contrib/libarchive/libarchive/archive_read_data_into_fd.c

   1 /*-
   2  * Copyright (c) 2003-2007 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "archive_platform.h"
  27 __FBSDID("$FreeBSD: src/lib/libarchive/archive_read_data_into_fd.c,v 1.16 2008/05/23 05:01:29 cperciva Exp $");
  28
  29 #ifdef HAVE_SYS_TYPES_H
  30 #include <sys/types.h>
  31 #endif
  32 #ifdef HAVE_ERRNO_H
  33 #include <errno.h>
  34 #endif
  35 #ifdef HAVE_UNISTD_H
  36 #include <unistd.h>
  37 #endif
  38
  39 #include "archive.h"
  40 #include "archive_private.h"
  41
  42 /* Maximum amount of data to write at one time. */
  43 #define MAX_WRITE       (1024 * 1024)
  44
  45 /*
  46  * This implementation minimizes copying of data and is sparse-file aware.
  47  */
  48 static int
  49 pad_to(struct archive *a, int fd, int can_lseek,
  50     size_t nulls_size, const char *nulls,
  51     int64_t target_offset, int64_t actual_offset)
  52 {
  53         size_t to_write;
  54         ssize_t bytes_written;
  55
  56         if (can_lseek) {
  57                 actual_offset = lseek(fd,
  58                     target_offset - actual_offset, SEEK_CUR);
  59                 if (actual_offset != target_offset) {
  60                         archive_set_error(a, errno, "Seek error");
  61                         return (ARCHIVE_FATAL);
  62                 }
  63                 return (ARCHIVE_OK);
  64         }
  65         while (target_offset > actual_offset) {
  66                 to_write = nulls_size;
  67                 if (target_offset < actual_offset + (int64_t)nulls_size)
  68                         to_write = (size_t)(target_offset - actual_offset);
  69                 bytes_written = write(fd, nulls, to_write);
  70                 if (bytes_written < 0) {
  71                         archive_set_error(a, errno, "Write error");
  72                         return (ARCHIVE_FATAL);
  73                 }
  74                 actual_offset += bytes_written;
  75         }
  76         return (ARCHIVE_OK);
  77 }
  78
  79
  80 int
  81 archive_read_data_into_fd(struct archive *a, int fd)
  82 {
  83         struct stat st;
  84         int r, r2;
  85         const void *buff;
  86         size_t size, bytes_to_write;
  87         ssize_t bytes_written;
  88         int64_t target_offset;
  89         int64_t actual_offset = 0;
  90         int can_lseek;
  91         char *nulls = NULL;
  92         size_t nulls_size = 16384;
  93
  94         archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
  95             "archive_read_data_into_fd");
  96
  97         can_lseek = (fstat(fd, &st) == 0) && S_ISREG(st.st_mode);
  98         if (!can_lseek)
  99                 nulls = calloc(1, nulls_size);
 100
 101         while ((r = archive_read_data_block(a, &buff, &size, &target_offset)) ==
 102             ARCHIVE_OK) {
 103                 const char *p = buff;
 104                 if (target_offset > actual_offset) {
 105                         r = pad_to(a, fd, can_lseek, nulls_size, nulls,
 106                             target_offset, actual_offset);
 107                         if (r != ARCHIVE_OK)
 108                                 break;
 109                         actual_offset = target_offset;
 110                 }
 111                 while (size > 0) {
 112                         bytes_to_write = size;
 113                         if (bytes_to_write > MAX_WRITE)
 114                                 bytes_to_write = MAX_WRITE;
 115                         bytes_written = write(fd, p, bytes_to_write);
 116                         if (bytes_written < 0) {
 117                                 archive_set_error(a, errno, "Write error");
 118                                 r = ARCHIVE_FATAL;
 119                                 goto cleanup;
 120                         }
 121                         actual_offset += bytes_written;
 122                         p += bytes_written;
 123                         size -= bytes_written;
 124                 }
 125         }
 126
 127         if (r == ARCHIVE_EOF && target_offset > actual_offset) {
 128                 r2 = pad_to(a, fd, can_lseek, nulls_size, nulls,
 129                     target_offset, actual_offset);
 130                 if (r2 != ARCHIVE_OK)
 131                         r = r2;
 132         }
 133
 134 cleanup:
 135         free(nulls);
 136         if (r != ARCHIVE_EOF)
 137                 return (r);
 138         return (ARCHIVE_OK);
 139 }