Provide readn() as a wrapper around read()

[users/jgh/exim.git] / src / src / exim.c

diff --git a/src/src/exim.c b/src/src/exim.c
index c990bc08ca4c22b1d1cf10599a614508cfe434d1..f09b26902a3a7b77b818b741503f0501c3a870f9 100644 (file)
--- a/src/src/exim.c
+++ b/src/src/exim.c
@@ -212,8 +212,7 @@ int fd;
 
 os_restarting_signal(sig, usr1_handler);
 
-fd = Uopen(process_log_path, O_APPEND|O_WRONLY, LOG_MODE);
-if (fd < 0)
+if ((fd = Uopen(process_log_path, O_APPEND|O_WRONLY, LOG_MODE)) < 0)
   {
   /* If we are already running as the Exim user, try to create it in the
   current process (assuming spool_directory exists). Otherwise, if we are
@@ -4154,6 +4153,7 @@ if (Uchdir(spool_directory) != 0)
   int dummy;
   (void)directory_make(spool_directory, US"", SPOOL_DIRECTORY_MODE, FALSE);
   dummy = /* quieten compiler */ Uchdir(spool_directory);
+  dummy = dummy;       /* yet more compiler quietening, sigh */
   }
 
 /* Handle calls with the -bi option. This is a sendmail option to rebuild *the*
@@ -5592,7 +5592,7 @@ while (more)
 
     if (!receive_timeout)
       {
-      struct timeval t = { 30*60, 0 }; /* 30 minutes */
+      struct timeval t = { .tv_sec = 30*60, .tv_usec = 0 };    /* 30 minutes */
       fd_set r;
 
       FD_ZERO(&r); FD_SET(0, &r);
@@ -5839,4 +5839,50 @@ exim_exit(EXIT_SUCCESS);   /* Never returns */
 return 0;                  /* To stop compiler warning */
 }
 
+/*************************************************
+*          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
+*/
+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;
+}
+
+
 /* End of exim.c */