lib: Use msghdr in unix_msg

Signed-off-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Ralph Boehme <slow@samba.org>

diff --git a/source3/lib/unix_msg/unix_msg.c b/source3/lib/unix_msg/unix_msg.c
index d85cde9fb3ffe7664b1f4cbd9dae4e7a6c490577..8d4960f6bcbaecdf82b580d733093e45d9264afd 100644 (file)
--- a/source3/lib/unix_msg/unix_msg.c
+++ b/source3/lib/unix_msg/unix_msg.c
@@ -24,6 +24,7 @@
 #include "dlinklist.h"
 #include "pthreadpool/pthreadpool.h"
 #include "lib/iov_buf.h"
+#include "lib/msghdr.h"
 #include <fcntl.h>
 
 /*
@@ -43,8 +44,6 @@ struct unix_dgram_msg {
        int sock;
        ssize_t sent;
        int sys_errno;
-       struct msghdr msg;
-       struct iovec iov;
 };
 
 struct unix_dgram_send_queue {
@@ -162,6 +161,22 @@ static void extract_fd_array_from_msghdr(struct msghdr *msg, int **fds,
 #endif
 }
 
+static size_t unix_dgram_msg_size(void)
+{
+       size_t msgsize = sizeof(struct unix_dgram_msg);
+       msgsize = (msgsize + 15) & ~15; /* align to 16 */
+       return msgsize;
+}
+
+static struct msghdr_buf *unix_dgram_msghdr(struct unix_dgram_msg *msg)
+{
+       /*
+        * Not portable in C99, but "msg" is aligned and so is
+        * unix_dgram_msg_size()
+        */
+       return (struct msghdr_buf *)(((char *)msg) + unix_dgram_msg_size());
+}
+
 static void close_fd_array(int *fds, size_t num_fds)
 {
        size_t i;
@@ -176,8 +191,10 @@ static void close_fd_array(int *fds, size_t num_fds)
        }
 }
 
-static void close_fd_array_cmsg(struct msghdr *msg)
+static void close_fd_array_dgram_msg(struct unix_dgram_msg *dmsg)
 {
+       struct msghdr_buf *hdr = unix_dgram_msghdr(dmsg);
+       struct msghdr *msg = msghdr_buf_msghdr(hdr);
        int *fds = NULL;
        size_t num_fds = 0;
 
@@ -448,7 +465,7 @@ static void unix_dgram_send_queue_free(struct unix_dgram_send_queue *q)
                struct unix_dgram_msg *msg;
                msg = q->msgs;
                DLIST_REMOVE(q->msgs, msg);
-               close_fd_array_cmsg(&msg->msg);
+               close_fd_array_dgram_msg(msg);
                free(msg);
        }
        close(q->sock);
@@ -470,55 +487,17 @@ static struct unix_dgram_send_queue *find_send_queue(
 }
 
 static int queue_msg(struct unix_dgram_send_queue *q,
-                    const struct iovec *iov, int iovlen,
+                    const struct iovec *iov, int iovcnt,
                     const int *fds, size_t num_fds)
 {
        struct unix_dgram_msg *msg;
-       ssize_t data_len;
-       uint8_t *data_buf;
-       size_t msglen = sizeof(struct unix_dgram_msg);
-       int i;
-       size_t tmp;
-       int ret = -1;
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       size_t fds_size = sizeof(int) * MIN(num_fds, INT8_MAX);
+       struct msghdr_buf *hdr;
+       size_t msglen, needed;
+       ssize_t msghdrlen;
        int fds_copy[MIN(num_fds, INT8_MAX)];
-       size_t cmsg_len = CMSG_LEN(fds_size);
-       size_t cmsg_space = CMSG_SPACE(fds_size);
-       char *cmsg_buf;
-
-       /*
-        * Note: No need to check for overflow here,
-        * since cmsg will store <= INT8_MAX fds.
-        */
-       msglen += cmsg_space;
-
-#endif /*  HAVE_STRUCT_MSGHDR_MSG_CONTROL */
-
-       if (num_fds > INT8_MAX) {
-               return EINVAL;
-       }
-
-#ifndef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       if (num_fds > 0) {
-               return ENOSYS;
-       }
-#endif
-
-       data_len = iov_buflen(iov, iovlen);
-       if (data_len == -1) {
-               return EINVAL;
-       }
-
-       tmp = msglen + data_len;
-       if ((tmp < msglen) || (tmp < data_len)) {
-               /* overflow */
-               return EINVAL;
-       }
-       msglen = tmp;
+       int i, ret;
 
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       for (i = 0; i < num_fds; i++) {
+       for (i=0; i<num_fds; i++) {
                fds_copy[i] = -1;
        }
 
@@ -529,67 +508,37 @@ static int queue_msg(struct unix_dgram_send_queue *q,
                        goto fail;
                }
        }
-#endif
 
-       msg = malloc(msglen);
-       if (msg == NULL) {
-               ret = ENOMEM;
+       msglen = unix_dgram_msg_size();
+
+       msghdrlen = msghdr_copy(NULL, 0, NULL, 0, iov, iovcnt,
+                               fds_copy, num_fds);
+       if (msghdrlen == -1) {
+               ret = EMSGSIZE;
                goto fail;
        }
 
