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-rw-r--r--apt-pkg/contrib/cdromutl.cc293
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+// -*- mode: cpp; mode: fold -*-
+// Description /*{{{*/
+/* ######################################################################
+
+ CDROM Utilities - Some functions to manipulate CDROM mounts.
+
+ These are here for the cdrom method and apt-cdrom.
+
+ ##################################################################### */
+ /*}}}*/
+// Include Files /*{{{*/
+#include <config.h>
+
+#include <apt-pkg/cdromutl.h>
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/hashes.h>
+#include <apt-pkg/strutl.h>
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <vector>
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+ /*}}}*/
+
+using std::string;
+
+// IsMounted - Returns true if the mount point is mounted /*{{{*/
+// ---------------------------------------------------------------------
+/* This is a simple algorithm that should always work, we stat the mount point
+ and the '..' file in the mount point and see if they are on the same device.
+ By definition if they are the same then it is not mounted. This should
+ account for symlinked mount points as well. */
+bool IsMounted(string &Path)
+{
+ if (Path.empty() == true)
+ return false;
+
+ // Need that trailing slash for directories
+ if (Path[Path.length() - 1] != '/')
+ Path += '/';
+
+ // if the path has a ".disk" directory we treat it as mounted
+ // this way even extracted copies of disks are recognized
+ if (DirectoryExists(Path + ".disk/") == true)
+ return true;
+
+ /* First we check if the path is actually mounted, we do this by
+ stating the path and the previous directory (careful of links!)
+ and comparing their device fields. */
+ struct stat Buf,Buf2;
+ if (stat(Path.c_str(),&Buf) != 0 ||
+ stat((Path + "../").c_str(),&Buf2) != 0)
+ return _error->Errno("stat",_("Unable to stat the mount point %s"),Path.c_str());
+
+ if (Buf.st_dev == Buf2.st_dev)
+ return false;
+ return true;
+}
+ /*}}}*/
+// UnmountCdrom - Unmount a cdrom /*{{{*/
+// ---------------------------------------------------------------------
+/* Forking umount works much better than the umount syscall which can
+ leave /etc/mtab inconsistent. We drop all messages this produces. */
+bool UnmountCdrom(string Path)
+{
+ // do not generate errors, even if the mountpoint does not exist
+ // the mountpoint might be auto-created by the mount command
+ // and a non-existing mountpoint is surely not mounted
+ _error->PushToStack();
+ bool const mounted = IsMounted(Path);
+ _error->RevertToStack();
+ if (mounted == false)
+ return true;
+
+ for (int i=0;i<3;i++)
+ {
+
+ int Child = ExecFork();
+
+ // The child
+ if (Child == 0)
+ {
+ // Make all the fds /dev/null
+ int const null_fd = open("/dev/null",O_RDWR);
+ for (int I = 0; I != 3; ++I)
+ dup2(null_fd, I);
+
+ if (_config->Exists("Acquire::cdrom::"+Path+"::UMount") == true)
+ {
+ if (system(_config->Find("Acquire::cdrom::"+Path+"::UMount").c_str()) != 0)
+ _exit(100);
+ _exit(0);
+ }
+ else
+ {
+ const char * const Args[] = {
+ "umount",
+ Path.c_str(),
+ nullptr
+ };
+ execvp(Args[0], const_cast<char **>(Args));
+ _exit(100);
+ }
+ }
+
+ // if it can not be umounted, give it a bit more time
+ // this can happen when auto-mount magic or fs/cdrom prober attack
+ if (ExecWait(Child,"umount",true) == true)
+ return true;
+ sleep(1);
+ }
+
+ return false;
+}
+ /*}}}*/
+// MountCdrom - Mount a cdrom /*{{{*/
+// ---------------------------------------------------------------------
+/* We fork mount and drop all messages */
+bool MountCdrom(string Path, string DeviceName)
+{
+ // do not generate errors, even if the mountpoint does not exist
+ // the mountpoint might be auto-created by the mount command
+ _error->PushToStack();
+ bool const mounted = IsMounted(Path);
+ _error->RevertToStack();
+ if (mounted == true)
+ return true;
+
+ int Child = ExecFork();
+
+ // The child
+ if (Child == 0)
+ {
+ // Make all the fds /dev/null
+ int const null_fd = open("/dev/null",O_RDWR);
