Refactor ShellManager process spawning

This commit is contained in:
Maxime Coste 2015-10-01 19:36:37 +01:00
parent 8898571a44
commit bb96ad44b2
2 changed files with 130 additions and 97 deletions

View File

@ -34,7 +34,7 @@ public:
void run(EventMode mode);
void close_fd();
bool closed() const { return m_fd == -1; }
void disable() { m_fd = -1; }
private:
int m_fd;

View File

@ -13,8 +13,6 @@
namespace Kakoune
{
static const Regex env_var_regex(R"(\bkak_(\w+)\b)");
ShellManager::ShellManager()
{
const char* path = getenv("PATH");
@ -22,117 +20,152 @@ ShellManager::ShellManager()
setenv("PATH", new_path.c_str(), 1);
}
namespace
{
struct Pipe
{
Pipe() { pipe(m_fd); }
~Pipe() { close_read_fd(); close_write_fd(); }
int read_fd() const { return m_fd[0]; }
int write_fd() const { return m_fd[1]; }
void close_read_fd() { close_fd(m_fd[0]); }
void close_write_fd() { close_fd(m_fd[1]); }
private:
void close_fd(int& fd) { if (fd != -1) { close(fd); fd = -1; } }
int m_fd[2];
};
pid_t spawn_process(StringView cmdline, ConstArrayView<String> params, ConstArrayView<String> kak_env,
const Pipe& child_stdout, const Pipe& child_stdin, const Pipe& child_stderr)
{
Vector<const char*> envptrs;
for (char** envp = environ; *envp; ++envp)
envptrs.push_back(*envp);
for (auto& env : kak_env)
envptrs.push_back(env.c_str());
envptrs.push_back(nullptr);
const char* shell = "/bin/sh";
auto cmdlinezstr = cmdline.zstr();
Vector<const char*> execparams = { shell, "-c", cmdlinezstr };
if (not params.empty())
execparams.push_back(shell);
for (auto& param : params)
execparams.push_back(param.c_str());
execparams.push_back(nullptr);
if (pid_t pid = fork())
return pid;
auto move = [](int oldfd, int newfd) { dup2(oldfd, newfd); close(oldfd); };
close(child_stdout.write_fd());
move(child_stdout.read_fd(), 0);
close(child_stdin.read_fd());
move(child_stdin.write_fd(), 1);
close(child_stderr.read_fd());
move(child_stderr.write_fd(), 2);
execve(shell, (char* const*)execparams.data(), (char* const*)envptrs.data());
exit(-1);
return -1;
}
}
std::pair<String, int> ShellManager::eval(
StringView cmdline, const Context& context, StringView input,
Flags flags, ConstArrayView<String> params, const EnvVarMap& env_vars)
{
int write_pipe[2]; // child stdin
int read_pipe[2]; // child stdout
int error_pipe[2]; // child stderr
static const Regex re(R"(\bkak_(\w+)\b)");
::pipe(write_pipe);
::pipe(read_pipe);
::pipe(error_pipe);
if (pid_t pid = fork())
Vector<String> kak_env;
for (RegexIterator<const char*> it{cmdline.begin(), cmdline.end(), re}, end;
it != end; ++it)
{
close(write_pipe[0]);
close(read_pipe[1]);
close(error_pipe[1]);
StringView name{(*it)[1].first, (*it)[1].second};
write(write_pipe[1], input.data(), (int)input.length());
close(write_pipe[1]);
auto match_name = [&](const String& s) {
return s.length() > name.length() and
prefix_match(s, name) and s[name.length()] == '=';
};
if (find_if(kak_env, match_name) != kak_env.end())
continue;
String child_stdout, child_stderr;
int status = 0;
auto var_it = env_vars.find(name);
try
{
auto pipe_reader = [](String& output) {
return [&output](FDWatcher& watcher, EventMode) {
char buffer[1024];
size_t size = read(watcher.fd(), buffer, 1024);
if (size <= 0)
watcher.close_fd();
output += StringView{buffer, buffer+size};
};
};
const String& value = var_it != env_vars.end() ?
var_it->value : get_val(name, context);
FDWatcher stdout_watcher{read_pipe[0], pipe_reader(child_stdout)};
FDWatcher stderr_watcher{error_pipe[0], pipe_reader(child_stderr)};
// block SIGCHLD to make sure we wont receive it before
// our call to pselect, that will end up blocking indefinitly.
sigset_t mask, orig_mask;
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
