Revert "weston: Drop priviledges early, and seteuid when needed"

This reverts commit fc6ccb868f.

We still need root permissions for drmDrop/SetMaster.  Without
integration with ConsoleKit or systemd we also don't have access
to /dev/dri/cardX in the case where we open a new VT.

src/compositor.c

@@ -2088,9 +2088,6 @@ int main(int argc, char *argv[])
 		{ NULL, }
 	};
 
-	/* Drop privilidges early, use getresuid when needed again */
-	seteuid(getuid());
-
 	while (o = getopt_long(argc, argv, opts, longopts, &o), o > 0) {
 		switch (o) {
 		case 'B':

src/evdev.c

@@ -20,8 +20,6 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#define _GNU_SOURCE
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -441,7 +439,6 @@ evdev_input_device_create(struct evdev_input *master,
 	struct evdev_input_device *device;
 	struct wl_event_loop *loop;
 	struct weston_compositor *ec;
-	uid_t saved_uid, uid, euid;
 
 	device = malloc(sizeof *device);
 	if (device == NULL)
@@ -459,10 +456,7 @@ evdev_input_device_create(struct evdev_input *master,
 	device->rel.dx = 0;
 	device->rel.dy = 0;
 
-	getresuid(&uid, &euid, &saved_uid);
-	seteuid(saved_uid);
 	device->fd = open(path, O_RDONLY);
-	seteuid(euid);
 	if (device->fd < 0)
 		goto err0;
 

src/tty.c

@@ -20,8 +20,6 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-#define _GNU_SOURCE
-
 #include <termios.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -130,7 +128,6 @@ tty_create(struct weston_compositor *compositor, tty_vt_func_t vt_func,
 	struct wl_event_loop *loop;
 	struct stat buf;
 	char filename[16];
-	uid_t saved_uid, uid, euid;
 
 	tty = malloc(sizeof *tty);
 	if (tty == NULL)
@@ -139,8 +136,6 @@ tty_create(struct weston_compositor *compositor, tty_vt_func_t vt_func,
 	memset(tty, 0, sizeof *tty);
 	tty->compositor = compositor;
 	tty->vt_func = vt_func;
-	getresuid(&uid, &euid, &saved_uid);
-	seteuid(saved_uid);
 	if (tty_nr > 0) {
 		snprintf(filename, sizeof filename, "/dev/tty%d", tty_nr);
 		fprintf(stderr, "compositor: using %s\n", filename);
@@ -157,13 +152,11 @@ tty_create(struct weston_compositor *compositor, tty_vt_func_t vt_func,
 
 	if (tty->fd <= 0) {
 		fprintf(stderr, "failed to open tty: %m\n");
-		seteuid(euid);
 		return NULL;
 	}
 
 	if (tcgetattr(tty->fd, &tty->terminal_attributes) < 0) {
 		fprintf(stderr, "could not get terminal attributes: %m\n");
-		seteuid(euid);
 		return NULL;
 	}
 
@@ -185,7 +178,6 @@ tty_create(struct weston_compositor *compositor, tty_vt_func_t vt_func,
 	ret = ioctl(tty->fd, KDSETMODE, KD_GRAPHICS);
 	if (ret) {
 		fprintf(stderr, "failed to set KD_GRAPHICS mode on tty: %m\n");
-		seteuid(euid);
 		return NULL;
 	}
 
@@ -195,12 +187,9 @@ tty_create(struct weston_compositor *compositor, tty_vt_func_t vt_func,
 	mode.acqsig = SIGUSR1;
 	if (ioctl(tty->fd, VT_SETMODE, &mode) < 0) {
 		fprintf(stderr, "failed to take control of vt handling\n");
-		seteuid(euid);
 		return NULL;
 	}
 
-	seteuid(euid);
-
 	tty->vt_source =
 		wl_event_loop_add_signal(loop, SIGUSR1, vt_handler, tty);