static void spawn_command(w_root_t *root,
struct watchman_trigger_command *cmd,
w_query_res *res,
struct w_clockspec *since_spec)
{
char **envp = NULL;
uint32_t i = 0;
int ret;
w_stm_t stdin_file = NULL;
json_t *args;
char **argv = NULL;
uint32_t env_size;
posix_spawn_file_actions_t actions;
posix_spawnattr_t attr;
#ifndef _WIN32
sigset_t mask;
#endif
long arg_max;
size_t argspace_remaining;
bool file_overflow = false;
int result_log_level;
char clockbuf[128];
w_string_t *working_dir = NULL;
#ifdef _WIN32
arg_max = 32*1024;
#else
arg_max = sysconf(_SC_ARG_MAX);
#endif
if (arg_max <= 0) {
argspace_remaining = UINT_MAX;
} else {
argspace_remaining = (uint32_t)arg_max;
}
// Allow some misc working overhead
argspace_remaining -= 32;
stdin_file = prepare_stdin(cmd, res);
if (!stdin_file) {
w_log(W_LOG_ERR, "trigger %.*s:%s %s\n",
(int)root->root_path->len,
root->root_path->buf,
cmd->triggername->buf, strerror(errno));
return;
}
// Assumption: that only one thread will be executing on a given
// cmd instance so that mutation of cmd->envht is safe.
// This is guaranteed in the current architecture.
if (cmd->max_files_stdin > 0 && res->num_results > cmd->max_files_stdin) {
file_overflow = true;
}
// It is way too much of a hassle to try to recreate the clock value if it's
// not a relative clock spec, and it's only going to happen on the first run
// anyway, so just skip doing that entirely.
if (since_spec && since_spec->tag == w_cs_clock &&
clock_id_string(since_spec->clock.root_number, since_spec->clock.ticks,
clockbuf, sizeof(clockbuf))) {
w_envp_set_cstring(cmd->envht, "WATCHMAN_SINCE", clockbuf);
} else {
w_envp_unset(cmd->envht, "WATCHMAN_SINCE");
}
if (clock_id_string(res->root_number, res->ticks,
clockbuf, sizeof(clockbuf))) {
w_envp_set_cstring(cmd->envht, "WATCHMAN_CLOCK", clockbuf);
} else {
w_envp_unset(cmd->envht, "WATCHMAN_CLOCK");
}
if (cmd->query->relative_root) {
w_envp_set(cmd->envht, "WATCHMAN_RELATIVE_ROOT", cmd->query->relative_root);
} else {
w_envp_unset(cmd->envht, "WATCHMAN_RELATIVE_ROOT");
}
// Compute args
args = json_deep_copy(cmd->command);
if (cmd->append_files) {
// Measure how much space the base args take up
for (i = 0; i < json_array_size(args); i++) {
const char *ele = json_string_value(json_array_get(args, i));
argspace_remaining -= strlen(ele) + 1 + sizeof(char*);
}
// Dry run with env to compute space
envp = w_envp_make_from_ht(cmd->envht, &env_size);
free(envp);
envp = NULL;
argspace_remaining -= env_size;
for (i = 0; i < res->num_results; i++) {
// also: NUL terminator and entry in argv
uint32_t size = res->results[i].relname->len + 1 + sizeof(char*);
if (argspace_remaining < size) {
file_overflow = true;
break;
}
argspace_remaining -= size;
json_array_append_new(
args,
json_string_nocheck(res->results[i].relname->buf)
);
}
}
argv = w_argv_copy_from_json(args, 0);
json_decref(args);
args = NULL;
w_envp_set_bool(cmd->envht, "WATCHMAN_FILES_OVERFLOW", file_overflow);
envp = w_envp_make_from_ht(cmd->envht, &env_size);
posix_spawnattr_init(&attr);
#ifndef _WIN32
sigemptyset(&mask);
posix_spawnattr_setsigmask(&attr, &mask);
