read_wim_header(): Check return value of lseek()

[wimlib] / src / file_io.c

diff --git a/src/file_io.c b/src/file_io.c
index 2852571c413cb13ea1f29ae4174c1155779b7b11..752c1121e8ee5f388452cc8bb9cfc8c927ef9c65 100644 (file)
--- a/src/file_io.c
+++ b/src/file_io.c
@@ -25,22 +25,19 @@
 #  include "config.h"
 #endif
 
-#include "wimlib/assert.h"
 #include "wimlib/error.h"
 #include "wimlib/file_io.h"
 #include "wimlib/util.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>
 
 
-/* Wrapper around read() that keeps retrying until all requested bytes have been
- * read or until end-of file has occurred.
+/* Wrapper around read() that checks for errors keeps retrying until all
+ * requested bytes have been read or until end-of file has occurred.
  *
  * Return values:
  *     WIMLIB_ERR_SUCCESS                      (0)
@@ -79,15 +76,17 @@ pipe_read(struct filedes *fd, void *buf, size_t count, off_t offset)
 {
        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);
+                     "        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];
@@ -96,13 +95,15 @@ pipe_read(struct filedes *fd, void *buf, size_t count, off_t offset)
                if (ret)
                        return ret;
        }
+
+       /* Do the actual read.  */
        return full_read(fd, buf, count);
 }
 
-/* Wrapper around pread() that keep 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
+/* 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:
@@ -110,7 +111,7 @@ pipe_read(struct filedes *fd, void *buf, size_t count, off_t offset)
  *     WIMLIB_ERR_READ                         (errno set)
  *     WIMLIB_ERR_UNEXPECTED_END_OF_FILE       (errno set to 0)
  *     WIMLIB_ERR_RESOURCE_ORDER               (errno set to ESPIPE)
- * */
+ */
 int
 full_pread(struct filedes *fd, void *buf, size_t count, off_t offset)
 {
@@ -123,7 +124,7 @@ full_pread(struct filedes *fd, void *buf, size_t count, off_t offset)
        for (bytes_remaining = count;
             bytes_remaining != 0;
             bytes_remaining -= bytes_read, buf += bytes_read,
-               offset += bytes_read)
+               offset += bytes_read)
        {
                bytes_read = pread(fd->fd, buf, bytes_remaining, offset);
                if (unlikely(bytes_read <= 0)) {
@@ -133,7 +134,6 @@ full_pread(struct filedes *fd, void *buf, size_t count, off_t offset)
                        } else if (errno == EINTR) {
                                continue;
                        } else if (errno == ESPIPE) {
-                               wimlib_assert(count == bytes_remaining);
                                fd->is_pipe = 1;
                                goto is_pipe;
                        } else {
@@ -147,8 +147,8 @@ is_pipe:
        return pipe_read(fd, buf, count, offset);
 }
 
-/* Wrapper around write() that keeps retrying until all requested bytes have
- * been written.
+/* Wrapper around write() that checks for errors and keeps retrying until all
+ * requested bytes have been written.
  *
  * Return values:
  *     WIMLIB_ERR_SUCCESS                      (0)
@@ -176,8 +176,8 @@ full_write(struct filedes *fd, const void *buf, size_t count)
 }
 
 
-/* Wrapper around pwrite() that keep retrying until all requested bytes have been
- * written.
+/* Wrapper around pwrite() that checks for errors and keeps retrying until all
+ * requested bytes have been written.
  *
  * Return values:
  *     WIMLIB_ERR_SUCCESS      (0)
@@ -192,7 +192,7 @@ full_pwrite(struct filedes *fd, const void *buf, size_t count, off_t offset)
        for (bytes_remaining = count;
             bytes_remaining != 0;
             bytes_remaining -= bytes_written, buf += bytes_written,
-               offset += bytes_written)
+               offset += bytes_written)
        {
                bytes_written = pwrite(fd->fd, buf, bytes_remaining, offset);
                if (unlikely(bytes_written < 0)) {
@@ -204,43 +204,6 @@ full_pwrite(struct filedes *fd, const void *buf, size_t count, off_t offset)
        return 0;
 }
 
-/* Wrapper around writev() that keep retrying until all requested bytes have been
- * written.
- *
- * Return values:
- *     WIMLIB_ERR_SUCCESS      (0)
- *     WIMLIB_ERR_WRITE        (errno set)
- * */
-int
-full_writev(struct filedes *fd, struct iovec *iov, int iovcnt)
-{
-       size_t total_bytes_written = 0;
-       while (iovcnt > 0) {
-               ssize_t bytes_written;
-
-               bytes_written = writev(fd->fd, iov, iovcnt);
-               if (bytes_written < 0) {
-                       if (errno == EINTR)
-                               continue;
-                       return WIMLIB_ERR_WRITE;
-               }
-               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;
-                       }
-               }
-       }
-       fd->offset += total_bytes_written;
-       return 0;
-}
-
 ssize_t
 raw_pread(struct filedes *fd, void *buf, size_t count, off_t offset)
 {