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
  26 /****************************************************************************
  27  Transfer some data between two fd's.
  28 ****************************************************************************/
  29
  30 #ifndef TRANSFER_BUF_SIZE
  31 #define TRANSFER_BUF_SIZE 65536
  32 #endif
  33
  34
  35 ssize_t transfer_file_internal(void *in_file,
  36                                void *out_file,
  37                                size_t n,
  38                                ssize_t (*read_fn)(void *, void *, size_t),
  39                                ssize_t (*write_fn)(void *, const void *, size_t))
  40 {
  41         char *buf;
  42         size_t total = 0;
  43         ssize_t read_ret;
  44         ssize_t write_ret;
  45         size_t num_to_read_thistime;
  46         size_t num_written = 0;
  47
  48         if (n == 0) {
  49                 return 0;
  50         }
  51
  52         if ((buf = SMB_MALLOC_ARRAY(char, TRANSFER_BUF_SIZE)) == NULL) {
  53                 return -1;
  54         }
  55
  56         do {
  57                 num_to_read_thistime = MIN((n - total), TRANSFER_BUF_SIZE);
  58
  59                 read_ret = (*read_fn)(in_file, buf, num_to_read_thistime);
  60                 if (read_ret == -1) {
  61                         DEBUG(0,("transfer_file_internal: read failure. "
  62                                  "Error = %s\n", strerror(errno) ));
  63                         SAFE_FREE(buf);
  64                         return -1;
  65                 }
  66                 if (read_ret == 0) {
  67                         break;
  68                 }
  69
  70                 num_written = 0;
  71
  72                 while (num_written < read_ret) {
  73                         write_ret = (*write_fn)(out_file, buf + num_written,
  74                                                 read_ret - num_written);
  75
  76                         if (write_ret == -1) {
  77                                 DEBUG(0,("transfer_file_internal: "
  78                                          "write failure. Error = %s\n",
  79                                          strerror(errno) ));
  80                                 SAFE_FREE(buf);
  81                                 return -1;
  82                         }
  83                         if (write_ret == 0) {
  84                                 return (ssize_t)total;
  85                         }
  86
  87                         num_written += (size_t)write_ret;
  88                 }
  89
  90                 total += (size_t)read_ret;
  91         } while (total < n);
  92
  93         SAFE_FREE(buf);
  94         return (ssize_t)total;
  95 }
  96
  97 static ssize_t sys_read_fn(void *file, void *buf, size_t len)
  98 {
  99         int *fd = (int *)file;
 100
 101         return sys_read(*fd, buf, len);
 102 }
 103
 104 static ssize_t sys_write_fn(void *file, const void *buf, size_t len)
 105 {
 106         int *fd = (int *)file;
 107
 108         return sys_write(*fd, buf, len);
 109 }
 110
 111 off_t transfer_file(int infd, int outfd, off_t n)
 112 {
 113         return (off_t)transfer_file_internal(&infd, &outfd, (size_t)n,
 114                                                  sys_read_fn, sys_write_fn);
 115 }