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-rw-r--r--session/direct.c205
1 files changed, 186 insertions, 19 deletions
diff --git a/session/direct.c b/session/direct.c
index f3be87b6..3615aec5 100644
--- a/session/direct.c
+++ b/session/direct.c
@@ -1,6 +1,8 @@
#define _POSIX_C_SOURCE 200809L
#include <errno.h>
#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
#include <stdbool.h>
#include <string.h>
#include <fcntl.h>
@@ -10,6 +12,8 @@
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/capability.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
#include <linux/kd.h>
#include <linux/major.h>
#include <linux/vt.h>
@@ -31,32 +35,89 @@ struct direct_session {
int tty_fd;
int drm_fd;
int kb_mode;
+ int sock;
+ pid_t child;
struct wl_event_source *vt_source;
};
+enum session_message_type {
+ SESSION_OPEN,
+ SESSION_SETMASTER,
+ SESSION_DROPMASTER,
+ SESSION_END,
+};
+
+struct session_message {
+ enum session_message_type type;
+ char path[60];
+};
+
+static int send_message(int sock, enum session_message_type type, const char *path) {
+ struct session_message msg = {
+ .type = type,
+ };
+ struct msghdr request = {
+ .msg_iov = &(struct iovec) {
+ .iov_base = &msg,
+ .iov_len = sizeof(msg),
+ },
+ .msg_iovlen = 1,
+ };
+
+ if (path) {
+ snprintf(msg.path, sizeof(msg.path), "%s", path);
+ }
+
+ sendmsg(sock, &request, 0);
+
+ int err = 0, fd = -1;
+ char control[CMSG_SPACE(sizeof(fd))] = {0};
+ struct msghdr reply = {
+ .msg_iov = &(struct iovec) {
+ .iov_base = &err,
+ .iov_len = sizeof(err),
+ },
+ .msg_iovlen = 1,
+ .msg_control = control,
+ .msg_controllen = sizeof(control),
+ };
+
+ recvmsg(sock, &reply, 0);
+
+ // The other types have no meaningful return value
+ if (type != SESSION_OPEN) {
+ return 0;
+ }
+
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&reply);
+ memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
+
+ return err ? -err : fd;
+}
+
static int direct_session_open(struct wlr_session *restrict base,
const char *restrict path) {
struct direct_session *session = wl_container_of(base, session, base);
- // These are the flags logind uses
- int fd = open(path, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
- if (fd == -1) {
- wlr_log_errno(L_ERROR, "Cannot open %s", path);
+ struct stat st;
+ if (stat(path, &st)) {
return -errno;
}
- struct stat st;
- if (fstat(fd, &st) == 0 && major(st.st_rdev) == DRM_MAJOR) {
- if (drmSetMaster(fd)) {
- // Save errno, in case close() clobbers it
- int e = errno;
- wlr_log(L_ERROR, "Cannot become DRM master: %s%s", strerror(e),
- e == EINVAL ? "; is another display server running?" : "");
- close(fd);
- return -e;
- }
+ uint32_t maj = major(st.st_rdev);
+ if (maj != DRM_MAJOR && maj != INPUT_MAJOR) {
+ return -EINVAL;
+ }
+ int fd = send_message(session->sock, SESSION_OPEN, path);
+ if (fd < 0) {
+ wlr_log(L_ERROR, "Failed to open %s: %s%s", path, strerror(-fd),
+ fd == -EINVAL ? "; is another display server running?" : "");
+ return fd;
+ }
+
+ if (maj == DRM_MAJOR) {
session->drm_fd = fd;
}
@@ -67,7 +128,7 @@ static void direct_session_close(struct wlr_session *base, int fd) {
struct direct_session *session = wl_container_of(base, session, base);
if (fd == session->drm_fd) {
- drmDropMaster(fd);
+ send_message(session->sock, SESSION_DROPMASTER, NULL);
session->drm_fd = -1;
}
@@ -91,6 +152,10 @@ static void direct_session_finish(struct wlr_session *base) {
ioctl(session->tty_fd, KDSETMODE, KD_TEXT);
ioctl(session->tty_fd, VT_SETMODE, &mode);
