home/src/shell_manager.cc
Maxime Coste 8a74ef9804 Read as much as possible data from shell processes on each read event
We were reading at most 1024 bytes every time, going back to the event
loop.
2016-12-03 12:41:36 +00:00

264 lines
8.4 KiB
C++

#include "shell_manager.hh"
#include "buffer_utils.hh"
#include "clock.hh"
#include "context.hh"
#include "display_buffer.hh"
#include "event_manager.hh"
#include "face_registry.hh"
#include "file.hh"
#include "regex.hh"
#include <cstring>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
extern char **environ;
namespace Kakoune
{
ShellManager::ShellManager()
{
const char* path = getenv("PATH");
auto new_path = format("{}:{}", path, split_path(get_kak_binary_path()).first);
setenv("PATH", new_path.c_str(), 1);
}
namespace
{
struct Pipe
{
Pipe(bool create = true)
: m_fd{-1, -1}
{
if (create and ::pipe(m_fd) < 0)
throw runtime_error(format("unable to create pipe (fds: {}/{}; errno: {})", m_fd[0], m_fd[1], ::strerror(errno)));
}
~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];
};
template<typename Func>
pid_t spawn_shell(StringView cmdline, ConstArrayView<String> params,
ConstArrayView<String> kak_env, Func setup_child)
{
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;
setup_child();
execve(shell, (char* const*)execparams.data(), (char* const*)envptrs.data());
exit(-1);
return -1;
}
Vector<String> generate_env(StringView cmdline, const Context& context, const ShellContext& shell_context)
{
static const Regex re(R"(\bkak_(\w+)\b)");
Vector<String> kak_env;
for (RegexIterator<const char*> it{cmdline.begin(), cmdline.end(), re}, end;
it != end; ++it)
{
StringView name{(*it)[1].first, (*it)[1].second};
auto match_name = [&](const String& s) {
return s.length() > name.length() and
prefix_match(s, name) and s[name.length()] == '=';
};
if (contains_that(kak_env, match_name))
continue;
auto var_it = shell_context.env_vars.find(name);
try
{
const String& value = var_it != shell_context.env_vars.end() ?
var_it->value : ShellManager::instance().get_val(name, context);
kak_env.push_back(format("kak_{}={}", name, value));
} catch (runtime_error&) {}
}
return kak_env;
}
}
std::pair<String, int> ShellManager::eval(
StringView cmdline, const Context& context, StringView input,
Flags flags, const ShellContext& shell_context)
{
const DebugFlags debug_flags = context.options()["debug"].get<DebugFlags>();
const bool profile = debug_flags & DebugFlags::Profile;
if (debug_flags & DebugFlags::Shell)
write_to_debug_buffer(format("shell:\n{}\n----\n", cmdline));
auto start_time = profile ? Clock::now() : Clock::time_point{};
auto kak_env = generate_env(cmdline, context, shell_context);
auto spawn_time = profile ? Clock::now() : Clock::time_point{};
Pipe child_stdin{not input.empty()}, child_stdout, child_stderr;
pid_t pid = spawn_shell(cmdline, shell_context.params, kak_env,
[&child_stdin, &child_stdout, &child_stderr] {
auto move = [](int oldfd, int newfd) { dup2(oldfd, newfd); close(oldfd); };
if (child_stdin.read_fd() != -1)
{
close(child_stdin.write_fd());
move(child_stdin.read_fd(), 0);
}
close(child_stdout.read_fd());
move(child_stdout.write_fd(), 1);
close(child_stderr.read_fd());
move(child_stderr.write_fd(), 2);
});
child_stdin.close_read_fd();
child_stdout.close_write_fd();
child_stderr.close_write_fd();
write(child_stdin.write_fd(), input);
child_stdin.close_write_fd();
auto wait_time = Clock::now();
struct PipeReader : FDWatcher
{
PipeReader(Pipe& pipe, String& contents)
: FDWatcher(pipe.read_fd(), FdEvents::Read,
[&contents, &pipe](FDWatcher& watcher, FdEvents, EventMode) {
char buffer[1024];
while (fd_readable(pipe.read_fd()))
{
size_t size = ::read(pipe.read_fd(), buffer, 1024);
if (size <= 0)
{
pipe.close_read_fd();
watcher.disable();
return;
}
contents += StringView{buffer, buffer+size};
}
})
{}
};
String stdout_contents, stderr_contents;
PipeReader stdout_reader{child_stdout, stdout_contents};
PipeReader stderr_reader{child_stderr, stderr_contents};
// 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); });
int status = 0;
// check for termination now that SIGCHLD is blocked
bool terminated = waitpid(pid, &status, WNOHANG);
using namespace std::chrono;
static constexpr seconds wait_timeout{1};
bool wait_notified = false;
Timer wait_timer{wait_time + wait_timeout, [&](Timer& timer)
{
auto wait_duration = Clock::now() - wait_time;
context.print_status({ format("waiting for shell command to finish ({}s)",
duration_cast<seconds>(wait_duration).count()),
get_face("Information") }, true);
timer.set_next_date(Clock::now() + wait_timeout);
wait_notified = true;
}, EventMode::Urgent};
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);
}
if (not stderr_contents.empty())
write_to_debug_buffer(format("shell stderr: <<<\n{}>>>", stderr_contents));
if (profile)
{
auto end_time = Clock::now();
auto full = duration_cast<milliseconds>(end_time - start_time);
auto spawn = duration_cast<milliseconds>(wait_time - spawn_time);
auto wait = duration_cast<milliseconds>(end_time - wait_time);
write_to_debug_buffer(format("shell execution took {} ms (spawn: {}, wait: {})",
(size_t)full.count(), (size_t)spawn.count(), (size_t)wait.count()));
}
if (wait_notified) // clear the status line
context.print_status({ "", get_face("Information") }, true);
return { std::move(stdout_contents), WIFEXITED(status) ? WEXITSTATUS(status) : -1 };
}
void ShellManager::register_env_var(StringView str, bool prefix,
EnvVarRetriever retriever)
{
m_env_vars.push_back({ str.str(), prefix, std::move(retriever) });
}
String ShellManager::get_val(StringView name, const Context& context) const
{
auto env_var = std::find_if(
m_env_vars.begin(), m_env_vars.end(),
[name](const EnvVarDesc& desc) {
return desc.prefix ? prefix_match(name, desc.str) : name == desc.str;
});
if (env_var == m_env_vars.end())
throw runtime_error("no such env var: " + name);
return env_var->func(name, context);
}
CandidateList ShellManager::complete_env_var(StringView prefix,
ByteCount cursor_pos) const
{
return complete(prefix, cursor_pos,
m_env_vars | transform(std::mem_fn(&EnvVarDesc::str)));
}
}