// -*- mode: cpp; mode: fold -*- // Description /*{{{*/ // $Id: fileutl.cc,v 1.42 2002/09/14 05:29:22 jgg Exp $ /* ###################################################################### File Utilities CopyFile - Buffered copy of a single file GetLock - dpkg compatible lock file manipulation (fcntl) Most of this source is placed in the Public Domain, do with it what you will It was originally written by Jason Gunthorpe <jgg@debian.org>. The exception is RunScripts() it is under the GPLv2 ##################################################################### */ /*}}}*/ // Include Files /*{{{*/ #include <apt-pkg/fileutl.h> #include <apt-pkg/error.h> #include <apt-pkg/sptr.h> #include <apt-pkg/configuration.h> #include <apti18n.h> #include <cstdlib> #include <cstring> #include <iostream> #include <unistd.h> #include <fcntl.h> #include <sys/stat.h> #include <sys/types.h> #include <sys/time.h> #include <sys/wait.h> #include <dirent.h> #include <signal.h> #include <errno.h> #include <set> #include <algorithm> /*}}}*/ using namespace std; // RunScripts - Run a set of scripts from a configuration subtree /*{{{*/ // --------------------------------------------------------------------- /* */ bool RunScripts(const char *Cnf) { Configuration::Item const *Opts = _config->Tree(Cnf); if (Opts == 0 || Opts->Child == 0) return true; Opts = Opts->Child; // Fork for running the system calls pid_t Child = ExecFork(); // This is the child if (Child == 0) { if (chdir("/tmp/") != 0) _exit(100); unsigned int Count = 1; for (; Opts != 0; Opts = Opts->Next, Count++) { if (Opts->Value.empty() == true) continue; if (system(Opts->Value.c_str()) != 0) _exit(100+Count); } _exit(0); } // Wait for the child int Status = 0; while (waitpid(Child,&Status,0) != Child) { if (errno == EINTR) continue; return _error->Errno("waitpid","Couldn't wait for subprocess"); } // Restore sig int/quit signal(SIGQUIT,SIG_DFL); signal(SIGINT,SIG_DFL); // Check for an error code. if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0) { unsigned int Count = WEXITSTATUS(Status); if (Count > 100) { Count -= 100; for (; Opts != 0 && Count != 1; Opts = Opts->Next, Count--); _error->Error("Problem executing scripts %s '%s'",Cnf,Opts->Value.c_str()); } return _error->Error("Sub-process returned an error code"); } return true; } /*}}}*/ // CopyFile - Buffered copy of a file /*{{{*/ // --------------------------------------------------------------------- /* The caller is expected to set things so that failure causes erasure */ bool CopyFile(FileFd &From,FileFd &To) { if (From.IsOpen() == false || To.IsOpen() == false) return false; // Buffered copy between fds SPtrArray<unsigned char> Buf = new unsigned char[64000]; unsigned long Size = From.Size(); while (Size != 0) { unsigned long ToRead = Size; if (Size > 64000) ToRead = 64000; if (From.Read(Buf,ToRead) == false || To.Write(Buf,ToRead) == false) return false; Size -= ToRead; } return true; } /*}}}*/ // GetLock - Gets a lock file /*{{{*/ // --------------------------------------------------------------------- /* This will create an empty file of the given name and lock it. Once this is done all other calls to GetLock in any other process will fail with -1. The return result is the fd of the file, the call should call close at some time. */ int GetLock(string File,bool Errors) { // GetLock() is used in aptitude on directories with public-write access // Use O_NOFOLLOW here to prevent symlink traversal attacks int FD = open(File.c_str(),O_RDWR | O_CREAT | O_NOFOLLOW,0640); if (FD < 0) { // Read only .. cant have locking problems there. if (errno == EROFS) { _error->Warning(_("Not using locking for read only lock file %s"),File.c_str()); return dup(0); // Need something for the caller to close } if (Errors == true) _error->Errno("open",_("Could not open lock file %s"),File.c_str()); // Feh.. We do this to distinguish the lock vs open case.. errno = EPERM; return -1; } SetCloseExec(FD,true); // Aquire a write lock struct flock fl; fl.l_type = F_WRLCK; fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = 0; if (fcntl(FD,F_SETLK,&fl) == -1) { if (errno == ENOLCK) { _error->Warning(_("Not using locking for nfs mounted lock file %s"),File.c_str()); return dup(0); // Need something for the caller to close } if (Errors == true) _error->Errno("open",_("Could not