-       msg->sock = q->sock;
-
-       data_buf = (uint8_t *)(msg + 1);
-
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       if (num_fds > 0) {
-               cmsg_buf = (char *)data_buf;
-               memset(cmsg_buf, 0, cmsg_space);
-               data_buf += cmsg_space;
-       } else {
-               cmsg_buf = NULL;
-               cmsg_space = 0;
+       needed = msglen + msghdrlen;
+       if (needed < msglen) {
+               ret = EMSGSIZE;
+               goto fail;
        }
-#endif
-
-       msg->iov = (struct iovec) {
-               .iov_base = (void *)data_buf,
-               .iov_len = data_len,
-       };
-
-       msg->msg = (struct msghdr) {
-               .msg_iov = &msg->iov,
-               .msg_iovlen = 1,
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-               .msg_control = cmsg_buf,
-               .msg_controllen = cmsg_space,
-#endif
-       };
-
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       if (num_fds > 0) {
-               struct cmsghdr *cmsg;
-               void *fdptr;
 
-               cmsg = CMSG_FIRSTHDR(&msg->msg);
-               cmsg->cmsg_level = SOL_SOCKET;
-               cmsg->cmsg_type = SCM_RIGHTS;
-               cmsg->cmsg_len = cmsg_len;
-               fdptr = CMSG_DATA(cmsg);
-               memcpy(fdptr, fds_copy, fds_size);
-               msg->msg.msg_controllen = cmsg->cmsg_len;
+       msg = malloc(needed);
+       if (msg == NULL) {
+               ret = ENOMEM;
+               goto fail;
        }
-#endif /*  HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+       hdr = unix_dgram_msghdr(msg);
 
-       iov_buf(iov, iovlen, data_buf, data_len);
+       msg->sock = q->sock;
+       msghdr_copy(hdr, msghdrlen, NULL, 0, iov, iovcnt,
+                   fds_copy, num_fds);
 
        DLIST_ADD_END(q->msgs, msg, struct unix_dgram_msg);
        return 0;
-
 fail:
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
        close_fd_array(fds_copy, num_fds);
-#endif
        return ret;
 }
 
@@ -598,7 +547,9 @@ static void unix_dgram_send_job(void *private_data)
        struct unix_dgram_msg *dmsg = private_data;
 
        do {
-               dmsg->sent = sendmsg(dmsg->sock, &dmsg->msg, 0);
+               struct msghdr_buf *hdr = unix_dgram_msghdr(dmsg);
+               struct msghdr *msg = msghdr_buf_msghdr(hdr);
+               dmsg->sent = sendmsg(dmsg->sock, msg, 0);
        } while ((dmsg->sent == -1) && (errno == EINTR));
 
        if (dmsg->sent == -1) {
@@ -632,7 +583,7 @@ static void unix_dgram_job_finished(struct poll_watch *w, int fd, short events,
 
        msg = q->msgs;
        DLIST_REMOVE(q->msgs, msg);
-       close_fd_array_cmsg(&msg->msg);
+       close_fd_array_dgram_msg(msg);
        free(msg);
 
        if (q->msgs != NULL) {
@@ -653,13 +604,7 @@ static int unix_dgram_send(struct unix_dgram_ctx *ctx,
 {
        struct unix_dgram_send_queue *q;
        struct msghdr msg;
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       struct cmsghdr *cmsg;
-       size_t fds_size = sizeof(int) * num_fds;
-       size_t cmsg_len = CMSG_LEN(fds_size);
-       size_t cmsg_space = CMSG_SPACE(fds_size);
-       char cmsg_buf[cmsg_space];
-#endif /* HAVE_STRUCT_MSGHDR_MSG_CONTROL */
+       ssize_t fdlen;
        int ret;
        int i;
 
@@ -714,25 +659,19 @@ static int unix_dgram_send(struct unix_dgram_ctx *ctx,
                .msg_iov = discard_const_p(struct iovec, iov),
                .msg_iovlen = iovlen
        };
-#ifdef HAVE_STRUCT_MSGHDR_MSG_CONTROL
-       if (num_fds > 0) {
-               void *fdptr;
 
-               memset(cmsg_buf, 0, cmsg_space);
+       fdlen = msghdr_prep_fds(&msg, NULL, 0, fds, num_fds);
+       if (fdlen == -1) {
+               return EINVAL;
+       }
+
+       {
+               uint8_t buf[fdlen];
+               msghdr_prep_fds(&msg, buf, 0, fds, num_fds);
 
-               msg.msg_control = cmsg_buf;
-               msg.msg_controllen = cmsg_space;
-               cmsg = CMSG_FIRSTHDR(&msg);
-               cmsg->cmsg_level = SOL_SOCKET;
-               cmsg->cmsg_type = SCM_RIGHTS;
-               cmsg->cmsg_len = cmsg_len;
-               fdptr = CMSG_DATA(cmsg);
-               memcpy(fdptr, fds, fds_size);
-               msg.msg_controllen = cmsg->cmsg_len;
+               ret = sendmsg(ctx->sock, &msg, 0);
        }
-#endif /*  HAVE_STRUCT_MSGHDR_MSG_CONTROL */
 
-       ret = sendmsg(ctx->sock, &msg, 0);
        if (ret >= 0) {
                return 0;
        }

diff --git a/source3/lib/unix_msg/wscript_build b/source3/lib/unix_msg/wscript_build
index e638ea677d92f117bc94b98b5fed009da5da6fd5..b16d52cc716be927f3d4f34f63ff655a9c7f8c58 100644 (file)
--- a/source3/lib/unix_msg/wscript_build
+++ b/source3/lib/unix_msg/wscript_build
@@ -2,7 +2,7 @@
 
 bld.SAMBA3_SUBSYSTEM('UNIX_MSG',
                      source='unix_msg.c',
-                    deps='replace PTHREADPOOL iov_buf')
+                    deps='replace PTHREADPOOL iov_buf msghdr')
 
 bld.SAMBA3_BINARY('unix_msg_test',
                   source='tests.c',