+ send_message(session->sock, SESSION_END, NULL);
+ close(session->sock);
+ wait(NULL);
+
wl_event_source_remove(session->vt_source);
close(session->tty_fd);
free(session);
@@ -102,11 +167,11 @@ static int vt_handler(int signo, void *data) {
if (session->base.active) {
session->base.active = false;
wl_signal_emit(&session->base.session_signal, session);
- drmDropMaster(session->drm_fd);
+ send_message(session->sock, SESSION_DROPMASTER, NULL);
ioctl(session->tty_fd, VT_RELDISP, 1);
} else {
ioctl(session->tty_fd, VT_RELDISP, VT_ACKACQ);
- drmSetMaster(session->drm_fd);
+ send_message(session->sock, SESSION_SETMASTER, NULL);
session->base.active = true;
wl_signal_emit(&session->base.session_signal, session);
}
@@ -184,6 +249,78 @@ error:
return false;
}
+static void communicate(int sock) {
+ struct session_message msg;
+ struct msghdr hdr = {
+ .msg_iov = &(struct iovec) {
+ .iov_base = &msg,
+ .iov_len = sizeof(msg),
+ },
+ .msg_iovlen = 1,
+ };
+
+ int drm_fd = -1;
+
+ while (recvmsg(sock, &hdr, 0) >= 0 || errno == EINTR) {
+ switch (msg.type) {
+ case SESSION_OPEN:
+ errno = 0;
+ // These are the flags that logind use
+ int fd = open(msg.path, O_RDWR | O_CLOEXEC | O_NOCTTY | O_NONBLOCK);
+ int e = errno;
+
+ struct stat st;
+ if (fstat(fd, &st) >= 0 && major(st.st_rdev) == DRM_MAJOR) {
+ if (drmSetMaster(fd)) {
+ close(fd);
+ fd = -1;
+ e = errno;
+ }
+
+ drm_fd = fd;
+ }
+
+ char control[CMSG_SPACE(sizeof(fd))] = {0};
+ struct msghdr reply = {
+ .msg_iov = &(struct iovec) {
+ .iov_base = &e,
+ .iov_len = sizeof(e),
+ },
+ .msg_iovlen = 1,
+ .msg_control = &control,
+ .msg_controllen = sizeof(control),
+ };
+ struct cmsghdr *cmsg = CMSG_FIRSTHDR(&reply);
+ cmsg->cmsg_level = SOL_SOCKET;
+ cmsg->cmsg_type = SCM_RIGHTS;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(fd));
+ memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
+
+ sendmsg(sock, &reply, 0);
+ break;
+ case SESSION_SETMASTER:
+ if (drm_fd != -1) {
+ drmSetMaster(drm_fd);
+ }
+
+ sendmsg(sock, &(struct msghdr){0}, 0);
+ break;
+ case SESSION_DROPMASTER:
+ if (drm_fd != -1) {
+ drmDropMaster(drm_fd);
+ }
+
+ sendmsg(sock, &(struct msghdr){0}, 0);
+ break;
+ case SESSION_END:
+ sendmsg(sock, &(struct msghdr){0}, 0);
+ return;
+ }
+ }
+
+
+}
+
static struct wlr_session *direct_session_start(struct wl_display *disp) {
cap_t cap = cap_get_proc();
cap_flag_value_t val;
@@ -196,12 +333,36 @@ static struct wlr_session *direct_session_start(struct wl_display *disp) {
cap_free(cap);
+ int sock[2];
+ if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sock) < 0) {
+ wlr_log_errno(L_ERROR, "Failed to create socket pair");
+ return NULL;
+ }
+
+ pid_t pid = fork();
+ if (pid < 0) {
+ wlr_log_errno(L_ERROR, "Fork failed");
+ goto error_sock;
+ } else if (pid == 0) {
+ close(sock[0]);
+
+ communicate(sock[1]);
+
+ _Exit(0);
+ }
+
+ close(sock[1]);
+ sock[1] = -1;
+
struct direct_session *session = calloc(1, sizeof(*session));
if (!session) {
- wlr_log(L_ERROR, "Allocation failed: %s", strerror(errno));
- return NULL;
+ wlr_log_errno(L_ERROR, "Allocation failed");
+ goto error_child;
}
+ session->child = pid;
+ session->sock = sock[0];
+
if (!setup_tty(session, disp)) {
goto error_session;
}
@@ -215,6 +376,12 @@ static struct wlr_session *direct_session_start(struct wl_display *disp) {
error_session:
free(session);
+error_child:
+ send_message(sock[0], SESSION_END, NULL);
+ wait(NULL);
+error_sock:
+ close(sock[0]);
+ close(sock[1]);
return NULL;
}