source3/lib/util_transfer_file.c

   1 /*
   2  * Unix SMB/CIFS implementation.
   3  * Utility functions to transfer files.
   4  *
   5  * Copyright (C) Jeremy Allison 2001-2002
   6  * Copyright (C) Michael Adam 2008
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22
  23 #include <includes.h>
  24 #include "transfer_file.h"
  25 #include "lib/util/sys_rw.h"
  26
  27 /****************************************************************************
  28  Transfer some data between two fd's.
  29 ****************************************************************************/
  30
  31 #ifndef TRANSFER_BUF_SIZE
  32 #define TRANSFER_BUF_SIZE 65536
  33 #endif
  34
  35
  36 ssize_t transfer_file_internal(void *in_file,
  37                                void *out_file,
  38                                size_t n,
  39                                ssize_t (*pread_fn)(void *, void *, size_t, off_t),
  40                                ssize_t (*pwrite_fn)(void *, const void *, size_t, off_t))
  41 {
  42         char *buf;
  43         size_t total = 0;
  44         ssize_t read_ret;
  45         ssize_t write_ret;
  46         size_t num_to_read_thistime;
  47         size_t num_written = 0;
  48         off_t offset = 0;
  49
  50         if (n == 0) {
  51                 return 0;
  52         }
  53
  54         if ((buf = SMB_MALLOC_ARRAY(char, TRANSFER_BUF_SIZE)) == NULL) {
  55                 return -1;
  56         }
  57
  58         do {
  59                 num_to_read_thistime = MIN((n - total), TRANSFER_BUF_SIZE);
  60
  61                 read_ret = (*pread_fn)(in_file, buf, num_to_read_thistime, offset);
  62                 if (read_ret == -1) {
  63                         DEBUG(0,("transfer_file_internal: read failure. "
  64                                  "Error = %s\n", strerror(errno) ));
  65                         SAFE_FREE(buf);
  66                         return -1;
  67                 }
  68                 if (read_ret == 0) {
  69                         break;
  70                 }
  71
  72                 num_written = 0;
  73
  74                 while (num_written < read_ret) {
  75                         write_ret = (*pwrite_fn)(out_file, buf + num_written,
  76                                                 read_ret - num_written,
  77                                                 offset + num_written);
  78
  79                         if (write_ret == -1) {
  80                                 DEBUG(0,("transfer_file_internal: "
  81                                          "write failure. Error = %s\n",
  82                                          strerror(errno) ));
  83                                 SAFE_FREE(buf);
  84                                 return -1;
  85                         }
  86                         if (write_ret == 0) {
  87                                 return (ssize_t)total;
  88                         }
  89
  90                         num_written += (size_t)write_ret;
  91                 }
  92
  93                 total += (size_t)read_ret;
  94                 offset += (off_t)read_ret;
  95         } while (total < n);
  96
  97         SAFE_FREE(buf);
  98         return (ssize_t)total;
  99 }
 100
 101 static ssize_t sys_pread_fn(void *file, void *buf, size_t len, off_t offset)
 102 {
 103         int *fd = (int *)file;
 104
 105         return sys_pread(*fd, buf, len, offset);
 106 }
 107
 108 static ssize_t sys_pwrite_fn(void *file, const void *buf, size_t len, off_t offset)
 109 {
 110         int *fd = (int *)file;
 111
 112         return sys_pwrite(*fd, buf, len, offset);
 113 }
 114
 115 off_t transfer_file(int infd, int outfd, off_t n)
 116 {
 117         return (off_t)transfer_file_internal(&infd, &outfd, (size_t)n,
 118                                                  sys_pread_fn, sys_pwrite_fn);
 119 }