, and fail */
+                                j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+                                close_many((int*) CMSG_DATA(cmsg), j);
+                                return -EIO;
 
-                        /* Whut? We received fds during the auth
-                         * protocol? Somebody is playing games with
-                         * us. Close them all, and fail */
-                        j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
-                        close_many((int*) CMSG_DATA(cmsg), j);
-                        return -EIO;
+                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
+                                   cmsg->cmsg_type == SCM_CREDENTIALS &&
+                                   cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
 
-                } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                    cmsg->cmsg_type == SCM_CREDENTIALS &&
-                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
+                                /* Ignore bogus data, which we might
+                                 * get on socketpair() sockets */
+                                if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
+                                        memcpy(&b->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
+                                        b->ucred_valid = true;
+                                }
 
-                        memcpy(&b->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
-                        b->ucred_valid = true;
+                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
+                                   cmsg->cmsg_type == SCM_SECURITY) {
 
-                } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                         cmsg->cmsg_type == SCM_SECURITY) {
+                                size_t l;
 
-                        size_t l;
-                        l = cmsg->cmsg_len - CMSG_LEN(0);
-                        memcpy(&b->label, CMSG_DATA(cmsg), l);
-                        b->label[l] = 0;
+                                l = cmsg->cmsg_len - CMSG_LEN(0);
+                                if (l > 0) {
+                                        memcpy(&b->label, CMSG_DATA(cmsg), l);
+                                        b->label[l] = 0;
+                                }
+                        }
                 }
         }
 
@@ -507,7 +602,7 @@ static int bus_socket_read_auth(sd_bus *b) {
         return 1;
 }
 
-static int bus_socket_setup(sd_bus *b) {
+void bus_socket_setup(sd_bus *b) {
         int enable;
 
         assert(b);
@@ -515,14 +610,25 @@ static int bus_socket_setup(sd_bus *b) {
         /* Enable SO_PASSCRED + SO_PASSEC. We try this on any
          * socket, just in case. */
         enable = !b->bus_client;
-        setsockopt(b->fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable));
-        setsockopt(b->fd, SOL_SOCKET, SO_PASSSEC, &enable, sizeof(enable));
+        setsockopt(b->input_fd, SOL_SOCKET, SO_PASSCRED, &enable, sizeof(enable));
 
-        /* Increase the buffers to a MB */
-        fd_inc_rcvbuf(b->fd, 1024*1024);
-        fd_inc_sndbuf(b->fd, 1024*1024);
+        enable = !b->bus_client && (b->attach_flags & KDBUS_ATTACH_SECLABEL);
+        setsockopt(b->input_fd, SOL_SOCKET, SO_PASSSEC, &enable, sizeof(enable));
 
-        return 0;
+        /* Increase the buffers to 8 MB */
+        fd_inc_rcvbuf(b->input_fd, SNDBUF_SIZE);
+        fd_inc_sndbuf(b->output_fd, SNDBUF_SIZE);
+
+        b->is_kernel = false;
+        b->message_version = 1;
+        b->message_endian = 0;
+}
+
+static void bus_get_peercred(sd_bus *b) {
+        assert(b);
+
+        /* Get the peer for socketpair() sockets */
+        b->ucred_valid = getpeercred(b->input_fd, &b->ucred) >= 0;
 }
 
 static int bus_socket_start_auth_client(sd_bus *b) {
@@ -552,7 +658,7 @@ static int bus_socket_start_auth_client(sd_bus *b) {
         if (!b->auth_buffer)
                 return -ENOMEM;
 
-        if (b->negotiate_fds)
+        if (b->hello_flags & KDBUS_HELLO_ACCEPT_FD)
                 auth_suffix = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
         else
                 auth_suffix = "\r\nBEGIN\r\n";
@@ -567,22 +673,20 @@ static int bus_socket_start_auth_client(sd_bus *b) {
         return bus_socket_write_auth(b);
 }
 
-static int bus_socket_start_auth(sd_bus *b) {
-        int domain = 0, r;
-        socklen_t sl;
-
+int bus_socket_start_auth(sd_bus *b) {
         assert(b);
 
+        bus_get_peercred(b);
+
         b->state = BUS_AUTHENTICATING;
         b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_DEFAULT_TIMEOUT;
 
-        sl = sizeof(domain);
-        r = getsockopt(b->fd, SOL_SOCKET, SO_DOMAIN, &domain, &sl);
-        if (r < 0)
-                return -errno;
+        if (sd_is_socket(b->input_fd, AF_UNIX, 0, 0) <= 0)
+                b->hello_flags &= ~KDBUS_HELLO_ACCEPT_FD;
 
