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Moved IPC to its own file.

This commit is contained in:
Scott Anderson 2017-07-09 22:12:50 +12:00
parent bd5bca5283
commit 2f2c8205d8
4 changed files with 303 additions and 225 deletions
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12
include/session/direct-ipc.h Normal file
View File

@ -0,0 +1,12 @@
#ifndef SESSION_DIRECT_IPC
#define SESSION_DIRECT_IPC
#include <sys/types.h>
int direct_ipc_open(int sock, const char *path);
void direct_ipc_setmaster(int sock);
void direct_ipc_dropmaster(int sock);
void direct_ipc_finish(int sock, pid_t pid);
int direct_ipc_start(pid_t *pid_out);
#endif

1
session/CMakeLists.txt
View File

@ -6,6 +6,7 @@ include_directories(
set(sources
session.c
direct.c
direct-ipc.c
)
set(libs

241
session/direct-ipc.c Normal file
View File

@ -0,0 +1,241 @@
#define _POSIX_C_SOURCE 200809L
#include <errno.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#include <sys/wait.h>
#include <xf86drm.h>
#include <linux/major.h>
#include <wlr/util/log.h>
#include "session/direct-ipc.h"
enum { DRM_MAJOR = 226 };
#ifdef 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(L_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) {
if (geteuid() != 0) {
wlr_log(L_ERROR, "Do not have root privileges; cannot become DRM master");
return false;
}
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)),
};
*(int *)CMSG_DATA(cmsg) = 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);
*fd_out = cmsg ? *(int *)CMSG_DATA(cmsg) : -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, NULL, &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;
}
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) {
if (drmSetMaster(fd)) {
ret = errno;
} else {
drm_fd = fd;
}
}
error:
send_msg(sock, ret ? -1 : fd, &ret, sizeof(ret));
if (fd != drm_fd) {
close(fd);
}
break;
case MSG_SETMASTER:
drmSetMaster(drm_fd);
send_msg(sock, -1, NULL, 0);
break;
case MSG_DROPMASTER:
drmDropMaster(drm_fd);
send_msg(sock, -1, NULL, 0);
break;
case MSG_END:
running = false;
send_msg(sock, -1, NULL, 0);
break;
}
}
close(drm_fd);
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;
recv_msg(sock, &fd, &err, sizeof(err));
return err ? -err : fd;
}
void direct_ipc_setmaster(int sock) {
struct msg msg = { .type = MSG_SETMASTER };
send_msg(sock, -1, &msg, sizeof(msg));
recv_msg(sock, NULL, NULL, 0);
}
void direct_ipc_dropmaster(int sock) {
struct msg msg = { .type = MSG_DROPMASTER };
send_msg(sock, -1, &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_start(pid_t *pid_out) {
if (!have_permissions()) {
return -1;
}
int sock[2];
if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sock) < 0) {
wlr_log_errno(L_ERROR, "Failed to create socket pair");
return -1;
}
pid_t pid = fork();
if (pid < 0) {
wlr_log_errno(L_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];
}

