]> wimlib.net Git - wimlib/blobdiff - src/write.c
filedes_t => int
[wimlib] / src / write.c
index 8b09449036b2ac52ad016278fe6f0f4180a91700..d184a64a23485689dc27ad3704b3c4b79da6875d 100644 (file)
@@ -48,6 +48,7 @@
 #endif
 
 #include <unistd.h>
+#include <fcntl.h>
 #include <errno.h>
 
 #ifdef WITH_NTFS_3G
 
 #include <limits.h>
 
+#ifndef __WIN32__
+#  include <sys/uio.h> /* for `struct iovec' */
+#endif
+
 /* Chunk table that's located at the beginning of each compressed resource in
  * the WIM.  (This is not the on-disk format; the on-disk format just has an
  * array of offsets.) */
@@ -85,7 +90,7 @@ struct chunk_table {
  */
 static int
 begin_wim_resource_chunk_tab(const struct wim_lookup_table_entry *lte,
-                            FILE *out_fp,
+                            int out_fd,
                             off_t file_offset,
                             struct chunk_table **chunk_tab_ret)
 {
@@ -110,8 +115,9 @@ begin_wim_resource_chunk_tab(const struct wim_lookup_table_entry *lte,
        chunk_tab->cur_offset = 0;
        chunk_tab->cur_offset_p = chunk_tab->offsets;
 
-       if (fwrite(chunk_tab, 1, chunk_tab->table_disk_size, out_fp) !=
-                  chunk_tab->table_disk_size) {
+       if (full_write(out_fd, chunk_tab,
+                      chunk_tab->table_disk_size) != chunk_tab->table_disk_size)
+       {
                ERROR_WITH_ERRNO("Failed to write chunk table in compressed "
                                 "file resource");
                FREE(chunk_tab);
@@ -161,7 +167,7 @@ get_compress_func(int out_ctype)
  *
  * @chunk:       Uncompressed data of the chunk.
  * @chunk_size:          Size of the chunk (<= WIM_CHUNK_SIZE)
- * @out_fp:      FILE * to write the chunk to.
+ * @out_fd:      File descriptor to write the chunk to.
  * @compress:     Compression function to use (NULL if writing uncompressed
  *                     data).
  * @chunk_tab:   Pointer to chunk table being created.  It is updated with the
@@ -172,7 +178,7 @@ get_compress_func(int out_ctype)
 static int
 write_wim_resource_chunk(const void * restrict chunk,
                         unsigned chunk_size,
-                        FILE * restrict out_fp,
+                        int out_fd,
                         compress_func_t compress,
                         struct chunk_table * restrict chunk_tab)
 {
@@ -197,7 +203,7 @@ write_wim_resource_chunk(const void * restrict chunk,
                out_chunk = chunk;
                out_chunk_size = chunk_size;
        }
-       if (fwrite(out_chunk, 1, out_chunk_size, out_fp) != out_chunk_size) {
+       if (full_write(out_fd, out_chunk, out_chunk_size) != out_chunk_size) {
                ERROR_WITH_ERRNO("Failed to write WIM resource chunk");
                return WIMLIB_ERR_WRITE;
        }
@@ -212,16 +218,10 @@ write_wim_resource_chunk(const void * restrict chunk,
  * @compressed_size_p.
  */
 static int
-finish_wim_resource_chunk_tab(struct chunk_table * restrict chunk_tab,
-                             FILE * restrict out_fp,
-                             u64 * restrict compressed_size_p)
+finish_wim_resource_chunk_tab(struct chunk_table *chunk_tab,
+                             int out_fd, u64 *compressed_size_p)
 {
        size_t bytes_written;
-       if (fseeko(out_fp, chunk_tab->file_offset, SEEK_SET) != 0) {
-               ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" of output "
-                                "WIM file", chunk_tab->file_offset);
-               return WIMLIB_ERR_WRITE;
-       }
 