get lock %s"),File.c_str()); int Tmp = errno; close(FD); errno = Tmp; return -1; } return FD; } /*}}}*/ // FileExists - Check if a file exists /*{{{*/ // --------------------------------------------------------------------- /* */ bool FileExists(string File) { struct stat Buf; if (stat(File.c_str(),&Buf) != 0) return false; return true; } /*}}}*/ // GetListOfFilesInDir - returns a vector of files in the given dir /*{{{*/ // --------------------------------------------------------------------- /* If an extension is given only files with this extension are included in the returned vector, otherwise every "normal" file is included. */ std::vector<string> GetListOfFilesInDir(string const &Dir, string const &Ext, bool const &SortList) { std::vector<string> List; DIR *D = opendir(Dir.c_str()); if (D == 0) { _error->Errno("opendir",_("Unable to read %s"),Dir.c_str()); return List; } for (struct dirent *Ent = readdir(D); Ent != 0; Ent = readdir(D)) { if (Ent->d_name[0] == '.') continue; if (Ext.empty() == false && flExtension(Ent->d_name) != Ext) continue; // Skip bad file names ala run-parts const char *C = Ent->d_name; for (; *C != 0; ++C) if (isalpha(*C) == 0 && isdigit(*C) == 0 && *C != '_' && *C != '-' && *C != '.') break; if (*C != 0) continue; // Make sure it is a file and not something else string const File = flCombine(Dir,Ent->d_name); struct stat St; if (stat(File.c_str(),&St) != 0 || S_ISREG(St.st_mode) == 0) continue; List.push_back(File); } closedir(D); if (SortList == true) std::sort(List.begin(),List.end()); return List; } /*}}}*/ // SafeGetCWD - This is a safer getcwd that returns a dynamic string /*{{{*/ // --------------------------------------------------------------------- /* We return / on failure. */ string SafeGetCWD() { // Stash the current dir. char S[300]; S[0] = 0; if (getcwd(S,sizeof(S)-2) == 0) return "/"; unsigned int Len = strlen(S); S[Len] = '/'; S[Len+1] = 0; return S; } /*}}}*/ // flNotDir - Strip the directory from the filename /*{{{*/ // --------------------------------------------------------------------- /* */ string flNotDir(string File) { string::size_type Res = File.rfind('/'); if (Res == string::npos) return File; Res++; return string(File,Res,Res - File.length()); } /*}}}*/ // flNotFile - Strip the file from the directory name /*{{{*/ // --------------------------------------------------------------------- /* Result ends in a / */ string flNotFile(string File) { string::size_type Res = File.rfind('/'); if (Res == string::npos) return "./"; Res++; return string(File,0,Res); } /*}}}*/ // flExtension - Return the extension for the file /*{{{*/ // --------------------------------------------------------------------- /* */ string flExtension(string File) { string::size_type Res = File.rfind('.'); if (Res == string::npos) return File; Res++; return string(File,Res,Res - File.length()); } /*}}}*/ // flNoLink - If file is a symlink then deref it /*{{{*/ // --------------------------------------------------------------------- /* If the name is not a link then the returned path is the input. */ string flNoLink(string File) { struct stat St; if (lstat(File.c_str(),&St) != 0 || S_ISLNK(St.st_mode) == 0) return File; if (stat(File.c_str(),&St) != 0) return File; /* Loop resolving the link. There is no need to limit the number of loops because the stat call above ensures that the symlink is not circular */ char Buffer[1024]; string NFile = File; while (1) { // Read the link int Res; if ((Res = readlink(NFile.c_str(),Buffer,sizeof(Buffer))) <= 0 || (unsigned)Res >= sizeof(Buffer)) return File; // Append or replace the previous path Buffer[Res] = 0; if (Buffer[0] == '/') NFile = Buffer; else NFile = flNotFile(NFile) + Buffer; // See if we are done if (lstat(NFile.c_str(),&St) != 0) return File; if (S_ISLNK(St.st_mode) == 0) return NFile; } } /*}}}*/ // flCombine - Combine a file and a directory /*{{{*/ // --------------------------------------------------------------------- /* If the file is an absolute path then it is just returned, otherwise the directory is pre-pended to it. */ string flCombine(string Dir,string File) { if (File.empty() == true) return string(); if (File[0] == '/' || Dir.empty() == true) return File; if (File.length() >= 2 && File[0] == '.' && File[1] == '/') return File; if (Dir[Dir.length()-1] == '/') return