274
session/direct.c
View File

@ -3,25 +3,19 @@
#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <linux/kd.h>
#include <linux/major.h>
#include <linux/input.h>
#include <linux/vt.h>
#include <wayland-server.h>
#include <xf86drm.h>
#include <wlr/session/interface.h>
#include <wlr/util/log.h>
#ifdef HAS_LIBCAP
#include <sys/capability.h>
#endif
#include "session/direct-ipc.h"
enum { DRM_MAJOR = 226 };
@ -37,82 +31,23 @@ struct direct_session {
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 *base, const char *path) {
struct direct_session *session = wl_container_of(base, session, base);
struct stat st;
if (stat(path, &st)) {
return -errno;
}
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);
int fd = direct_ipc_open(session->sock, 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) {
struct stat st;
if (fstat(fd, &st) < 0) {
close(fd);
return -errno;
}
if (major(st.st_rdev) == DRM_MAJOR) {
session->base.drm_fd = fd;
}
@ -122,9 +57,18 @@ static int direct_session_open(struct wlr_session *base, const char *path) {
static void direct_session_close(struct wlr_session *base, int fd) {
struct direct_session *session = wl_container_of(base, session, base);
if (fd == session->base.drm_fd) {
send_message(session->sock, SESSION_DROPMASTER, NULL);
struct stat st;
if (fstat(fd, &st) < 0) {
wlr_log_errno(L_ERROR, "Stat failed");
close(fd);
return;
}
if (major(st.st_rdev) == DRM_MAJOR) {
direct_ipc_dropmaster(session->sock);
session->base.drm_fd = -1;
} else if (major(st.st_rdev) == INPUT_MAJOR) {
ioctl(fd, EVIOCREVOKE, 0);
}
close(fd);
@ -151,9 +95,8 @@ static void direct_session_finish(struct wlr_session *base) {
wlr_log(L_ERROR, "Failed to restore tty");
}
send_message(session->sock, SESSION_END, NULL);
direct_ipc_finish(session->sock, session->child);
close(session->sock);
wait(NULL);
wl_event_source_remove(session->vt_source);
close(session->tty_fd);
@ -166,11 +109,11 @@ static int vt_handler(int signo, void *data) {
if (session->base.active) {
session->base.active = false;
wl_signal_emit(&session->base.session_signal, session);
send_message(session->sock, SESSION_DROPMASTER, NULL);
direct_ipc_dropmaster(session->sock);
ioctl(session->tty_fd, VT_RELDISP, 1);
} else {
ioctl(session->tty_fd, VT_RELDISP, VT_ACKACQ);
send_message(session->sock, SESSION_SETMASTER, NULL);
direct_ipc_setmaster(session->sock);
session->base.active = true;
wl_signal_emit(&session->base.session_signal, session);
}
@ -179,24 +122,22 @@ static int vt_handler(int signo, void *data) {
}
static bool setup_tty(struct direct_session *session, struct wl_display *display) {
session->tty_fd = dup(STDIN_FILENO);
if (session->tty_fd == -1) {
int fd = dup(STDIN_FILENO);
if (fd == -1) {
wlr_log_errno(L_ERROR, "Cannot open tty");
return false;
}
struct stat st;
if (fstat(session->tty_fd, &st) == -1 || major(st.st_rdev) != TTY_MAJOR ||
minor(st.st_rdev) == 0) {
if (fstat(fd, &st) == -1 || major(st.st_rdev) != TTY_MAJOR || minor(st.st_rdev) == 0) {
wlr_log(L_ERROR, "Not running from a virtual terminal");
goto error;
}
int tty = minor(st.st_rdev);
int ret, kd_mode;
session->base.vtnr = tty;
int ret, kd_mode, old_kbmode;
ret = ioctl(session->tty_fd, KDGETMODE, &kd_mode);
ret = ioctl(fd, KDGETMODE, &kd_mode);
if (ret) {
wlr_log_errno(L_ERROR, "Failed to get tty mode");
goto error;
@ -208,20 +149,20 @@ static bool setup_tty(struct direct_session *session, struct wl_display *display
goto error;
}
ioctl(session->tty_fd, VT_ACTIVATE, tty);
ioctl(session->tty_fd, VT_WAITACTIVE, tty);
ioctl(fd, VT_ACTIVATE, tty);
ioctl(fd, VT_WAITACTIVE, tty);
if (ioctl(session->tty_fd, KDGKBMODE, &session->old_kbmode)) {
if (ioctl(fd, KDGKBMODE, &old_kbmode)) {
wlr_log_errno(L_ERROR, "Failed to read keyboard mode");
goto error;
}
if (ioctl(session->tty_fd, KDSKBMODE, K_OFF)) {
if (ioctl(fd, KDSKBMODE, K_OFF)) {
wlr_log_errno(L_ERROR, "Failed to set keyboard mode");
goto error;
}
if (ioctl(session->tty_fd, KDSETMODE, KD_GRAPHICS)) {
if (ioctl(fd, KDSETMODE, KD_GRAPHICS)) {
wlr_log_errno(L_ERROR, "Failed to set graphics mode on tty");
goto error;
}
@ -232,7 +173,7 @@ static bool setup_tty(struct direct_session *session, struct wl_display *display
.acqsig = SIGUSR1,
};
if (ioctl(session->tty_fd, VT_SETMODE, &mode) < 0) {
if (ioctl(fd, VT_SETMODE, &mode) < 0) {
wlr_log(L_ERROR, "Failed to take control of tty");
goto error;
}
@ -244,145 +185,31 @@ static bool setup_tty(struct direct_session *session, struct wl_display *display
goto error;
}
session->base.vtnr = tty;
session->tty_fd = fd;
session->old_kbmode = old_kbmode;
return true;
error:
close(session->tty_fd);
close(fd);
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;
}
}
}
#ifdef HAS_LIBCAP
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(L_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) {
if (geteuid() != 0) {
wlr_log(L_ERROR, "Do not have root privileges; cannot become DRM master");
return false;
}
return true;
}
#endif
static struct wlr_session *direct_session_start(struct wl_display *disp) {
if (!have_permissions()) {
return NULL;
}
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_errno(L_ERROR, "Allocation failed");
goto error_child;
return NULL;
}
session->child = pid;
session->sock = sock[0];
session->sock = direct_ipc_start(&session->child);
if (session->sock == -1) {
goto error_session;
}
if (!setup_tty(session, disp)) {
goto error_session;
goto error_ipc;
}
// XXX: Is it okay to trust the environment like this?
@ -400,14 +227,11 @@ static struct wlr_session *direct_session_start(struct wl_display *disp) {
wl_signal_init(&session->base.session_signal);
return &session->base;
error_ipc:
direct_ipc_finish(session->sock, session->child);
close(session->sock);
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;
}