        if (chunk_tab->bytes_per_chunk_entry == 8) {
                array_cpu_to_le64(chunk_tab->offsets, chunk_tab->num_chunks);
@@ -230,31 +230,26 @@ finish_wim_resource_chunk_tab(struct chunk_table * restrict chunk_tab,
                        ((u32*)chunk_tab->offsets)[i] =
                                cpu_to_le32(chunk_tab->offsets[i]);
        }
-       bytes_written = fwrite((u8*)chunk_tab->offsets +
-                                       chunk_tab->bytes_per_chunk_entry,
-                              1, chunk_tab->table_disk_size, out_fp);
+       bytes_written = full_pwrite(out_fd,
+                                   (u8*)chunk_tab->offsets + chunk_tab->bytes_per_chunk_entry,
+                                   chunk_tab->table_disk_size,
+                                   chunk_tab->file_offset);
        if (bytes_written != chunk_tab->table_disk_size) {
                ERROR_WITH_ERRNO("Failed to write chunk table in compressed "
                                 "file resource");
                return WIMLIB_ERR_WRITE;
        }
-       if (fseeko(out_fp, 0, SEEK_END) != 0) {
-               ERROR_WITH_ERRNO("Failed to seek to end of output WIM file");
-               return WIMLIB_ERR_WRITE;
-       }
        *compressed_size_p = chunk_tab->cur_offset + chunk_tab->table_disk_size;
        return 0;
 }
 
 static int
-fflush_and_ftruncate(FILE *out_fp, off_t offset)
+seek_and_truncate(int out_fd, off_t offset)
 {
-       if (fseeko(out_fp, offset, SEEK_SET) ||
-           fflush(out_fp) ||
-           ftruncate(fileno(out_fp), offset))
+       if (lseek(out_fd, offset, SEEK_SET) == -1 ||
+           ftruncate(out_fd, offset))
        {
-               ERROR_WITH_ERRNO("Failed to flush and/or truncate "
-                                "output WIM file");
+               ERROR_WITH_ERRNO("Failed to truncate output WIM file");
                return WIMLIB_ERR_WRITE;
        } else {
                return 0;
@@ -285,7 +280,7 @@ finalize_and_check_sha1(SHA_CTX * restrict sha_ctx,
 struct write_resource_ctx {
        compress_func_t compress;
        struct chunk_table *chunk_tab;
-       FILE *out_fp;
+       int out_fd;
        SHA_CTX sha_ctx;
        bool doing_sha;
 };
@@ -299,7 +294,7 @@ write_resource_cb(const void *restrict chunk, size_t chunk_size,
        if (ctx->doing_sha)
                sha1_update(&ctx->sha_ctx, chunk, chunk_size);
        return write_wim_resource_chunk(chunk, chunk_size,
-                                       ctx->out_fp, ctx->compress,
+                                       ctx->out_fd, ctx->compress,
                                        ctx->chunk_tab);
 }
 
@@ -309,7 +304,7 @@ write_resource_cb(const void *restrict chunk, size_t chunk_size,
  * @lte:  Lookup table entry for the resource, which could be in another WIM,
  *        in an external file, or in another location.
  *
- * @out_fp:  FILE * opened to the output WIM.
+ * @out_fd:  File descriptor opened to the output WIM.
  *
  * @out_ctype:  One of the WIMLIB_COMPRESSION_TYPE_* constants to indicate
  *              which compression algorithm to use.
@@ -329,7 +324,7 @@ write_resource_cb(const void *restrict chunk, size_t chunk_size,
  */
 int
 write_wim_resource(struct wim_lookup_table_entry *lte,
-                  FILE *out_fp, int out_ctype,
+                  int out_fd, int out_ctype,
                   struct resource_entry *out_res_entry,
                   int flags)
 {
@@ -342,7 +337,7 @@ write_wim_resource(struct wim_lookup_table_entry *lte,
        flags &= ~WIMLIB_RESOURCE_FLAG_RECOMPRESS;
 
        /* Get current position in output WIM */
-       offset = ftello(out_fp);
+       offset = filedes_offset(out_fd);
        if (offset == -1) {
                ERROR_WITH_ERRNO("Can't get position in output WIM");
                return WIMLIB_ERR_WRITE;
@@ -375,7 +370,7 @@ write_wim_resource(struct wim_lookup_table_entry *lte,
                write_ctx.chunk_tab = NULL;
        } else {
                write_ctx.compress = get_compress_func(out_ctype);
-               ret = begin_wim_resource_chunk_tab(lte, out_fp,
+               ret = begin_wim_resource_chunk_tab(lte, out_fd,
                                                   offset,
                                                   &write_ctx.chunk_tab);
                if (ret)
@@ -384,7 +379,7 @@ write_wim_resource(struct wim_lookup_table_entry *lte,
 
