fix: cpu.c was not coded correctly; some edge cases and using static-width integers

src/cpu.c

@@ -1,39 +1,44 @@
 #include "cpu.h"
 
+#include <assert.h>
+#include <math.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <unistd.h>
 
-const char *const cpu_path = "/sys/devices/system/cpu/cpu%i/online";
+const char cpu_path[] = "/sys/devices/system/cpu/cpu%i/online";
 
-bool getcpu(uint32_t id) {
-	// get the file path
-	char path[64];                    // contains the file path (max length is 64 due to the path and a bunch of extra wiggle room)
-	snprintf(path, 64, cpu_path, id); // writes the path using the id
+int cpu_getenabled(uint id) {
+	const size_t pathlen = sizeof(cpu_path) + (uint)(log10(-1u) + 1);
+	char path[pathlen];
+	snprintf(path, pathlen, cpu_path, id);
 
-	// if the file doesn't exist; return true
 	if (access(path, R_OK) != 0)
-		return true;
+		return 1;
 
-	// read a character from the file, store in state
 	char state = '\0';
 	FILE *f = fopen(path, "r");
+	assert(f);
 	fread(&state, 1, 1, f);
 	fclose(f);
 
-	// return whether state is truthy
-	return !!(state - 0x30);
+	return state != '0';
 }
 
-void setcpu(uint32_t id, bool state) {
-	char path[64];
-	snprintf(path, 64, cpu_path, id);
+int cpu_setenabled(uint id, int state) {
+	const size_t pathlen = sizeof(cpu_path) + (uint)(log10(-1u) + 1);
+	char path[pathlen];
+	snprintf(path, pathlen, cpu_path, id);
 
-	char s = 0x30 + (char)state; // convert the state to a character
+	char s = 0x30 + (state & 1);
+
+	if (access(path, W_OK) != 0)
+		return 1;
 
-	// write the state to the file (creates file if it doesn't exist)
 	FILE *f = fopen(path, "w");
+	assert(f);
 	fwrite(&s, 1, 1, f);
 	fclose(f);
+	return 0;
 }

src/cpu.h

@@ -1,6 +1,10 @@
 #pragma once
-#include <stdbool.h>
-#include <stdint.h>
+#include "util/intdef.h"
 
-bool getcpu(uint32_t);       // gets the state of core (id)
-void setcpu(uint32_t, bool); // sets the state of core (id)
+/* gets the current state of a CPU thread,
+ * returns a boolean value (`1` for enabled, `0` for disabled) */
+int cpu_getenabled(uint id);
+
+/* sets the current state of a CPU thread.
+ * returns `0` upon success, `1` upon failure */
+int cpu_setenabled(uint id, int state);

src/main.c

@@ -1,3 +1,4 @@
+#include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <sys/sysinfo.h>
@@ -10,10 +11,10 @@
 static inline bool cpu_setter(uint32_t id, bool nstate, uint8_t opts) {
 	bool cstate = !nstate;
 	if (!(opts & OPT_SET_ALL))
-		cstate = getcpu(id);
+		cstate = cpu_getenabled(id);
 
 	if (cstate != nstate) {
-		setcpu(id, nstate);
+		cpu_setenabled(id, nstate);
 		return true;
 	}
 	return false;