diff options
Diffstat (limited to 'zen/shell_execute.cpp')
| -rw-r--r-- | zen/shell_execute.cpp | 256 |
1 files changed, 0 insertions, 256 deletions
diff --git a/zen/shell_execute.cpp b/zen/shell_execute.cpp deleted file mode 100644 index 241b9786..00000000 --- a/zen/shell_execute.cpp +++ /dev/null @@ -1,256 +0,0 @@ -// ***************************************************************************** -// * This file is part of the FreeFileSync project. It is distributed under * -// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0 * -// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved * -// ***************************************************************************** - -#include "shell_execute.h" -#include <chrono> -#include "guid.h" -#include "file_access.h" -#include "file_io.h" - - #include <unistd.h> //fork, pipe - #include <sys/wait.h> //waitpid - #include <fcntl.h> - -using namespace zen; - - -std::vector<Zstring> zen::parseCommandline(const Zstring& cmdLine) -{ - std::vector<Zstring> args; - //"Parsing C++ Command-Line Arguments": https://docs.microsoft.com/en-us/cpp/cpp/parsing-cpp-command-line-arguments - //we do the job ourselves! both wxWidgets and ::CommandLineToArgvW() parse "C:\" "D:\" as single line C:\" D:\" - //-> "solution": we just don't support protected quotation mark! - - auto itStart = cmdLine.end(); //end() means: no token - for (auto it = cmdLine.begin(); it != cmdLine.end(); ++it) - if (*it == Zstr(' ')) //space commits token - { - if (itStart != cmdLine.end()) - { - args.emplace_back(itStart, it); - itStart = cmdLine.end(); //expect consecutive blanks! - } - } - else - { - //start new token - if (itStart == cmdLine.end()) - itStart = it; - - if (*it == Zstr('"')) - { - it = std::find(it + 1, cmdLine.end(), Zstr('"')); - if (it == cmdLine.end()) - break; - } - } - if (itStart != cmdLine.end()) - args.emplace_back(itStart, cmdLine.end()); - - for (Zstring& str : args) - if (str.size() >= 2 && startsWith(str, Zstr('"')) && endsWith(str, Zstr('"'))) - str = Zstring(str.c_str() + 1, str.size() - 2); - - return args; -} - - - - -std::pair<int /*exit code*/, std::wstring> zen::consoleExecute(const Zstring& cmdLine, std::optional<int> timeoutMs) //throw SysError, SysErrorTimeOut -{ - const Zstring tempFilePath = appendSeparator(getTempFolderPath()) + //throw FileError - Zstr("FFS-") + utfTo<Zstring>(formatAsHexString(generateGUID())); - /* can't use popen(): does NOT return the exit code on Linux (despite the documentation!), although it works correctly on macOS - => use pipes instead: https://linux.die.net/man/2/waitpid - bonus: no need for "2>&1" to redirect STDERR to STDOUT - - What about premature exit via SysErrorTimeOut? - Linux: child process' end of the pipe *still works* even after the parent process is gone: - There does not seem to be any output buffer size limit + no observable strain on system memory or disk space! :) - macOS: child process exits if parent end of pipe is closed: fuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu.......... - - => solution: buffer output in temporary file - - Unresolved problem: premature exit via SysErrorTimeOut (=> no waitpid()) creates zombie proceses: - "As long as a zombie is not removed from the system via a wait, - it will consume a slot in the kernel process table, and if this table fills, - it will not be possible to create further processes." */ - - const int EC_CHILD_LAUNCH_FAILED = 120; //avoid 127: used by the system, e.g. failure to execute due to missing .so file - - //use O_TMPFILE? sounds