+/*************************************************
+* 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;
+}
+
+
git://git.exim.org / users / jgh / exim.git / blobdiff