X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/acec9514b1006e352ef283f205ecec75a9b6ff0d..c5db348c5e29e93e51389fa0079f829967c5da82:/src/src/deliver.c

diff --git a/src/src/deliver.c b/src/src/deliver.c
index 0bd67d823..a7f561c9c 100644
--- a/src/src/deliver.c
+++ b/src/src/deliver.c
@@ -2,7 +2,7 @@
 *     Exim - an Internet mail transport agent    *
 *************************************************/
 
-/* Copyright (c) University of Cambridge 1995 - 2016 */
+/* Copyright (c) University of Cambridge 1995 - 2017 */
 /* See the file NOTICE for conditions of use and distribution. */
 
 /* The main code for delivering a message. */
@@ -10,6 +10,7 @@
 
 #include "exim.h"
 #include "transports/smtp.h"
+#include <sys/uio.h>
 #include <assert.h>
 
 
@@ -79,6 +80,52 @@ static uschar *used_return_path = NULL;
 
 
 
+/*************************************************
+*          read as much as requested             *
+*************************************************/
+
+/* The syscall read(2) doesn't always returns as much as we want. For
+several reasons it might get less. (Not talking about signals, as syscalls
+are restartable). When reading from a network or pipe connection the sender
+might send in smaller chunks, with delays between these chunks. The read(2)
+may return such a chunk.
+
+The more the writer writes and the smaller the pipe between write and read is,
+the more we get the chance of reading leass than requested. (See bug 2130)
+
+This function read(2)s until we got all the data we *requested*.
+
+Note: This function may block. Use it only if you're sure about the
+amount of data you will get.
+
+Argument:
+  fd          the file descriptor to read from
+  buffer      pointer to a buffer of size len
+  len         the requested(!) amount of bytes
+
+Returns:      the amount of bytes read
+*/
+static ssize_t
+readn(int fd, void * buffer, size_t len)
+{
+  void * next = buffer;
+  void * end = buffer + len;
+
+  while (next < end)
+    {
+    ssize_t got = read(fd, next, end - next);
+
+    /* I'm not sure if there are signals that can interrupt us,
+    for now I assume the worst */
+    if (got == -1 && errno == EINTR) continue;
+    if (got <= 0) return next - buffer;
+    next += got;
+    }
+
+  return len;
+}
+
+
 /*************************************************
 *             Make a new address item            *
 *************************************************/
@@ -3311,14 +3358,13 @@ while (!done)
   If we get less, we can assume the subprocess do be done and do not expect any further
   information from it. */
 
-  got = readn(fd, pipeheader, required);
-  if (got != required)
+  if ((got = readn(fd, pipeheader, required)) != required)
     {
-      msg = string_sprintf("got %d of %d bytes (pipeheader) "
-        "from transport process %d for transport %s",
-        got, PIPE_HEADER_SIZE, pid, addr->transport->driver_name);
-      done = TRUE;
-      break;
+    msg = string_sprintf("got " SSIZE_T_FMT " of %d bytes (pipeheader) "
+      "from transport process %d for transport %s",
+      got, PIPE_HEADER_SIZE, pid, addr->transport->driver_name);
+    done = TRUE;
+    break;
     }
 
   pipeheader[PIPE_HEADER_SIZE] = '\0';
@@ -3348,14 +3394,13 @@ while (!done)
   /* Same as above, the transport process will write the bytes announced
   in a timely manner, so we can just wait for the bytes, getting less than expected
   is considered a problem of the subprocess, we do not expect anything else from it. */
-  got = readn(fd, big_buffer, required);
-  if (got != required)
+  if ((got = readn(fd, big_buffer, required)) != required)
     {
-      msg = string_sprintf("got only %d of %d bytes (pipedata) "
-        "from transport process %d for transport %s",
-        got, required, pid, addr->transport->driver_name);
-      done = TRUE;
-      break;
+    msg = string_sprintf("got only " SSIZE_T_FMT " of " SIZE_T_FMT
+      " bytes (pipedata) from transport process %d for transport %s",
+      got, required, pid, addr->transport->driver_name);
+    done = TRUE;
+    break;
     }
 
   /* Handle each possible type of item, assuming the complete item is
@@ -8506,14 +8551,10 @@ if (cutthrough.fd >= 0 && cutthrough.callout_hold_only)
       goto fail;
 
     else if (pid == 0)		/* child: fork again to totally disconnect */
-      {
-      close(pfd[1]);
-      if ((pid = fork()))
-	_exit(pid ? EXIT_FAILURE : EXIT_SUCCESS);
-      smtp_proxy_tls(big_buffer, big_buffer_size, pfd[0], 5*60);
-      exim_exit(0);
-      }
+      /* does not return */
+      smtp_proxy_tls(big_buffer, big_buffer_size, pfd, 5*60);
 
+    DEBUG(D_transport) debug_printf("proxy-proc inter-pid %d\n", pid);
     close(pfd[0]);
     waitpid(pid, NULL, 0);
     (void) close(channel_fd);	/* release the client socket */