+ for (int I = 0; I != 3; ++I)
+ dup2(null_fd, I);
+
+ if (_config->Exists("Acquire::cdrom::"+Path+"::Mount") == true)
+ {
+ if (system(_config->Find("Acquire::cdrom::"+Path+"::Mount").c_str()) != 0)
+ _exit(100);
+ _exit(0);
+ }
+ else
+ {
+ const char *Args[10];
+ Args[0] = "mount";
+ if (DeviceName == "")
+ {
+ Args[1] = Path.c_str();
+ Args[2] = 0;
+ } else {
+ Args[1] = DeviceName.c_str();
+ Args[2] = Path.c_str();
+ Args[3] = 0;
+ }
+ execvp(Args[0],(char **)Args);
+ _exit(100);
+ }
+ }
+
+ // Wait for mount
+ return ExecWait(Child,"mount",true);
+}
+ /*}}}*/
+// IdentCdrom - Generate a unique string for this CD /*{{{*/
+// ---------------------------------------------------------------------
+/* We convert everything we hash into a string, this prevents byte size/order
+ from effecting the outcome. */
+bool IdentCdrom(string CD,string &Res,unsigned int Version)
+{
+ Hashes Hash(Hashes::MD5SUM);
+ bool writable_media = false;
+
+ int dirfd = open(CD.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+ if (dirfd == -1)
+ return _error->Errno("open",_("Unable to read %s"),CD.c_str());
+
+ // if we are on a writable medium (like a usb-stick) that is just
+ // used like a cdrom don't use "." as it will constantly change,
+ // use .disk instead
+ if (faccessat(dirfd, ".", W_OK, 0) == 0)
+ {
+ int diskfd = openat(dirfd, "./.disk", O_RDONLY | O_DIRECTORY | O_CLOEXEC, 0);
+ if (diskfd != -1)
+ {
+ close(dirfd);
+ dirfd = diskfd;
+ writable_media = true;
+ CD = CD.append("/.disk");
+ if (_config->FindB("Debug::aptcdrom",false) == true)
+ std::clog << "Found writable cdrom, using alternative path: " << CD
+ << std::endl;
+ }
+ }
+
+ DIR * const D = fdopendir(dirfd);
+ if (D == nullptr)
+ return _error->Errno("opendir",_("Unable to read %s"),CD.c_str());
+
+ /* Run over the directory, we assume that the reader order will never
+ change as the media is read-only. In theory if the kernel did
+ some sort of wacked caching this might not be true.. */
+ for (struct dirent *Dir = readdir(D); Dir != 0; Dir = readdir(D))
+ {
+ // Skip some files..
+ if (strcmp(Dir->d_name,".") == 0 ||
+ strcmp(Dir->d_name,"..") == 0)
+ continue;
+
+ std::string S;
+ if (Version <= 1)
+ S = std::to_string(Dir->d_ino);
+ else
+ {
+ struct stat Buf;
+ if (fstatat(dirfd, Dir->d_name, &Buf, 0) != 0)
+ continue;
+ S = std::to_string(Buf.st_mtime);
+ }
+
+ Hash.Add(S.c_str());
+ Hash.Add(Dir->d_name);
+ }
+
+ // Some stats from the fsys
+ std::string S;
+ if (_config->FindB("Debug::identcdrom",false) == false)
+ {
+ struct statvfs Buf;
+ if (fstatvfs(dirfd, &Buf) != 0)
+ return _error->Errno("statfs",_("Failed to stat the cdrom"));
+
+ // We use a kilobyte block size to avoid overflow
+ S = std::to_string(Buf.f_blocks * (Buf.f_bsize / 1024));
+ if (writable_media == false)
+ S.append(" ").append(std::to_string(Buf.f_bfree * (Buf.f_bsize / 1024)));
+ Hash.Add(S.c_str(), S.length());
+ strprintf(S, "-%u", Version);
+ }
+ else
+ strprintf(S, "-%u.debug", Version);
+
+ closedir(D);
+ Res = Hash.GetHashString(Hashes::MD5SUM).HashValue().append(std::move(S));
+ return true;
+}
+ /*}}}*/
+// FindMountPointForDevice - Find mountpoint for the given device /*{{{*/
+string FindMountPointForDevice(const char *devnode)
+{
+ // this is the order that mount uses as well
+ std::vector<std::string> const mounts = _config->FindVector("Dir::state::MountPoints", "/etc/mtab,/proc/mount");
+
+ for (std::vector<std::string>::const_iterator m = mounts.begin(); m != mounts.end(); ++m)
+ if (FileExists(*m) == true)
+ {
+ char * line = NULL;
+ size_t line_len = 0;
+ FILE * f = fopen(m->c_str(), "r");
+ while(getline(&line, &line_len, f) != -1)
+ {
+ char * out[] = { NULL, NULL, NULL };
+ TokSplitString(' ', line, out, 3);
+ if (out[2] != NULL || out[1] == NULL || out[0] == NULL)
+ continue;
+ if (strcmp(out[0], devnode) != 0)
+ continue;
+ fclose(f);
+ // unescape the \0XXX chars in the path
+ string mount_point = out[1];
+ free(line);
+ return DeEscapeString(mount_point);
+ }
+ fclose(f);
+ free(line);
+ }
+
+ return string();
+}
+ /*}}}*/