sway/swaybar/status_line.c
Ludvig Michaelsson f627cd77d6 swaybar: signal status command's process group
Make the status command a process group leader and change the kill(2)
calls to target the new process group. Signals sent by swaybar will then
be received by both the status command and its children, if any. While
here, check the result of fork(2).

Without this, children spawned by the status command may not receive the
signals sent by swaybar. As a result, these children may be orphaned on
reload.

The issue could be shown by setting the bar to

    bar {
        status_command i3status | tee /tmp/i3status.out
    }

which would leave orphaned processes for each reload of sway

    $ ps o pid,ppid,cmd | grep i3status | grep -v grep
    43633   43624 sh -c i3status | tee /tmp/i3status.out
    43634   43633 i3status
    43635   43633 tee /tmp/i3status.out

    $ swaymsg reload

    $ ps o pid,ppid,cmd | grep i3status | grep -v grep
    43634       1 i3status
    43635       1 tee /tmp/i3status.out
    43801   43788 sh -c i3status | tee /tmp/i3status.out
    43802   43801 i3status
    43803   43801 tee /tmp/i3status.out

This fixes #5584.
2021-11-25 12:09:12 +01:00

207 lines
6.0 KiB
C

#define _POSIX_C_SOURCE 200809L
#include <assert.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <json.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "log.h"
#include "loop.h"
#include "swaybar/bar.h"
#include "swaybar/config.h"
#include "swaybar/i3bar.h"
#include "swaybar/status_line.h"
static void status_line_close_fds(struct status_line *status) {
if (status->read_fd != -1) {
loop_remove_fd(status->bar->eventloop, status->read_fd);
close(status->read_fd);
status->read_fd = -1;
}
if (status->write_fd != -1) {
close(status->write_fd);
status->write_fd = -1;
}
}
void status_error(struct status_line *status, const char *text) {
status_line_close_fds(status);
status->protocol = PROTOCOL_ERROR;
status->text = text;
}
bool status_handle_readable(struct status_line *status) {
ssize_t read_bytes = 1;
switch (status->protocol) {
case PROTOCOL_UNDEF:
errno = 0;
int available_bytes;
if (ioctl(status->read_fd, FIONREAD, &available_bytes) == -1) {
sway_log(SWAY_ERROR, "Unable to read status command output size");
status_error(status, "[error reading from status command]");
return true;
}
if ((size_t)available_bytes + 1 > status->buffer_size) {
// need room for leading '\0' too
status->buffer_size = available_bytes + 1;
status->buffer = realloc(status->buffer, status->buffer_size);
}
if (status->buffer == NULL) {
sway_log_errno(SWAY_ERROR, "Unable to read status line");
status_error(status, "[error reading from status command]");
return true;
}
read_bytes = read(status->read_fd, status->buffer, available_bytes);
if (read_bytes != available_bytes) {
status_error(status, "[error reading from status command]");
return true;
}
status->buffer[available_bytes] = 0;
// the header must be sent completely the first time round
char *newline = strchr(status->buffer, '\n');
json_object *header, *version;
if (newline != NULL
&& (header = json_tokener_parse(status->buffer))
&& json_object_object_get_ex(header, "version", &version)
&& json_object_get_int(version) == 1) {
sway_log(SWAY_DEBUG, "Using i3bar protocol.");
status->protocol = PROTOCOL_I3BAR;
json_object *click_events;
if (json_object_object_get_ex(header, "click_events", &click_events)
&& json_object_get_boolean(click_events)) {
sway_log(SWAY_DEBUG, "Enabling click events.");
status->click_events = true;
if (write(status->write_fd, "[\n", 2) != 2) {
status_error(status, "[failed to write to status command]");
json_object_put(header);
return true;
}
}
json_object *float_event_coords;
if (json_object_object_get_ex(header, "float_event_coords", &float_event_coords)
&& json_object_get_boolean(float_event_coords)) {
sway_log(SWAY_DEBUG, "Enabling floating-point coordinates.");
status->float_event_coords = true;
}
json_object *signal;
if (json_object_object_get_ex(header, "stop_signal", &signal)) {
status->stop_signal = json_object_get_int(signal);
sway_log(SWAY_DEBUG, "Setting stop signal to %d", status->stop_signal);
}
if (json_object_object_get_ex(header, "cont_signal", &signal)) {
status->cont_signal = json_object_get_int(signal);
sway_log(SWAY_DEBUG, "Setting cont signal to %d", status->cont_signal);
}
json_object_put(header);
wl_list_init(&status->blocks);
status->tokener = json_tokener_new();
status->buffer_index = strlen(newline + 1);
memmove(status->buffer, newline + 1, status->buffer_index + 1);
return i3bar_handle_readable(status);
}
sway_log(SWAY_DEBUG, "Using text protocol.");
status->protocol = PROTOCOL_TEXT;
status->text = status->buffer;
// intentional fall-through
case PROTOCOL_TEXT:
errno = 0;
while (true) {
if (status->buffer[read_bytes - 1] == '\n') {
status->buffer[read_bytes - 1] = '\0';
}
read_bytes = getline(&status->buffer,
&status->buffer_size, status->read);
if (errno == EAGAIN) {
clearerr(status->read);
return true;
} else if (errno) {
status_error(status, "[error reading from status command]");
return true;
}
}
case PROTOCOL_I3BAR:
return i3bar_handle_readable(status);
default:
return false;
}
}
struct status_line *status_line_init(char *cmd) {
struct status_line *status = calloc(1, sizeof(struct status_line));
status->stop_signal = SIGSTOP;
status->cont_signal = SIGCONT;
status->buffer_size = 8192;
status->buffer = malloc(status->buffer_size);
int pipe_read_fd[2];
int pipe_write_fd[2];
if (pipe(pipe_read_fd) != 0 || pipe(pipe_write_fd) != 0) {
sway_log(SWAY_ERROR, "Unable to create pipes for status_command fork");
exit(1);
}
assert(!getenv("WAYLAND_SOCKET") && "display must be initialized before "
" starting `status-command`; WAYLAND_SOCKET should not be set");
status->pid = fork();
if (status->pid < 0) {
sway_log_errno(SWAY_ERROR, "fork failed");
exit(1);
} else if (status->pid == 0) {
setpgid(0, 0);
dup2(pipe_read_fd[1], STDOUT_FILENO);
close(pipe_read_fd[0]);
close(pipe_read_fd[1]);
dup2(pipe_write_fd[0], STDIN_FILENO);
close(pipe_write_fd[0]);
close(pipe_write_fd[1]);
char *const _cmd[] = { "sh", "-c", cmd, NULL, };
execvp(_cmd[0], _cmd);
exit(1);
}
close(pipe_read_fd[1]);
status->read_fd = pipe_read_fd[0];
fcntl(status->read_fd, F_SETFL, O_NONBLOCK);
close(pipe_write_fd[0]);
status->write_fd = pipe_write_fd[1];
fcntl(status->write_fd, F_SETFL, O_NONBLOCK);
status->read = fdopen(status->read_fd, "r");
status->write = fdopen(status->write_fd, "w");
return status;
}
void status_line_free(struct status_line *status) {
status_line_close_fds(status);
kill(-status->pid, status->cont_signal);
kill(-status->pid, SIGTERM);
waitpid(status->pid, NULL, 0);
if (status->protocol == PROTOCOL_I3BAR) {
struct i3bar_block *block, *tmp;
wl_list_for_each_safe(block, tmp, &status->blocks, link) {
wl_list_remove(&block->link);
i3bar_block_unref(block);
}
json_tokener_free(status->tokener);
}
free(status->buffer);
free(status);
}