        /* Write the entire resource by reading the entire resource and feeding
         * the data through the write_resource_cb function. */
-       write_ctx.out_fp = out_fp;
+       write_ctx.out_fd = out_fd;
 try_write_again:
        ret = read_resource_prefix(lte, read_size,
                                   write_resource_cb, &write_ctx, flags);
@@ -415,7 +410,7 @@ try_write_again:
                /* Using a different compression type:  Call
                 * finish_wim_resource_chunk_tab() and it will provide the new
                 * compressed size. */
-               ret = finish_wim_resource_chunk_tab(write_ctx.chunk_tab, out_fp,
+               ret = finish_wim_resource_chunk_tab(write_ctx.chunk_tab, out_fd,
                                                    &new_size);
                if (ret)
                        goto out_free_chunk_tab;
@@ -425,7 +420,7 @@ try_write_again:
                        DEBUG("Compressed %"PRIu64" => %"PRIu64" bytes; "
                              "writing uncompressed instead",
                              wim_resource_size(lte), new_size);
-                       ret = fflush_and_ftruncate(out_fp, offset);
+                       ret = seek_and_truncate(out_fd, offset);
                        if (ret)
                                goto out_free_chunk_tab;
                        write_ctx.compress = NULL;
@@ -542,10 +537,10 @@ struct compressor_thread_params {
 struct message {
        struct wim_lookup_table_entry *lte;
        u8 *uncompressed_chunks[MAX_CHUNKS_PER_MSG];
-       u8 *out_compressed_chunks[MAX_CHUNKS_PER_MSG];
        u8 *compressed_chunks[MAX_CHUNKS_PER_MSG];
        unsigned uncompressed_chunk_sizes[MAX_CHUNKS_PER_MSG];
-       unsigned compressed_chunk_sizes[MAX_CHUNKS_PER_MSG];
+       struct iovec out_chunks[MAX_CHUNKS_PER_MSG];
+       size_t total_out_bytes;
        unsigned num_chunks;
        struct list_head list;
        bool complete;
@@ -555,20 +550,25 @@ struct message {
 static void
 compress_chunks(struct message *msg, compress_func_t compress)
 {
+       msg->total_out_bytes = 0;
        for (unsigned i = 0; i < msg->num_chunks; i++) {
                unsigned len = compress(msg->uncompressed_chunks[i],
                                        msg->uncompressed_chunk_sizes[i],
                                        msg->compressed_chunks[i]);
+               void *out_chunk;
+               unsigned out_len;
                if (len) {
                        /* To be written compressed */
-                       msg->out_compressed_chunks[i] = msg->compressed_chunks[i];
-                       msg->compressed_chunk_sizes[i] = len;
+                       out_chunk = msg->compressed_chunks[i];
+                       out_len = len;
                } else {
                        /* To be written uncompressed */
-                       msg->out_compressed_chunks[i] = msg->uncompressed_chunks[i];
-                       msg->compressed_chunk_sizes[i] = msg->uncompressed_chunk_sizes[i];
-
+                       out_chunk = msg->uncompressed_chunks[i];
+                       out_len = msg->uncompressed_chunk_sizes[i];
                }
+               msg->out_chunks[i].iov_base = out_chunk;
+               msg->out_chunks[i].iov_len = out_len;
+               msg->total_out_bytes += out_len;
        }
 }
 
