list_dir.c

   1 /*
   2  * User FTP Server,  Share folders over FTP without being root.
   3  * Copyright (C) 2008  Isaac Jurado
   4  *
   5  * This program is free software; you can redistribute it and/or modify it under
   6  * the terms of the GNU General Public License as published by the Free Software
   7  * Foundation; either version 2 of the License, or (at your option) any later
   8  * version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  12  * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  13  * details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  18  */
  19
  20 #include "uftps.h"
  21 #include <sys/stat.h>
  22 #include <unistd.h>
  23 #include <dirent.h>
  24 #include <time.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27
  28 /* Month names */
  29 static const char const month[12][4] = {
  30         "Jan\0", "Feb\0", "Mar\0", "Apr\0", "May\0", "Jun\0", "Jul\0", "Aug\0",
  31         "Sep\0", "Oct\0", "Nov\0", "Dec\0"
  32 };
  33
  34
  35 /*
  36  * Send a listing line of length "len", contained in "str" over the socket "sk".
  37  * Return 0 when all "len" bytes has been transferred or -1 if there was an
  38  * error or less bytes were sent.
  39  */
  40 static int send_data_line (int sk, const char *str, int len)
  41 {
  42         int  b, l = 0;
  43
  44         while (l < len)
  45         {
  46                 b = send(sk, &str[l], len - l, 0);
  47                 if (b <= 0)
  48                 {
  49                         error("Sending listing data");
  50                         return -1;
  51                 }
  52
  53                 l += b;
  54         }
  55
  56         return 0;
  57 }
  58
  59
  60 /*
  61  * LIST and NLST commands implementation.  The boolean argument enables LIST
  62  * mode, otherwise NSLT listing is sent.
  63  *
  64  * To make Mozilla Firefox list the directory contents correctly, some research
  65  * work had to be done.  That concluded in:
  66  *
  67  *     http://cr.yp.to/ftp.html
  68  *
  69  * In particular:
  70  *
  71  *     http://cr.yp.to/ftp/list/binls.html
  72  *
  73  * Only files or subdirectories are shown, the rest of items (symlinks, named
  74  * pipes, sockets...) are ignored.  The following line is sent when a file is
  75  * found:
  76  *
  77  * -rw-r--r-- 1 ftp ftp       999 Mon  88 7777 filename
  78  *
  79  * In case of a subdirectory, the line is:
  80  *
  81  * drwxr-xr-x 1 ftp ftp       999 Mon  88 7777 dirname
  82  *
  83  * Where '999' is the item size, 'Mon  88 7777' is the month, day and year,
  84  * respectively, of the last modification date.  Some servers display the hour
  85  * and minute when the distance between current time and last modification time
  86  * is less than six months.  We don't do that as it is considered irrelevant.
  87  * To obtain a more precise value for the last modification time, let the client
  88  * send an MDTM command.
  89  *
  90  * Note that most clients will appreciate listings where all its items are
  91  * stat()-able.
  92  */
  93 void list_dir (int full_list)
  94 {
  95         int             len, l, e;
  96         DIR            *dir;
  97         struct dirent  *dentry;
  98         struct stat     s;
  99         struct tm       t;
 100         char            item[512];
 101
 102         /* Workaround for Konqueror and Nautilus */
 103         if (SS.arg != NULL && SS.arg[0] == '-')
 104                 SS.arg = NULL;
 105         len = expand_arg();
 106
 107         dir = opendir(SS.arg);
 108         if (dir == NULL)
 109         {
 110                 error("Opening directory '%s'", SS.arg);
 111                 reply_c("550 Could not open directory.\r\n");
 112                 return;
 113         }
 114
 115         /* Prepare the argument for the listing, see below */
 116         if (len > 3)
 117         {
 118                 SS.arg[len - 1] = '/';
 119                 len++;
 120         }
 121
 122         e = open_data_channel();
 123         if (e == -1)
 124         {
 125                 closedir(dir);
 126                 return;
 127         }
 128
 129         reply_c("150 Sending directory list.\r\n");
 130
 131         do {
 132                 dentry = readdir(dir);
 133                 if (dentry == NULL)
 134                         break;
 135
 136                 /*
 137                  * Due to the chroot emulation, each dentry needs to be
 138                  * prepended by the expanded argument (stored in the auxiliary
 139                  * buffer) after checking bounds.  Otherwise, the stat() call
 140                  * would fail.
 141                  */
 142                 l = strlen(dentry->d_name);
 143                 if (len + l >= LINE_SIZE)
 144                         fatal("Path overflow in LIST/NLST");
 145                 strcpy(&SS.arg[len - 1], dentry->d_name);
 146
 147                 debug("Stating %s", SS.arg);
 148                 e = lstat(SS.arg, &s);
 149                 if (e == -1 || (!S_ISDIR(s.st_mode) && !S_ISREG(s.st_mode)))
 150                 {
 151                         debug("Dentry %s skipped", SS.arg);
 152                         continue;
 153                 }
 154
 155                 if (full_list)
 156                 {
 157                         /* LIST */
 158                         gmtime_r(&(s.st_mtime), &t);
 159                         l = snprintf(item, 512,
 160                                      "%s 1 ftp ftp %13lld %s %3d %4d %s\r\n",
 161                                      (S_ISDIR(s.st_mode) ? "dr-xr-xr-x"
 162                                       : "-r--r--r--"), (long long) s.st_size,
 163                                      month[t.tm_mon], t.tm_mday, t.tm_year + 1900,
 164                                      dentry->d_name);
 165                 }
 166                 else
 167                 {
 168                         /* NLST */
 169                         l = snprintf(item, 512, "%s%s", dentry->d_name,
 170                                      (S_ISDIR(s.st_mode) ? "/\r\n" : "\r\n"));
 171                 }
 172
 173                 e = send_data_line(SS.data_sk, item, l);
 174         } while (e == 0);
 175
 176         if (e == 0)
 177                 reply_c("226 Directory list sent.\r\n");
 178         else
 179                 reply_c("426 Connection closed, transfer aborted.\r\n");
 180
 181         closedir(dir);
 182         close(SS.data_sk);
 183         SS.data_sk = -1;
 184 }
 185