From a7ff41a9f4586a8e3d39d3193e9e267e53d06558 Mon Sep 17 00:00:00 2001
From: Mitchell Riedstra <mitch@riedstra.dev>
Date: Thu, 29 Dec 2022 23:56:44 -0500
Subject: Add a small program to tell Linux it's time to sleep

---
 bin/.gitignore |  1 +
 bin/Makefile   |  4 +++
 bin/zzz.c      | 86 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 bin/.gitignore
 create mode 100644 bin/zzz.c

diff --git a/bin/.gitignore b/bin/.gitignore
new file mode 100644
index 0000000..b1a17ba
--- /dev/null
+++ b/bin/.gitignore
@@ -0,0 +1 @@
+zzz
diff --git a/bin/Makefile b/bin/Makefile
index 0de88b5..c7e37e6 100644
--- a/bin/Makefile
+++ b/bin/Makefile
@@ -1,6 +1,10 @@
 
 default: install
 
+install-zzz: zzz
+	install -D -o root -g root -m 755 zzz /sbin/
+	chmod 6755 /sbin/zzz
+
 linux:
 	install backlight $(HOME)/bin
 	install wpa $(HOME)/bin
diff --git a/bin/zzz.c b/bin/zzz.c
new file mode 100644
index 0000000..2170c78
--- /dev/null
+++ b/bin/zzz.c
@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+
+#define POWER_STATE_F "/sys/power/state"
+
+void
+die(const char *msg)
+{
+	puts(msg);
+	exit(1);
+}
+
+void
+err(const char *msg)
+{
+	perror(msg);
+	exit(1);
+}
+
+void
+suspend()
+{
+	int fh = open(POWER_STATE_F, O_WRONLY);
+	int n;
+	const char *cmd = "mem";
+
+	if (fh == -1)
+		err("Opening "POWER_STATE_F);
+
+	n = write(fh, cmd, 3);
+	if (n == -1)
+		err("Writing to "POWER_STATE_F);
+	
+	exit(0);
+}
+
+int
+main(int argc, char **argv)
+{
+	uid_t uid = getuid();
+	gid_t gid = getgid();
+	uid_t euid = geteuid();
+	char **a = argv+1;
+	char *lockProg = "slock";
+	pid_t pid;
+	int ret;
+
+	if (euid != 0)
+		die("Program must be run as root/setuid");
+
+	for (;*a;a++) {
+		if (strcmp("-l", *a) == 0) {
+			a++;
+			if (*a)
+				lockProg = *a;
+			else
+				die("-l must have an argument");
+		} else {
+			printf("Unknown argument: '%s'\n", *a);
+			exit(1);
+		}
+	}
+
+
+	pid = fork();
+	switch (pid) {
+	case -1:
+		err("fork");
+	case 0:
+		ret = setuid(uid);
+		if (ret == -1)
+			err("setuid");
+		ret = setgid(gid);
+		if (ret == -1)
+			err("setgid");
+
+		ret = execlp(lockProg, lockProg);
+		err("execlp");
+	default:
+		suspend();
+	}
+
+}
-- 
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