/*
- * Copyright (C) 2006-2012 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2014 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
#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.
*
- * \return Standard.
+ * 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.
+ *
+ * \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 len;
+ return written;
}
/**
- * Send a buffer given by a format string.
+ * Write a buffer to a file descriptor, re-writing on short writes.
*
* \param fd The file descriptor.
- * \param fmt A format string.
+ * \param buf The buffer to write.
+ * \param len The number of bytes to write.
*
- * \return Standard.
+ * This is a simple wrapper for \ref xwritev().
+ *
+ * \return The return value of the underlying call to \ref xwritev().
*/
-__printf_2_3 int write_va_buffer(int fd, const char *fmt, ...)
+int xwrite(int fd, const char *buf, size_t len)
{
- char *msg;
- int ret;
-
- PARA_VSPRINTF(fmt, msg);
- ret = write_buffer(fd, msg);
- free(msg);
- return ret;
+ struct iovec iov = {.iov_base = (void *)buf, .iov_len = len};
+ return xwritev(fd, &iov, 1);
}
/**
- * 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;
+ va_list ap;
+
+ va_start(ap, fmt);
+ ret = xvasprintf(&msg, fmt, ap);
+ ret = write_all(fd, msg, ret);
+ free(msg);
+ return ret;
}
/**
*
* 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
- * is.
+ * Otherwise The function tries to read up to \a sz bytes from \a fd, where \a
+ * sz is the sum of the lengths of all vectors in \a iov. As for xwrite(),
+ * \p EAGAIN is not considered an error condition. However, \p EOF is.
*
* \return Zero or a negative error code. If the underlying call to readv(2)
* returned zero (indicating an end of file condition) or failed for some
- * reason other than \p EAGAIN, a negative return value is returned.
+ * reason other than \p EAGAIN, a negative error code is returned.
*
* In any case, \a num_bytes contains the number of bytes that have been
* successfully read from \a fd (zero if the first readv() call failed with
* 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)
{
int ret;
+ *dir = NULL;
if (cwd) {
ret = para_open(".", O_RDONLY, 0);
if (ret < 0)
goto out;
}
*size = file_status.st_size;
+ /*
+ * If the file is empty, *size is zero and mmap() would return EINVAL
+ * (Invalid argument). This error is common enough to spend an extra
+ * error code which explicitly states the problem.
+ */
+ ret = -E_EMPTY;
+ if (*size == 0)
+ goto out;
+ /*
+ * If fd refers to a directory, mmap() returns ENODEV (No such device),
+ * at least on Linux. "Is a directory" seems to be more to the point.
+ */
+ ret = -ERRNO_TO_PARA_ERROR(EISDIR);
+ if (S_ISDIR(file_status.st_mode))
+ goto out;
+
ret = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map);
out:
if (ret < 0 || !fd_ptr)
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