commandline: Add commandline parsing abilities

This commit adds commandline parsing abilities to KTF. Parameters are passed via
multiboot and then parsed and compared against the compile-time available
parameters.

Signed-off-by: Martin Mazein <[email protected]>

common/setup.c

@@ -24,6 +24,7 @@
  */
 #include <acpi.h>
 #include <apic.h>
+#include <cmdline.h>
 #include <console.h>
 #include <ktf.h>
 #include <lib.h>
@@ -44,12 +45,78 @@
 #include <drivers/serial.h>
 #include <slab.h>
 
-bool opt_debug;
+bool opt_debug = false;
+bool_cmd("debug", opt_debug);
 
 io_port_t com_ports[2];
 
 const char *kernel_cmdline;
 
+static __text_init int parse_bool(const char *s) {
+    if (!strcmp("no", s) || !strcmp("off", s) || !strcmp("false", s) ||
+        !strcmp("disable", s) || !strcmp("0", s))
+        return 0;
+
+    if (!strcmp("yes", s) || !strcmp("on", s) || !strcmp("true", s) ||
+        !strcmp("enable", s) || !strcmp("1", s))
+        return 1;
+
+    return -1;
+}
+
+void __text_init cmdline_parse(const char *cmdline) {
+    static __bss_init char opt[PAGE_SIZE];
+    char *optval, *optkey, *q;
+    const char *p = cmdline;
+    struct ktf_param *param;
+
+    if (cmdline == NULL)
+        return;
+
+    for (;;) {
+        p = string_trim_whitspace(p);
+
+        if (iseostr(*p))
+            break;
+
+        q = optkey = opt;
+        while ((!isspace(*p)) && (!iseostr(*p))) {
+            ASSERT(_ul(q - opt) < sizeof(opt) - 1);
+            *q++ = *p++;
+        }
+        *q = '\0';
+
+        /* split on '=' */
+        optval = strchr(opt, '=');
+        if (optval != NULL)
+            *optval++ = '\0';
+        else
+            /* assume a bool later */
+            optval = opt;
+
+        for (param = __start_cmdline; param < __end_cmdline; param++) {
+            if (strcmp(param->name, optkey))
+                continue;
+
+            switch (param->type) {
+            case STRING:
+                strcpy(param->var, optval);
+                break;
+            case ULONG:
+                *(unsigned long *) param->var = strtoul(optval, NULL, 0);
+                break;
+            case BOOL:
+                *(bool *) param->var =
+                    !!parse_bool(!strcmp(optval, optkey) ? "1" : optval);
+                break;
+            default:
+                panic("Unkown cmdline type detected...");
+                break;
+            }
+        }
+    }
+}
+
 static void init_console(void) {
     get_com_ports();
 
@@ -95,6 +162,9 @@ void __noreturn __text_init kernel_start(uint32_t multiboot_magic,
         init_multiboot(mbi, &kernel_cmdline);
     }
 
+    /* Parse commandline parameters */
+    cmdline_parse(kernel_cmdline);
+
     /* Initialize Physical Memory Manager */
     init_pmm();
 

include/cmdline.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright © 2020 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef KTF_CMDLINE_H
+#define KTF_CMDLINE_H
+
+#ifndef __ASSEMBLY__
+
+#define PARAM_MAX_LENGTH 32
+
+struct __packed ktf_param {
+    char name[PARAM_MAX_LENGTH];
+    enum { STRING, ULONG, BOOL } type;
+    void *var;
+};
+
+#define __ktfparam static __cmdline __used __aligned(1) struct ktf_param
+
+/* compile time check for param name size */
+#define __param_size_check(_name, _sizename)                                             \
+    char __unused_##_name[(sizeof(_sizename) >= PARAM_MAX_LENGTH) ? -1 : 0]
+
+#define cmd_param(_name, _var, _type)                                                    \
+    __param_size_check(_var, _name);                                                     \
+    __ktfparam __cmd_##_var = {_name, _type, &_var};
+
+#define bool_cmd(_cmdname, _varname)   cmd_param(_cmdname, _varname, BOOL)
+#define ulong_cmd(_cmdname, _varname)  cmd_param(_cmdname, _varname, ULONG)
+#define string_cmd(_cmdname, _varname) cmd_param(_cmdname, _varname, STRING)
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* KTF_CMDLINE_H */

include/mm/pmm.h

@@ -34,6 +34,7 @@
 #define BIOS_ROM_ADDR_START 0xF0000
 
 #ifndef __ASSEMBLY__
+#include <cmdline.h>
 #include <list.h>
 #include <page.h>
 
@@ -52,6 +53,8 @@ extern unsigned long __start_bss_init[], __end_bss_init[];
 
 extern unsigned long __start_rmode[], __end_rmode[];
 
+extern struct ktf_param __start_cmdline[], __end_cmdline[];
+
 struct addr_range {
     const char *name;
     unsigned long base;

include/setup.h

@@ -26,6 +26,7 @@
 #define KTF_SETUP_H
 
 #ifndef __ASSEMBLY__
+#include <cmdline.h>
 #include <page.h>
 #include <string.h>
 

include/string.h

@@ -177,6 +177,13 @@ static inline int strncmp(const char *s1, const char *s2, size_t n) {
     return res;
 }
 
+static inline const char *string_trim_whitspace(const char *s) {
+    while (isspace(*s))
+        s++;
+
+    return s;
+}
+
 /* External declarations */
 
 extern unsigned long strtoul(const char *nptr, char **endptr, int base);