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lua: subprocess: tunnel stderr through mp_log 

Pretty much a fringe-feature, but also it's awkward if something appears
on the terminal with no indication for the source.

This is made quite awkward by the fact that stderr and stdout could be
closed at different times, and that poll() doesn't accept "holes" in its
FD list. Invalid (.e.g negative) FDs just make it return immediately, as
required by the standard. So sparse_poll() takes care of the messy
details.
This commit is contained in:
wm4 2014-10-26 01:39:01 +02:00
parent 6f88bc7761
commit d0643fa02d
1 changed files with 63 additions and 20 deletions
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83
player/lua.c
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@ -1182,6 +1182,27 @@ static int script_join_path(lua_State *L)
extern char **environ;
#endif
// A silly helper: automatically skips entries with negative FDs
static int sparse_poll(struct pollfd *fds, int num_fds, int timeout)
{
struct pollfd p_fds[10];
int map[10];
if (num_fds > MP_ARRAY_SIZE(p_fds))
return -1;
int p_num_fds = 0;
for (int n = 0; n < num_fds; n++) {
map[n] = -1;
if (fds[n].fd < 0)
break;
map[n] = p_num_fds;
p_fds[p_num_fds++] = fds[n];
}
int r = poll(p_fds, p_num_fds, timeout);
for (int n = 0; n < num_fds; n++)
fds[n].revents = (map[n] < 0 && r >= 0) ? 0 : p_fds[map[n]].revents;
return r;
}
static int script_subprocess(lua_State *L)
{
struct script_ctx *ctx = get_ctx(L);
@ -1223,19 +1244,22 @@ static int script_subprocess(lua_State *L)
bool fa_destroy = false;
bstr output = {0};
int status = -1;
int pipes[2] = {-1, -1};
int p_stdout[2] = {-1, -1};
int p_stderr[2] = {-1, -1};
pid_t pid = -1;
if (pipe(pipes))
if (mp_make_cloexec_pipe(p_stdout) < 0)
goto done;
if (mp_make_cloexec_pipe(p_stderr) < 0)
goto done;
mp_set_cloexec(pipes[0]);
mp_set_cloexec(pipes[1]);
if (posix_spawn_file_actions_init(&fa))
goto done;
fa_destroy = true;
// redirect stdout, but not stderr or stdin
if (posix_spawn_file_actions_adddup2(&fa, pipes[1], 1))
// redirect stdout and stderr
if (posix_spawn_file_actions_adddup2(&fa, p_stdout[1], 1))
goto done;
if (posix_spawn_file_actions_adddup2(&fa, p_stderr[1], 2))
goto done;
if (posix_spawnp(&pid, args[0], &fa, NULL, args, environ)) {
@ -1243,29 +1267,46 @@ static int script_subprocess(lua_State *L)
goto done;
}
close(pipes[1]);
pipes[1] = -1;
close(p_stdout[1]);
p_stdout[1] = -1;
close(p_stderr[1]);
p_stderr[1] = -1;
while (1) {
while (p_stdout[0] >= 0 || p_stderr[0] >= 0) {
struct pollfd fds[] = {
{.events = POLLIN, .fd = pipes[0]},
{.events = POLLIN, .fd = p_stdout[0]},
{.events = POLLIN, .fd = p_stderr[0]},
{.events = POLLIN, .fd = cancel ? mp_cancel_get_fd(cancel) : -1},
};
if (poll(fds, fds[1].fd >= 0 ? 2 : 1, -1) < 0 && errno != EINTR)
if (sparse_poll(fds, MP_ARRAY_SIZE(fds), -1) < 0 && errno != EINTR)
break;
if (fds[1].revents) {
kill(pid, SIGKILL);
break;
}
if (fds[0].revents) {
char buf[4096];
ssize_t r = read(pipes[0], buf, sizeof(buf));
ssize_t r = read(p_stdout[0], buf, sizeof(buf));
if (r < 0 && errno == EINTR)
continue;
if (r > 0)
bstr_xappend(tmp, &output, (bstr){buf, r});
if (r <= 0)
break;
if (r <= 0) {
close(p_stdout[0]);
p_stdout[0] = -1;
}
}
if (fds[1].revents) {
char buf[4096];
ssize_t r = read(p_stderr[0], buf, sizeof(buf));
if (r < 0 && errno == EINTR)
continue;
if (r > 0)
MP_INFO(ctx, "%.*s", (int)r, buf);
if (r <= 0) {
close(p_stderr[0]);
p_stderr[0] = -1;
}
}
if (fds[2].revents) {
kill(pid, SIGKILL);
break;
}
if (output.len >= max_size)
break;
@ -1280,8 +1321,10 @@ static int script_subprocess(lua_State *L)
done:
if (fa_destroy)
posix_spawn_file_actions_destroy(&fa);
close(pipes[0]);
close(pipes[1]);
close(p_stdout[0]);
close(p_stdout[1]);
close(p_stderr[0]);
close(p_stderr[1]);
// --- Lua errors are ok again from here
char *error = NULL;