/*
* Copyright (C) 2013 Eric Biggers
*
- * This file is part of wimlib, a library for working with WIM files.
+ * This file is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option) any
+ * later version.
*
- * wimlib is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License as published by the Free
- * Software Foundation; either version 3 of the License, or (at your option)
- * any later version.
- *
- * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
- * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- * A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * This file is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
- * You should have received a copy of the GNU General Public License
- * along with wimlib; if not, see http://www.gnu.org/licenses/.
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this file; if not, see http://www.gnu.org/licenses/.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
-#include "wimlib/file_io.h"
-#ifdef __WIN32__
-# include "wimlib/win32.h" /* For pread(), pwrite() replacements */
-#else
-# include <sys/uio.h> /* for writev() and `struct iovec' */
-#endif
-
#include <errno.h>
#include <unistd.h>
+#include "wimlib/error.h"
+#include "wimlib/file_io.h"
+#include "wimlib/util.h"
+#include "wimlib/win32.h" /* For pread(), pwrite() replacements */
-/* Like read(), but keep trying until everything has been written or we know for
- * sure that there was an error (or end-of-file). */
-size_t
-full_read(int fd, void *buf, size_t count)
+/*
+ * Wrapper around read() that checks for errors and keeps retrying until all
+ * requested bytes have been read or until end-of file has occurred.
+ *
+ * Return values:
+ * WIMLIB_ERR_SUCCESS (0)
+ * WIMLIB_ERR_READ (errno set)
+ * WIMLIB_ERR_UNEXPECTED_END_OF_FILE (errno set to EINVAL)
+ */
+int
+full_read(struct filedes *fd, void *buf, size_t count)
{
- ssize_t bytes_read;
- size_t bytes_remaining;
-
- for (bytes_remaining = count;
- bytes_remaining != 0;
- bytes_remaining -= bytes_read, buf += bytes_read)
- {
- bytes_read = read(fd, buf, bytes_remaining);
- if (bytes_read <= 0) {
- if (bytes_read == 0)
- errno = EIO;
- else if (errno == EINTR)
+ while (count) {
+ ssize_t ret = read(fd->fd, buf, count);
+ if (unlikely(ret <= 0)) {
+ if (ret == 0) {
+ errno = EINVAL;
+ return WIMLIB_ERR_UNEXPECTED_END_OF_FILE;
+ }
+ if (errno == EINTR)
continue;
- break;
+ return WIMLIB_ERR_READ;
}
+ buf += ret;
+ count -= ret;
+ fd->offset += ret;
}
- return count - bytes_remaining;
+ return 0;
}
-/* Like write(), but keep trying until everything has been written or we know
- * for sure that there was an error. */
-size_t
-full_write(int fd, const void *buf, size_t count)
+static int
+pipe_read(struct filedes *fd, void *buf, size_t count, off_t offset)
{
- ssize_t bytes_written;
- size_t bytes_remaining;
-
- for (bytes_remaining = count;
- bytes_remaining != 0;
- bytes_remaining -= bytes_written, buf += bytes_written)
- {
- bytes_written = write(fd, buf, bytes_remaining);
- if (bytes_written < 0) {
- if (errno == EINTR)
- continue;
- break;
- }
+ int ret;
+
+ /* Verify the offset. */
+ if (offset < fd->offset) {
+ ERROR("Can't seek backwards in pipe "
+ "(offset %"PRIu64" => %"PRIu64").\n"
+ " Make sure the WIM was captured as "
+ "pipable.", fd->offset, offset);
+ errno = ESPIPE;
+ return WIMLIB_ERR_RESOURCE_ORDER;
+ }
+
+ /* Manually seek to the requested position. */
+ while (fd->offset != offset) {
+ size_t bytes_to_read = min(offset - fd->offset, BUFFER_SIZE);
+ u8 dummy[bytes_to_read];
+
+ ret = full_read(fd, dummy, bytes_to_read);
+ if (ret)
+ return ret;
}
- return count - bytes_remaining;
+
+ /* Do the actual read. */
+ return full_read(fd, buf, count);
}
-/* Like pread(), but keep trying until everything has been read or we know for
- * sure that there was an error (or end-of-file) */
-size_t
-full_pread(int fd, void *buf, size_t count, off_t offset)
+/*
+ * Wrapper around pread() that checks for errors and keeps retrying until all
+ * requested bytes have been read or until end-of file has occurred. This also
+ * transparently handle reading from pipe files, but the caller needs to be sure
+ * the requested offset is greater than or equal to the current offset, or else
+ * WIMLIB_ERR_RESOURCE_ORDER will be returned.
