static bool winwatch_root_start(watchman_global_watcher_t watcher,
w_root_t *root) {
struct winwatch_root_state *state = root->watch;
int err;
unused_parameter(watcher);
unused_parameter(root);
// Spin up the changes reading thread; it owns a ref on the root
w_root_addref(root);
// Acquire the mutex so thread initialization waits until we release it
pthread_mutex_lock(&state->mtx);
err = pthread_create(&state->thread, NULL, readchanges_thread, root);
if (err == 0) {
// Allow thread init to proceed; wait for its signal
pthread_cond_wait(&state->cond, &state->mtx);
pthread_mutex_unlock(&state->mtx);
if (root->failure_reason) {
w_log(W_LOG_ERR, "failed to start readchanges thread: %.*s\n",
root->failure_reason->len, root->failure_reason->buf);
return false;
}
return true;
}
pthread_mutex_unlock(&state->mtx);
w_root_delref(root);
w_log(W_LOG_ERR, "failed to start readchanges thread: %s\n", strerror(err));
return false;
}
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;
int stdin_fd = -1;
json_t *args;
char **argv = NULL;
uint32_t env_size;
posix_spawn_file_actions_t actions;
posix_spawnattr_t attr;
sigset_t mask;
long arg_max;
uint32_t argspace_remaining;
bool file_overflow = false;
int result_log_level;
char clockbuf[128];
const char *cwd = NULL;
arg_max = sysconf(_SC_ARG_MAX);
if (arg_max <= 0) {
argspace_remaining = UINT_MAX;
} else {
argspace_remaining = (uint32_t)arg_max;
}
// Allow some misc working overhead
argspace_remaining -= 32;
stdin_fd = prepare_stdin(cmd, res);
// 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);
sigemptyset(&mask);
posix_spawnattr_setsigmask(&attr, &mask);
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);
posix_spawn_file_actions_adddup2(&actions, stdin_fd, STDIN_FILENO);
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);
}
pthread_mutex_lock(&spawn_lock);
if (cmd->query->relative_root) {
ignore_result(chdir(cmd->query->relative_root->buf));
} else {
ignore_result(chdir(root->root_path->buf));
}
json_unpack(cmd->definition, "{s:s}", "chdir", &cwd);
if (cwd) {
ignore_result(chdir(cwd));
}
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;
}
ignore_result(chdir("/"));
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_fd != -1) {
close(stdin_fd);
}
}
