From 23aa6f84539ba320a91235fb81681d0754178f62 Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Mon, 5 Jul 2021 23:22:24 +0200
Subject: ACPI and config parsing

---
 src/loader/cfg.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 173 insertions(+)
 create mode 100644 src/loader/cfg.c

(limited to 'src/loader/cfg.c')

diff --git a/src/loader/cfg.c b/src/loader/cfg.c
new file mode 100644
index 0000000..37794e6
--- /dev/null
+++ b/src/loader/cfg.c
@@ -0,0 +1,173 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#include <cfg.h>
+#include <dev.h>
+#include <lib.h>
+#include <log.h>
+#include <pnc.h>
+
+// Keys
+#define TIMEOUT "TIMEOUT"
+#define PATH "PATH"
+
+// Config struct (gettable using cfg_get)
+struct {
+	u32 timeout;
+	struct {
+		u8 exists : 1;
+		char name[64];
+		char path[64];
+	} elem[16]; // Up to 16 different selections
+} cfg = { 0 };
+
+// Config file contents (if found)
+static char file[1024] = { 0 };
+
+// Find config file
+static u8 cfg_find(struct dev *dev)
+{
+	if (!dev->fs.read)
+		return 0; // No fs found or not readable - continue!
+
+	s32 res = dev->fs.read("/boot/segelboot.cfg", file, 0, sizeof(file), dev);
+	if (res > 0)
+		return 1; // Break foreach
+
+	// Continue foreach
+	return 0;
+}
+
+// Checks if index is appropriate as some key/value need to be in element
+static void cfg_in_element(u8 index)
+{
+	if (index == 0xff)
+		panic("No element name given\n");
+}
+
+// Add/overwrite value by key and element index
+static void cfg_add(u8 index, enum cfg_key key, const char *value)
+{
+	cfg.elem[index].exists = 1;
+
+	switch (key) {
+	case CFG_NAME:
+		cfg_in_element(index);
+		strlcpy(cfg.elem[index].name, value, sizeof(cfg.elem[index].name));
+		break;
+	case CFG_TIMEOUT:
+		cfg.timeout = atoi(value);
+		break;
+	case CFG_PATH:
+		cfg_in_element(index);
+		strlcpy(cfg.elem[index].path, value, sizeof(cfg.elem[index].path));
+		break;
+	case CFG_NONE:
+	default:
+		panic("Invalid config\n");
+	}
+}
+
+// TODO: This code is kind of messy
+// Structure per line: KEY=VALUE
+static void cfg_parse(void)
+{
+	// Element index
+	u8 elem = 0xff;
+
+	// Value per key
+	char value[64] = { 0 };
+	u8 value_index = 0;
+
+	// States
+	enum cfg_key current = CFG_NONE; // Value key type
+	u8 state = 0; // 0 is key, 1 is value, 2 is elem
+
+	const char *start = file; // Start is at the beginning of the key
+	for (const char *p = start; *p; p++) {
+		if (state == 0) {
+			// We're at key parsing
+			if (*p == '\n') { // A key can't just end but ok
+				start = p + 1;
+			} else if (*p == '#') {
+				state = 2; // Let's parse the element name
+				p++;
+				continue;
+			} else if (*p != '=') {
+				continue;
+			}
+
+			// The key is now at start until p
+			u8 diff = p - start;
+
+			// Timeout key
+			if (diff == sizeof(TIMEOUT) - 1 && memcmp(start, TIMEOUT, diff) == 0) {
+				current = CFG_TIMEOUT;
+				state = 1;
+				continue;
+			}
+
+			// Path key
+			if (diff == sizeof(PATH) - 1 && memcmp(start, PATH, diff) == 0) {
+				current = CFG_PATH;
+				state = 1;
+				continue;
+			}
+		} else if (state == 1) {
+			// We're at value parsing
+			assert(value_index + 1 < (u8)sizeof(value));
+			if (*p == '\n') { // Finished
+				value[value_index] = 0;
+				cfg_add(elem, current, value);
+				value_index = 0;
+				state = 0;
+				p--; // Repeat parse normally
+			} else {
+				value[value_index++] = *p;
+			}
+		} else if (state == 2) {
+			// We're at element name parsing
+			assert(value_index + 1 < (u8)sizeof(value));
+			if (*p == '\n') { // Finished
+				elem = elem == 0xff ? 0 : elem + 1;
+				value[value_index] = 0;
+				cfg_add(elem, CFG_NAME, value);
+				value_index = 0;
+				state = 0;
+				p--; // Repeat parse normally
+			} else {
+				value[value_index++] = *p;
+			}
+		}
+	}
+}
+
+const void *cfg_get(u8 index, enum cfg_key key)
+{
+	switch (key) {
+	case CFG_NAME:
+		return &cfg.elem[index].path;
+	case CFG_TIMEOUT:
+		return &cfg.timeout;
+	case CFG_PATH:
+		return &cfg.elem[index].path;
+	case CFG_NONE:
+	default:
+		return NULL;
+	}
+}
+
+void cfg_print(void)
+{
+	log("[CFG] Global: %d\n", cfg.timeout);
+
+	for (u8 i = 0; i < COUNT(cfg.elem) && cfg.elem[i].exists; i++)
+		log("[CFG] Element: %s at %s\n", cfg.elem[i].name, cfg.elem[i].path);
+}
+
+void cfg_exec(void)
+{
+	dev_foreach(DEV_DISK, &cfg_find);
+	if (!file[0])
+		panic("No config found\n");
+	cfg_parse();
+}
-- 
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