Files
gpu-screen-recorder/kms/client/kms_client.c
2025-12-28 13:55:10 -08:00

505 lines
18 KiB
C

#include "kms_client.h"
#include "../../include/utils.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <stdbool.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <poll.h>
#include <sys/stat.h>
#ifdef __linux__
#include <sys/capability.h>
#endif
#ifdef __FreeBSD__
#include <sys/sysctl.h>
#endif
#define GSR_SOCKET_PAIR_LOCAL 0
#define GSR_SOCKET_PAIR_REMOTE 1
static void cleanup_socket(gsr_kms_client *self, bool kill_server);
static int gsr_kms_client_replace_connection(gsr_kms_client *self);
static void close_fds(gsr_kms_response *response) {
for(int i = 0; i < response->num_items; ++i) {
for(int j = 0; j < response->items[i].num_dma_bufs; ++j) {
gsr_kms_response_dma_buf *dma_buf = &response->items[i].dma_buf[j];
if(dma_buf->fd > 0) {
close(dma_buf->fd);
dma_buf->fd = -1;
}
}
response->items[i].num_dma_bufs = 0;
}
response->num_items = 0;
}
static int send_msg_to_server(int server_fd, gsr_kms_request *request) {
struct iovec iov;
iov.iov_base = request;
iov.iov_len = sizeof(*request);
struct msghdr response_message = {0};
response_message.msg_iov = &iov;
response_message.msg_iovlen = 1;
char cmsgbuf[CMSG_SPACE(sizeof(int) * 1)];
memset(cmsgbuf, 0, sizeof(cmsgbuf));
if(request->new_connection_fd > 0) {
response_message.msg_control = cmsgbuf;
response_message.msg_controllen = sizeof(cmsgbuf);
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&response_message);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(sizeof(int) * 1);
int *fds = (int*)CMSG_DATA(cmsg);
fds[0] = request->new_connection_fd;
response_message.msg_controllen = cmsg->cmsg_len;
}
return sendmsg(server_fd, &response_message, 0);
}
static int recv_msg_from_server(int server_pid, int server_fd, gsr_kms_response *response) {
struct iovec iov;
iov.iov_base = response;
iov.iov_len = sizeof(*response);
struct msghdr response_message = {0};
response_message.msg_iov = &iov;
response_message.msg_iovlen = 1;
char cmsgbuf[CMSG_SPACE(sizeof(int) * GSR_KMS_MAX_ITEMS * GSR_KMS_MAX_DMA_BUFS)];
memset(cmsgbuf, 0, sizeof(cmsgbuf));
response_message.msg_control = cmsgbuf;
response_message.msg_controllen = sizeof(cmsgbuf);
int res = 0;
for(;;) {
res = recvmsg(server_fd, &response_message, MSG_DONTWAIT);
if(res <= 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) {
// If we are replacing the connection and closing the application at the same time
// then recvmsg can get stuck (because the server died), so we prevent that by doing
// non-blocking recvmsg and checking if the server died
int status = 0;
int wait_result = waitpid(server_pid, &status, WNOHANG);
if(wait_result != 0) {
res = -1;
break;
}
usleep(1000);
} else {
break;
}
}
if(res > 0 && response->num_items > 0) {
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&response_message);
if(cmsg) {
int *fds = (int*)CMSG_DATA(cmsg);
int fd_index = 0;
for(int i = 0; i < response->num_items; ++i) {
for(int j = 0; j < response->items[i].num_dma_bufs; ++j) {
gsr_kms_response_dma_buf *dma_buf = &response->items[i].dma_buf[j];
dma_buf->fd = fds[fd_index++];
}
}
} else {
close_fds(response);
}
}
return res;
}
/* We have to use $HOME because in flatpak there is no simple path that is accessible, read and write, that multiple flatpak instances can access */
static bool create_socket_path(char *output_path, size_t output_path_size) {
const bool inside_flatpak = getenv("FLATPAK_ID") != NULL;
const char *home = getenv("HOME");
// Portable home with AppImage can cause the socket path to be longer than 108 characters (unix domain socket path max length).