sigprocmask(SIG_BLOCK, &mask, &orig_mask);
// check for termination now that SIGCHLD is blocked
bool terminated = waitpid(pid, &status, WNOHANG);
while (not terminated or
((flags & Flags::WaitForStdout) and
(not stdout_watcher.closed() or
not stderr_watcher.closed())))
{
EventManager::instance().handle_next_events(EventMode::Urgent, &orig_mask);
if (not terminated)
terminated = waitpid(pid, &status, WNOHANG);
}
stdout_watcher.close_fd();
stderr_watcher.close_fd();
sigprocmask(SIG_SETMASK, &orig_mask, nullptr);
}
if (not child_stderr.empty())
write_to_debug_buffer(format("shell stderr: <<<\n{}>>>", child_stderr));
return { child_stdout, WIFEXITED(status) ? WEXITSTATUS(status) : - 1 };
kak_env.push_back(format("kak_{}={}", name, value));
} catch (runtime_error&) {}
}
else try
Pipe child_stdin, child_stdout, child_stderr;
pid_t pid = spawn_process(cmdline, params, kak_env,
child_stdin, child_stdout, child_stderr);
child_stdin.close_read_fd();
child_stdout.close_write_fd();
child_stderr.close_write_fd();
write(child_stdin.write_fd(), input.data(), (int)input.length());
child_stdin.close_write_fd();
struct PipeReader : FDWatcher
{
close(write_pipe[1]);
close(read_pipe[0]);
close(error_pipe[0]);
PipeReader(Pipe& pipe, String& contents)
: FDWatcher(pipe.read_fd(),
[&contents, &pipe](FDWatcher& watcher, EventMode) {
char buffer[1024];
size_t size = read(pipe.read_fd(), buffer, 1024);
if (size <= 0)
{
pipe.close_read_fd();
watcher.disable();
return;
}
contents += StringView{buffer, buffer+size};
})
{}
};
dup2(read_pipe[1], 1); close(read_pipe[1]);
dup2(error_pipe[1], 2); close(error_pipe[1]);
dup2(write_pipe[0], 0); close(write_pipe[0]);
String stdout_contents, stderr_contents;
PipeReader stdout_reader{child_stdout, stdout_contents};
PipeReader stderr_reader{child_stderr, stderr_contents};
using RegexIt = RegexIterator<StringView::iterator>;
for (RegexIt it{cmdline.begin(), cmdline.end(), env_var_regex}, end;
it != end; ++it)
{
auto& match = *it;
// block SIGCHLD to make sure we wont receive it before
// our call to pselect, that will end up blocking indefinitly.
sigset_t mask, orig_mask;
sigemptyset(&mask);
sigaddset(&mask, SIGCHLD);
sigprocmask(SIG_BLOCK, &mask, &orig_mask);
auto restore_mask = on_scope_end([&] { sigprocmask(SIG_SETMASK, &orig_mask, nullptr); });
StringView name{match[1].first, match[1].second};
kak_assert(name.length() > 0);
int status = 0;
// check for termination now that SIGCHLD is blocked
bool terminated = waitpid(pid, &status, WNOHANG);
auto local_var = env_vars.find(name);
if (local_var != env_vars.end())
setenv(("kak_" + name).c_str(), local_var->value.c_str(), 1);
else try
{
String value = get_val(name, context);
setenv(format("kak_{}", name).c_str(), value.c_str(), 1);
}
catch (runtime_error&) {}
}
const char* shell = "/bin/sh";
auto cmdlinezstr = cmdline.zstr();
Vector<const char*> execparams = { shell, "-c", cmdlinezstr };
if (not params.empty())
execparams.push_back(shell);
for (auto& param : params)
execparams.push_back(param.c_str());
execparams.push_back(nullptr);
execvp(shell, (char* const*)execparams.data());
exit(-1);
while (not terminated or
((flags & Flags::WaitForStdout) and
(child_stdout.read_fd() != -1 or child_stderr.read_fd() != -1)))
{
EventManager::instance().handle_next_events(EventMode::Urgent, &orig_mask);
if (not terminated)
terminated = waitpid(pid, &status, WNOHANG);
}
catch (...) { exit(-1); }
return {};
if (not stderr_contents.empty())
write_to_debug_buffer(format("shell stderr: <<<\n{}>>>", stderr_contents));
return { stdout_contents, WIFEXITED(status) ? WEXITSTATUS(status) : -1 };
}
void ShellManager::register_env_var(StringView str, bool prefix,