@@ -620,7 +620,7 @@ do_write_streams_progress(union wimlib_progress_info *progress,
 }
 
 struct serial_write_stream_ctx {
-       FILE *out_fp;
+       int out_fd;
        int out_ctype;
        int write_resource_flags;
 };
@@ -629,7 +629,7 @@ static int
 serial_write_stream(struct wim_lookup_table_entry *lte, void *_ctx)
 {
        struct serial_write_stream_ctx *ctx = _ctx;
-       return write_wim_resource(lte, ctx->out_fp,
+       return write_wim_resource(lte, ctx->out_fd,
                                  ctx->out_ctype, &lte->output_resource_entry,
                                  ctx->write_resource_flags);
 }
@@ -715,14 +715,14 @@ do_write_stream_list(struct list_head *stream_list,
 static int
 do_write_stream_list_serial(struct list_head *stream_list,
                            struct wim_lookup_table *lookup_table,
-                           FILE *out_fp,
+                           int out_fd,
                            int out_ctype,
                            int write_resource_flags,
                            wimlib_progress_func_t progress_func,
                            union wimlib_progress_info *progress)
 {
        struct serial_write_stream_ctx ctx = {
-               .out_fp = out_fp,
+               .out_fd = out_fd,
                .out_ctype = out_ctype,
                .write_resource_flags = write_resource_flags,
        };
@@ -747,7 +747,7 @@ write_flags_to_resource_flags(int write_flags)
 static int
 write_stream_list_serial(struct list_head *stream_list,
                         struct wim_lookup_table *lookup_table,
-                        FILE *out_fp,
+                        int out_fd,
                         int out_ctype,
                         int write_resource_flags,
                         wimlib_progress_func_t progress_func,
@@ -759,7 +759,7 @@ write_stream_list_serial(struct list_head *stream_list,
                progress_func(WIMLIB_PROGRESS_MSG_WRITE_STREAMS, progress);
        return do_write_stream_list_serial(stream_list,
                                           lookup_table,
-                                          out_fp,
+                                          out_fd,
                                           out_ctype,
                                           write_resource_flags,
                                           progress_func,
@@ -768,21 +768,18 @@ write_stream_list_serial(struct list_head *stream_list,
 
 #ifdef ENABLE_MULTITHREADED_COMPRESSION
 static int
-write_wim_chunks(struct message *msg, FILE *out_fp,
+write_wim_chunks(struct message *msg, int out_fd,
                 struct chunk_table *chunk_tab)
 {
        for (unsigned i = 0; i < msg->num_chunks; i++) {
-               unsigned chunk_csize = msg->compressed_chunk_sizes[i];
-
-               if (fwrite(msg->out_compressed_chunks[i], 1, chunk_csize, out_fp)
-                   != chunk_csize)
-               {
-                       ERROR_WITH_ERRNO("Failed to write WIM chunk");
-                       return WIMLIB_ERR_WRITE;
-               }
-
                *chunk_tab->cur_offset_p++ = chunk_tab->cur_offset;
-               chunk_tab->cur_offset += chunk_csize;
+               chunk_tab->cur_offset += msg->out_chunks[i].iov_len;
+       }
+       if (full_writev(out_fd, msg->out_chunks,
+                       msg->num_chunks) != msg->total_out_bytes)
+       {
+               ERROR_WITH_ERRNO("Failed to write WIM chunks");
+               return WIMLIB_ERR_WRITE;
        }
        return 0;
 }
@@ -790,7 +787,7 @@ write_wim_chunks(struct message *msg, FILE *out_fp,
 struct main_writer_thread_ctx {
        struct list_head *stream_list;
        struct wim_lookup_table *lookup_table;
-       FILE *out_fp;
+       int out_fd;
        int out_ctype;
        int write_resource_flags;
        struct shared_queue *res_to_compress_queue;
@@ -946,11 +943,11 @@ receive_compressed_chunks(struct main_writer_thread_ctx *ctx)
                if (msg->begin_chunk == 0) {
                        /* This is the first set of chunks.  Leave space
                         * for the chunk table in the output file. */
-                       off_t cur_offset = ftello(ctx->out_fp);
+                       off_t cur_offset = filedes_offset(ctx->out_fd);
                        if (cur_offset == -1)
                                return WIMLIB_ERR_WRITE;
                        ret = begin_wim_resource_chunk_tab(cur_lte,
-                                                          ctx->out_fp,
+                                                          ctx->out_fd,
                                                           cur_offset,
                                                           &ctx->cur_chunk_tab);
                        if (ret)
@@ -958,7 +955,7 @@ receive_compressed_chunks(struct main_writer_thread_ctx *ctx)
                }
 
