apt-pkg/contrib/cdromutl.cc

   1 // -*- mode: cpp; mode: fold -*-
   2 // Description                                                          /*{{{*/
   3 // $Id: cdromutl.cc,v 1.1 1998/11/29 01:19:27 jgg Exp $
   4 /* ######################################################################
   5
   6    CDROM Utilities - Some functions to manipulate CDROM mounts.
   7
   8    These are here for the cdrom method and apt-cdrom.
   9
  10    ##################################################################### */
  11                                                                         /*}}}*/
  12 // Include Files                                                        /*{{{*/
  13 #ifdef __GNUG__
  14 #pragma implementation "apt-pkg/cdromutl.h"
  15 #endif
  16 #include <apt-pkg/cdromutl.h>
  17 #include <apt-pkg/error.h>
  18 #include <apt-pkg/md5.h>
  19 #include <apt-pkg/fileutl.h>
  20
  21 #include <sys/wait.h>
  22 #include <sys/errno.h>
  23 #include <sys/vfs.h>
  24 #include <dirent.h>
  25 #include <fcntl.h>
  26 #include <unistd.h>
  27 #include <stdio.h>
  28                                                                         /*}}}*/
  29
  30 // UnmountCdrom - Unmount a cdrom                                       /*{{{*/
  31 // ---------------------------------------------------------------------
  32 /* Forking umount works much better than the umount syscall which can
  33    leave /etc/mtab inconsitant. We drop all messages this produces. */
  34 bool UnmountCdrom(string Path)
  35 {
  36    int Child = fork();
  37    if (Child < -1)
  38       return _error->Errno("fork","Failed to fork");
  39
  40    // The child
  41    if (Child == 0)
  42    {
  43       // Make all the fds /dev/null
  44       for (int I = 0; I != 10; I++)
  45          close(I);
  46       for (int I = 0; I != 3; I++)
  47          dup2(open("/dev/null",O_RDWR),I);
  48
  49       const char *Args[10];
  50       Args[0] = "umount";
  51       Args[1] = Path.c_str();
  52       Args[2] = 0;
  53       execvp(Args[0],(char **)Args);
  54       exit(100);
  55    }
  56
  57    // Wait for mount
  58    int Status = 0;
  59    while (waitpid(Child,&Status,0) != Child)
  60    {
  61       if (errno == EINTR)
  62          continue;
  63       return _error->Errno("waitpid","Couldn't wait for subprocess");
  64    }
  65
  66    // Check for an error code.
  67    if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
  68       return false;
  69    return true;
  70 }
  71                                                                         /*}}}*/
  72 // MountCdrom - Mount a cdrom                                           /*{{{*/
  73 // ---------------------------------------------------------------------
  74 /* We fork mount and drop all messages */
  75 bool MountCdrom(string Path)
  76 {
  77    int Child = fork();
  78    if (Child < -1)
  79       return _error->Errno("fork","Failed to fork");
  80
  81    // The child
  82    if (Child == 0)
  83    {
  84       // Make all the fds /dev/null
  85       for (int I = 0; I != 10; I++)
  86          close(I);
  87       for (int I = 0; I != 3; I++)
  88          dup2(open("/dev/null",O_RDWR),I);
  89
  90       const char *Args[10];
  91       Args[0] = "mount";
  92       Args[1] = Path.c_str();
  93       Args[2] = 0;
  94       execvp(Args[0],(char **)Args);
  95       exit(100);
  96    }
  97
  98    // Wait for mount
  99    int Status = 0;
 100    while (waitpid(Child,&Status,0) != Child)
 101    {
 102       if (errno == EINTR)
 103          continue;
 104       return _error->Errno("waitpid","Couldn't wait for subprocess");
 105    }
 106
 107    // Check for an error code.
 108    if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0)
 109       return false;
 110    return true;
 111 }
 112                                                                         /*}}}*/
 113 // IdentCdrom - Generate a unique string for this CD                    /*{{{*/
 114 // ---------------------------------------------------------------------
 115 /* We convert everything we hash into a string, this prevents byte size/order
 116    from effecting the outcome. */
 117 bool IdentCdrom(string CD,string &Res)
 118 {
 119    MD5Summation Hash;
 120
 121    string StartDir = SafeGetCWD();
 122    if (chdir(CD.c_str()) != 0)
 123       return _error->Errno("chdir","Unable to change to %s",CD.c_str());
 124
 125    DIR *D = opendir(".");
 126    if (D == 0)
 127       return _error->Errno("opendir","Unable to read %s",CD.c_str());
 128
 129    // Run over the directory
 130    char S[300];
 131    for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
 132    {
 133       // Skip some files..
 134       if (strcmp(Dir->d_name,".") == 0 ||
 135           strcmp(Dir->d_name,"..") == 0)
 136          continue;
 137
 138       sprintf(S,"%lu",Dir->d_ino);
 139       Hash.Add(S);
 140       Hash.Add(Dir->d_name);
 141    };
 142
 143    chdir(StartDir.c_str());
 144    closedir(D);
 145
 146    // Some stats from the fsys
 147    struct statfs Buf;
 148    if (statfs(CD.c_str(),&Buf) != 0)
 149       return _error->Errno("statfs","Failed to stat the cdrom");
 150
 151    sprintf(S,"%u %u",Buf.f_blocks,Buf.f_bfree);
 152    Hash.Add(S);
 153
 154    Res = Hash.Result().Value();
 155    return true;
 156 }
 157                                                                         /*}}}*/