chiark / gitweb /
bus: implement support for FD passing
authorLennart Poettering <lennart@poettering.net>
Sun, 24 Mar 2013 21:02:05 +0000 (22:02 +0100)
committerLennart Poettering <lennart@poettering.net>
Mon, 25 Mar 2013 01:33:34 +0000 (02:33 +0100)
src/libsystemd-bus/bus-internal.h
src/libsystemd-bus/bus-message.c
src/libsystemd-bus/bus-message.h
src/libsystemd-bus/sd-bus.c
src/libsystemd-bus/sd-bus.h
src/libsystemd-bus/test-bus-chat.c
src/libsystemd-bus/test-bus-marshal.c
src/shared/util.c

index 82f6084..cdd7b21 100644 (file)
@@ -114,6 +114,9 @@ struct sd_bus {
 
         struct ucred ucred;
         char label[NAME_MAX];
+
+        int *fds;
+        unsigned n_fds;
 };
 
 static inline void bus_unrefp(sd_bus **b) {
@@ -137,6 +140,8 @@ static inline void bus_unrefp(sd_bus **b) {
  * bytes */
 #define BUS_ARRAY_MAX_SIZE 67108864
 
+#define BUS_FDS_MAX 1024
+
 bool object_path_is_valid(const char *p);
 bool interface_name_is_valid(const char *p);
 bool service_name_is_valid(const char *p);
index 01213e3..22e6404 100644 (file)
@@ -20,6 +20,7 @@
 ***/
 
 #include <errno.h>
+#include <fcntl.h>
 
 #include "util.h"
 #include "utf8.h"
@@ -50,8 +51,6 @@ static void reset_containers(sd_bus_message *m) {
 }
 
 static void message_free(sd_bus_message *m) {
-        unsigned i;
-
         assert(m);
 
         if (m->free_header)
@@ -63,8 +62,10 @@ static void message_free(sd_bus_message *m) {
         if (m->free_body)
                 free(m->body);
 
-        for (i = 0; i < m->n_fds; i++)
-                close_nointr_nofail(m->fds[i]);
+        if (m->free_fds) {
+                close_many(m->fds, m->n_fds);
+                free(m->fds);
+        }
 
         reset_containers(m);
         free(m->root_container.signature);
@@ -227,7 +228,9 @@ static int message_append_field_uint32(sd_bus_message *m, uint8_t h, uint32_t x)
 int bus_message_from_malloc(
                 void *buffer,
                 size_t length,
-                struct ucred *ucred,
+                int *fds,
+                unsigned n_fds,
+                const struct ucred *ucred,
                 const char *label,
                 sd_bus_message **ret) {
 
@@ -237,6 +240,7 @@ int bus_message_from_malloc(
         int r;
 
         assert(buffer || length <= 0);
+        assert(fds || n_fds <= 0);
         assert(ret);
 
         if (length < sizeof(struct bus_header))
@@ -276,11 +280,12 @@ int bus_message_from_malloc(
                 return -ENOMEM;
 
         m->n_ref = 1;
+        m->sealed = true;
         m->header = h;
-        m->free_header = true;
         m->fields = (uint8_t*) buffer + sizeof(struct bus_header);
         m->body = (uint8_t*) buffer + sizeof(struct bus_header) + ALIGN_TO(fs, 8);
-        m->sealed = true;
+        m->fds = fds;
+        m->n_fds = n_fds;
 
         if (ucred) {
                 m->uid = ucred->uid;
@@ -299,13 +304,19 @@ int bus_message_from_malloc(
         m->iovec[0].iov_len = length;
 
         r = message_parse_fields(m);
-        if (r < 0) {
-                message_free(m);
-                return r;
-        }
+        if (r < 0)
+                goto fail;
+
+        /* We take possession of the memory and fds now */
+        m->free_header = true;
+        m->free_fds = true;
 
         *ret = m;
         return 0;
+
+fail:
+        message_free(m);
+        return r;
 }
 
 static sd_bus_message *message_new(sd_bus *bus, uint8_t type) {
@@ -320,6 +331,7 @@ static sd_bus_message *message_new(sd_bus *bus, uint8_t type) {
         m->header->endian = SD_BUS_NATIVE_ENDIAN;
         m->header->type = type;
         m->header->version = bus ? bus->message_version : 1;
+        m->allow_fds = !bus || bus->can_fds;
 
         return m;
 }
@@ -770,9 +782,14 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
         uint32_t k;
         void *a;
         char *e = NULL;
+        int fd = -1;
+        uint32_t fdi;
+        int r;
 
         if (!m)
                 return -EINVAL;
+        if (!p)
+                return -EINVAL;
         if (m->sealed)
                 return -EPERM;
         if (!bus_type_is_basic(type))
@@ -800,26 +817,12 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
         case SD_BUS_TYPE_STRING:
         case SD_BUS_TYPE_OBJECT_PATH:
 