// Using gsr-kms-socket in $HOME is only needed in flatpak, so use /tmp everywhere else instead.
if(!home || !inside_flatpak)
home = "/tmp";
char random_characters[11];
random_characters[10] = '\0';
if(!generate_random_characters_standard_alphabet(random_characters, 10))
return false;
snprintf(output_path, output_path_size, "%s/.gsr-kms-socket-%s", home, random_characters);
return true;
}
#ifdef __linux__
static bool readlink_realpath(const char *filepath, char *buffer) {
char symlinked_path[PATH_MAX];
ssize_t bytes_written = readlink(filepath, symlinked_path, sizeof(symlinked_path) - 1);
if(bytes_written == -1 && errno == EINVAL) {
/* Not a symlink */
snprintf(symlinked_path, sizeof(symlinked_path), "%s", filepath);
} else if(bytes_written == -1) {
return false;
} else {
symlinked_path[bytes_written] = '\0';
}
if(!realpath(symlinked_path, buffer))
return false;
return true;
}
#endif
static bool strcat_safe(char *str, int size, const char *str_to_add) {
const int str_len = strlen(str);
const int str_to_add_len = strlen(str_to_add);
if(str_len + str_to_add_len + 1 >= size)
return false;
memcpy(str + str_len, str_to_add, str_to_add_len);
str[str_len + str_to_add_len] = '\0';
return true;
}
static void file_get_directory(char *filepath) {
char *end = strrchr(filepath, '/');
if(end == NULL)
filepath[0] = '\0';
else
*end = '\0';
}
static bool find_program_in_path(const char *program_name, char *filepath, int filepath_len) {
const char *path = getenv("PATH");
if(!path)
return false;
int program_name_len = strlen(program_name);
const char *end = path + strlen(path);
while(path != end) {
const char *part_end = strchr(path, ':');
const char *next = part_end;
if(part_end) {
next = part_end + 1;
} else {
part_end = end;
next = end;
}
int len = part_end - path;
if(len + 1 + program_name_len < filepath_len) {
memcpy(filepath, path, len);
filepath[len] = '/';
memcpy(filepath + len + 1, program_name, program_name_len);
filepath[len + 1 + program_name_len] = '\0';
if(access(filepath, F_OK) == 0)
return true;
}
path = next;
}
return false;
}
int gsr_kms_client_init(gsr_kms_client *self, const char *card_path) {
int result = -1;
self->kms_server_pid = -1;
self->initial_socket_fd = -1;
self->initial_client_fd = -1;
self->initial_socket_path[0] = '\0';
self->socket_pair[0] = -1;
self->socket_pair[1] = -1;
struct sockaddr_un local_addr = {0};
struct sockaddr_un remote_addr = {0};
if(!create_socket_path(self->initial_socket_path, sizeof(self->initial_socket_path))) {
fprintf(stderr, "gsr error: gsr_kms_client_init: failed to create path to kms socket\n");
return -1;
}
char server_filepath[PATH_MAX];
#ifdef __linux__
if(!readlink_realpath("/proc/self/exe", server_filepath)) {
fprintf(stderr, "gsr error: gsr_kms_client_init: failed to resolve /proc/self/exe\n");
return -1;
}
#elif defined(__FreeBSD__)
int mib[4] = { CTL_KERN, KERN_PROC, KERN_PROC_PATHNAME, getpid() };
size_t size = PATH_MAX;
if (sysctl(mib, 4, server_filepath, &size, NULL, 0) != 0) {
fprintf(stderr, "gsr error: gsr_kms_client_init: failed to resolve pathname using sysctl\n");
return -1;
}
#else
#error "Implement it by yourself"
#endif
file_get_directory(server_filepath);
if(!strcat_safe(server_filepath, sizeof(server_filepath), "/gsr-kms-server")) {
fprintf(stderr, "gsr error: gsr_kms_client_init: gsr-kms-server path too long\n");
return -1;
}
if(access(server_filepath, F_OK) != 0) {
fprintf(stderr, "gsr info: gsr_kms_client_init: gsr-kms-server is not installed in the same directory as gpu-screen-recorder (%s not found), looking for gsr-kms-server in PATH instead\n", server_filepath);