-        if (domain != AF_UNIX)
-                b->negotiate_fds = false;
+        if (b->output_fd != b->input_fd)
+                if (sd_is_socket(b->output_fd, AF_UNIX, 0, 0) <= 0)
+                        b->hello_flags &= ~KDBUS_HELLO_ACCEPT_FD;
 
         if (b->is_server)
                 return bus_socket_read_auth(b);
@@ -594,18 +698,19 @@ int bus_socket_connect(sd_bus *b) {
         int r;
 
         assert(b);
-        assert(b->fd < 0);
+        assert(b->input_fd < 0);
+        assert(b->output_fd < 0);
         assert(b->sockaddr.sa.sa_family != AF_UNSPEC);
 
-        b->fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
-        if (b->fd < 0)
+        b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (b->input_fd < 0)
                 return -errno;
 
-        r = bus_socket_setup(b);
-        if (r < 0)
-                return r;
+        b->output_fd = b->input_fd;
 
-        r = connect(b->fd, &b->sockaddr.sa, b->sockaddr_size);
+        bus_socket_setup(b);
+
+        r = connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size);
         if (r < 0) {
                 if (errno == EINPROGRESS)
                         return 1;
@@ -617,15 +722,16 @@ int bus_socket_connect(sd_bus *b) {
 }
 
 int bus_socket_exec(sd_bus *b) {
-        int s[2];
+        int s[2], r;
         pid_t pid;
 
         assert(b);
-        assert(b->fd < 0);
+        assert(b->input_fd < 0);
+        assert(b->output_fd < 0);
         assert(b->exec_path);
 
-        b->fd = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s);
-        if (b->fd < 0)
+        r = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s);
+        if (r < 0)
                 return -errno;
 
         pid = fork();
@@ -636,8 +742,9 @@ int bus_socket_exec(sd_bus *b) {
         if (pid == 0) {
                 /* Child */
 
-                close_all_fds(s, 2);
-                close_nointr_nofail(s[0]);
+                reset_all_signal_handlers();
+
+                close_all_fds(s+1, 1);
 
                 assert_se(dup3(s[1], STDIN_FILENO, 0) == STDIN_FILENO);
                 assert_se(dup3(s[1], STDOUT_FILENO, 0) == STDOUT_FILENO);
@@ -661,48 +768,39 @@ int bus_socket_exec(sd_bus *b) {
         }
 
         close_nointr_nofail(s[1]);
-        b->fd = s[0];
+        b->output_fd = b->input_fd = s[0];
+
+        bus_socket_setup(b);
 
         return bus_socket_start_auth(b);
 }
 
 int bus_socket_take_fd(sd_bus *b) {
-        int  r;
         assert(b);
 
-        r = bus_socket_setup(b);
-        if (r < 0)
-                return r;
+        bus_socket_setup(b);
 
         return bus_socket_start_auth(b);
 }
 
 int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
-        struct msghdr mh;
         struct iovec *iov;
         ssize_t k;
         size_t n;
         unsigned j;
+        int r;
 
         assert(bus);
         assert(m);
         assert(idx);
         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 
-        if (*idx >= m->size)
+        if (*idx >= BUS_MESSAGE_SIZE(m))
                 return 0;
-        zero(mh);
-
-        if (m->n_fds > 0) {
-                struct cmsghdr *control;
-                control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
 
-                mh.msg_control = control;
-                control->cmsg_level = SOL_SOCKET;
-                control->cmsg_type = SCM_RIGHTS;
-                mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
-                memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
-        }
+        r = bus_message_setup_iovec(m);
+        if (r < 0)
+                return r;
 
         n = m->n_iovec * sizeof(struct iovec);
         iov = alloca(n);
@@ -711,10 +809,33 @@ int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) {
         j = 0;
         iovec_advance(iov, &j, *idx);
 
-        mh.msg_iov = iov;
-        mh.msg_iovlen = m->n_iovec;
+        if (bus->prefer_writev)
+                k = writev(bus->output_fd, iov, m->n_iovec);
+        else {
+                struct msghdr mh;
+                zero(mh);
+
+                if (m->n_fds > 0) {
+                        struct cmsghdr *control;
+                        control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
+
+                        mh.msg_control = control;
+                        control->cmsg_level = SOL_SOCKET;
+                        control->cmsg_type = SCM_RIGHTS;
+                        mh.msg_controllen = control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds);
+                        memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds);
+                }
+
+                mh.msg_iov = iov;
+                mh.msg_iovlen = m->n_iovec;
+
+                k = sendmsg(bus->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
+                if (k < 0 && errno == ENOTSOCK) {
+                        bus->prefer_writev = true;
+                        k = writev(bus->output_fd, iov, m->n_iovec);
+                }
+        }
 