                /* Write the compressed chunks from the message. */
-               ret = write_wim_chunks(msg, ctx->out_fp, ctx->cur_chunk_tab);
+               ret = write_wim_chunks(msg, ctx->out_fd, ctx->cur_chunk_tab);
                if (ret)
                        return ret;
 
@@ -971,7 +968,7 @@ receive_compressed_chunks(struct main_writer_thread_ctx *ctx)
                        off_t offset;
 
                        ret = finish_wim_resource_chunk_tab(ctx->cur_chunk_tab,
-                                                           ctx->out_fp,
+                                                           ctx->out_fd,
                                                            &res_csize);
                        if (ret)
                                return ret;
@@ -992,11 +989,11 @@ receive_compressed_chunks(struct main_writer_thread_ctx *ctx)
                                DEBUG("Compressed %"PRIu64" => %"PRIu64" bytes; "
                                      "writing uncompressed instead",
                                      wim_resource_size(cur_lte), res_csize);
-                               ret = fflush_and_ftruncate(ctx->out_fp, offset);
+                               ret = seek_and_truncate(ctx->out_fd, offset);
                                if (ret)
                                        return ret;
                                ret = write_wim_resource(cur_lte,
-                                                        ctx->out_fp,
+                                                        ctx->out_fd,
                                                         WIMLIB_COMPRESSION_TYPE_NONE,
                                                         &cur_lte->output_resource_entry,
                                                         ctx->write_resource_flags);
@@ -1030,7 +1027,7 @@ receive_compressed_chunks(struct main_writer_thread_ctx *ctx)
                        if (!list_empty(&ctx->serial_streams)) {
                                ret = do_write_stream_list_serial(&ctx->serial_streams,
                                                                  ctx->lookup_table,
-                                                                 ctx->out_fp,
+                                                                 ctx->out_fd,
                                                                  ctx->out_ctype,
                                                                  ctx->write_resource_flags,
                                                                  ctx->progress_func,
@@ -1129,7 +1126,7 @@ main_writer_thread_finish(void *_ctx)
        wimlib_assert(list_empty(&ctx->outstanding_streams));
        return do_write_stream_list_serial(&ctx->serial_streams,
                                           ctx->lookup_table,
-                                          ctx->out_fp,
+                                          ctx->out_fd,
                                           ctx->out_ctype,
                                           ctx->write_resource_flags,
                                           ctx->progress_func,
@@ -1226,7 +1223,7 @@ get_default_num_threads()
 static int
 write_stream_list_parallel(struct list_head *stream_list,
                           struct wim_lookup_table *lookup_table,
-                          FILE *out_fp,
+                          int out_fd,
                           int out_ctype,
                           int write_resource_flags,
                           wimlib_progress_func_t progress_func,
@@ -1299,12 +1296,12 @@ write_stream_list_parallel(struct list_head *stream_list,
        struct main_writer_thread_ctx ctx;
        ctx.stream_list           = stream_list;
        ctx.lookup_table          = lookup_table;
-       ctx.out_fp                = out_fp;
+       ctx.out_fd                = out_fd;
        ctx.out_ctype             = out_ctype;
        ctx.res_to_compress_queue = &res_to_compress_queue;
        ctx.compressed_res_queue  = &compressed_res_queue;
        ctx.num_messages          = queue_size;
-       ctx.write_resource_flags  = write_resource_flags | WIMLIB_RESOURCE_FLAG_THREADSAFE_READ;
+       ctx.write_resource_flags  = write_resource_flags;
        ctx.progress_func         = progress_func;
        ctx.progress              = progress;
        ret = main_writer_thread_init_ctx(&ctx);
@@ -1348,7 +1345,7 @@ out_serial:
 out_serial_quiet:
        return write_stream_list_serial(stream_list,
                                        lookup_table,
-                                       out_fp,
+                                       out_fd,
                                        out_ctype,
                                        write_resource_flags,
                                        progress_func,
@@ -1358,13 +1355,13 @@ out_serial_quiet:
 #endif
 