-                if (!p) {
-                        if (e)
-                                c->signature[c->index] = 0;
-
-                        return -EINVAL;
-                }
-
                 align = 4;
                 sz = 4 + strlen(p) + 1;
                 break;
 
         case SD_BUS_TYPE_SIGNATURE:
 
-                if (!p) {
-                        if (e)
-                                c->signature[c->index] = 0;
-
-                        return -EINVAL;
-                }
-
                 align = 1;
                 sz = 1 + strlen(p) + 1;
                 break;
@@ -833,6 +836,41 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
                 p = &k;
                 break;
 
+        case SD_BUS_TYPE_UNIX_FD: {
+                int z, *f;
+
+                if (!m->allow_fds) {
+                        r = -ENOTSUP;
+                        goto fail;
+                }
+
+                align = sz = 4;
+
+                z = *(int*) p;
+                if (z < 0) {
+                        r = -EINVAL;
+                        goto fail;
+                }
+
+                fd = fcntl(z, F_DUPFD_CLOEXEC, 3);
+                if (fd < 0) {
+                        r = -errno;
+                        goto fail;
+                }
+
+                f = realloc(m->fds, sizeof(int) * (m->n_fds + 1));
+                if (!f) {
+                        r = -ENOMEM;
+                        goto fail;
+                }
+
+                fdi = m->n_fds;
+                f[fdi] = fd;
+                m->fds = f;
+                m->free_fds = true;
+                break;
+        }
+
         default:
                 align = bus_type_get_alignment(type);
                 sz = bus_type_get_size(type);
@@ -844,11 +882,8 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
 
         a = message_extend_body(m, align, sz);
         if (!a) {
-                /* Truncate extended signature again */
-                if (e)
-                        c->signature[c->index] = 0;
-
-                return -ENOMEM;
+                r = -ENOMEM;
+                goto fail;
         }
 
         if (type == SD_BUS_TYPE_STRING || type == SD_BUS_TYPE_OBJECT_PATH) {
@@ -864,6 +899,13 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
 
                 if (stored)
                         *stored = (const uint8_t*) a + 1;
+        } else if (type == SD_BUS_TYPE_UNIX_FD) {
+                *(uint32_t*) a = fdi;
+
+                if (stored)
+                        *stored = a;
+
+                m->n_fds ++;
 
         } else {
                 memcpy(a, p, sz);
@@ -876,6 +918,16 @@ int message_append_basic(sd_bus_message *m, char type, const void *p, const void
                 c->index++;
 
         return 0;
+
+fail:
+        /* Truncate extended signature again */
+        if (e)
+                c->signature[c->index] = 0;
+
+        if (fd >= 0)
+                close_nointr_nofail(fd);
+
+        return r;
 }
 
 int sd_bus_message_append_basic(sd_bus_message *m, char type, const void *p) {
@@ -1464,6 +1516,8 @@ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
                 return -EPERM;
         if (!bus_type_is_basic(type))
                 return -EINVAL;
+        if (!p)
+                return -EINVAL;
 
         c = message_get_container(m);
 
@@ -1530,12 +1584,13 @@ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
         }
 
         default: {
-                size_t sz, align;
+                size_t sz, align, rindex;
 
                 align = bus_type_get_alignment(type);
                 sz = bus_type_get_size(type);
 
-                r = message_peek_body(m, &m->rindex, align, sz, &q);
+                rindex = m->rindex;
+                r = message_peek_body(m, &rindex, align, sz, &q);
                 if (r <= 0)
                         return r;
 
@@ -1565,10 +1620,28 @@ int sd_bus_message_read_basic(sd_bus_message *m, char type, void *p) {
                         *(uint64_t*) p = BUS_MESSAGE_BSWAP64(m, *(uint64_t*) q);
                         break;
 
+                case SD_BUS_TYPE_UNIX_FD: {
+                        int copy;
+                        uint32_t j;
+
+                        j = BUS_MESSAGE_BSWAP32(m, *(uint32_t*) q);
+                        if (j >= m->n_fds)
+                                return -EBADMSG;
+
+                        copy = fcntl(m->fds[j], F_DUPFD_CLOEXEC, 3);
+                        if (copy < 0)
+                                return -errno;
+
+                        *(int*) p = copy;
+                        break;
+                }
+
                 default:
                         assert_not_reached("Unknown basic type...");
                 }
 