-        k = sendmsg(bus->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
         if (k < 0)
                 return errno == EAGAIN ? 0 : -errno;
 
@@ -757,10 +878,10 @@ static int bus_socket_read_message_need(sd_bus *bus, size_t *need) {
         b = ((const uint32_t*) bus->rbuffer)[3];
 
         e = ((const uint8_t*) bus->rbuffer)[0];
-        if (e == SD_BUS_LITTLE_ENDIAN) {
+        if (e == BUS_LITTLE_ENDIAN) {
                 a = le32toh(a);
                 b = le32toh(b);
-        } else if (e == SD_BUS_BIG_ENDIAN) {
+        } else if (e == BUS_BIG_ENDIAN) {
                 a = be32toh(a);
                 b = be32toh(b);
         } else
@@ -774,16 +895,19 @@ static int bus_socket_read_message_need(sd_bus *bus, size_t *need) {
         return 0;
 }
 
-static int bus_socket_make_message(sd_bus *bus, size_t size, sd_bus_message **m) {
+static int bus_socket_make_message(sd_bus *bus, size_t size) {
         sd_bus_message *t;
         void *b;
         int r;
 
         assert(bus);
-        assert(m);
         assert(bus->rbuffer_size >= size);
         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 
+        r = bus_rqueue_make_room(bus);
+        if (r < 0)
+                return r;
+
         if (bus->rbuffer_size > size) {
                 b = memdup((const uint8_t*) bus->rbuffer + size,
                            bus->rbuffer_size - size);
@@ -792,10 +916,11 @@ static int bus_socket_make_message(sd_bus *bus, size_t size, sd_bus_message **m)
         } else
                 b = NULL;
 
-        r = bus_message_from_malloc(bus->rbuffer, size,
+        r = bus_message_from_malloc(bus,
+                                    bus->rbuffer, size,
                                     bus->fds, bus->n_fds,
-                                    bus->ucred_valid ? &bus->ucred : NULL,
-                                    bus->label[0] ? bus->label : NULL,
+                                    !bus->bus_client && bus->ucred_valid ? &bus->ucred : NULL,
+                                    !bus->bus_client && bus->label[0] ? bus->label : NULL,
                                     &t);
         if (r < 0) {
                 free(b);
@@ -808,11 +933,12 @@ static int bus_socket_make_message(sd_bus *bus, size_t size, sd_bus_message **m)
         bus->fds = NULL;
         bus->n_fds = 0;
 
-        *m = t;
+        bus->rqueue[bus->rqueue_size++] = t;
+
         return 1;
 }
 
-int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
+int bus_socket_read_message(sd_bus *bus) {
         struct msghdr mh;
         struct iovec iov;
         ssize_t k;
@@ -826,9 +952,9 @@ int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
                             CMSG_SPACE(NAME_MAX)]; /*selinux label */
         } control;
         struct cmsghdr *cmsg;
+        bool handle_cmsg = false;
 
         assert(bus);
-        assert(m);
         assert(bus->state == BUS_RUNNING || bus->state == BUS_HELLO);
 
         r = bus_socket_read_message_need(bus, &need);
@@ -836,7 +962,7 @@ int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
                 return r;
 
         if (bus->rbuffer_size >= need)
-                return bus_socket_make_message(bus, need, m);
+                return bus_socket_make_message(bus, need);
 
         b = realloc(bus->rbuffer, need);
         if (!b)
@@ -848,13 +974,22 @@ int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
         iov.iov_base = (uint8_t*) bus->rbuffer + bus->rbuffer_size;
         iov.iov_len = need - bus->rbuffer_size;
 
-        zero(mh);
-        mh.msg_iov = &iov;
-        mh.msg_iovlen = 1;
-        mh.msg_control = &control;
-        mh.msg_controllen = sizeof(control);
-
-        k = recvmsg(bus->fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
+        if (bus->prefer_readv)
+                k = readv(bus->input_fd, &iov, 1);
+        else {
+                zero(mh);
+                mh.msg_iov = &iov;
+                mh.msg_iovlen = 1;
+                mh.msg_control = &control;
+                mh.msg_controllen = sizeof(control);
+
+                k = recvmsg(bus->input_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL|MSG_CMSG_CLOEXEC);
+                if (k < 0 && errno == ENOTSOCK) {
+                        bus->prefer_readv = true;
+                        k = readv(bus->input_fd, &iov, 1);
+                } else
+                        handle_cmsg = true;
+        }
         if (k < 0)
                 return errno == EAGAIN ? 0 : -errno;
         if (k == 0)
@@ -862,45 +997,53 @@ int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
 
         bus->rbuffer_size += k;
 