Dir + File; return Dir + '/' + File; } /*}}}*/ // SetCloseExec - Set the close on exec flag /*{{{*/ // --------------------------------------------------------------------- /* */ void SetCloseExec(int Fd,bool Close) { if (fcntl(Fd,F_SETFD,(Close == false)?0:FD_CLOEXEC) != 0) { cerr << "FATAL -> Could not set close on exec " << strerror(errno) << endl; exit(100); } } /*}}}*/ // SetNonBlock - Set the nonblocking flag /*{{{*/ // --------------------------------------------------------------------- /* */ void SetNonBlock(int Fd,bool Block) { int Flags = fcntl(Fd,F_GETFL) & (~O_NONBLOCK); if (fcntl(Fd,F_SETFL,Flags | ((Block == false)?0:O_NONBLOCK)) != 0) { cerr << "FATAL -> Could not set non-blocking flag " << strerror(errno) << endl; exit(100); } } /*}}}*/ // WaitFd - Wait for a FD to become readable /*{{{*/ // --------------------------------------------------------------------- /* This waits for a FD to become readable using select. It is useful for applications making use of non-blocking sockets. The timeout is in seconds. */ bool WaitFd(int Fd,bool write,unsigned long timeout) { fd_set Set; struct timeval tv; FD_ZERO(&Set); FD_SET(Fd,&Set); tv.tv_sec = timeout; tv.tv_usec = 0; if (write == true) { int Res; do { Res = select(Fd+1,0,&Set,0,(timeout != 0?&tv:0)); } while (Res < 0 && errno == EINTR); if (Res <= 0) return false; } else { int Res; do { Res = select(Fd+1,&Set,0,0,(timeout != 0?&tv:0)); } while (Res < 0 && errno == EINTR); if (Res <= 0) return false; } return true; } /*}}}*/ // ExecFork - Magical fork that sanitizes the context before execing /*{{{*/ // --------------------------------------------------------------------- /* This is used if you want to cleanse the environment for the forked child, it fixes up the important signals and nukes all of the fds, otherwise acts like normal fork. */ pid_t ExecFork() { // Fork off the process pid_t Process = fork(); if (Process < 0) { cerr << "FATAL -> Failed to fork." << endl; exit(100); } // Spawn the subprocess if (Process == 0) { // Setup the signals signal(SIGPIPE,SIG_DFL); signal(SIGQUIT,SIG_DFL); signal(SIGINT,SIG_DFL); signal(SIGWINCH,SIG_DFL); signal(SIGCONT,SIG_DFL); signal(SIGTSTP,SIG_DFL); set<int> KeepFDs; Configuration::Item const *Opts = _config->Tree("APT::Keep-Fds"); if (Opts != 0 && Opts->Child != 0) { Opts = Opts->Child; for (; Opts != 0; Opts = Opts->Next) { if (Opts->Value.empty() == true) continue; int fd = atoi(Opts->Value.c_str()); KeepFDs.insert(fd); } } // Close all of our FDs - just in case for (int K = 3; K != 40; K++) { if(KeepFDs.find(K) == KeepFDs.end()) fcntl(K,F_SETFD,FD_CLOEXEC); } } return Process; } /*}}}*/ // ExecWait - Fancy waitpid /*{{{*/ // --------------------------------------------------------------------- /* Waits for the given sub process. If Reap is set then no errors are generated. Otherwise a failed subprocess will generate a proper descriptive message */ bool ExecWait(pid_t Pid,const char *Name,bool Reap) { if (Pid <= 1) return true; // Wait and collect the error code int Status; while (waitpid(Pid,&Status,0) != Pid) { if (errno == EINTR) continue; if (Reap == true) return false; return _error->Error(_("Waited for %s but it wasn't there"),Name); } // Check for an error code. if (WIFEXITED(Status) == 0 || WEXITSTATUS(Status) != 0) { if (Reap == true) return false; if (WIFSIGNALED(Status) != 0) { if( WTERMSIG(Status) == SIGSEGV) return _error->Error(_("Sub-process %s received a segmentation fault."),Name); else return _error->Error(_("Sub-process %s received signal %u."),Name, WTERMSIG(Status)); } if (WIFEXITED(Status) != 0) return _error->Error(_("Sub-process %s returned an error code (%u)"),Name,WEXITSTATUS(Status)); return _error->Error(_("Sub-process %s exited unexpectedly"),Name); } return true; } /*}}}*/ // FileFd::Open - Open a file /*{{{*/ // --------------------------------------------------------------------- /* The most commonly used open mode combinations are given with Mode */ bool FileFd::Open(string FileName,OpenMode Mode, unsigned long Perms) { Close(); Flags = AutoClose; switch (Mode) { case ReadOnly: iFd = open(FileName.c_str(),O_RDONLY); break; case WriteEmpty: { struct stat Buf; if (lstat(FileName.c_str(),&Buf) == 0 && S_ISLNK(Buf.st_mode)) unlink(FileName.c_str()); iFd = open(FileName.c_str(),O_RDWR | O_CREAT | O_TRUNC,Perms); break; } case WriteExists: iFd = open(FileName.c_str(),O_RDWR); break; case WriteAny: iFd = open(FileName.c_str(),O_RDWR | O_CREAT,Perms); break; case WriteTemp: unlink(FileName.c_str()); iFd = open(FileName.c_str(),O_RDWR | O_CREAT | O_EXCL,Perms); break; } if (iFd < 0) return _error->Errno("open",_("Could not open file %s"),FileName.c_str()); this->FileName = FileName; SetCloseExec(iFd,true); return true; } /*}}}*/ // FileFd::~File - Closes the file /*{{{*/ // --------------------------------------------------------------------- /* If the proper modes are selected then we close the Fd and possibly unlink the file on error. */ FileFd::~FileFd() { Close(); } /*}}}*/ // FileFd::Read - Read a bit of the file /*{{{*/ // --------------------------------------------------------------------- /* We are carefull to handle interruption by a signal while reading gracefully. */ bool FileFd::Read(void *To,unsigned long Size,unsigned long *Actual) { int Res; errno = 0; if (Actual != 0) *Actual = 0; do { Res = read(iFd,To,Size); if (Res < 0 && errno == EINTR) continue; if (Res < 0) { Flags |= Fail; return _error->Errno("read",_("Read error")); } To = (char *)To + Res; Size -= Res; if (Actual != 0) *Actual += Res; } while (Res > 0 && Size > 0); if (Size == 0) return true; // Eof handling if (Actual != 0) { Flags |= HitEof; return true; } Flags |= Fail; return _error->Error(_("read, still have %lu to read but none left"),Size); } /*}}}*/ // FileFd::Write - Write to the file /*{{{*/ // --------------------------------------------------------------------- /* */ bool FileFd::Write(const void *From,unsigned long Size) { int Res; errno = 0; do { Res = write(iFd,From,Size); if (Res < 0 && errno == EINTR) continue; if (Res < 0) { Flags |= Fail; return _error->Errno("write",_("Write error")); } From = (char *)From + Res; Size -= Res; } while (Res > 0 && Size > 0); if (Size == 0) return true; Flags |= Fail; return _error->Error(_("write, still have %lu to write but couldn't"),Size); } /*}}}*/ // FileFd::Seek - Seek in the file /*{{{*/ // --------------------------------------------------------------------- /* */ bool FileFd::Seek(unsigned long To) { if (lseek(iFd,To,SEEK_SET) != (signed)To) { Flags |= Fail; return _error->Error("Unable to seek to %lu",To); } return true; } /*}}}*/ // FileFd::Skip - Seek in the file /*{{{*/ // --------------------------------------------------------------------- /* */ bool FileFd::Skip(unsigned long Over) { if (lseek(iFd,Over,SEEK_CUR) < 0) { Flags |= Fail; return _error->Error("Unable to seek ahead %lu",Over); } return true; } /*}}}*/ // FileFd::Truncate - Truncate the file /*{{{*/ // --------------------------------------------------------------------- /* */ bool FileFd::Truncate(unsigned long To) { if (ftruncate(iFd,To) != 0) { Flags |= Fail; return _error->Error("Unable to truncate to %lu",To); } return true; } /*}}}*/ // FileFd::Tell - Current seek position /*{{{*/ // --------------------------------------------------------------------- /* */ unsigned long FileFd::Tell() { off_t Res = lseek(iFd,0,SEEK_CUR); if (Res == (off_t)-1) _error->Errno("lseek","Failed to determine the current file position"); return Res; } /*}}}*/ // FileFd::Size - Return the size of the file /*{{{*/ // --------------------------------------------------------------------- /* */ unsigned long FileFd::Size() { struct stat Buf; if (fstat(iFd,&Buf) != 0) return _error->Errno("fstat","Unable to determine the file size"); return Buf.st_size; } /*}}}*/ // FileFd::Close - Close the file if the close flag is set /*{{{*/ // --------------------------------------------------------------------- /* */ bool FileFd::Close() { bool Res = true; if ((Flags & AutoClose) == AutoClose) if (iFd >= 0 && close(iFd) != 0) Res &= _error->Errno("close",_("Problem closing the file")); iFd = -1; if ((Flags & Fail) == Fail && (Flags & DelOnFail) == DelOnFail && FileName.empty() == false) if (unlink(FileName.c_str()) != 0) Res &= _error->WarningE("unlnk",_("Problem unlinking the file")); return Res; } /*}}}*/ // FileFd::Sync - Sync the file /*{{{*/ // --------------------------------------------------------------------- /* */ bool FileFd::Sync() { #ifdef _POSIX_SYNCHRONIZED_IO if (fsync(iFd) != 0) return _error->Errno("sync",_("Problem syncing the file")); #endif return true; } /*}}}*/