 /*
- * Write a list of streams to a WIM (@out_fp) using the compression type
+ * Write a list of streams to a WIM (@out_fd) using the compression type
  * @out_ctype and up to @num_threads compressor threads.
  */
 static int
 write_stream_list(struct list_head *stream_list,
                  struct wim_lookup_table *lookup_table,
-                 FILE *out_fp, int out_ctype, int write_flags,
+                 int out_fd, int out_ctype, int write_flags,
                  unsigned num_threads, wimlib_progress_func_t progress_func)
 {
        struct wim_lookup_table_entry *lte;
@@ -1406,7 +1403,7 @@ write_stream_list(struct list_head *stream_list,
        if (total_compression_bytes >= 1000000 && num_threads != 1)
                ret = write_stream_list_parallel(stream_list,
                                                 lookup_table,
-                                                out_fp,
+                                                out_fd,
                                                 out_ctype,
                                                 write_resource_flags,
                                                 progress_func,
@@ -1416,7 +1413,7 @@ write_stream_list(struct list_head *stream_list,
 #endif
                ret = write_stream_list_serial(stream_list,
                                               lookup_table,
-                                              out_fp,
+                                              out_fd,
                                               out_ctype,
                                               write_resource_flags,
                                               progress_func,
@@ -1661,7 +1658,7 @@ prepare_stream_list(WIMStruct *wim, int image, struct list_head *stream_list)
        return ret;
 }
 
-/* Writes the streams for the specified @image in @wim to @wim->out_fp.
+/* Writes the streams for the specified @image in @wim to @wim->out_fd.
  */
 static int
 write_wim_streams(WIMStruct *wim, int image, int write_flags,
@@ -1676,7 +1673,7 @@ write_wim_streams(WIMStruct *wim, int image, int write_flags,
                return ret;
        return write_stream_list(&stream_list,
                                 wim->lookup_table,
-                                wim->out_fp,
+                                wim->out_fd,
                                 wimlib_get_compression_type(wim),
                                 write_flags,
                                 num_threads,
@@ -1718,7 +1715,6 @@ finish_write(WIMStruct *w, int image, int write_flags,
 {
        int ret;
        struct wim_header hdr;
-       FILE *out = w->out_fp;
 
        /* @hdr will be the header for the new WIM.  First copy all the data
         * from the header in the WIMStruct; then set all the fields that may
@@ -1754,7 +1750,7 @@ finish_write(WIMStruct *w, int image, int write_flags,
                        goto out_close_wim;
        }
 
-       ret = write_xml_data(w->wim_info, image, out,
+       ret = write_xml_data(w->wim_info, image, w->out_fd,
                             (write_flags & WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE) ?
                              wim_info_get_total_bytes(w->wim_info) : 0,
                             &hdr.xml_res_entry);
@@ -1766,28 +1762,9 @@ finish_write(WIMStruct *w, int image, int write_flags,
                        struct wim_header checkpoint_hdr;
                        memcpy(&checkpoint_hdr, &hdr, sizeof(struct wim_header));
                        zero_resource_entry(&checkpoint_hdr.integrity);
-                       if (fseeko(out, 0, SEEK_SET)) {
-                               ERROR_WITH_ERRNO("Failed to seek to beginning "
-                                                "of WIM being written");
-                               ret = WIMLIB_ERR_WRITE;
-                               goto out_close_wim;
-                       }
-                       ret = write_header(&checkpoint_hdr, out);
+                       ret = write_header(&checkpoint_hdr, w->out_fd);
                        if (ret)
                                goto out_close_wim;
-
-                       if (fflush(out) != 0) {
-                               ERROR_WITH_ERRNO("Can't write data to WIM");
-                               ret = WIMLIB_ERR_WRITE;
-                               goto out_close_wim;
-                       }
-
-                       if (fseeko(out, 0, SEEK_END) != 0) {
-                               ERROR_WITH_ERRNO("Failed to seek to end "
-                                                "of WIM being written");
-                               ret = WIMLIB_ERR_WRITE;
-                               goto out_close_wim;
-                       }
                }
 
                off_t old_lookup_table_end;
@@ -1801,7 +1778,7 @@ finish_write(WIMStruct *w, int image, int write_flags,
                new_lookup_table_end = hdr.lookup_table_res_entry.offset +
                                       hdr.lookup_table_res_entry.size;
 