-        for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
-                if (cmsg->cmsg_level == SOL_SOCKET &&
-                    cmsg->cmsg_type == SCM_RIGHTS) {
-                        int n, *f;
-
-                        n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
-
-                        if (!bus->can_fds) {
-                                /* Whut? We received fds but this
-                                 * isn't actually enabled? Close them,
-                                 * and fail */
-
-                                close_many((int*) CMSG_DATA(cmsg), n);
-                                return -EIO;
+        if (handle_cmsg) {
+                for (cmsg = CMSG_FIRSTHDR(&mh); cmsg; cmsg = CMSG_NXTHDR(&mh, cmsg)) {
+                        if (cmsg->cmsg_level == SOL_SOCKET &&
+                            cmsg->cmsg_type == SCM_RIGHTS) {
+                                int n, *f;
+
+                                n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
+
+                                if (!bus->can_fds) {
+                                        /* Whut? We received fds but this
+                                         * isn't actually enabled? Close them,
+                                         * and fail */
+
+                                        close_many((int*) CMSG_DATA(cmsg), n);
+                                        return -EIO;
+                                }
+
+                                f = realloc(bus->fds, sizeof(int) + (bus->n_fds + n));
+                                if (!f) {
+                                        close_many((int*) CMSG_DATA(cmsg), n);
+                                        return -ENOMEM;
+                                }
+
+                                memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int));
+                                bus->fds = f;
+                                bus->n_fds += n;
+                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
+                                   cmsg->cmsg_type == SCM_CREDENTIALS &&
+                                   cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
+
+                                /* Ignore bogus data, which we might
+                                 * get on socketpair() sockets */
+                                if (((struct ucred*) CMSG_DATA(cmsg))->pid != 0) {
+                                        memcpy(&bus->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
+                                        bus->ucred_valid = true;
+                                }
+
+                        } else if (cmsg->cmsg_level == SOL_SOCKET &&
+                                   cmsg->cmsg_type == SCM_SECURITY) {
+
+                                size_t l;
+                                l = cmsg->cmsg_len - CMSG_LEN(0);
+                                if (l > 0) {
+                                        memcpy(&bus->label, CMSG_DATA(cmsg), l);
+                                        bus->label[l] = 0;
+                                }
                         }
-
-                        f = realloc(bus->fds, sizeof(int) + (bus->n_fds + n));
-                        if (!f) {
-                                close_many((int*) CMSG_DATA(cmsg), n);
-                                return -ENOMEM;
-                        }
-
-                        memcpy(f + bus->n_fds, CMSG_DATA(cmsg), n * sizeof(int));
-                        bus->fds = f;
-                        bus->n_fds += n;
-                } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                    cmsg->cmsg_type == SCM_CREDENTIALS &&
-                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred))) {
-
-                        memcpy(&bus->ucred, CMSG_DATA(cmsg), sizeof(struct ucred));
-                        bus->ucred_valid = true;
-
-                } else if (cmsg->cmsg_level == SOL_SOCKET &&
-                         cmsg->cmsg_type == SCM_SECURITY) {
-
-                        size_t l;
-                        l = cmsg->cmsg_len - CMSG_LEN(0);
-                        memcpy(&bus->label, CMSG_DATA(cmsg), l);
-                        bus->label[l] = 0;
                 }
         }
 
@@ -909,7 +1052,7 @@ int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
                 return r;
 
         if (bus->rbuffer_size >= need)
-                return bus_socket_make_message(bus, need, m);
+                return bus_socket_make_message(bus, need);
 
         return 1;
 }
@@ -917,16 +1060,14 @@ int bus_socket_read_message(sd_bus *bus, sd_bus_message **m) {
 int bus_socket_process_opening(sd_bus *b) {
         int error = 0;
         socklen_t slen = sizeof(error);
-        struct pollfd p;
+        struct pollfd p = {
+                .fd = b->output_fd,
+                .events = POLLOUT,
+        };
         int r;
 
-        assert(b);
         assert(b->state == BUS_OPENING);
 
-        zero(p);
-        p.fd = b->fd;
-        p.events = POLLOUT;
-
         r = poll(&p, 1, 0);
         if (r < 0)
                 return -errno;
@@ -934,7 +1075,7 @@ int bus_socket_process_opening(sd_bus *b) {
         if (!(p.revents & (POLLOUT|POLLERR|POLLHUP)))
                 return 0;
 
-        r = getsockopt(b->fd, SOL_SOCKET, SO_ERROR, &error, &slen);
+        r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen);
         if (r < 0)
                 b->last_connect_error = errno;
         else if (error != 0)