X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=a73325ba5af60adb712213aa789243dc02f74d90;hp=54eddb3c46445ff625dfc1becb6bf7c5bfa75311;hb=779cfd85fd90d1f9182deade08d5fe3f2f3a1530;hpb=b5b5d00eea33eccd3d2d75057c5254bf85568b00

diff --git a/fd.c b/fd.c
index 54eddb3c..a73325ba 100644
--- a/fd.c
+++ b/fd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2010 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2012 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -19,60 +19,93 @@
 #include "fd.h"
 
 /**
- * Write a buffer to a file descriptor, re-write on short writes.
+ * Write a buffer to a file descriptor, re-writing on short writes.
  *
  * \param fd The file descriptor.
- * \param buf The buffer to be sent.
- * \param len The length of \a buf.
- *
- * \return Standard. In any case, the number of bytes that have been written is
- * stored in \a len.
+ * \param buf The buffer to write.
+ * \param len The number of bytes to write.
+ *
+ * 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 \a len 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: A positive return value < \a
+ * len indicates that some bytes have been written but the next write would
+ * block.
  */
-int write_all(int fd, const char *buf, size_t *len)
+int xwrite(int fd, const char *buf, size_t len)
 {
-	size_t total = *len;
+	size_t written = 0;
 
-	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;
+	while (written < len) {
+		ssize_t ret = write(fd, buf + written, len - written);
+		if (ret >= 0) {
+			written += ret;
+			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 all data to a file descriptor.
  *
  * \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 be sent.
+ * \param len The length of \a buf.
  *
- * 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 like \ref xwrite() but returns \p -E_SHORT_WRITE if not
+ * all data could be written.
  *
- * \return Negative on errors, number of bytes written else.
+ * \return Number of bytes written on success, negative error code else.
  */
-int write_nonblock(int fd, const char *buf, size_t len)
+int write_all(int fd, const char *buf, size_t len)
 {
-	size_t written = 0;
-	int ret = 0;
+	int ret = xwrite(fd, buf, len);
 
-	while (written < len) {
-		size_t num = len - written;
+	if (ret < 0)
+		return ret;
+	if (ret != len)
+		return -E_SHORT_WRITE;
+	return ret;
+}
 
-		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;
+/**
+ * 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 +120,7 @@ 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 +133,7 @@ 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)
@@ -446,7 +479,7 @@ int para_chdir(const char *path)
  * \sa getcwd(3).
  *
  */
-int para_opendir(const char *dirname, DIR **dir, int *cwd)
+static int para_opendir(const char *dirname, DIR **dir, int *cwd)
 {
 	int ret;
 
@@ -480,7 +513,7 @@ close_cwd:
  *
  * \return Standard.
  */
-int para_fchdir(int fd)
+static int para_fchdir(int fd)
 {
 	if (fchdir(fd) < 0)
 		return -ERRNO_TO_PARA_ERROR(errno);
@@ -563,6 +596,9 @@ out:
 int para_munmap(void *start, size_t length)
 {
 	int err;
+
+	if (!start)
+		return 0;
 	if (munmap(start, length) >= 0)
 		return 1;
 	err = errno;