nice, but support is probably crap: https://github.com/libvips/libvips/issues/1151 - const int fdTempFile = ::open(tempFilePath.c_str(), O_CREAT | O_EXCL | O_RDWR | O_CLOEXEC, - S_IRUSR | S_IWUSR); //0600 - if (fdTempFile == -1) - THROW_LAST_SYS_ERROR("open"); - auto guardTmpFile = makeGuard<ScopeGuardRunMode::onExit>([&] { ::close(fdTempFile); }); - - //"deleting while handle is open" == FILE_FLAG_DELETE_ON_CLOSE - if (::unlink(tempFilePath.c_str()) != 0) - THROW_LAST_SYS_ERROR("unlink"); - - //-------------------------------------------------------------- - //waitpid() is a useless pile of garbage without time out => check EOF from dummy pipe instead - int pipe[2] = {}; - if (::pipe2(pipe, O_CLOEXEC) != 0) - THROW_LAST_SYS_ERROR("pipe2"); - - - const int fdLifeSignR = pipe[0]; //for parent process - const int fdLifeSignW = pipe[1]; //for child process - ZEN_ON_SCOPE_EXIT(::close(fdLifeSignR)); - auto guardFdLifeSignW = makeGuard<ScopeGuardRunMode::onExit>([&] { ::close(fdLifeSignW ); }); - //-------------------------------------------------------------- - - //follow implemenation of ::system(): https://github.com/lattera/glibc/blob/master/sysdeps/posix/system.c - const pid_t pid = ::fork(); - if (pid < 0) //pids are never negative, empiric proof: https://linux.die.net/man/2/wait - THROW_LAST_SYS_ERROR("fork"); - - if (pid == 0) //child process - try - { - //first task: set STDOUT redirection in case an error needs to be reported - if (::dup2(fdTempFile, STDOUT_FILENO) != STDOUT_FILENO) //O_CLOEXEC does NOT propagate with dup2() - THROW_LAST_SYS_ERROR("dup2(STDOUT)"); - - if (::dup2(fdTempFile, STDERR_FILENO) != STDERR_FILENO) //O_CLOEXEC does NOT propagate with dup2() - THROW_LAST_SYS_ERROR("dup2(STDERR)"); - - //avoid blocking scripts waiting for user input - // => appending " < /dev/null" is not good enough! e.g. hangs for: read -p "still hanging here"; echo fuuuuu... - const int fdDevNull = ::open("/dev/null", O_RDONLY | O_CLOEXEC); - if (fdDevNull == -1) //don't check "< 0" -> docu seems to allow "-2" to be a valid file handle - THROW_LAST_SYS_ERROR("open(/dev/null)"); - ZEN_ON_SCOPE_EXIT(::close(fdDevNull)); - - if (::dup2(fdDevNull, STDIN_FILENO) != STDIN_FILENO) //O_CLOEXEC does NOT propagate with dup2() - THROW_LAST_SYS_ERROR("dup2(STDIN)"); - - //*leak* the fd and have it closed automatically on child process exit after execv() - if (::dup(fdLifeSignW) == -1) //O_CLOEXEC does NOT propagate with dup() - THROW_LAST_SYS_ERROR("dup(fdLifeSignW)"); - - - const char* argv[] = { "sh", "-c", cmdLine.c_str(), nullptr }; - /*int rv =*/::execv("/bin/sh", const_cast<char**>(argv)); //only returns if an error occurred - //safe to cast away const: https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html - // "The statement about argv[] and envp[] being constants is included to make explicit to future - // writers of language bindings that these objects are completely constant. Due to a limitation of - // the ISO C standard, it is not possible to state that idea in standard C." - THROW_LAST_SYS_ERROR("execv"); - } - catch (const SysError& e) - { - ::puts(utfTo<std::string>(e.toString()).c_str()); - ::fflush(stdout); //note: stderr is unbuffered by default - ::_exit(EC_CHILD_LAUNCH_FAILED); //[!] avoid flushing I/O buffers or doing other clean up from child process like with "exit()"! - } - //else: parent process - - - if (timeoutMs) - { - guardFdLifeSignW.dismiss(); - ::close(fdLifeSignW); //[!] make sure we get EOF when fd is closed by child! - - const int flags = ::fcntl(fdLifeSignR, F_GETFL); - if (flags == -1) - THROW_LAST_SYS_ERROR("fcntl(F_GETFL)"); - - if (::fcntl(fdLifeSignR, F_SETFL, flags | O_NONBLOCK) == -1) - THROW_LAST_SYS_ERROR("fcntl(F_SETFL, O_NONBLOCK)"); - - - const auto endTime = std::chrono::steady_clock::now() + std::chrono::milliseconds(*timeoutMs); - for (;;) //EINTR handling? => allow interruption!? - { - //read until EAGAIN - char buf[16]; - const ssize_t bytesRead = ::read(fdLifeSignR, buf, sizeof(buf)); - if (bytesRead < 0) - { - if (errno != EAGAIN) - THROW_LAST_SYS_ERROR("read"); - } - else if (bytesRead > 0) - throw SysError(formatSystemError("read", L"", L"Unexpected data.")); - else //bytesRead == 0: EOF - break; - - //wait for stream input - const auto now = std::chrono::steady_clock::now(); - if (now > endTime) - throw SysErrorTimeOut(_P("Operation timed out after 1 second.", "Operation timed out after %x seconds.", *timeoutMs / 1000)); - - const auto waitTimeMs = std::chrono::duration_cast<std::chrono::milliseconds>(endTime - now).count(); - - struct ::timeval tv = {}; - tv.tv_sec = static_cast<long>(waitTimeMs / 1000); - tv.tv_usec = static_cast<long>(waitTimeMs - tv.tv_sec * 1000) * 1000; - - fd_set rfd = {}; //includes FD_ZERO - FD_SET(fdLifeSignR, &rfd); - - if (const int rv = ::select(fdLifeSignR + 1, //int nfds, - &rfd, //fd_set* readfds, - nullptr, //fd_set* writefds, - nullptr, //fd_set* exceptfds, - &tv); //struct timeval* timeout - rv < 0) - THROW_LAST_SYS_ERROR("select"); - else if (rv == 0) - throw SysErrorTimeOut(_P("Operation timed out after 1 second.", "Operation timed out after %x seconds.", *timeoutMs / 1000)); - } - } - - //https://linux.die.net/man/2/waitpid - int statusCode = 0; - if (::waitpid(pid, //pid_t pid - &statusCode, //int* status - 0) != pid) //int options - THROW_LAST_SYS_ERROR("waitpid"); - - - if (::lseek(fdTempFile, 0, SEEK_SET) != 0) - THROW_LAST_SYS_ERROR("lseek"); - - guardTmpFile.dismiss(); - FileInput streamIn(fdTempFile, tempFilePath, nullptr /*notifyUnbufferedIO*/); //takes ownership! - const std::wstring output = utfTo<std::wstring>(bufferedLoad<std::string>(streamIn)); //throw FileError - - - if (!WIFEXITED(statusCode)) //signalled, crashed? - throw SysError(formatSystemError("waitpid", WIFSIGNALED(statusCode) ? - L"Killed by signal " + numberTo<std::wstring>(WTERMSIG(statusCode)) : - L"Exit status " + numberTo<std::wstring>(statusCode), - utfTo<std::wstring>(trimCpy(output)))); - - const int exitCode = WEXITSTATUS(statusCode); //precondition: "WIFEXITED() == true" - if (exitCode == EC_CHILD_LAUNCH_FAILED || //child process should already have provided details to STDOUT - exitCode == 127) //details should have been streamed to STDERR: used by /bin/sh, e.g. failure to execute due to missing .so file - throw SysError(utfTo<std::wstring>(trimCpy(output))); - - return { exitCode, output }; -} - - -void zen::openWithDefaultApp(const Zstring& itemPath) //throw FileError -{ - try - { - const Zstring cmdTemplate = R"(xdg-open "%x")"; //doesn't block => no need for time out! - const Zstring cmdLine = replaceCpy(cmdTemplate, Zstr("%x"), itemPath); - - if (const auto& [exitCode, output] = consoleExecute(cmdLine, std::nullopt /*timeoutMs*/); //throw SysError, (SysErrorTimeOut) - exitCode != 0) - throw SysError(formatSystemError(utfTo<std::string>(cmdTemplate), replaceCpy(_("Exit code %x"), L"%x", numberTo<std::wstring>(exitCode)), output)); - } - catch (const SysError& e) { throw FileError(replaceCpy(_("Cannot open file %x."), L"%x", fmtPath(itemPath)), e.toString()); } -} - - |