Create pid file to detect if gpu-screen-recorder is already running and only allow one instance to run at once

This commit is contained in:
dec05eba 2022-03-31 01:24:27 +02:00
parent 5a4d8ce21b
commit 7228d36647

View File

@ -27,6 +27,7 @@
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "../include/sound.hpp"
@ -632,8 +633,16 @@ static void usage() {
exit(1);
}
static sig_atomic_t started = 0;
static sig_atomic_t running = 1;
static sig_atomic_t save_replay = 0;
static const char *pid_file = "/tmp/gpu-screen-recorder";
static void term_handler(int) {
if(started)
unlink(pid_file);
exit(0);
}
static void int_handler(int) {
running = 0;
@ -771,10 +780,70 @@ static void save_replay_async(AVCodecContext *video_codec_context, AVCodecContex
});
}
static bool is_process_running_program(pid_t pid, const char *program_name) {
char filepath[256];
snprintf(filepath, sizeof(filepath), "/proc/%ld/exe", (long)pid);
char resolved_path[PATH_MAX];
const ssize_t resolved_path_len = readlink(filepath, resolved_path, sizeof(resolved_path) - 1);
if(resolved_path_len == -1)
return false;
resolved_path[resolved_path_len] = '\0';
const int program_name_len = strlen(program_name);
return resolved_path_len >= program_name_len && memcmp(resolved_path + resolved_path_len - program_name_len, program_name, program_name_len) == 0;
}
static void handle_existing_pid_file() {
char buffer[256];
int fd = open(pid_file, O_RDONLY);
if(fd == -1)
return;
ssize_t bytes_read = read(fd, buffer, sizeof(buffer) - 1);
if(bytes_read < 0) {
perror("failed to read gpu-screen-recorder pid file");
exit(1);
}
buffer[bytes_read] = '\0';
close(fd);
long pid = 0;
if(sscanf(buffer, "%ld %120s", &pid, buffer) == 2) {
if(is_process_running_program(pid, "gpu-screen-recorder")) {
fprintf(stderr, "Error: gpu-screen-recorder is already running\n");
exit(1);
}
} else {
fprintf(stderr, "Warning: gpu-screen-recorder pid file is in incorrect format, it's possible that its corrupt. Replacing file and continuing...\n");
}
unlink(pid_file);
}
static void handle_new_pid_file(const char *mode) {
int fd = open(pid_file, O_WRONLY|O_CREAT|O_TRUNC, 0777);
if(fd == -1) {
perror("failed to create gpu-screen-recorder pid file");
exit(1);
}
char buffer[256];
const int buffer_size = snprintf(buffer, sizeof(buffer), "%ld %s", (long)getpid(), mode);
if(write(fd, buffer, buffer_size) == -1) {
perror("failed to write gpu-screen-recorder pid file");
exit(1);
}
close(fd);
}
int main(int argc, char **argv) {
signal(SIGTERM, term_handler);
signal(SIGINT, int_handler);
signal(SIGUSR1, save_replay_handler);
handle_existing_pid_file();
std::map<std::string, Arg> args = {
{ "-w", Arg { nullptr, false } },
//{ "-s", Arg { nullptr, true } },
@ -1231,6 +1300,9 @@ int main(int argc, char **argv) {
}, av_format_context, audio_stream, audio_frame_buf, &sound_device, audio_frame, &write_output_mutex);
}
handle_new_pid_file(replay_buffer_size_secs == -1 ? "record" : "replay");
started = 1;
bool redraw = true;
XEvent e;
while (running) {
@ -1434,4 +1506,6 @@ int main(int argc, char **argv) {
XCompositeUnredirectWindow(dpy, src_window_id, CompositeRedirectAutomatic);
XCloseDisplay(dpy);
}
unlink(pid_file);
}