Initial commit

kernel/boot/cmdline.c

@@ -0,0 +1,70 @@
+#include <kernel/cmdline.h>
+#include <kernel/init.h>
+#include <stddef.h>
+#include <string.h>
+
+// Defined in linker script.
+extern struct cmdline_option __ld_cmdline_start[];
+extern struct cmdline_option __ld_cmdline_end[];
+
+static char cmdline_buf[CMDLINE_MAX];
+
+[[__init]]
+void cmdline_parse(const char* cmdline) {
+    struct cmdline_option* opt = __ld_cmdline_start;
+    const size_t len = strnlen(cmdline, CMDLINE_MAX - 1);
+    size_t idx = 0;
+    memcpy(cmdline_buf, cmdline, len);
+
+    while (1) {
+        char* name = nullptr;
+        char* value = nullptr;
+
+        // Skip all leading spaces.
+        while (idx < len && cmdline_buf[idx] == ' ')
+            idx++;
+        if (idx >= len)
+            break;
+        size_t name_idx = idx;
+        name = cmdline_buf + name_idx;
+
+        // Find the next equal sign or space.
+        while (idx < len && cmdline_buf[idx] != '=' && cmdline_buf[idx] != ' ')
+            idx++;
+        if (idx > len)
+            break;
+
+        // Check if the option has a value (=foo).
+        char seperator = cmdline_buf[idx];
+        cmdline_buf[idx++] = 0;
+        if (seperator == '=') {
+            // Check if we need to escape the value.
+            char check;
+            if (cmdline_buf[idx] == '"') {
+                check = '"';
+                cmdline_buf[idx++] = 0;
+            } else {
+                check = ' ';
+            }
+
+            value = cmdline_buf + idx;
+
+            // Skip the value.
+            while (idx < len && cmdline_buf[idx] != check)
+                idx++;
+            if (idx > len)
+                break;
+            cmdline_buf[idx++] = 0;
+        }
+
+        // Find the corresponding option.
+        while (opt < __ld_cmdline_end) {
+            if (!strcmp(opt->name, name))
+                opt->func(value);
+            opt++;
+        }
+
+        if (idx >= len)
+            break;
+    }
+}