contrib/libarchive-1.3.1/libarchive/archive_read_open_fd.c

   1 /*-
   2  * Copyright (c) 2003-2004 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  *    in this position and unchanged.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "archive_platform.h"
  28 __FBSDID("$FreeBSD: src/lib/libarchive/archive_read_open_fd.c,v 1.6 2006/07/30 00:29:00 kientzle Exp $");
  29
  30 #include <sys/stat.h>
  31 #include <errno.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34 #include <unistd.h>
  35
  36 #include "archive.h"
  37
  38 struct read_fd_data {
  39         int      fd;
  40         size_t   block_size;
  41         void    *buffer;
  42 };
  43
  44 static int      file_close(struct archive *, void *);
  45 static int      file_open(struct archive *, void *);
  46 static ssize_t  file_read(struct archive *, void *, const void **buff);
  47 static ssize_t  file_skip(struct archive *, void *, size_t request);
  48
  49 int
  50 archive_read_open_fd(struct archive *a, int fd, size_t block_size)
  51 {
  52         struct read_fd_data *mine;
  53
  54         mine = malloc(sizeof(*mine));
  55         if (mine == NULL) {
  56                 archive_set_error(a, ENOMEM, "No memory");
  57                 return (ARCHIVE_FATAL);
  58         }
  59         mine->block_size = block_size;
  60         mine->buffer = malloc(mine->block_size);
  61         if (mine->buffer == NULL) {
  62                 archive_set_error(a, ENOMEM, "No memory");
  63                 free(mine);
  64                 return (ARCHIVE_FATAL);
  65         }
  66         mine->fd = fd;
  67         return (archive_read_open2(a, mine, file_open, file_read, file_skip, file_close));
  68 }
  69
  70 static int
  71 file_open(struct archive *a, void *client_data)
  72 {
  73         struct read_fd_data *mine = client_data;
  74         struct stat st;
  75
  76         if (fstat(mine->fd, &st) != 0) {
  77                 archive_set_error(a, errno, "Can't stat fd %d", mine->fd);
  78                 return (ARCHIVE_FATAL);
  79         }
  80
  81         if (S_ISREG(st.st_mode))
  82                 archive_read_extract_set_skip_file(a, st.st_dev, st.st_ino);
  83
  84         return (ARCHIVE_OK);
  85 }
  86
  87 static ssize_t
  88 file_read(struct archive *a, void *client_data, const void **buff)
  89 {
  90         struct read_fd_data *mine = client_data;
  91         ssize_t bytes_read;
  92
  93         *buff = mine->buffer;
  94         bytes_read = read(mine->fd, mine->buffer, mine->block_size);
  95         if (bytes_read < 0) {
  96                 archive_set_error(a, errno, "Error reading fd %d", mine->fd);
  97         }
  98         return (bytes_read);
  99 }
 100
 101 static ssize_t
 102 file_skip(struct archive *a, void *client_data, size_t request)
 103 {
 104         struct read_fd_data *mine = client_data;
 105         off_t old_offset, new_offset;
 106
 107         /* Reduce request to the next smallest multiple of block_size */
 108         request = (request / mine->block_size) * mine->block_size;
 109         /*
 110          * Hurray for lazy evaluation: if the first lseek fails, the second
 111          * one will not be executed.
 112          */
 113         if (((old_offset = lseek(mine->fd, 0, SEEK_CUR)) < 0) ||
 114             ((new_offset = lseek(mine->fd, request, SEEK_CUR)) < 0))
 115         {
 116                 if (errno == ESPIPE)
 117                 {
 118                         /*
 119                          * Failure to lseek() can be caused by the file
 120                          * descriptor pointing to a pipe, socket or FIFO.
 121                          * Return 0 here, so the compression layer will use
 122                          * read()s instead to advance the file descriptor.
 123                          * It's slower of course, but works as well.
 124                          */
 125                         return (0);
 126                 }
 127                 /*
 128                  * There's been an error other than ESPIPE. This is most
 129                  * likely caused by a programmer error (too large request)
 130                  * or a corrupted archive file.
 131                  */
 132                 archive_set_error(a, errno, "Error seeking");
 133                 return (-1);
 134         }
 135         return (new_offset - old_offset);
 136 }
 137
 138 static int
 139 file_close(struct archive *a, void *client_data)
 140 {
 141         struct read_fd_data *mine = client_data;
 142
 143         (void)a; /* UNUSED */
 144         if (mine->buffer != NULL)
 145                 free(mine->buffer);
 146         free(mine);
 147         return (ARCHIVE_OK);
 148 }