#endif
posix_spawnattr_setflags(&attr,
POSIX_SPAWN_SETSIGMASK|
#ifdef POSIX_SPAWN_CLOEXEC_DEFAULT
// Darwin: close everything except what we put in file actions
POSIX_SPAWN_CLOEXEC_DEFAULT|
#endif
POSIX_SPAWN_SETPGROUP);
posix_spawn_file_actions_init(&actions);
#ifndef _WIN32
posix_spawn_file_actions_adddup2(&actions, w_stm_fileno(stdin_file),
STDIN_FILENO);
#else
posix_spawn_file_actions_adddup2_handle_np(&actions,
w_stm_handle(stdin_file), STDIN_FILENO);
#endif
if (cmd->stdout_name) {
posix_spawn_file_actions_addopen(&actions, STDOUT_FILENO,
cmd->stdout_name, cmd->stdout_flags, 0666);
} else {
posix_spawn_file_actions_adddup2(&actions, STDOUT_FILENO, STDOUT_FILENO);
}
if (cmd->stderr_name) {
posix_spawn_file_actions_addopen(&actions, STDERR_FILENO,
cmd->stderr_name, cmd->stderr_flags, 0666);
} else {
posix_spawn_file_actions_adddup2(&actions, STDERR_FILENO, STDERR_FILENO);
}
// Figure out the appropriate cwd
{
const char *cwd = NULL;
working_dir = NULL;
if (cmd->query->relative_root) {
working_dir = cmd->query->relative_root;
} else {
working_dir = root->root_path;
}
w_string_addref(working_dir);
json_unpack(cmd->definition, "{s:s}", "chdir", &cwd);
if (cwd) {
w_string_t *cwd_str = w_string_new(cwd);
if (w_is_path_absolute(cwd)) {
w_string_delref(working_dir);
working_dir = cwd_str;
} else {
w_string_t *joined;
joined = w_string_path_cat(working_dir, cwd_str);
w_string_delref(cwd_str);
w_string_delref(working_dir);
working_dir = joined;
}
}
w_log(W_LOG_DBG, "using %.*s for working dir\n", working_dir->len, working_dir->buf);
}
pthread_mutex_lock(&spawn_lock);
#ifndef _WIN32
ignore_result(chdir(working_dir->buf));
#else
posix_spawnattr_setcwd_np(&attr, working_dir->buf);
#endif
w_string_delref(working_dir);
working_dir = NULL;
ret = posix_spawnp(&cmd->current_proc, argv[0], &actions, &attr, argv, envp);
if (ret == 0) {
w_root_addref(root);
insert_running_pid(cmd->current_proc, root);
} else {
// On Darwin (at least), posix_spawn can fail but will still populate the
// pid. Since we use the pid to gate future spawns, we need to ensure
// that we clear out the pid on failure, otherwise the trigger would be
// effectively disabled for the rest of the watch lifetime
cmd->current_proc = 0;
}
#ifndef _WIN32
ignore_result(chdir("/"));
#endif
pthread_mutex_unlock(&spawn_lock);
// If failed, we want to make sure we log enough info to figure out why
result_log_level = res == 0 ? W_LOG_DBG : W_LOG_ERR;
w_log(result_log_level, "posix_spawnp:\n");
for (i = 0; argv[i]; i++) {
w_log(result_log_level, "argv[%d] %s\n", i, argv[i]);
}
for (i = 0; envp[i]; i++) {
w_log(result_log_level, "envp[%d] %s\n", i, envp[i]);
}
w_log(result_log_level, "trigger %.*s:%s pid=%d ret=%d %s\n",
(int)root->root_path->len,
root->root_path->buf,
cmd->triggername->buf, (int)cmd->current_proc, ret, strerror(ret));
free(argv);
free(envp);
posix_spawnattr_destroy(&attr);
posix_spawn_file_actions_destroy(&actions);
if (stdin_file) {
w_stm_close(stdin_file);
}
}
void ChildProcess::Options::chdir(w_string_piece path) {
cwd_ = std::string(path.data(), path.size());
#ifdef _WIN32
