xhotplug

commit 4f4c4cb10d48251b46c8a9c81730dceaa5f3e756
Author: Daniel Moch <daniel@danielmoch.com>
Date:   Sat, 20 Jun 2020 17:44:43 -0400

Initial commit

Diffstat:
A
.gitignore
 | 
1
+
A
Makefile
 | 
20
++++++++++++++++++++
A
config.mk
 | 
12
++++++++++++
A
xhotplug.c
 | 
146
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

4 files changed, 179 insertions(+), 0 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1 @@
+xhotplug
diff --git a/Makefile b/Makefile
@@ -0,0 +1,20 @@
+include config.mk
+
+all: xhotplug
+
+.c.o:
+	${CC} ${CFLAGS} ${CPPFLAGS} -o $@ $<
+
+xhotplug: ${OBJ}
+	${CC} -o $@ ${OBJ} ${LDFLAGS}
+
+install: xhotplug
+	install -Dm755 xhotplug ${DESTDIR}${PREFIX}/bin/xhotplug
+
+uninstall:
+	-rm -f ${DESTDIR}${PREFIX}/bin/xhotplug
+
+clean:
+	-rm *.o xhotplug
+
+.PHONY: all clean install uninstall
diff --git a/config.mk b/config.mk
@@ -0,0 +1,12 @@
+PREFIX := /usr/local
+MANPATH := ${PREFIX}/share/man
+X11BASE := /usr/X11R6
+
+SRC = xhotplug.c
+OBJ = ${SRC:.c=.o}
+INCS = -I${X11BASE}/include
+LIBS = -L${X11BASE}/lib -lxcb -lxcb-randr
+
+CPPFLAGS := -DVERSION=\"0.1.0dev0\"
+CFLAGS := -std=c99 -pedantic-errors -Wall -Wextra -Werror -O2 -c ${INCS}
+LDFLAGS := ${LIBS}
diff --git a/xhotplug.c b/xhotplug.c
@@ -0,0 +1,146 @@
+/*
+ * Compile with -lxcb -lxcb-randr
+ */
+
+#include <errno.h>
+#include <libgen.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/syslimits.h>
+#include <unistd.h>
+#include <xcb/xcb.h>
+#include <xcb/randr.h>
+
+void
+usage(const char *argv, const int e_val) {
+	printf("usage: %s [-h] [-v] script\n", argv);
+	exit(e_val);
+}
+
+void
+xhotplug(const char *cmd) {
+	xcb_connection_t* conn;
+	xcb_screen_t* screen;
+	xcb_window_t window;
+	xcb_generic_event_t* evt;
+	xcb_randr_screen_change_notify_event_t* randr_evt;
+	xcb_timestamp_t last_time;
+	int monitor_connected = 1;
+
+	conn = xcb_connect(NULL, NULL);
+
+	screen = xcb_setup_roots_iterator(xcb_get_setup(conn)).data;
+	window = screen->root;
+	xcb_randr_select_input(conn, window, XCB_RANDR_NOTIFY_MASK_SCREEN_CHANGE);
+	xcb_flush(conn);
+
+	while ((evt = xcb_wait_for_event(conn)) != NULL) {
+		if (evt->response_type & XCB_RANDR_NOTIFY_MASK_SCREEN_CHANGE) {
+			randr_evt = (xcb_randr_screen_change_notify_event_t*) evt;
+			if (last_time != randr_evt->timestamp) {
+				last_time = randr_evt->timestamp;
+				monitor_connected = !monitor_connected;
+				if (monitor_connected) {
+					system(cmd);
+				} else {
+					system(cmd);
+				}
+			}
+		}
+		free(evt);
+	}
+	xcb_disconnect(conn);
+}
+
+int
+can_execute(const char *bname, const char *path) {
+	uid_t uid = getuid();
+	gid_t gid = getgid();
+	gid_t gidset[NGROUPS_MAX];
+	struct stat sb;
+
+	if (stat(path, &sb) != 0) {
+		fprintf(stderr, "%s: ERROR -- Unable to stat file %s\n", bname, path);
+		fprintf(stderr, "%s: errno -- %d\n", bname, errno);
+		return 0;
+	}
+	if (sb.st_uid != uid && sb.st_uid != 0) {
+		fprintf(stderr, "%s: script not owned by user or root\n", bname);
+		return 0;
+	}
+	if (sb.st_uid == uid && (sb.st_mode & S_IXUSR) == 0) {
+		fprintf(stderr, "%s: script is not executable\n", bname);
+		return 0;
+	}
+	if (sb.st_uid == 0) {
+		for (int i=0; i<getgroups(NGROUPS_MAX, gidset); i++) {
+			if (gidset[i] == gid) {
+				if ((sb.st_mode & S_IXGRP) == 0) {
+					fprintf(stderr, "%s: script is not executable\n", bname);
+					return 0;
+				}
+				else {
+					return 1;
+				}
+			}
+		}
+	}
+	if ((sb.st_mode & (S_IWGRP | S_IWOTH)) != 0) {
+		fprintf(stderr, "%s: script is writeable by others\n", bname);
+		return 0;
+	}
+	return 1;
+}
+
+int
+main(int argc, char **argv) {
+	char ch, *bname = basename(argv[0]), script[PATH_MAX], sbuf[PATH_MAX];
+	ssize_t sbuf_len;
+	int pval;
+
+	while ((ch = getopt(argc, argv, "vh")) != -1) {
+		switch (ch) {
+		case 'v':
+			printf("%s %s\n", bname, VERSION);
+			exit(0);
+			break;
+		case 'h':
+			usage(bname, 0);
+			break;
+		default:
+			usage(bname, 1);
+		}
+	}
+	argc -= optind;
+	argv += optind;
+
+	if ( argc < 1 || argc > 1) {
+		printf("%s: invalid number of arguments\n", bname);
+		usage(bname, 2);
+	}
+
+	sbuf_len = strnlen(argv[0], PATH_MAX);
+	strncpy(script, argv[0], PATH_MAX - 1);
+	script[PATH_MAX - 1] = '\0';
+	while ((sbuf_len = readlink(script, sbuf, PATH_MAX)) != -1) {
+		sbuf[sbuf_len] = '\0';
+		strncpy(script, sbuf, PATH_MAX - 1);
+		script[PATH_MAX - 1] = '\0';
+	}
+
+	if(!can_execute(bname, script)) {
+		fprintf(stderr, "%s: cannot run provided script. quitting.\n", bname);
+		usage(bname, 3);
+	}
+
+#ifdef __OpenBSD__
+	if ((pval = pledge("stdio unix rpath proc exec", NULL)) != 0) {
+		fprintf(stderr, "%s: call to pledge(2) failed -- %d. quitting.\n", bname, pval);
+		exit(6);
+	}
+#endif
+
+	xhotplug(script);
+}