X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=d2f93611de1e66ad9bbcd8dcd5aada40546f560f;hp=2e05313ea26ece1fd65315e80561fdd626f45fe1;hb=c953ad4edff1bb64fb54124bfec7c3726cb2865a;hpb=1cefe6a503c74d609db4e99e689d46575a5e40fd

diff --git a/fd.c b/fd.c
index 2e05313e..d2f93611 100644
--- a/fd.c
+++ b/fd.c
@@ -19,60 +19,134 @@
 #include "fd.h"
 
 /**
- * Write a buffer to a file descriptor, re-write on short writes.
+ * Write an array of buffers to a file descriptor.
  *
  * \param fd The file descriptor.
- * \param buf The buffer to be sent.
- * \param len The length of \a buf.
+ * \param iov Pointer to one or more buffers.
+ * \param iovcnt The number of buffers.
+ *
+ * EAGAIN/EWOULDBLOCK is not considered a fatal error condition. For example
+ * DCCP CCID3 has a sending wait queue which fills up and is emptied
+ * asynchronously. The EAGAIN case means that there is currently no space in
+ * the wait queue, but this can change at any moment.
+ *
+ * \return Negative on fatal errors, number of bytes written else.
+ *
+ * For blocking file descriptors, this function returns either the sum of all
+ * buffer sizes, or the error code of the fatal error that caused the last
+ * write call to fail.
+ *
+ * For nonblocking file descriptors there is a third possibility: Any positive
+ * return value less than the sum of the buffer sizes indicates that some bytes
+ * have been written but the next write would block.
  *
- * \return Standard. In any case, the number of bytes that have been written is
- * stored in \a len.
+ * \sa writev(2), \ref xwrite().
  */
-int write_all(int fd, const char *buf, size_t *len)
+int xwritev(int fd, struct iovec *iov, int iovcnt)
 {
-	size_t total = *len;
-
-	assert(total);
-	*len = 0;
-	while (*len < total) {
-		int ret = write(fd, buf + *len, total - *len);
-		if (ret == -1)
-			return -ERRNO_TO_PARA_ERROR(errno);
-		*len += ret;
+	size_t written = 0;
+	int i;
+	struct iovec saved_iov, *curiov;
+
+	i = 0;
+	curiov = iov;
+	saved_iov = *curiov;
+	while (i < iovcnt && curiov->iov_len > 0) {
+		ssize_t ret = writev(fd, curiov, iovcnt - i);
+		if (ret >= 0) {
+			written += ret;
+			while (ret > 0) {
+				if (ret < curiov->iov_len) {
+					curiov->iov_base += ret;
+					curiov->iov_len -= ret;
+					break;
+				}
+				ret -= curiov->iov_len;
+				*curiov = saved_iov;
+				i++;
+				if (i >= iovcnt)
+					return written;
+				curiov++;
+				saved_iov = *curiov;
+			}
+			continue;
+		}
+		if (errno == EINTR)
+			/*
+			 * The write() call was interrupted by a signal before
+			 * any data was written. Try again.
+			 */
+			continue;
+		if (errno == EAGAIN || errno == EWOULDBLOCK)
+			/*
+			 * We don't consider this an error. Note that POSIX
+			 * allows either error to be returned, and does not
+			 * require these constants to have the same value.
+			 */
+			return written;
+		/* fatal error */
+		return -ERRNO_TO_PARA_ERROR(errno);
 	}
-	return 1;
+	return written;
 }
 
 /**
- * Write a buffer to a non-blocking file descriptor.
+ * Write a buffer to a file descriptor, re-writing on short writes.
  *
  * \param fd The file descriptor.
- * \param buf the buffer to write.
- * \param len the number of bytes of \a buf.
+ * \param buf The buffer to write.
+ * \param len The number of bytes to write.
  *
- * EAGAIN is not considered an error condition.  For example CCID3 has a
- * sending wait queue which fills up and is emptied asynchronously. The EAGAIN
- * case means that there is currently no space in the wait queue, but this can
- * change at any moment.
+ * This is a simple wrapper for \ref xwritev().
  *
- * \return Negative on errors, number of bytes written else.
+ * \return The return value of the underlying call to \ref xwritev().
  */
-int write_nonblock(int fd, const char *buf, size_t len)
+int xwrite(int fd, const char *buf, size_t len)
 {
-	size_t written = 0;
-	int ret = 0;
+	struct iovec iov = {.iov_base = (void *)buf, .iov_len = len};
+	return xwritev(fd, &iov, 1);
+}
 
-	while (written < len) {
-		size_t num = len - written;
+/**
+ * Write all data to a file descriptor.
+ *
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
+ *
+ * This is like \ref xwrite() but returns \p -E_SHORT_WRITE if not
+ * all data could be written.
+ *
+ * \return Number of bytes written on success, negative error code else.
+ */
+int write_all(int fd, const char *buf, size_t len)
+{
+	int ret = xwrite(fd, buf, len);
 
-		ret = write(fd, buf + written, num);
-		if (ret < 0 && errno == EAGAIN)
-			return written;
-		if (ret < 0)
-			return -ERRNO_TO_PARA_ERROR(errno);
-		written += ret;
-	}
-	return written;
+	if (ret < 0)
+		return ret;
+	if (ret != len)
+		return -E_SHORT_WRITE;
+	return ret;
+}
+
+/**
+ * Write a buffer given by a format string.
+ *
+ * \param fd The file descriptor.
+ * \param fmt A format string.
+ *
+ * \return The return value of the underlying call to \ref write_all().
+ */
+__printf_2_3 int write_va_buffer(int fd, const char *fmt, ...)
+{
+	char *msg;
+	int ret;
+
+	PARA_VSPRINTF(fmt, msg);
+	ret = write_buffer(fd, msg);
+	free(msg);
+	return ret;
 }
 
 /**
@@ -87,7 +161,7 @@ int write_nonblock(int fd, const char *buf, size_t len)
  * If \a rfds is not \p NULL and the (non-blocking) file descriptor \a fd is
  * not set in \a rfds, this function returns early without doing anything.
  * Otherwise The function tries to read up to \a sz bytes from \a fd. As for
- * write_nonblock(), EAGAIN is not considered an error condition. However, EOF
+ * xwrite(), EAGAIN is not considered an error condition. However, EOF
  * is.
  *
  * \return Zero or a negative error code. If the underlying call to readv(2)
@@ -100,7 +174,7 @@ int write_nonblock(int fd, const char *buf, size_t len)
  * have been read before the error occurred. In this case \a num_bytes is
  * positive.
  *
- * \sa \ref write_nonblock(), read(2), readv(2).
+ * \sa \ref xwrite(), read(2), readv(2).
  */
 int readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds,
 		size_t *num_bytes)