s3: add Darwin sendfile support and merge with the FreeBSD code

This is based on the adpotion of the FreeBSD sendfile code that was done by
James Peach for Darwin.

Autobuild-User(master): Björn Jacke <bj@sernet.de>
Autobuild-Date(master): Thu Jul 26 17:19:09 CEST 2012 on sn-devel-104

diff --git a/source3/lib/sendfile.c b/source3/lib/sendfile.c
index 196ef6889b910f37fe6c06984d0ba846ba31600b..d5fd5a6ab5903f5ea708e302eb123e8495ba0524 100644 (file)
--- a/source3/lib/sendfile.c
+++ b/source3/lib/sendfile.c
@@ -248,80 +248,74 @@ ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset
        return count + hdr_len;
 }
 
-#elif defined(FREEBSD_SENDFILE_API)
+#elif defined(FREEBSD_SENDFILE_API) || defined(DARWIN_SENDFILE_API)
 
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
 
-ssize_t sys_sendfile(int tofd, int fromfd, const DATA_BLOB *header, off_t offset, size_t count)
+ssize_t sys_sendfile(int tofd, int fromfd,
+           const DATA_BLOB *header, off_t offset, size_t count)
 {
-       size_t total=0;
-       struct sf_hdtr hdr;
-       struct iovec hdtrl;
-       size_t hdr_len = 0;
+       struct sf_hdtr  sf_header = {0};
+       struct iovec    io_header = {0};
 
-       hdr.headers = &hdtrl;
-       hdr.hdr_cnt = 1;
-       hdr.trailers = NULL;
-       hdr.trl_cnt = 0;
+       off_t   nwritten;
+       int     ret;
 
-       /* Set up the header iovec. */
        if (header) {
-               hdtrl.iov_base = (void *)header->data;
-               hdtrl.iov_len = hdr_len = header->length;
-       } else {
-               hdtrl.iov_base = NULL;
-               hdtrl.iov_len = 0;
+               sf_header.headers = &io_header;
+               sf_header.hdr_cnt = 1;
+               io_header.iov_base = header->data;
+               io_header.iov_len = header->length;
+               sf_header.trailers = NULL;
+               sf_header.trl_cnt = 0;
        }
 
-       total = count;
-       while (total + hdtrl.iov_len) {
-               off_t nwritten;
-               int ret;
-
-               /*
-                * FreeBSD sendfile returns 0 on success, -1 on error.
-                * Remember, the tofd and fromfd are reversed..... :-).
-                * nwritten includes the header data sent.
-                */
+       while (count != 0) {
 
-               do {
-                       ret = sendfile(fromfd, tofd, offset, total, &hdr, &nwritten, 0);
+               nwritten = count;
+#if defined(DARWIN_SENDFILE_API)
+               /* Darwin recycles nwritten as a value-result parameter, apart from that this
+                  sendfile implementation is quite the same as the FreeBSD one */
+               ret = sendfile(fromfd, tofd, offset, &nwritten, &sf_header, 0);
+#else
+               ret = sendfile(fromfd, tofd, offset, count, &sf_header, &nwritten, 0);
+#endif
 #if defined(EWOULDBLOCK)
-               } while (ret == -1 && (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK));
+               if (ret == -1 && errno != EINTR && errno != EAGAIN && errno != EWOULDBLOCK) {
 #else
-               } while (ret == -1 && (errno == EINTR || errno == EAGAIN));
+               if (ret == -1 && errno != EINTR && errno != EAGAIN) {
 #endif
-               if (ret == -1)
+                       /* Send failed, we are toast. */
                        return -1;
+               }
 
-               if (nwritten == 0)
-                       return -1; /* I think we're at EOF here... */
-
-               /*
-                * If this was a short (signal interrupted) write we may need
-                * to subtract it from the header data, or null out the header
-                * data altogether if we wrote more than hdtrl.iov_len bytes.
-                * We change nwritten to be the number of file bytes written.
-                */
+               if (nwritten == 0) {
+                       /* EOF of offset is after EOF. */
+                       break;
+               }
 
-               if (hdtrl.iov_base && hdtrl.iov_len) {
-                       if (nwritten >= hdtrl.iov_len) {
-                               nwritten -= hdtrl.iov_len;
-                               hdtrl.iov_base = NULL;
-                               hdtrl.iov_len = 0;
+               if (sf_header.hdr_cnt) {
+                       if (io_header.iov_len <= nwritten) {
+                               /* Entire header was sent. */
+                               sf_header.headers = NULL;
+                               sf_header.hdr_cnt = 0;
+                               nwritten -= io_header.iov_len;
                        } else {
-                               hdtrl.iov_base =
-                                   (void *)((caddr_t)hdtrl.iov_base + nwritten);
-                               hdtrl.iov_len -= nwritten;
+                               /* Partial header was sent. */
+                               io_header.iov_len -= nwritten;
+                               io_header.iov_base =
+                                   ((uint8_t *)io_header.iov_base) + nwritten;
                                nwritten = 0;
                        }
                }
-               total -= nwritten;
+
                offset += nwritten;
+               count -= nwritten;
        }
-       return count + hdr_len;
+
+       return nwritten;
 }
 
 #elif defined(AIX_SENDFILE_API)