posix_spawnattr_setcwd_np(&inner_->attr, cwd_.c_str());
#endif
}
static void spawn_command(
const std::shared_ptr<w_root_t>& root,
struct watchman_trigger_command* cmd,
w_query_res* res,
struct w_clockspec* since_spec) {
char **envp = NULL;
uint32_t i = 0;
int ret;
char **argv = NULL;
uint32_t env_size;
posix_spawn_file_actions_t actions;
posix_spawnattr_t attr;
#ifndef _WIN32
sigset_t mask;
#endif
long arg_max;
size_t argspace_remaining;
bool file_overflow = false;
int result_log_level;
w_string_t *working_dir = NULL;
#ifdef _WIN32
arg_max = 32*1024;
#else
arg_max = sysconf(_SC_ARG_MAX);
#endif
if (arg_max <= 0) {
argspace_remaining = UINT_MAX;
} else {
argspace_remaining = (uint32_t)arg_max;
}
// Allow some misc working overhead
argspace_remaining -= 32;
// Record an overflow before we call prepare_stdin(), which mutates
// and resizes the results to fit the specified limit.
if (cmd->max_files_stdin > 0 &&
res->resultsArray.array().size() > cmd->max_files_stdin) {
file_overflow = true;
}
auto stdin_file = prepare_stdin(cmd, res);
if (!stdin_file) {
w_log(
W_LOG_ERR,
"trigger %s:%s %s\n",
root->root_path.c_str(),
cmd->triggername.c_str(),
strerror(errno));
return;
}
// Assumption: that only one thread will be executing on a given
// cmd instance so that mutation of cmd->envht is safe.
// This is guaranteed in the current architecture.
// It is way too much of a hassle to try to recreate the clock value if it's
// not a relative clock spec, and it's only going to happen on the first run
// anyway, so just skip doing that entirely.
if (since_spec && since_spec->tag == w_cs_clock) {
w_envp_set_cstring(
cmd->envht,
"WATCHMAN_SINCE",
since_spec->clock.position.toClockString().c_str());
} else {
w_envp_unset(cmd->envht, "WATCHMAN_SINCE");
}
w_envp_set_cstring(
cmd->envht,
"WATCHMAN_CLOCK",
res->clockAtStartOfQuery.toClockString().c_str());
if (cmd->query->relative_root) {
w_envp_set(cmd->envht, "WATCHMAN_RELATIVE_ROOT", cmd->query->relative_root);
} else {
w_envp_unset(cmd->envht, "WATCHMAN_RELATIVE_ROOT");
}
// Compute args
auto args = json_deep_copy(cmd->command);
if (cmd->append_files) {
// Measure how much space the base args take up
for (i = 0; i < json_array_size(args); i++) {
const char *ele = json_string_value(json_array_get(args, i));
argspace_remaining -= strlen(ele) + 1 + sizeof(char*);
}
// Dry run with env to compute space
envp = w_envp_make_from_ht(cmd->envht, &env_size);
free(envp);
envp = NULL;
argspace_remaining -= env_size;
for (const auto& item : res->dedupedFileNames) {
// also: NUL terminator and entry in argv
uint32_t size = item.size() + 1 + sizeof(char*);
if (argspace_remaining < size) {
file_overflow = true;
break;
}
argspace_remaining -= size;
json_array_append_new(args, w_string_to_json(item));
}
}
argv = w_argv_copy_from_json(args, 0);
args = nullptr;
w_envp_set_bool(cmd->envht, "WATCHMAN_FILES_OVERFLOW", file_overflow);
envp = w_envp_make_from_ht(cmd->envht, &env_size);
posix_spawnattr_init(&attr);
#ifndef _WIN32
sigemptyset(&mask);
posix_spawnattr_setsigmask(&attr, &mask);
#endif
posix_spawnattr_setflags(&attr,
POSIX_SPAWN_SETSIGMASK|