if(!find_program_in_path("gsr-kms-server", server_filepath, sizeof(server_filepath)) || access(server_filepath, F_OK) != 0) {
fprintf(stderr, "gsr error: gsr_kms_client_init: gsr-kms-server was not found in PATH. Please install gpu-screen-recorder properly\n");
return -1;
}
}
fprintf(stderr, "gsr info: gsr_kms_client_init: setting up connection to %s\n", server_filepath);
const bool inside_flatpak = getenv("FLATPAK_ID") != NULL;
const char *home = getenv("HOME");
if(!home)
home = "/tmp";
bool has_perm = 0;
if(geteuid() == 0) {
has_perm = true;
} else {
#ifdef __linux__
cap_t kms_server_cap = cap_get_file(server_filepath);
if(kms_server_cap) {
cap_flag_value_t res = CAP_CLEAR;
cap_get_flag(kms_server_cap, CAP_SYS_ADMIN, CAP_PERMITTED, &res);
if(res == CAP_SET) {
//fprintf(stderr, "has permission!\n");
has_perm = true;
} else {
//fprintf(stderr, "No permission:(\n");
}
cap_free(kms_server_cap);
} else if(!inside_flatpak) {
if(errno == ENODATA)
fprintf(stderr, "gsr info: gsr_kms_client_init: gsr-kms-server is missing sys_admin cap and will require root authentication. To bypass this automatically, run: sudo setcap cap_sys_admin+ep '%s'\n", server_filepath);
else
fprintf(stderr, "gsr info: gsr_kms_client_init: failed to get cap\n");
}
#else
fprintf(stderr, "gsr info: gsr_kms_client_init: platform doesn't support cap\n");
#endif
}
if(socketpair(AF_UNIX, SOCK_STREAM, 0, self->socket_pair) == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_init: socketpair failed, error: %s\n", strerror(errno));
goto err;
}
self->initial_socket_fd = socket(AF_UNIX, SOCK_STREAM, 0);
if(self->initial_socket_fd == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_init: socket failed, error: %s\n", strerror(errno));
goto err;
}
local_addr.sun_family = AF_UNIX;
snprintf(local_addr.sun_path, sizeof(local_addr.sun_path), "%s", (const char*)self->initial_socket_path);
const mode_t prev_mask = umask(0000);
const int bind_res = bind(self->initial_socket_fd, (struct sockaddr*)&local_addr, sizeof(local_addr.sun_family) + strlen(local_addr.sun_path));
umask(prev_mask);
if(bind_res == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_init: failed to bind socket, error: %s\n", strerror(errno));
goto err;
}
if(listen(self->initial_socket_fd, 1) == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_init: failed to listen on socket, error: %s\n", strerror(errno));
goto err;
}
pid_t pid = fork();
if(pid == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_init: fork failed, error: %s\n", strerror(errno));
goto err;
} else if(pid == 0) { /* child */
if(inside_flatpak) {
const char *args[] = { "flatpak-spawn", "--host", "/var/lib/flatpak/app/com.dec05eba.gpu_screen_recorder/current/active/files/bin/kms-server-proxy", self->initial_socket_path, card_path, home, NULL };
execvp(args[0], (char *const*)args);
} else if(has_perm) {
const char *args[] = { server_filepath, self->initial_socket_path, card_path, NULL };
execvp(args[0], (char *const*)args);
} else {
const char *args[] = { "pkexec", server_filepath, self->initial_socket_path, card_path, NULL };
execvp(args[0], (char *const*)args);
}
fprintf(stderr, "gsr error: gsr_kms_client_init: failed to launch \"gsr-kms-server\", error: %s\n", strerror(errno));
_exit(127);
} else { /* parent */
self->kms_server_pid = pid;
}
// We need this dumb-shit retardation with unix domain socket and then replace it with socketpair because
// pkexec doesn't work with socketpair................