-               ret = write_integrity_table(out,
+               ret = write_integrity_table(w->out_fd,
                                            &hdr.integrity,
                                            new_lookup_table_end,
                                            old_lookup_table_end,
@@ -1812,42 +1789,33 @@ finish_write(WIMStruct *w, int image, int write_flags,
                zero_resource_entry(&hdr.integrity);
        }
 
-       if (fseeko(out, 0, SEEK_SET) != 0) {
-               ERROR_WITH_ERRNO("Failed to seek to beginning of WIM "
-                                "being written");
-               ret = WIMLIB_ERR_WRITE;
-               goto out_close_wim;
-       }
-
-       ret = write_header(&hdr, out);
+       ret = write_header(&hdr, w->out_fd);
        if (ret)
                goto out_close_wim;
 
        if (write_flags & WIMLIB_WRITE_FLAG_FSYNC) {
-               if (fflush(out) != 0
-                   || fsync(fileno(out)) != 0)
-               {
-                       ERROR_WITH_ERRNO("Error flushing data to WIM file");
+               if (fsync(w->out_fd)) {
+                       ERROR_WITH_ERRNO("Error syncing data to WIM file");
                        ret = WIMLIB_ERR_WRITE;
                }
        }
 out_close_wim:
-       if (fclose(out) != 0) {
+       if (close(w->out_fd)) {
                ERROR_WITH_ERRNO("Failed to close the output WIM file");
                if (ret == 0)
                        ret = WIMLIB_ERR_WRITE;
        }
-       w->out_fp = NULL;
+       w->out_fd = -1;
        return ret;
 }
 
 #if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
 int
-lock_wim(WIMStruct *w, FILE *fp)
+lock_wim(WIMStruct *w, int fd)
 {
        int ret = 0;
-       if (fp && !w->wim_locked) {
-               ret = flock(fileno(fp), LOCK_EX | LOCK_NB);
+       if (fd != -1 && !w->wim_locked) {
+               ret = flock(fd, LOCK_EX | LOCK_NB);
                if (ret != 0) {
                        if (errno == EWOULDBLOCK) {
                                ERROR("`%"TS"' is already being modified or has been "
@@ -1868,37 +1836,24 @@ lock_wim(WIMStruct *w, FILE *fp)
 #endif
 
 static int
-open_wim_writable(WIMStruct *w, const tchar *path,
-                 bool trunc, bool also_readable)
+open_wim_writable(WIMStruct *w, const tchar *path, int open_flags)
 {
-       const tchar *mode;
-       if (trunc)
-               if (also_readable)
-                       mode = T("w+b");
-               else
-                       mode = T("wb");
-       else
-               mode = T("r+b");
-
-       wimlib_assert(w->out_fp == NULL);
-       w->out_fp = tfopen(path, mode);
-       if (w->out_fp) {
-               return 0;
-       } else {
+       w->out_fd = topen(path, open_flags | O_BINARY, 0644);
+       if (w->out_fd == -1) {
                ERROR_WITH_ERRNO("Failed to open `%"TS"' for writing", path);
                return WIMLIB_ERR_OPEN;
        }
+       return 0;
 }
 
 
 void
 close_wim_writable(WIMStruct *w)
 {
-       if (w->out_fp) {
-               if (fclose(w->out_fp) != 0) {
+       if (w->out_fd != -1) {
+               if (close(w->out_fd))
                        WARNING_WITH_ERRNO("Failed to close output WIM");
-               }
-               w->out_fp = NULL;
+               w->out_fd = -1;
        }
 }
 
