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/*
* Copyright (c) 2020, Sahan Fernando <sahan.h.fernando@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/DeprecatedString.h>
#include <AK/StringBuilder.h>
#include <AK/Time.h>
#include <AK/Vector.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <LibCore/FileWatcher.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <errno.h>
#include <spawn.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
static int opt_interval = 2;
static bool flag_noheader = false;
static bool flag_beep_on_fail = false;
static int volatile exit_code = 0;
static volatile pid_t child_pid = -1;
static DeprecatedString build_header_string(Vector<char const*> const& command, struct timeval const& interval)
{
StringBuilder builder;
builder.appendff("Every {}.{}s: \x1b[1m", interval.tv_sec, interval.tv_usec / 100000);
builder.join(' ', command);
builder.append("\x1b[0m"sv);
return builder.build();
}
static DeprecatedString build_header_string(Vector<char const*> const& command, Vector<DeprecatedString> const& filenames)
{
StringBuilder builder;
builder.appendff("Every time any of {} changes: \x1b[1m", filenames);
builder.join(' ', command);
builder.append("\x1b[0m"sv);
return builder.build();
}
static struct timeval get_current_time()
{
struct timespec ts;
struct timeval tv;
clock_gettime(CLOCK_MONOTONIC_COARSE, &ts);
timespec_to_timeval(ts, tv);
return tv;
}
static int64_t usecs_from(struct timeval const& start, struct timeval const& end)
{
struct timeval diff;
timeval_sub(end, start, diff);
return 1000000 * diff.tv_sec + diff.tv_usec;
}
static void handle_signal(int signal)
{
if (child_pid > 0) {
if (kill(child_pid, signal) < 0) {
perror("kill");
}
int status;
if (waitpid(child_pid, &status, 0) < 0) {
perror("waitpid");
} else if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
exit_code = 1;
}
}
exit(exit_code);
}
static int run_command(Vector<char const*> const& command)
{
VERIFY(command[command.size() - 1] == nullptr);
if ((errno = posix_spawnp(const_cast<pid_t*>(&child_pid), command[0], nullptr, nullptr, const_cast<char**>(command.data()), environ))) {
exit_code = 1;
perror("posix_spawn");
return errno;
}
// Wait for the child to terminate, then return its exit code.
int status;
pid_t exited_pid;
do {
exited_pid = waitpid(child_pid, &status, 0);
} while (exited_pid < 0 && errno == EINTR);
VERIFY(exited_pid == child_pid);
child_pid = -1;
if (exited_pid < 0) {
perror("waitpid");
return 1;
}
if (WIFEXITED(status)) {
return WEXITSTATUS(status);
} else {
return 1;
}
}
ErrorOr<int> serenity_main(Main::Arguments arguments)
{
TRY(Core::System::signal(SIGINT, handle_signal));
TRY(Core::System::pledge("stdio proc exec rpath"));
Vector<DeprecatedString> files_to_watch;
Vector<char const*> command;
Core::ArgsParser args_parser;
args_parser.set_stop_on_first_non_option(true);
args_parser.set_general_help("Execute a command repeatedly, and watch its output over time.");
args_parser.add_option(opt_interval, "Amount of time between updates", "interval", 'n', "seconds");
args_parser.add_option(flag_noheader, "Turn off the header describing the command and interval", "no-title", 't');
args_parser.add_option(flag_beep_on_fail, "Beep if the command has a non-zero exit code", "beep", 'b');
Core::ArgsParser::Option file_arg {
.argument_mode = Core::ArgsParser::OptionArgumentMode::Required,
.help_string = "Run command whenever this file changes. Can be used multiple times.",
.long_name = "file",
.short_name = 'f',
.value_name = "file",
.accept_value = [&files_to_watch](auto filename) {
files_to_watch.append(filename);
return true;
}
};
args_parser.add_option(move(file_arg));
args_parser.add_positional_argument(command, "Command to run", "command");
args_parser.parse(arguments);
command.append(nullptr);
DeprecatedString header;
auto watch_callback = [&] {
// Clear the screen, then reset the cursor position to the top left.
warn("\033[H\033[2J");
// Print the header.
if (!flag_noheader) {
warnln("{}", header);
warnln();
} else {
fflush(stderr);
}
if (run_command(command) != 0) {
exit_code = 1;
if (flag_beep_on_fail) {
warnln("\a");
fflush(stderr);
}
}
};
if (!files_to_watch.is_empty()) {
header = build_header_string(command, files_to_watch);
auto file_watcher = Core::BlockingFileWatcher();
for (auto const& file : files_to_watch) {
if (!Core::File::exists(file)) {
warnln("Cannot watch '{}', it does not exist.", file);
return 1;
}
if (!file_watcher.is_watching(file)) {
auto could_add_to_watch = TRY(file_watcher.add_watch(file, Core::FileWatcherEvent::Type::MetadataModified));
if (!could_add_to_watch) {
warnln("Could not add '{}' to watch list.", file);
return 1;
}
}
}
watch_callback();
while (true) {
auto maybe_event = file_watcher.wait_for_event();
if (maybe_event.has_value()) {
watch_callback();
}
}
} else {
TRY(Core::System::pledge("stdio proc exec"));
struct timeval interval;
if (opt_interval <= 0) {
interval = { 0, 100000 };
} else {
interval = { opt_interval, 0 };
}
auto now = get_current_time();
auto next_run_time = now;
header = build_header_string(command, interval);
while (true) {
int usecs_to_sleep = usecs_from(now, next_run_time);
while (usecs_to_sleep > 0) {
usleep(usecs_to_sleep);
now = get_current_time();
usecs_to_sleep = usecs_from(now, next_run_time);
}
watch_callback();
now = get_current_time();
timeval_add(next_run_time, interval, next_run_time);
if (usecs_from(now, next_run_time) < 0) {
// The next execution is overdue, so we set next_run_time to now to prevent drift.
next_run_time = now;
}
}
}
}
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