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trigger.cpp
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trigger.cpp
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/* Copyright 2013-present Facebook, Inc.
* Licensed under the Apache License, Version 2.0 */
#include "watchman.h"
#include <memory>
bool watchman_trigger_command::waitNoIntr() {
if (!w_is_stopping() && !stopTrigger_) {
if (current_proc && current_proc->terminated()) {
current_proc.reset();
return true;
}
}
return false;
}
void watchman_trigger_command::run(const std::shared_ptr<w_root_t>& root) {
std::vector<std::shared_ptr<const watchman::Publisher::Item>> pending;
w_set_thread_name(
"trigger %s %s", triggername.c_str(), root->root_path.c_str());
try {
watchman_event_poll pfd[1];
pfd[0].evt = ping_.get();
watchman::log(watchman::DBG, "waiting for settle\n");
while (!w_is_stopping() && !stopTrigger_) {
ignore_result(w_poll_events(pfd, 1, 86400));
if (w_is_stopping() || stopTrigger_) {
break;
}
while (ping_->testAndClear()) {
pending.clear();
subscriber_->getPending(pending);
bool seenSettle = false;
for (auto& item : pending) {
if (item->payload.get_default("settled")) {
seenSettle = true;
break;
}
}
if (seenSettle) {
if (!maybeSpawn(root)) {
continue;
}
waitNoIntr();
}
}
}
if (current_proc) {
current_proc->kill();
current_proc->wait();
}
} catch (const std::exception& exc) {
watchman::log(
watchman::ERR,
"Uncaught exception in trigger thread: ",
exc.what(),
"\n");
}
watchman::log(watchman::DBG, "out of loop\n");
}
/* trigger-del /root triggername
* Delete a trigger from a root
*/
static void cmd_trigger_delete(
struct watchman_client* client,
const json_ref& args) {
w_string tname;
bool res;
auto root = resolveRoot(client, args);
if (json_array_size(args) != 3) {
send_error_response(client, "wrong number of arguments");
return;
}
auto jname = args.at(2);
if (!jname.isString()) {
send_error_response(client, "expected 2nd parameter to be trigger name");
return;
}
tname = json_to_w_string(jname);
std::unique_ptr<watchman_trigger_command> cmd;
{
auto map = root->triggers.wlock();
auto it = map->find(tname);
if (it == map->end()) {
res = false;
} else {
std::swap(cmd, it->second);
map->erase(it);
res = true;
}
}
if (cmd) {
// Stop the thread
cmd->stop();
}
if (res) {
w_state_save();
}
auto resp = make_response();
resp.set({{"deleted", json_boolean(res)}, {"trigger", json_ref(jname)}});
send_and_dispose_response(client, std::move(resp));
}
W_CMD_REG("trigger-del", cmd_trigger_delete, CMD_DAEMON, w_cmd_realpath_root)
/* trigger-list /root
* Displays a list of registered triggers for a given root
*/
static void cmd_trigger_list(
struct watchman_client* client,
const json_ref& args) {
auto root = resolveRoot(client, args);
auto resp = make_response();
auto arr = root->triggerListToJson();
resp.set("triggers", std::move(arr));
send_and_dispose_response(client, std::move(resp));
}
W_CMD_REG("trigger-list", cmd_trigger_list, CMD_DAEMON, w_cmd_realpath_root)
static json_ref build_legacy_trigger(
const std::shared_ptr<w_root_t>& root,
struct watchman_client* client,
const json_ref& args) {
uint32_t next_arg = 0;
uint32_t i;
size_t n;
auto trig = json_object({{"name", args.at(2)},
{"append_files", json_true()},
{"stdin",
json_array({typed_string_to_json("name"),
typed_string_to_json("exists"),
typed_string_to_json("new"),
typed_string_to_json("size"),
typed_string_to_json("mode")})}});
json_ref expr;
auto query = w_query_parse_legacy(root, args, 3, &next_arg, nullptr, &expr);
json_object_set(trig, "expression", expr.get_default("expression"));
if (next_arg >= args.array().size()) {
send_error_response(client, "no command was specified");
return nullptr;
}
n = json_array_size(args) - next_arg;
auto command = json_array_of_size(n);
for (i = 0; i < n; i++) {
auto ele = args.at(i + next_arg);
if (!ele.isString()) {
send_error_response(client, "expected argument %d to be a string", i);
return nullptr;
}
json_array_append(command, ele);
}
json_object_set_new(trig, "command", std::move(command));
return trig;
}
static bool parse_redirection(const char **name_p, int *flags,
const char *label, char **errmsg)
{
const char *name = *name_p;
if (!name) {
return true;
}
if (name[0] != '>') {
ignore_result(asprintf(errmsg,
"%s: must be prefixed with either > or >>, got %s",
label, name));
return false;
}
*flags = O_CREAT | O_WRONLY;
if (name[1] == '>') {
#ifdef _WIN32
ignore_result(asprintf(errmsg,
"Windows does not support O_APPEND"));
return false;
#else
*flags |= O_APPEND;
*name_p = name + 2;
#endif
} else {
*flags |= O_TRUNC;
*name_p = name + 1;
}
return true;
}
watchman_trigger_command::watchman_trigger_command(
const std::shared_ptr<w_root_t>& root,
const json_ref& trig,
char** errmsg)
: definition(trig),
append_files(false),
stdin_style(input_dev_null),
max_files_stdin(0),
stdout_flags(0),
stderr_flags(0),
stdout_name(nullptr),
stderr_name(nullptr),
ping_(w_event_make()) {
auto queryDef = json_object();
auto expr = definition.get_default("expression");
if (expr) {
queryDef.set("expression", json_ref(expr));
}
auto relative_root = definition.get_default("relative_root");
if (relative_root) {
json_object_set_nocheck(queryDef, "relative_root", relative_root);
}
query = w_query_parse(root, queryDef);
if (!query) {
return;
}
auto name = trig.get_default("name");
if (!name || !name.isString()) {
*errmsg = strdup("invalid or missing name");
return;
}
triggername = json_to_w_string(name);
command = definition.get_default("command");
if (!command || !command.isArray() || !json_array_size(command)) {
*errmsg = strdup("invalid command array");
return;
}
append_files = trig.get_default("append_files", json_false()).asBool();
if (append_files) {
// This is unfortunately a bit of a hack. When appending files to the
// command line we need a list of just the file names. We would normally
// just set the field list to contain the name, but that may conflict with
// the setting for the "stdin" property that is managed below; if they
// didn't ask for the name, we can't just force it in. As a bit of an
// "easy" workaround, we'll capture the list of names from the deduping
// mechanism.