#ifdef POSIX_SPAWN_CLOEXEC_DEFAULT
// Darwin: close everything except what we put in file actions
POSIX_SPAWN_CLOEXEC_DEFAULT|
#endif
POSIX_SPAWN_SETPGROUP);
posix_spawn_file_actions_init(&actions);
#ifndef _WIN32
posix_spawn_file_actions_adddup2(
&actions, stdin_file->getFileDescriptor(), STDIN_FILENO);
#else
posix_spawn_file_actions_adddup2_handle_np(
&actions, stdin_file->getWindowsHandle(), STDIN_FILENO);
#endif
if (cmd->stdout_name) {
posix_spawn_file_actions_addopen(&actions, STDOUT_FILENO,
cmd->stdout_name, cmd->stdout_flags, 0666);
} else {
posix_spawn_file_actions_adddup2(&actions, STDOUT_FILENO, STDOUT_FILENO);
}
if (cmd->stderr_name) {
posix_spawn_file_actions_addopen(&actions, STDERR_FILENO,
cmd->stderr_name, cmd->stderr_flags, 0666);
} else {
posix_spawn_file_actions_adddup2(&actions, STDERR_FILENO, STDERR_FILENO);
}
// Figure out the appropriate cwd
{
const char *cwd = NULL;
working_dir = NULL;
if (cmd->query->relative_root) {
working_dir = cmd->query->relative_root;
} else {
working_dir = root->root_path;
}
w_string_addref(working_dir);
json_unpack(cmd->definition, "{s:s}", "chdir", &cwd);
if (cwd) {
w_string_t *cwd_str = w_string_new_typed(cwd, W_STRING_BYTE);
if (w_is_path_absolute_cstr(cwd)) {
w_string_delref(working_dir);
working_dir = cwd_str;
} else {
w_string_t *joined;
joined = w_string_path_cat(working_dir, cwd_str);
w_string_delref(cwd_str);
w_string_delref(working_dir);
working_dir = joined;
}
}
w_log(W_LOG_DBG, "using %.*s for working dir\n", working_dir->len,
working_dir->buf);
}
#ifndef _WIN32
// This mutex is present to avoid fighting over the cwd when multiple
// triggers run at the same time. It doesn't coordinate with all
// possible chdir() calls, but this is the only place that we do this
// in the watchman server process.
static std::mutex cwdMutex;
{
std::unique_lock<std::mutex> lock(cwdMutex);
ignore_result(chdir(working_dir->buf));
#else
posix_spawnattr_setcwd_np(&attr, working_dir->buf);
#endif
w_string_delref(working_dir);
working_dir = nullptr;
ret =
posix_spawnp(&cmd->current_proc, argv[0], &actions, &attr, argv, envp);
if (ret != 0) {
// On Darwin (at least), posix_spawn can fail but will still populate the
// pid. Since we use the pid to gate future spawns, we need to ensure
// that we clear out the pid on failure, otherwise the trigger would be
// effectively disabled for the rest of the watch lifetime
cmd->current_proc = 0;
}
#ifndef _WIN32
ignore_result(chdir("/"));
}
#endif
// If failed, we want to make sure we log enough info to figure out why
result_log_level = res == 0 ? W_LOG_DBG : W_LOG_ERR;
w_log(result_log_level, "posix_spawnp: %s\n", cmd->triggername.c_str());
for (i = 0; argv[i]; i++) {
w_log(result_log_level, "argv[%d] %s\n", i, argv[i]);
}
for (i = 0; envp[i]; i++) {
w_log(result_log_level, "envp[%d] %s\n", i, envp[i]);
}
w_log(
result_log_level,
"trigger %s:%s pid=%d ret=%d %s\n",
root->root_path.c_str(),
cmd->triggername.c_str(),
(int)cmd->current_proc,
ret,
strerror(ret));
free(argv);
free(envp);
posix_spawnattr_destroy(&attr);
posix_spawn_file_actions_destroy(&actions);
}
