wlroots-hyprland/backend/session/direct-ipc.c
sghctoma 7a5d3c4d3b Implement device type discovery using ioctl calls
This commit implements device type discovery by calling two ioctls
(DRM_IOCTL_VERSION and EVIOCGVERSION) on the device. These iocts are
specific to drm and input devices respectively, therefore we can
determine the device type based on which one returns an error.
2018-09-07 16:37:25 +02:00

270 lines
5.3 KiB
C

#define _POSIX_C_SOURCE 200809L
#ifdef __FreeBSD__
#define __BSD_VISIBLE 1
#define INPUT_MAJOR 0
#endif
#include <dev/evdev/input.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <wlr/config.h>
#include <wlr/util/log.h>
#include <xf86drm.h>
#ifdef __linux__
#include <sys/sysmacros.h>
#include <linux/major.h>
#endif
#include "backend/session/direct-ipc.h"
enum { DRM_MAJOR = 226 };
#ifdef WLR_HAS_LIBCAP
#include <sys/capability.h>
static bool have_permissions(void) {
cap_t cap = cap_get_proc();
cap_flag_value_t val;
if (!cap || cap_get_flag(cap, CAP_SYS_ADMIN, CAP_PERMITTED, &val) || val != CAP_SET) {
wlr_log(WLR_ERROR, "Do not have CAP_SYS_ADMIN; cannot become DRM master");
cap_free(cap);
return false;
}
cap_free(cap);
return true;
}
#else
static bool have_permissions(void) {
#ifdef __linux__
if (geteuid() != 0) {
wlr_log(WLR_ERROR, "Do not have root privileges; cannot become DRM master");
return false;
}
#endif
return true;
}
#endif
static void send_msg(int sock, int fd, void *buf, size_t buf_len) {
char control[CMSG_SPACE(sizeof(fd))] = {0};
struct iovec iovec = { .iov_base = buf, .iov_len = buf_len };
struct msghdr msghdr = {0};
if (buf) {
msghdr.msg_iov = &iovec;
msghdr.msg_iovlen = 1;
}
if (fd >= 0) {
msghdr.msg_control = &control;
msghdr.msg_controllen = sizeof(control);
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msghdr);
*cmsg = (struct cmsghdr) {
.cmsg_level = SOL_SOCKET,
.cmsg_type = SCM_RIGHTS,
.cmsg_len = CMSG_LEN(sizeof(fd)),
};
memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
}
ssize_t ret;
do {
ret = sendmsg(sock, &msghdr, 0);
} while (ret < 0 && errno == EINTR);
}
static ssize_t recv_msg(int sock, int *fd_out, void *buf, size_t buf_len) {
char control[CMSG_SPACE(sizeof(*fd_out))] = {0};
struct iovec iovec = { .iov_base = buf, .iov_len = buf_len };
struct msghdr msghdr = {0};
if (buf) {
msghdr.msg_iov = &iovec;
msghdr.msg_iovlen = 1;
}
if (fd_out) {
msghdr.msg_control = &control;
msghdr.msg_controllen = sizeof(control);
}
ssize_t ret;
do {
ret = recvmsg(sock, &msghdr, MSG_CMSG_CLOEXEC);
} while (ret < 0 && errno == EINTR);
if (fd_out) {
struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msghdr);
if (cmsg) {
memcpy(fd_out, CMSG_DATA(cmsg), sizeof(*fd_out));
} else {
*fd_out = -1;
}
}
return ret;
}
enum msg_type {
MSG_OPEN,
MSG_SETMASTER,
MSG_DROPMASTER,
MSG_END,
};
struct msg {
enum msg_type type;
char path[256];
};
static void communicate(int sock) {
struct msg msg;
int drm_fd = -1;
bool running = true;
while (running && recv_msg(sock, &drm_fd, &msg, sizeof(msg)) > 0) {
switch (msg.type) {
case MSG_OPEN:
errno = 0;
// These are the same flags that logind opens files with
int fd = open(msg.path, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NONBLOCK);
int ret = errno;
if (fd == -1) {
goto error;
}
#ifndef __FreeBSD__
struct stat st;
if (fstat(fd, &st) < 0) {
ret = errno;
goto error;
}
uint32_t maj = major(st.st_rdev);
if (maj != INPUT_MAJOR && maj != DRM_MAJOR) {
ret = ENOTSUP;
goto error;
}
if (maj == DRM_MAJOR && drmSetMaster(fd)) {
ret = errno;
}
#else
int ev;
struct drm_version dv = {0};
if (ioctl(fd, EVIOCGVERSION, &ev) == -1 &&
ioctl(fd, DRM_IOCTL_VERSION, &dv) == -1) {
ret = ENOTSUP;
goto error;
}
if (dv.version_major != 0 && drmSetMaster(fd)) {
ret = errno;
}
#endif
error:
send_msg(sock, ret ? -1 : fd, &ret, sizeof(ret));
if (fd >= 0) {
close(fd);
}
break;
case MSG_SETMASTER:
drmSetMaster(drm_fd);
close(drm_fd);
send_msg(sock, -1, NULL, 0);
break;
case MSG_DROPMASTER:
drmDropMaster(drm_fd);
close(drm_fd);
send_msg(sock, -1, NULL, 0);
break;
case MSG_END:
running = false;
send_msg(sock, -1, NULL, 0);
break;
}
}
close(sock);
}
int direct_ipc_open(int sock, const char *path) {
struct msg msg = { .type = MSG_OPEN };
snprintf(msg.path, sizeof(msg.path), "%s", path);
send_msg(sock, -1, &msg, sizeof(msg));
int fd, err, ret;
int retry = 0;
do {
ret = recv_msg(sock, &fd, &err, sizeof(err));
} while (ret == 0 && retry++ < 3);
return err ? -err : fd;
}
void direct_ipc_setmaster(int sock, int fd) {
struct msg msg = { .type = MSG_SETMASTER };
send_msg(sock, fd, &msg, sizeof(msg));
recv_msg(sock, NULL, NULL, 0);
}
void direct_ipc_dropmaster(int sock, int fd) {
struct msg msg = { .type = MSG_DROPMASTER };
send_msg(sock, fd, &msg, sizeof(msg));
recv_msg(sock, NULL, NULL, 0);
}
void direct_ipc_finish(int sock, pid_t pid) {
struct msg msg = { .type = MSG_END };
send_msg(sock, -1, &msg, sizeof(msg));
recv_msg(sock, NULL, NULL, 0);
waitpid(pid, NULL, 0);
}
int direct_ipc_init(pid_t *pid_out) {
if (!have_permissions()) {
return -1;
}
int sock[2];
if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sock) < 0) {
wlr_log_errno(WLR_ERROR, "Failed to create socket pair");
return -1;
}
pid_t pid = fork();
if (pid < 0) {
wlr_log_errno(WLR_ERROR, "Fork failed");
close(sock[0]);
close(sock[1]);
return -1;
} else if (pid == 0) {
close(sock[0]);
communicate(sock[1]);
_Exit(0);
}
close(sock[1]);
*pid_out = pid;
return sock[0];
}