+bool CheckDropPrivsMustBeDisabled(pkgAcquire &Fetcher) /*{{{*/
+{
+ // no need/possibility to drop privs
+ if(getuid() != 0)
+ return true;
+
+ // the user does not want to drop privs
+ std::string SandboxUser = _config->Find("APT::Sandbox::User");
+ if (SandboxUser.empty())
+ return true;
+
+ struct passwd const * const pw = getpwnam(SandboxUser.c_str());
+ if (pw == NULL)
+ return true;
+
+ if (seteuid(pw->pw_uid) != 0)
+ return _error->Errno("seteuid", "seteuid %u failed", pw->pw_uid);
+
+ bool res = true;
+ // check if we can write to destfile
+ for (pkgAcquire::ItemIterator I = Fetcher.ItemsBegin();
+ I != Fetcher.ItemsEnd() && res == true; ++I)
+ {
+ if ((*I)->DestFile.empty())
+ continue;
+ // we assume that an existing (partial) file means that we have sufficient rights
+ if (RealFileExists((*I)->DestFile))
+ continue;
+ int fd = open((*I)->DestFile.c_str(), O_CREAT | O_EXCL | O_RDWR, 0600);
+ if (fd < 0)
+ {
+ res = false;
+ std::string msg;
+ strprintf(msg, _("Can't drop privileges for downloading as file '%s' couldn't be accessed by user '%s'."),
+ (*I)->DestFile.c_str(), SandboxUser.c_str());
+ std::cerr << "W: " << msg << std::endl;
+ _config->Set("APT::Sandbox::User", "");
+ break;
+ }
+ unlink((*I)->DestFile.c_str());
+ close(fd);
+ }
+
+ if (seteuid(0) != 0)
+ return _error->Errno("seteuid", "seteuid %u failed", 0);
+
+ return res;
+}
+ /*}}}*/