+                        m->rindex = rindex;
+
                 break;
         }
         }
@@ -2028,7 +2101,8 @@ static int message_read_ap(sd_bus_message *m, const char *types, va_list ap) {
                 case SD_BUS_TYPE_DOUBLE:
                 case SD_BUS_TYPE_STRING:
                 case SD_BUS_TYPE_OBJECT_PATH:
-                case SD_BUS_TYPE_SIGNATURE: {
+                case SD_BUS_TYPE_SIGNATURE:
+                case SD_BUS_TYPE_UNIX_FD: {
                         void *p;
 
                         p = va_arg(ap, void*);
@@ -2399,6 +2473,7 @@ static int message_skip_fields(
 static int message_parse_fields(sd_bus_message *m) {
         size_t ri;
         int r;
+        uint32_t unix_fds = 0;
 
         assert(m);
 
@@ -2419,6 +2494,10 @@ static int message_parse_fields(sd_bus_message *m) {
                         return -EBADMSG;
 
                 case SD_BUS_MESSAGE_HEADER_PATH:
+
+                        if (m->path)
+                                return -EBADMSG;
+
                         if (!streq(signature, "o"))
                                 return -EBADMSG;
 
@@ -2426,6 +2505,10 @@ static int message_parse_fields(sd_bus_message *m) {
                         break;
 
                 case SD_BUS_MESSAGE_HEADER_INTERFACE:
+
+                        if (m->interface)
+                                return -EBADMSG;
+
                         if (!streq(signature, "s"))
                                 return -EBADMSG;
 
@@ -2433,6 +2516,10 @@ static int message_parse_fields(sd_bus_message *m) {
                         break;
 
                 case SD_BUS_MESSAGE_HEADER_MEMBER:
+
+                        if (m->member)
+                                return -EBADMSG;
+
                         if (!streq(signature, "s"))
                                 return -EBADMSG;
 
@@ -2440,6 +2527,10 @@ static int message_parse_fields(sd_bus_message *m) {
                         break;
 
                 case SD_BUS_MESSAGE_HEADER_ERROR_NAME:
+
+                        if (m->error.name)
+                                return -EBADMSG;
+
                         if (!streq(signature, "s"))
                                 return -EBADMSG;
 
@@ -2447,6 +2538,10 @@ static int message_parse_fields(sd_bus_message *m) {
                         break;
 
                 case SD_BUS_MESSAGE_HEADER_DESTINATION:
+
+                        if (m->destination)
+                                return -EBADMSG;
+
                         if (!streq(signature, "s"))
                                 return -EBADMSG;
 
@@ -2454,6 +2549,10 @@ static int message_parse_fields(sd_bus_message *m) {
                         break;
 
                 case SD_BUS_MESSAGE_HEADER_SENDER:
+
+                        if (m->sender)
+                                return -EBADMSG;
+
                         if (!streq(signature, "s"))
                                 return -EBADMSG;
 
@@ -2465,6 +2564,9 @@ static int message_parse_fields(sd_bus_message *m) {
                         const char *s;
                         char *c;
 
+                        if (m->root_container.signature)
+                                return -EBADMSG;
+
                         if (!streq(signature, "g"))
                                 return -EBADMSG;
 
@@ -2482,6 +2584,9 @@ static int message_parse_fields(sd_bus_message *m) {
                 }
 
                 case SD_BUS_MESSAGE_HEADER_REPLY_SERIAL:
+                        if (m->reply_serial != 0)
+                                return -EBADMSG;
+
                         if (!streq(signature, "u"))
                                 return -EBADMSG;
 
@@ -2494,6 +2599,22 @@ static int message_parse_fields(sd_bus_message *m) {
 
                         break;
 
+                case SD_BUS_MESSAGE_HEADER_UNIX_FDS:
+                        if (unix_fds != 0)
+                                return -EBADMSG;
+
+                        if (!streq(signature, "u"))
+                                return -EBADMSG;
+
+                        r = message_peek_field_uint32(m, &ri, &unix_fds);
+                        if (r < 0)
+                                return -EBADMSG;
+
+                        if (unix_fds == 0)
+                                return -EBADMSG;
+
+                        break;
+
                 default:
                         r = message_skip_fields(m, &ri, (uint32_t) -1, (const char **) &signature);
                 }
@@ -2502,6 +2623,9 @@ static int message_parse_fields(sd_bus_message *m) {
                         return r;
         }
 