+ *
+ * Return values:
+ * WIMLIB_ERR_SUCCESS (0)
+ * WIMLIB_ERR_READ (errno set)
+ * WIMLIB_ERR_UNEXPECTED_END_OF_FILE (errno set to EINVAL)
+ * WIMLIB_ERR_RESOURCE_ORDER (errno set to ESPIPE)
+ */
+int
+full_pread(struct filedes *fd, void *buf, size_t count, off_t offset)
{
- ssize_t bytes_read;
- size_t bytes_remaining;
-
- for (bytes_remaining = count;
- bytes_remaining != 0;
- bytes_remaining -= bytes_read, buf += bytes_read,
- offset += bytes_read)
- {
- bytes_read = pread(fd, buf, bytes_remaining, offset);
- if (bytes_read <= 0) {
- if (bytes_read == 0)
- errno = EIO;
- else if (errno == EINTR)
+ if (fd->is_pipe)
+ goto is_pipe;
+
+ while (count) {
+ ssize_t ret = pread(fd->fd, buf, count, offset);
+ if (unlikely(ret <= 0)) {
+ if (ret == 0) {
+ errno = EINVAL;
+ return WIMLIB_ERR_UNEXPECTED_END_OF_FILE;
+ }
+ if (errno == EINTR)
continue;
- break;
+ if (errno == ESPIPE) {
+ fd->is_pipe = 1;
+ goto is_pipe;
+ }
+ return WIMLIB_ERR_READ;
}
+ buf += ret;
+ count -= ret;
+ offset += ret;
}
- return count - bytes_remaining;
+ return 0;
+
+is_pipe:
+ return pipe_read(fd, buf, count, offset);
}
-/* Like pwrite(), but keep trying until everything has been written or we know
- * for sure that there was an error. */
-size_t
-full_pwrite(int fd, const void *buf, size_t count, off_t offset)
+/*
+ * Wrapper around write() that checks for errors and keeps retrying until all
+ * requested bytes have been written.
+ *
+ * Return values:
+ * WIMLIB_ERR_SUCCESS (0)
+ * WIMLIB_ERR_WRITE (errno set)
+ */
+int
+full_write(struct filedes *fd, const void *buf, size_t count)
{
- ssize_t bytes_written;
- size_t bytes_remaining;
-
- for (bytes_remaining = count;
- bytes_remaining != 0;
- bytes_remaining -= bytes_written, buf += bytes_written,
- offset += bytes_written)
- {
- bytes_written = pwrite(fd, buf, bytes_remaining, offset);
- if (bytes_written < 0) {
+ while (count) {
+ ssize_t ret = write(fd->fd, buf, count);
+ if (unlikely(ret < 0)) {
if (errno == EINTR)
continue;
- break;
+ return WIMLIB_ERR_WRITE;
}
+ buf += ret;
+ count -= ret;
+ fd->offset += ret;
}
- return count - bytes_remaining;
+ return 0;
}
-/* Like writev(), but keep trying until everything has been written or we know
- * for sure that there was an error. */
-size_t
-full_writev(int fd, struct iovec *iov, int iovcnt)
-{
- size_t total_bytes_written = 0;
- while (iovcnt > 0) {
- ssize_t bytes_written;
- bytes_written = writev(fd, iov, iovcnt);
- if (bytes_written < 0) {
+/*
+ * Wrapper around pwrite() that checks for errors and keeps retrying until all
+ * requested bytes have been written.
+ *
+ * Return values:
+ * WIMLIB_ERR_SUCCESS (0)
+ * WIMLIB_ERR_WRITE (errno set)
+ */
+int
+full_pwrite(struct filedes *fd, const void *buf, size_t count, off_t offset)
+{
+ while (count) {
+ ssize_t ret = pwrite(fd->fd, buf, count, offset);
+ if (unlikely(ret < 0)) {
if (errno == EINTR)
continue;
- break;
- }
- total_bytes_written += bytes_written;
- while (bytes_written) {
- if (bytes_written >= iov[0].iov_len) {
- bytes_written -= iov[0].iov_len;
- iov++;
- iovcnt--;
- } else {
- iov[0].iov_base += bytes_written;
- iov[0].iov_len -= bytes_written;
- bytes_written = 0;
- }
+ return WIMLIB_ERR_WRITE;
}
+ buf += ret;
+ count -= ret;
+ offset += ret;
+ }
+ return 0;
+}
+
+off_t filedes_seek(struct filedes *fd, off_t offset)
+{
+ if (fd->is_pipe) {
+ errno = ESPIPE;
+ return -1;
+ }
+ if (fd->offset != offset) {
+ if (lseek(fd->fd, offset, SEEK_SET) == -1)
+ return -1;
+ fd->offset = offset;
}
- return total_bytes_written;
+ return offset;
}
-off_t
-filedes_offset(int fd)
+bool filedes_is_seekable(struct filedes *fd)
{
- return lseek(fd, 0, SEEK_CUR);
+ return !fd->is_pipe && lseek(fd->fd, 0, SEEK_CUR) != -1;
}
git://wimlib.net / wimlib / blobdiff