@@ -1907,12 +1862,23 @@ int
 begin_write(WIMStruct *w, const tchar *path, int write_flags)
 {
        int ret;
-       ret = open_wim_writable(w, path, true,
-                               (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY) != 0);
+       int open_flags = O_TRUNC | O_CREAT;
+       if (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY)
+               open_flags |= O_RDWR;
+       else
+               open_flags |= O_WRONLY;
+       ret = open_wim_writable(w, path, open_flags);
        if (ret)
                return ret;
        /* Write dummy header. It will be overwritten later. */
-       return write_header(&w->hdr, w->out_fp);
+       ret = write_header(&w->hdr, w->out_fd);
+       if (ret)
+               return ret;
+       if (lseek(w->out_fd, WIM_HEADER_DISK_SIZE, SEEK_SET) == -1) {
+               ERROR_WITH_ERRNO("Failed to seek to end of WIM header");
+               return WIMLIB_ERR_WRITE;
+       }
+       return 0;
 }
 
 /* Writes a stand-alone WIM to a file.  */
@@ -2041,6 +2007,7 @@ overwrite_wim_inplace(WIMStruct *w, int write_flags,
        struct list_head stream_list;
        off_t old_wim_end;
        u64 old_lookup_table_end, old_xml_begin, old_xml_end;
+       int open_flags;
 
        DEBUG("Overwriting `%"TS"' in-place", w->filename);
 
@@ -2091,18 +2058,22 @@ overwrite_wim_inplace(WIMStruct *w, int write_flags,
        if (ret)
                return ret;
 
-       ret = open_wim_writable(w, w->filename, false,
-                               (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY) != 0);
+       open_flags = 0;
+       if (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY)
+               open_flags |= O_RDWR;
+       else
+               open_flags |= O_WRONLY;
+       ret = open_wim_writable(w, w->filename, open_flags);
        if (ret)
                return ret;
 
-       ret = lock_wim(w, w->out_fp);
+       ret = lock_wim(w, w->out_fd);
        if (ret) {
                close_wim_writable(w);
                return ret;
        }
 
-       if (fseeko(w->out_fp, old_wim_end, SEEK_SET) != 0) {
+       if (lseek(w->out_fd, old_wim_end, SEEK_SET) == -1) {
                ERROR_WITH_ERRNO("Can't seek to end of WIM");
                close_wim_writable(w);
                w->wim_locked = 0;
@@ -2113,7 +2084,7 @@ overwrite_wim_inplace(WIMStruct *w, int write_flags,
              old_wim_end);
        ret = write_stream_list(&stream_list,
                                w->lookup_table,
-                               w->out_fp,
+                               w->out_fd,
                                wimlib_get_compression_type(w),
                                write_flags,
                                num_threads,
@@ -2171,19 +2142,9 @@ overwrite_wim_via_tmpfile(WIMStruct *w, int write_flags,
                goto out_unlink;
        }
 
-       DEBUG("Renaming `%"TS"' to `%"TS"'", tmpfile, w->filename);
-
-#ifdef __WIN32__
-       /* Windows won't let you delete open files unless FILE_SHARE_DELETE was
-        * specified to CreateFile().  The WIM was opened with fopen(), which
-        * didn't provided this flag to CreateFile, so the handle must be closed
-        * before executing the rename(). */
-       if (w->fp != NULL) {
-               fclose(w->fp);
-               w->fp = NULL;
-       }
-#endif
+       close_wim(w);
 
+       DEBUG("Renaming `%"TS"' to `%"TS"'", tmpfile, w->filename);
        /* Rename the new file to the old file .*/
        if (trename(tmpfile, w->filename) != 0) {
                ERROR_WITH_ERRNO("Failed to rename `%"TS"' to `%"TS"'",
@@ -2198,22 +2159,6 @@ overwrite_wim_via_tmpfile(WIMStruct *w, int write_flags,
                progress.rename.to = w->filename;
                progress_func(WIMLIB_PROGRESS_MSG_RENAME, &progress);
        }
-
-       /* Close the original WIM file that was opened for reading. */
-       if (w->fp != NULL) {
-               fclose(w->fp);
-               w->fp = NULL;
-       }
-
-       /* Re-open the WIM read-only. */
-       w->fp = tfopen(w->filename, T("rb"));
-       if (w->fp == NULL) {
-               ret = WIMLIB_ERR_REOPEN;
-               WARNING_WITH_ERRNO("Failed to re-open `%"TS"' read-only",
-                                  w->filename);
-               FREE(w->filename);
-               w->filename = NULL;
-       }
        goto out;
 out_unlink:
        /* Remove temporary file. */