+        if (m->n_fds != unix_fds)
+                return -EBADMSG;
+
         if (isempty(m->root_container.signature) != (BUS_MESSAGE_BODY_SIZE(m) == 0))
                 return -EBADMSG;
 
index 1a6c614..3289b37 100644 (file)
@@ -67,12 +67,14 @@ struct sd_bus_message {
         pid_t tid;
 
         bool sealed:1;
+        bool dont_send:1;
+        bool allow_fds:1;
         bool uid_valid:1;
         bool gid_valid:1;
         bool free_header:1;
         bool free_fields:1;
         bool free_body:1;
-        bool dont_send:1;
+        bool free_fds:1;
 
         struct bus_header *header;
         void *fields;
@@ -130,5 +132,13 @@ static inline void bus_message_unrefp(sd_bus_message **m) {
 int bus_message_seal(sd_bus_message *m, uint64_t serial);
 int bus_message_dump(sd_bus_message *m);
 int bus_message_get_blob(sd_bus_message *m, void **buffer, size_t *sz);
-int bus_message_from_malloc(void *buffer, size_t length, struct ucred *ucred, const char *label, sd_bus_message **ret);
 int bus_message_read_strv_extend(sd_bus_message *m, char ***l);
+
+int bus_message_from_malloc(
+                void *buffer,
+                size_t length,
+                int *fds,
+                unsigned n_fds,
+                const struct ucred *ucred,
+                const char *label,
+                sd_bus_message **ret);
index 0acc6b2..72c790b 100644 (file)
@@ -53,6 +53,9 @@ static void bus_free(sd_bus *b) {
         free(b->auth_uid);
         free(b->address);
 
+        close_many(b->fds, b->n_fds);
+        free(b->fds);
+
         for (i = 0; i < b->rqueue_size; i++)
                 sd_bus_message_unref(b->rqueue[i]);
         free(b->rqueue);
@@ -889,6 +892,18 @@ static int message_write(sd_bus *bus, sd_bus_message *m, size_t *idx) {
 
         if (*idx >= m->size)
                 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);
+        }
 
         n = m->n_iovec * sizeof(struct iovec);
         iov = alloca(n);
@@ -897,7 +912,6 @@ static int message_write(sd_bus *bus, sd_bus_message *m, size_t *idx) {
         j = 0;
         iovec_advance(iov, &j, *idx);
 
-        zero(mh);
         mh.msg_iov = iov;
         mh.msg_iovlen = m->n_iovec;
 
@@ -963,7 +977,7 @@ static int message_read_need(sd_bus *bus, size_t *need) {
 
 static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
         sd_bus_message *t;
-        void *b = NULL;
+        void *b;
         int r;
 
         assert(bus);
@@ -976,11 +990,14 @@ static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
                            bus->rbuffer_size - size);
                 if (!b)
                         return -ENOMEM;
-        }
+        } else
+                b = NULL;
 
         r = bus_message_from_malloc(bus->rbuffer, size,
+                                    bus->fds, bus->n_fds,
                                     bus->ucred_valid ? &bus->ucred : NULL,
-                                    bus->label[0] ? bus->label : NULL, &t);
+                                    bus->label[0] ? bus->label : NULL,
+                                    &t);
         if (r < 0) {
                 free(b);
                 return r;
@@ -989,6 +1006,9 @@ static int message_make(sd_bus *bus, size_t size, sd_bus_message **m) {
         bus->rbuffer = b;
         bus->rbuffer_size -= size;
 
+        bus->fds = NULL;
+        bus->n_fds = 0;
+
         *m = t;
         return 1;
 }
@@ -1002,7 +1022,8 @@ static int message_read(sd_bus *bus, sd_bus_message **m) {
         void *b;
         union {
                 struct cmsghdr cmsghdr;
-                uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) +
+                uint8_t buf[CMSG_SPACE(sizeof(int) * BUS_FDS_MAX) +
+                            CMSG_SPACE(sizeof(struct ucred)) +
                             CMSG_SPACE(NAME_MAX)]; /*selinux label */
         } control;
         struct cmsghdr *cmsg;
@@ -1039,11 +1060,24 @@ static int message_read(sd_bus *bus, sd_bus_message **m) {
                 return errno == EAGAIN ? 0 : -errno;
 
         bus->rbuffer_size += k;
-        bus->ucred_valid = false;
-        bus->label[0] = 0;
 
         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);
+
+                        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))) {
 
@@ -1157,6 +1191,8 @@ int sd_bus_send(sd_bus *bus, sd_bus_message *m, uint64_t *serial) {
                 return -ENOTCONN;
         if (!m)
                 return -EINVAL;
+        if (m->n_fds > 0 && !bus->can_fds)
+                return -ENOTSUP;
 
