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/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 (*read_fn)(void *, void *, size_t),
  40                                ssize_t (*write_fn)(void *, const void *, size_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
  49         if (n == 0) {
  50                 return 0;
  51         }
  52
  53         if ((buf = SMB_MALLOC_ARRAY(char, TRANSFER_BUF_SIZE)) == NULL) {
  54                 return -1;
  55         }
  56
  57         do {
  58                 num_to_read_thistime = MIN((n - total), TRANSFER_BUF_SIZE);
  59
  60                 read_ret = (*read_fn)(in_file, buf, num_to_read_thistime);
  61                 if (read_ret == -1) {
  62                         DEBUG(0,("transfer_file_internal: read failure. "
  63                                  "Error = %s\n", strerror(errno) ));
  64                         SAFE_FREE(buf);
  65                         return -1;
  66                 }
  67                 if (read_ret == 0) {
  68                         break;
  69                 }
  70
  71                 num_written = 0;
  72
  73                 while (num_written < read_ret) {
  74                         write_ret = (*write_fn)(out_file, buf + num_written,
  75                                                 read_ret - num_written);
  76
  77                         if (write_ret == -1) {
  78                                 DEBUG(0,("transfer_file_internal: "
  79                                          "write failure. Error = %s\n",
  80                                          strerror(errno) ));
  81                                 SAFE_FREE(buf);
  82                                 return -1;
  83                         }
  84                         if (write_ret == 0) {
  85                                 return (ssize_t)total;
  86                         }
  87
  88                         num_written += (size_t)write_ret;
  89                 }
  90
  91                 total += (size_t)read_ret;
  92         } while (total < n);
  93
  94         SAFE_FREE(buf);
  95         return (ssize_t)total;
  96 }
  97
  98 static ssize_t sys_read_fn(void *file, void *buf, size_t len)
  99 {
 100         int *fd = (int *)file;
 101
 102         return sys_read(*fd, buf, len);
 103 }
 104
 105 static ssize_t sys_write_fn(void *file, const void *buf, size_t len)
 106 {
 107         int *fd = (int *)file;
 108
 109         return sys_write(*fd, buf, len);
 110 }
 111
 112 off_t transfer_file(int infd, int outfd, off_t n)
 113 {
 114         return (off_t)transfer_file_internal(&infd, &outfd, (size_t)n,
 115                                                  sys_read_fn, sys_write_fn);
 116 }