From 7a6ec996ae523c667ccc0bec24d0aa274b914a49 Mon Sep 17 00:00:00 2001
From: Ali Mashtizadeh <mashti@uwaterloo.ca>
Date: Mon, 21 Aug 2023 17:01:14 -0400
Subject: [PATCH] Cleanup sysctl command

---
 sbin/sysctl/sysctl.c | 133 +++++++++++++++++++++++++++++++------------
 1 file changed, 98 insertions(+), 35 deletions(-)

diff --git a/sbin/sysctl/sysctl.c b/sbin/sysctl/sysctl.c
index e647939..91990b4 100644
--- a/sbin/sysctl/sysctl.c
+++ b/sbin/sysctl/sysctl.c
@@ -1,5 +1,7 @@
 
 #include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
 #include <errno.h>
 #include <syscall.h>
 
@@ -26,49 +28,110 @@ SysCtlEntry SYSCTLTable[] = {
 #undef SYSCTL_INT
 #undef SYSCTL_BOOL
 
+void
+PrintVal(int idx)
+{
+    switch (SYSCTLTable[idx].type) {
+	case SYSCTL_TYPE_STR: {
+	    SysCtlString scStr;
+
+	    OSSysCtl(SYSCTLTable[idx].path, &scStr, NULL);
+	    printf("%s: %s\n", SYSCTLTable[idx].path, scStr.value);
+	    break;
+	}
+	case SYSCTL_TYPE_INT: {
+	    SysCtlInt scInt;
+
+	    OSSysCtl(SYSCTLTable[idx].path, &scInt, NULL);
+	    printf("%s: %ld\n", SYSCTLTable[idx].path, scInt.value);
+	    break;
+	}
+	case SYSCTL_TYPE_BOOL: {
+	    SysCtlBool scBool;
+
+	    OSSysCtl(SYSCTLTable[idx].path, &scBool, NULL);
+	    printf("%s: %s\n", SYSCTLTable[idx].path,
+		    scBool.value ? "true" : "false");
+	    break;
+	}
+	default:
+	    printf("%s: Unsupported type\n", SYSCTLTable[idx].path);
+	    break;
+    }
+}
+
+void
+UpdateVal(int idx, const char *val)
+{
+    switch (SYSCTLTable[idx].type) {
+	case SYSCTL_TYPE_STR: {
+	    SysCtlString scStr;
+
+	    strncpy(scStr.value, val, sizeof(scStr.value) - 1);
+	    OSSysCtl(SYSCTLTable[idx].path, NULL, &scStr);
+	    break;
+	}
+	case SYSCTL_TYPE_INT: {
+	    SysCtlInt scInt;
+
+	    scInt.value = atoi(val);
+	    printf("%ld\n", scInt.value);
+	    OSSysCtl(SYSCTLTable[idx].path, NULL, &scInt);
+	    break;
+	}
+	case SYSCTL_TYPE_BOOL: {
+	    SysCtlBool scBool;
+
+	    if (strcmp(val,"true") == 0)
+		scBool.value = true;
+	    else if (strcmp(val,"false") == 0)
+		scBool.value = false;
+	    else {
+		printf("Value must be true or false\n");
+		exit(1);
+	    }
+	    OSSysCtl(SYSCTLTable[idx].path, NULL, &scBool);
+	    break;
+	}
+	default:
+	    printf("%s: Unsupported type\n", SYSCTLTable[idx].path);
+	    break;
+    }
+}
+
 int
 main(int argc, const char *argv[])
 {
-    int i;
-
-    printf("%d\n", argc);
-    if (true) {
-        printf("%-20s %s\n", "Name", "Description");
-	for (i = 0; SYSCTLTable[i].type != 0; i++) {
-	    printf("%-20s %s\n",
-		    SYSCTLTable[i].path,
-		    SYSCTLTable[i].description);
-	}
-    }
-
-    if (false) {
+    if (argc == 2 && strcmp(argv[1],"-h") == 0) {
 	printf("Usage: sysctl [NODE] [VALUE]\n");
 	return 1;
     }
 
-    for (i = 0; SYSCTLTable[i].type != 0; i++) {
-	SysCtlString scStr;
-	SysCtlInt scInt;
-	SysCtlBool scBool;
-
-	switch (SYSCTLTable[i].type) {
-	    case SYSCTL_TYPE_STR:
-		OSSysCtl(SYSCTLTable[i].path, &scStr, NULL);
-		printf("%s: %s\n", SYSCTLTable[i].path, scStr.value);
-		break;
-	    case SYSCTL_TYPE_INT:
-		OSSysCtl(SYSCTLTable[i].path, &scInt, NULL);
-		printf("%s: %ld\n", SYSCTLTable[i].path, scInt.value);
-		break;
-	    case SYSCTL_TYPE_BOOL:
-		OSSysCtl(SYSCTLTable[i].path, &scBool, NULL);
-		printf("%s: %s\n", SYSCTLTable[i].path,
-			scBool.value ? "true" : "false");
-		break;
-	    default:
-		printf("%s: Unsupported type\n", SYSCTLTable[i].path);
-		break;
+    if (argc == 2 && strcmp(argv[1],"-d") == 0) {
+        printf("%-20s %s\n", "Name", "Description");
+	for (int i = 0; SYSCTLTable[i].type != 0; i++) {
+	    printf("%-20s %s\n",
+		    SYSCTLTable[i].path,
+		    SYSCTLTable[i].description);
 	}
+	return 0;
+    }
+
+    if (argc == 2 || argc == 3) {
+	for (int i = 0; SYSCTLTable[i].type != 0; i++) {
+	    if (strcmp(SYSCTLTable[i].path, argv[1]) == 0) {
+		if (argc == 2)
+		    PrintVal(i);
+		else
+		    UpdateVal(i, argv[2]);
+	    }
+	}
+
+	return 0;
+    }
+
+    for (int i = 0; SYSCTLTable[i].type != 0; i++) {
+	PrintVal(i);
     }
 
     return 0;