         /* If the serial number isn't kept, then we know that no reply
          * is expected */
index b82caec..bffce10 100644 (file)
@@ -28,7 +28,6 @@
 #include "sd-bus-protocol.h"
 
 /* TODO:
- * - make unix fd passing work
  * - implicitly add stub introspection calls
  * - implement unix exec protocol
  * - server side
index 92fdd13..bdcca18 100644 (file)
@@ -23,6 +23,7 @@
 #include <stdlib.h>
 #include <pthread.h>
 #include <unistd.h>
+#include <fcntl.h>
 
 #include "log.h"
 #include "util.h"
@@ -202,6 +203,31 @@ static int server(sd_bus *bus) {
                         }
 
                         sleep(1);
+
+                } else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "FileDescriptor")) {
+                        int fd;
+                        static const char x = 'X';
+
+                        r = sd_bus_message_read(m, "h", &fd);
+                        if (r < 0) {
+                                log_error("Failed to get parameter: %s", strerror(-r));
+                                goto fail;
+                        }
+
+                        if (write(fd, &x, 1) < 0) {
+                                log_error("Failed to write to fd: %m");
+                                close_nointr_nofail(fd);
+                                goto fail;
+                        }
+
+                        close_nointr_nofail(fd);
+
+                        r = sd_bus_message_new_method_return(bus, m, &reply);
+                        if (r < 0) {
+                                log_error("Failed to allocate return: %s", strerror(-r));
+                                goto fail;
+                        }
+
                 } else if (sd_bus_message_is_method_call(m, NULL, NULL)) {
                         const sd_bus_error e = SD_BUS_ERROR_INIT_CONST("org.freedesktop.DBus.Error.UnknownMethod", "Unknown method.");
 
@@ -242,6 +268,8 @@ static void* client1(void*p) {
         sd_bus_error error = SD_BUS_ERROR_INIT;
         const char *hello;
         int r;
+        int pp[2] = { -1, -1 };
+        char x;
 
         r = sd_bus_open_user(&bus);
         if (r < 0) {
@@ -281,6 +309,46 @@ static void* client1(void*p) {
 
         assert(streq(hello, "hello"));
 
+        if (pipe2(pp, O_CLOEXEC|O_NONBLOCK) < 0) {
+                log_error("Failed to allocate pipe: %m");
+                r = -errno;
+                goto finish;
+        }
+
+        sd_bus_message_unref(m);
+        m = NULL;
+        r = sd_bus_message_new_method_call(
+                        bus,
+                        "org.freedesktop.systemd.test",
+                        "/",
+                        "org.freedesktop.systemd.test",
+                        "FileDescriptor",
+                        &m);
+        if (r < 0) {
+                log_error("Failed to allocate method call: %s", strerror(-r));
+                goto finish;
+        }
+
+        r = sd_bus_message_append(m, "h", pp[1]);
+        if (r < 0) {
+                log_error("Failed to append string: %s", strerror(-r));
+                goto finish;
+        }
+
+        sd_bus_message_unref(reply);
+        reply = NULL;
+        r = sd_bus_send_with_reply_and_block(bus, m, 0, &error, &reply);
+        if (r < 0) {
+                log_error("Failed to issue method call: %s", bus_error_message(&error, -r));
+                goto finish;
+        }
+
+        errno = 0;
+        if (read(pp[0], &x, 1) <= 0) {
+                log_error("Failed to read from pipe: %s", errno ? strerror(errno) : "early read");
+                goto finish;
+        }
+
         r = 0;
 
 finish:
@@ -305,6 +373,9 @@ finish:
         }
 
         sd_bus_error_free(&error);
+
+        close_pipe(pp);
+
         return INT_TO_PTR(r);
 }
 
index 32bf44f..e7d0cc7 100644 (file)
@@ -121,7 +121,7 @@ int main(int argc, char *argv[]) {
 
         m = sd_bus_message_unref(m);
 
-        r = bus_message_from_malloc(buffer, sz, NULL, NULL, &m);
+        r = bus_message_from_malloc(buffer, sz, NULL, 0, NULL, NULL, &m);
         assert_se(r >= 0);
 
         bus_message_dump(m);
index 260c100..03d6f00 100644 (file)
@@ -219,6 +219,8 @@ void close_nointr_nofail(int fd) {
 void close_many(const int fds[], unsigned n_fd) {
         unsigned i;
 
+        assert(fds || n_fd <= 0);
+
         for (i = 0; i < n_fd; i++)
                 close_nointr_nofail(fds[i]);
 }