query->dedup_results = true;
}
auto ele = definition.get_default("stdin");
if (!ele) {
stdin_style = input_dev_null;
} else if (ele.isArray()) {
stdin_style = input_json;
parse_field_list(ele, &query->fieldList);
} else if (ele.isString()) {
const char *str = json_string_value(ele);
if (!strcmp(str, "/dev/null")) {
stdin_style = input_dev_null;
} else if (!strcmp(str, "NAME_PER_LINE")) {
stdin_style = input_name_list;
parse_field_list(
json_array({typed_string_to_json("name")}), &query->fieldList);
} else {
ignore_result(asprintf(errmsg, "invalid stdin value %s", str));
return;
}
} else {
*errmsg = strdup("invalid value for stdin");
return;
}
// unlimited unless specified
auto ival =
json_integer_value(trig.get_default("max_files_stdin", json_integer(0)));
if (ival < 0) {
*errmsg = strdup("max_files_stdin must be >= 0");
return;
}
max_files_stdin = ival;
json_unpack(trig, "{s:s}", "stdout", &stdout_name);
json_unpack(trig, "{s:s}", "stderr", &stderr_name);
if (!parse_redirection(&stdout_name, &stdout_flags, "stdout", errmsg)) {
return;
}
if (!parse_redirection(&stderr_name, &stderr_flags, "stderr", errmsg)) {
return;
}
// Set some standard vars
env.set({{"WATCHMAN_ROOT", root->root_path},
{"WATCHMAN_SOCK", get_sock_name()},
{"WATCHMAN_TRIGGER", triggername}});
}
void watchman_trigger_command::stop() {
stopTrigger_ = true;
if (triggerThread_.joinable()) {
ping_->notify();
triggerThread_.join();
}
}
watchman_trigger_command::~watchman_trigger_command() {
if (triggerThread_.joinable() && !stopTrigger_) {
// We could try to call stop() here, but that is paving over the problem,
// especially if we happen to be the triggerThread_ for some reason.
watchman::log(
watchman::FATAL, "destroying trigger without stopping it first\n");
}
}
void watchman_trigger_command::start(const std::shared_ptr<w_root_t>& root) {
subscriber_ =
root->unilateralResponses->subscribe([this] { ping_->notify(); });
triggerThread_ = std::thread([this, root] {
try {
run(root);
} catch (const std::exception& e) {
watchman::log(
watchman::ERR, "exception in trigger thread: ", e.what(), "\n");
}
});
}
/* trigger /root triggername [watch patterns] -- cmd to run
* Sets up a trigger so that we can execute a command when a change
* is detected */
static void cmd_trigger(struct watchman_client* client, const json_ref& args) {
char *errmsg = NULL;
bool need_save = true;
std::unique_ptr<watchman_trigger_command> cmd;
json_ref trig;
json_ref resp;
auto root = resolveRoot(client, args);
if (json_array_size(args) < 3) {
send_error_response(client, "not enough arguments");
goto done;
}
trig = args.at(2);
if (trig.isString()) {
trig = build_legacy_trigger(root, client, args);
if (!trig) {
goto done;
}
}
cmd = std::make_unique<watchman_trigger_command>(root, trig, &errmsg);
if (errmsg) {
send_error_response(client, "%s", errmsg);
goto done;
}
resp = make_response();
resp.set("triggerid", w_string_to_json(cmd->triggername));
{
auto wlock = root->triggers.wlock();
auto& map = *wlock;
auto& old = map[cmd->triggername];
if (old && json_equal(cmd->definition, old->definition)) {
// Same definition: we don't and shouldn't touch things, so that we
// preserve the associated trigger clock and don't cause the trigger
// to re-run immediately
resp.set(
"disposition",
typed_string_to_json("already_defined", W_STRING_UNICODE));
need_save = false;
} else {
resp.set(
"disposition",
typed_string_to_json(old ? "replaced" : "created", W_STRING_UNICODE));
if (old) {
// If we're replacing an old definition, be sure to stop the old
// one before we destroy it, and before we start the new one.
old->stop();
}
// Start the new trigger thread
cmd->start(root);
old = std::move(cmd);
need_save = true;
}
}
if (need_save) {
w_state_save();
}
send_and_dispose_response(client, std::move(resp));
done:
if (errmsg) {
free(errmsg);
}
}
W_CMD_REG("trigger", cmd_trigger, CMD_DAEMON, w_cmd_realpath_root)
/* vim:ts=2:sw=2:et:
*/