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      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 
     28 #ifdef HAVE_SYS_TYPES_H
     29 #include <sys/types.h>
     30 #endif
     31 #ifdef HAVE_ERRNO_H
     32 #include <errno.h>
     33 #endif
     34 #ifdef HAVE_UNISTD_H
     35 #include <unistd.h>
     36 #endif
     37 
     38 #include "archive.h"
     39 #include "archive_private.h"
     40 
     41 /* Maximum amount of data to write at one time. */
     42 #define	MAX_WRITE	(1024 * 1024)
     43 
     44 /*
     45  * This implementation minimizes copying of data and is sparse-file aware.
     46  */
     47 static int
     48 pad_to(struct archive *a, int fd, int can_lseek,
     49     size_t nulls_size, const char *nulls,
     50     int64_t target_offset, int64_t actual_offset)
     51 {
     52 	size_t to_write;
     53 	ssize_t bytes_written;
     54 
     55 	if (can_lseek) {
     56 		actual_offset = lseek(fd,
     57 		    target_offset - actual_offset, SEEK_CUR);
     58 		if (actual_offset != target_offset) {
     59 			archive_set_error(a, errno, "Seek error");
     60 			return (ARCHIVE_FATAL);
     61 		}
     62 		return (ARCHIVE_OK);
     63 	}
     64 	while (target_offset > actual_offset) {
     65 		to_write = nulls_size;
     66 		if (target_offset < actual_offset + (int64_t)nulls_size)
     67 			to_write = (size_t)(target_offset - actual_offset);
     68 		bytes_written = write(fd, nulls, to_write);
     69 		if (bytes_written < 0) {
     70 			archive_set_error(a, errno, "Write error");
     71 			return (ARCHIVE_FATAL);
     72 		}
     73 		actual_offset += bytes_written;
     74 	}
     75 	return (ARCHIVE_OK);
     76 }
     77 
     78 
     79 int
     80 archive_read_data_into_fd(struct archive *a, int fd)
     81 {
     82 	struct stat st;
     83 	int r, r2;
     84 	const void *buff;
     85 	size_t size, bytes_to_write;
     86 	ssize_t bytes_written;
     87 	int64_t target_offset;
     88 	int64_t actual_offset = 0;
     89 	int can_lseek;
     90 	char *nulls = NULL;
     91 	size_t nulls_size = 16384;
     92 
     93 	archive_check_magic(a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_DATA,
     94 	    "archive_read_data_into_fd");
     95 
     96 	can_lseek = (fstat(fd, &st) == 0) && S_ISREG(st.st_mode);
     97 	if (!can_lseek) {
     98 		nulls = calloc(1, nulls_size);
     99 		if (!nulls) {
    100 			r = ARCHIVE_FATAL;
    101 			goto cleanup;
    102 		}
    103 	}
    104 
    105 	while ((r = archive_read_data_block(a, &buff, &size, &target_offset)) ==
    106 	    ARCHIVE_OK) {
    107 		const char *p = buff;
    108 		if (target_offset > actual_offset) {
    109 			r = pad_to(a, fd, can_lseek, nulls_size, nulls,
    110 			    target_offset, actual_offset);
    111 			if (r != ARCHIVE_OK)
    112 				break;
    113 			actual_offset = target_offset;
    114 		}
    115 		while (size > 0) {
    116 			bytes_to_write = size;
    117 			if (bytes_to_write > MAX_WRITE)
    118 				bytes_to_write = MAX_WRITE;
    119 			bytes_written = write(fd, p, bytes_to_write);
    120 			if (bytes_written < 0) {
    121 				archive_set_error(a, errno, "Write error");
    122 				r = ARCHIVE_FATAL;
    123 				goto cleanup;
    124 			}
    125 			actual_offset += bytes_written;
    126 			p += bytes_written;
    127 			size -= bytes_written;
    128 		}
    129 	}
    130 
    131 	if (r == ARCHIVE_EOF && target_offset > actual_offset) {
    132 		r2 = pad_to(a, fd, can_lseek, nulls_size, nulls,
    133 		    target_offset, actual_offset);
    134 		if (r2 != ARCHIVE_OK)
    135 			r = r2;
    136 	}
    137 
    138 cleanup:
    139 	free(nulls);
    140 	if (r != ARCHIVE_EOF)
    141 		return (r);
    142 	return (ARCHIVE_OK);
    143 }
    144