fprintf(stderr, "gsr info: gsr_kms_client_init: waiting for server to connect\n");
struct pollfd poll_fd = {
.fd = self->initial_socket_fd,
.events = POLLIN,
.revents = 0
};
for(;;) {
int poll_res = poll(&poll_fd, 1, 100);
if(poll_res > 0 && (poll_fd.revents & POLLIN)) {
socklen_t sock_len = 0;
self->initial_client_fd = accept(self->initial_socket_fd, (struct sockaddr*)&remote_addr, &sock_len);
if(self->initial_client_fd == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_init: accept failed on socket, error: %s\n", strerror(errno));
goto err;
}
break;
} else {
int status = 0;
int wait_result = waitpid(self->kms_server_pid, &status, WNOHANG);
if(wait_result != 0) {
int exit_code = -1;
if(WIFEXITED(status))
exit_code = WEXITSTATUS(status);
fprintf(stderr, "gsr error: gsr_kms_client_init: kms server died or never started, exit code: %d\n", exit_code);
self->kms_server_pid = -1;
if(exit_code != 0)
result = exit_code;
goto err;
}
}
}
fprintf(stderr, "gsr info: gsr_kms_client_init: server connected\n");
fprintf(stderr, "gsr info: replacing file-backed unix domain socket with socketpair\n");
if(gsr_kms_client_replace_connection(self) != 0)
goto err;
cleanup_socket(self, false);
fprintf(stderr, "gsr info: using socketpair\n");
return 0;
err:
gsr_kms_client_deinit(self);
return result;
}
void cleanup_socket(gsr_kms_client *self, bool kill_server) {
if(self->initial_client_fd > 0) {
close(self->initial_client_fd);
self->initial_client_fd = -1;
}
if(self->initial_socket_fd > 0) {
close(self->initial_socket_fd);
self->initial_socket_fd = -1;
}
if(kill_server) {
for(int i = 0; i < 2; ++i) {
if(self->socket_pair[i] > 0) {
close(self->socket_pair[i]);
self->socket_pair[i] = -1;
}
}
}
if(kill_server && self->kms_server_pid > 0) {
kill(self->kms_server_pid, SIGKILL);
// TODO:
//int status;
//waitpid(self->kms_server_pid, &status, 0);
self->kms_server_pid = -1;
}
if(self->initial_socket_path[0] != '\0') {
remove(self->initial_socket_path);
self->initial_socket_path[0] = '\0';
}
}
void gsr_kms_client_deinit(gsr_kms_client *self) {
cleanup_socket(self, true);
}
int gsr_kms_client_replace_connection(gsr_kms_client *self) {
gsr_kms_response response;
response.version = 0;
response.result = KMS_RESULT_FAILED_TO_SEND;
response.err_msg[0] = '\0';
gsr_kms_request request;
request.version = GSR_KMS_PROTOCOL_VERSION;
request.type = KMS_REQUEST_TYPE_REPLACE_CONNECTION;
request.new_connection_fd = self->socket_pair[GSR_SOCKET_PAIR_REMOTE];
if(send_msg_to_server(self->initial_client_fd, &request) == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_replace_connection: failed to send request message to server\n");
return -1;
}
const int recv_res = recv_msg_from_server(self->kms_server_pid, self->socket_pair[GSR_SOCKET_PAIR_LOCAL], &response);
if(recv_res == 0) {
fprintf(stderr, "gsr warning: gsr_kms_client_replace_connection: kms server shut down\n");
return -1;
} else if(recv_res == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_replace_connection: failed to receive response\n");
return -1;
}
if(response.version != GSR_KMS_PROTOCOL_VERSION) {
fprintf(stderr, "gsr error: gsr_kms_client_replace_connection: expected gsr-kms-server protocol version to be %u, but it's %u. please reinstall gpu screen recorder\n", GSR_KMS_PROTOCOL_VERSION, response.version);
/*close_fds(response);*/
return -1;
}
return 0;
}
int gsr_kms_client_get_kms(gsr_kms_client *self, gsr_kms_response *response) {
response->version = 0;
response->result = KMS_RESULT_FAILED_TO_SEND;
response->err_msg[0] = '\0';
response->num_items = 0;
gsr_kms_request request;
request.version = GSR_KMS_PROTOCOL_VERSION;
request.type = KMS_REQUEST_TYPE_GET_KMS;
request.new_connection_fd = 0;
if(send_msg_to_server(self->socket_pair[GSR_SOCKET_PAIR_LOCAL], &request) == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to send request message to server\n");
strcpy(response->err_msg, "failed to send");
return -1;
}
const int recv_res = recv_msg_from_server(self->kms_server_pid, self->socket_pair[GSR_SOCKET_PAIR_LOCAL], response);
if(recv_res == 0) {
fprintf(stderr, "gsr warning: gsr_kms_client_get_kms: kms server shut down\n");
strcpy(response->err_msg, "failed to receive");
return -1;
} else if(recv_res == -1) {
fprintf(stderr, "gsr error: gsr_kms_client_get_kms: failed to receive response\n");
strcpy(response->err_msg, "failed to receive");
return -1;
}
if(response->version != GSR_KMS_PROTOCOL_VERSION) {
fprintf(stderr, "gsr error: gsr_kms_client_get_kms: expected gsr-kms-server protocol version to be %u, but it's %u. please reinstall gpu screen recorder\n", GSR_KMS_PROTOCOL_VERSION, response->version);
/*close_fds(response);*/
strcpy(response->err_msg, "mismatching protocol version");
return -1;
}
return 0;
}