kakoune/src/shell_manager.cc
Johannes Altmanninger c1bdafef48 Avoid "env var" in error message for unknown %val expansion
This meaning is only used in C++ sources. The docs use "env
var"/"environment variable" a few times for actual environment
variables.
2021-08-10 08:23:14 +02:00

405 lines
13 KiB
C++

#include "shell_manager.hh"
#include "buffer_utils.hh"
#include "client.hh"
#include "clock.hh"
#include "context.hh"
#include "command_manager.hh"
#include "display_buffer.hh"
#include "event_manager.hh"
#include "face_registry.hh"
#include "file.hh"
#include "flags.hh"
#include "option.hh"
#include "option_types.hh"
#include "regex.hh"
#include <cstring>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <fcntl.h>
#include <cstdlib>
#include <errno.h>
#if defined(__CYGWIN__)
#define vfork fork
#endif
extern char **environ;
namespace Kakoune
{
ShellManager::ShellManager(ConstArrayView<EnvVarDesc> builtin_env_vars)
: m_env_vars{builtin_env_vars}
{
auto is_executable = [](StringView path) {
struct stat st;
if (stat(path.zstr(), &st))
return false;
bool executable = (st.st_mode & S_IXUSR)
| (st.st_mode & S_IXGRP)
| (st.st_mode & S_IXOTH);
return S_ISREG(st.st_mode) and executable;
};
if (const char* shell = getenv("KAKOUNE_POSIX_SHELL"))
{
if (not is_executable(shell))
throw runtime_error{format("KAKOUNE_POSIX_SHELL '{}' is not executable", shell)};
m_shell = shell;
}
else // Get a guaranteed to be POSIX shell binary
{
auto size = confstr(_CS_PATH, nullptr, 0);
String path; path.resize(size-1, 0);
confstr(_CS_PATH, path.data(), size);
for (auto dir : StringView{path} | split<StringView>(':'))
{
auto candidate = format("{}/sh", dir);
if (is_executable(candidate))
{
m_shell = std::move(candidate);
break;
}
}
if (m_shell.empty())
throw runtime_error{format("unable to find a posix shell in {}", path)};
}
// Add Kakoune binary location to the path to guarantee that %sh{ ... }
// have access to the kak command regardless of if the user installed it
{
const char* path = getenv("PATH");
auto new_path = format("{}../libexec/kak:{}", split_path(get_kak_binary_path()).first, path);
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(const char* shell, StringView cmdline,
ConstArrayView<String> params,
ConstArrayView<String> kak_env,
Func setup_child) noexcept
{
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);
auto cmdlinezstr = cmdline.zstr();
Vector<const char*> execparams = { "sh", "-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 = vfork())
return pid;
setup_child();
execve(shell, (char* const*)execparams.data(), (char* const*)envptrs.data());
char buffer[1024];
write(STDERR_FILENO, format_to(buffer, "execve failed: {}\n", errno));
_exit(-1);
return -1;
}
template<typename GetValue>
Vector<String> generate_env(StringView cmdline, const Context& context, GetValue&& get_value)
{
static const Regex re(R"(\bkak_(quoted_)?(\w+)\b)");
Vector<String> env;
for (auto&& match : RegexIterator{cmdline.begin(), cmdline.end(), re})
{
StringView name{match[2].first, match[2].second};
StringView shell_name{match[0].first, match[0].second};
auto match_name = [&](const String& s) {
return s.substr(0_byte, shell_name.length()) == shell_name and
s.substr(shell_name.length(), 1_byte) == "=";
};
if (any_of(env, match_name))
continue;
try
{
StringView quoted{match[1].first, match[1].second};
Quoting quoting = match[1].matched ? Quoting::Shell : Quoting::Raw;
env.push_back(format("kak_{}{}={}", quoted, name, get_value(name, quoting)));
} catch (runtime_error&) {}
}
return env;
}
template<typename OnClose>
FDWatcher make_reader(int fd, String& contents, OnClose&& on_close)
{
return {fd, FdEvents::Read, EventMode::Urgent,
[fd, &contents, on_close](FDWatcher& watcher, FdEvents, EventMode) {
char buffer[1024];
while (fd_readable(fd))
{
size_t size = ::read(fd, buffer, sizeof(buffer));
if (size <= 0)
{
watcher.disable();
on_close();
return;
}
contents += StringView{buffer, buffer+size};
}
}};
}
FDWatcher make_pipe_writer(Pipe& pipe, StringView contents)
{
int flags = fcntl(pipe.write_fd(), F_GETFL, 0);
fcntl(pipe.write_fd(), F_SETFL, flags | O_NONBLOCK);
return {pipe.write_fd(), FdEvents::Write, EventMode::Urgent,
[contents, &pipe](FDWatcher& watcher, FdEvents, EventMode) mutable {
while (fd_writable(pipe.write_fd()))
{
ssize_t size = ::write(pipe.write_fd(), contents.begin(),
(size_t)contents.length());
if (size > 0)
contents = contents.substr(ByteCount{(int)size});
if (size == -1 and (errno == EAGAIN or errno == EWOULDBLOCK))
return;
if (size < 0 or contents.empty())
{
pipe.close_write_fd();
