kakoune/src/shell_manager.cc

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#include "shell_manager.hh"
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#include "buffer_utils.hh"
#include "client.hh"
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#include "clock.hh"
#include "context.hh"
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#include "display_buffer.hh"
#include "event_manager.hh"
#include "face_registry.hh"
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#include "file.hh"
#include "flags.hh"
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#include "option.hh"
#include "option_types.hh"
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#include "regex.hh"
#include <cstring>
#include <sys/types.h>
#include <sys/wait.h>
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#include <unistd.h>
#include <fcntl.h>
#include <cstdlib>
#if defined(__CYGWIN__)
#define vfork fork
#endif
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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("{}:{}", path, split_path(get_kak_binary_path()).first);
setenv("PATH", new_path.c_str(), 1);
}
}
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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)));
}
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~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];
};
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template<typename Func>
pid_t spawn_shell(const char* shell, StringView cmdline,
ConstArrayView<String> params,
ConstArrayView<String> kak_env,
Func setup_child)
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{
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 };
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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())
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return pid;
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setup_child();
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execve(shell, (char* const*)execparams.data(), (char* const*)envptrs.data());
_exit(-1);
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return -1;
}
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Vector<String> generate_env(StringView cmdline, const Context& context, const ShellContext& shell_context)
{
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static const Regex re(R"(\bkak_(\w+)\b)");
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Vector<String> kak_env;
for (RegexIterator<const char*> it{cmdline.begin(), cmdline.end(), re}, end;
it != end; ++it)
{
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StringView name{(*it)[1].first, (*it)[1].second};
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auto match_name = [&](const String& s) {
return s.substr(0_byte, name.length()) == name and
s.substr(name.length(), 1_byte) == "=";
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};
if (any_of(kak_env, match_name))
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continue;
auto var_it = shell_context.env_vars.find(name);
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try
{
const String& value = var_it != shell_context.env_vars.end() ?
var_it->value : ShellManager::instance().get_val(name, context, Quoting::Shell);
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kak_env.push_back(format("kak_{}={}", name, value));
} catch (runtime_error&) {}
}
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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));
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auto start_time = profile ? Clock::now() : Clock::time_point{};
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auto kak_env = generate_env(cmdline, context, shell_context);
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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,
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[&child_stdin, &child_stdout, &child_stderr] {
auto move = [](int oldfd, int newfd)
{
if (oldfd == newfd)
return;
dup2(oldfd, newfd); close(oldfd);
};
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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);
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close(child_stdout.read_fd());
move(child_stdout.write_fd(), 1);
close(child_stderr.read_fd());
move(child_stderr.write_fd(), 2);
});
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child_stdin.close_read_fd();
child_stdout.close_write_fd();
child_stderr.close_write_fd();
auto wait_time = Clock::now();
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struct PipeReader : FDWatcher
{
PipeReader(Pipe& pipe, String& contents)
: FDWatcher(pipe.read_fd(), FdEvents::Read,
[&contents, &pipe](FDWatcher& watcher, FdEvents, EventMode) {
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char buffer[1024];
while (fd_readable(pipe.read_fd()))
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{
size_t size = ::read(pipe.read_fd(), buffer, 1024);
if (size <= 0)
{
pipe.close_read_fd();
watcher.disable();
return;
}
contents += StringView{buffer, buffer+size};
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}
})
{}
};
struct PipeWriter : FDWatcher
{
PipeWriter(Pipe& pipe, StringView contents)
: FDWatcher(pipe.write_fd(), FdEvents::Write,
[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;
}
}
})
{
int flags = fcntl(pipe.write_fd(), F_GETFL, 0);
fcntl(pipe.write_fd(), F_SETFL, flags | O_NONBLOCK);
}
};
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String stdout_contents, stderr_contents;
PipeReader stdout_reader{child_stdout, stdout_contents};
PipeReader stderr_reader{child_stderr, stderr_contents};
PipeWriter stdin_writer{child_stdin, input};
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// 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;
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using namespace std::chrono;
static constexpr seconds wait_timeout{1};
Optional<DisplayLine> previous_status;
Timer wait_timer{wait_time + wait_timeout, [&](Timer& timer)
{
auto wait_duration = Clock::now() - wait_time;
if (context.has_client())
{
auto& client = context.client();
if (not previous_status)
previous_status = client.current_status();
client.print_status({ format("waiting for shell command to finish ({}s)",
duration_cast<seconds>(wait_duration).count()),
context.faces()["Information"] });
client.redraw_ifn();
}
timer.set_next_date(Clock::now() + wait_timeout);
}, EventMode::Urgent};
while (not terminated or child_stdin.write_fd() != -1 or
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((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) != 0;
}
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if (not stderr_contents.empty())
write_to_debug_buffer(format("shell stderr: <<<\n{}>>>", stderr_contents));
if (profile)
{
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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 };
}
String ShellManager::get_val(StringView name, const Context& context, Quoting quoting) 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 env var: " + name);
return env_var->func(name, context, quoting);
}
CandidateList ShellManager::complete_env_var(StringView prefix,
ByteCount cursor_pos) const
{
return complete(prefix, cursor_pos,
m_env_vars | transform(&EnvVarDesc::str));
}
}