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authorB Stack <bgstack15@gmail.com>2021-02-02 11:44:31 -0500
committerB Stack <bgstack15@gmail.com>2021-02-02 11:44:31 -0500
commitd299ddd2f27a437f0fc0cb49abdfd6dd8e3d94f8 (patch)
tree4d7c950512836f473a6a8cbb521c61e800db6584 /zen/shell_execute.cpp
parentMerge branch '11.5' into 'master' (diff)
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add upstream 11.6
Diffstat (limited to 'zen/shell_execute.cpp')
-rw-r--r--zen/shell_execute.cpp256
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()); }
-}
-
-
bgstack15