watcher.disable();
return;
}
}
}};
}
struct CommandFifos
{
String base_dir;
String command;
FDWatcher command_watcher;
CommandFifos(Context& context, const ShellContext& shell_context)
: base_dir(format("{}/kak-fifo.XXXXXX", tmpdir())),
command_watcher([&] {
mkdtemp(base_dir.data()),
mkfifo(command_fifo_path().c_str(), 0600);
mkfifo(response_fifo_path().c_str(), 0600);
int fd = open(command_fifo_path().c_str(), O_RDONLY | O_NONBLOCK);
return make_reader(fd, command, [&, fd] {
close(fd);
CommandManager::instance().execute(command, context, shell_context);
command.clear();
command_watcher.reset_fd(open(command_fifo_path().c_str(), O_RDONLY | O_NONBLOCK));
});
}())
{
}
~CommandFifos()
{
command_watcher.close_fd();
unlink(command_fifo_path().c_str());
unlink(response_fifo_path().c_str());
rmdir(base_dir.c_str());
}
String command_fifo_path() const { return format("{}/command-fifo", base_dir); }
String response_fifo_path() const { return format("{}/response-fifo", base_dir); }
};
}
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{};
Optional<CommandFifos> command_fifos;
auto kak_env = generate_env(cmdline, context, [&](StringView name, Quoting quoting) {
if (name == "command_fifo" or name == "response_fifo")
{
if (not command_fifos)
command_fifos.emplace(const_cast<Context&>(context), shell_context);
return name == "command_fifo" ?
command_fifos->command_fifo_path() : command_fifos->response_fifo_path();
}
if (auto it = shell_context.env_vars.find(name); it != shell_context.env_vars.end())
return it->value;
return join(get_val(name, context) | transform(quoter(quoting)), ' ', false);
});
auto spawn_time = profile ? Clock::now() : Clock::time_point{};
Pipe child_stdin{not input.empty()}, child_stdout, child_stderr;
pid_t pid = spawn_shell(m_shell.c_str(), cmdline, shell_context.params, kak_env,
[&child_stdin, &child_stdout, &child_stderr] {
auto move = [](int oldfd, int newfd)
{
if (oldfd == newfd)
return;
dup2(oldfd, newfd); close(oldfd);
};
if (child_stdin.read_fd() != -1)
{
close(child_stdin.write_fd());
move(child_stdin.read_fd(), 0);
}
else
move(open("/dev/null", O_RDONLY), 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();
auto wait_time = Clock::now();
String stdout_contents, stderr_contents;
auto stdout_reader = make_reader(child_stdout.read_fd(), stdout_contents, [&]{ child_stdout.close_read_fd(); });
auto stderr_reader = make_reader(child_stderr.read_fd(), stderr_contents, [&]{ child_stderr.close_read_fd(); });
auto stdin_writer = make_pipe_writer(child_stdin, input);
// 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) != 0;
bool failed = false;
using namespace std::chrono;
static constexpr seconds wait_timeout{1};
Optional<DisplayLine> previous_status;
Timer wait_timer{wait_time + wait_timeout, [&](Timer& timer) {
if (not context.has_client())
return;
const auto now = Clock::now();
timer.set_next_date(now + wait_timeout);
auto& client = context.client();
if (not previous_status)
previous_status = client.current_status();
client.print_status({format("waiting for shell command to finish{} ({}s)",
terminated ? " (shell terminated)" : "",
duration_cast<seconds>(now - wait_time).count()),
context.faces()[failed ? "Error" : "Information"]});
client.redraw_ifn();
}, EventMode::Urgent};
while (not terminated or child_stdin.write_fd() != -1 or
((flags & Flags::WaitForStdout) and
(child_stdout.read_fd() != -1 or child_stderr.read_fd() != -1)))
{
try
{
EventManager::instance().handle_next_events(EventMode::Urgent, &orig_mask);
}
catch (runtime_error& error)
{
write_to_debug_buffer(format("error while waiting for shell: {}", error.what()));
failed = true;
}
if (not terminated)
terminated = waitpid(pid, &status, WNOHANG) == pid;
}
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<microseconds>(end_time - start_time);
auto spawn = duration_cast<microseconds>(wait_time - spawn_time);
auto wait = duration_cast<microseconds>(end_time - wait_time);
write_to_debug_buffer(format("shell execution took {} us (spawn: {}, wait: {})",
(size_t)full.count(), (size_t)spawn.count(), (size_t)wait.count()));
}
if (previous_status) // restore the status line
{
context.print_status(std::move(*previous_status));
context.client().redraw_ifn();
}
return { std::move(stdout_contents), WIFEXITED(status) ? WEXITSTATUS(status) : -1 };
}
Vector<String> ShellManager::get_val(StringView name, const Context& context) const
{
auto env_var = find_if(m_env_vars, [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 variable: " + 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(&EnvVarDesc::str));
}
}