--- /dev/null
+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2011 Shao Miller - All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston MA 02110-1301, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/****
+ * @file ifmemdsk.c
+ *
+ * This COM32 module detects if there are MEMDISKs established.
+ */
+
+static const char usage_text[] = "\
+Usage:\n\
+ ifmemdsk.c32 [<option> [...]] --info [<option> [...]]\n\
+ ifmemdsk.c32 [<option> [...]] [<detected_cmd>] -- [<not_detected_cmd>]\n\
+\n\
+Options:\n\
+ --info . . . . . Displays info about MEMDISK(s)\n\
+ --safe-hooks . . Will scan INT 13h \"safe hook\" chain\n\
+ --mbfts . . . . . Will scan memory for MEMDISK mBFTs\n\
+ --no-sequential Suppresses probing all drive numbers\n\
+\n\
+If a MEMDISK is found, or if a particular MEMDISK is sought by the options\n\
+and is found, then the 'detected_cmd' action will be taken, else the\n\
+'not_detected_cmd' action will be taken.\n\
+\n";
+
+#include <stdio.h>
+#include <string.h>
+#include <alloca.h>
+#include <com32.h>
+#include <console.h>
+#include <syslinux/boot.h>
+
+/* Pull in MEMDISK common structures */
+#include "../../memdisk/mstructs.h"
+
+/*** Macros */
+#define M_GET_DRIVE_PARAMS (0x08)
+#define M_SEGOFFTOPTR(seg, off) (((seg) << 4) + (off))
+#define M_INT13H M_SEGOFFTOPTR(0x0000, 0x0013 * 4)
+#define M_FREEBASEMEM M_SEGOFFTOPTR(0x0040, 0x0013)
+#define M_TOP M_SEGOFFTOPTR(0x9FFF, 0x0000)
+
+/*** Object types */
+typedef struct mdi s_mdi;
+typedef real_addr_t u_segoff;
+typedef struct safe_hook s_safe_hook;
+typedef struct mBFT s_mbft;
+
+/*** Function types */
+typedef int f_find(void);
+
+/*** Function declarations */
+static const s_mdi * installation_check(int);
+static f_find scan_drives;
+static f_find walk_safe_hooks;
+static const s_safe_hook * is_safe_hook(const void *);
+static const s_mdi * is_memdisk_hook(const s_safe_hook *);
+static f_find scan_mbfts;
+static const s_mbft * is_mbft(const void *);
+static f_find do_nothing;
+static void memdisk_info(const s_mdi *);
+static void boot_args(char **);
+static const char * bootloadername(uint8_t);
+
+/*** Structure/union definitions */
+
+/*** Objects */
+static int show_info = 0;
+
+/*** Function definitions */
+
+int main(int argc, char ** argv) {
+ static f_find * do_scan_drives = scan_drives;
+ static f_find * do_walk_safe_hooks = do_nothing;
+ static f_find * do_scan_mbfts = do_nothing;
+ char ** detected_cmd;
+ char ** not_detected_cmd;
+ char ** cmd;
+ char ** cur_arg;
+ int show_usage;
+ int found;
+
+ (void) argc;
+
+ openconsole(&dev_null_r, &dev_stdcon_w);
+
+ detected_cmd = NULL;
+ not_detected_cmd = NULL;
+ show_usage = 1;
+ for (cur_arg = argv + 1; *cur_arg; ++cur_arg) {
+ /* Check for command divider */
+ if (!strcmp(*cur_arg, "--")) {
+ show_usage = 0;
+ *cur_arg = NULL;
+ not_detected_cmd = cur_arg + 1;
+ break;
+ }
+
+ /* Check for '--info' */
+ if (!strcmp(*cur_arg, "--info")) {
+ show_usage = 0;
+ show_info = 1;
+ continue;
+ }
+
+ /* Other options */
+ if (!strcmp(*cur_arg, "--no-sequential")) {
+ do_scan_drives = do_nothing;
+ continue;
+ }
+
+ if (!strcmp(*cur_arg, "--safe-hooks")) {
+ do_walk_safe_hooks = walk_safe_hooks;
+ continue;
+ }
+
+ if (!strcmp(*cur_arg, "--mbfts")) {
+ do_scan_mbfts = scan_mbfts;
+ continue;
+ }
+
+ /* Check for invalid option */
+ if (!memcmp(*cur_arg, "--", sizeof "--" - 1)) {
+ puts("Invalid option!");
+ show_usage = 1;
+ break;
+ }
+
+ /* Set 'detected_cmd' if it's null */
+ if (!detected_cmd)
+ detected_cmd = cur_arg;
+
+ continue;
+ }
+
+ if (show_usage) {
+ fprintf(stderr, usage_text);
+ return 1;
+ }
+
+ found = 0;
+ found += do_walk_safe_hooks();
+ found += do_scan_mbfts();
+ found += do_scan_drives();
+
+ cmd = found ? detected_cmd : not_detected_cmd;
+ if (cmd && *cmd)
+ boot_args(cmd);
+
+ return 0;
+ }
+
+static const s_mdi * installation_check(int drive) {
+ com32sys_t params, results;
+ int found;
+
+ /* Set parameters for INT 0x13 call */
+ memset(¶ms, 0, sizeof params);
+ params.eax.w[0] = M_GET_DRIVE_PARAMS << 8;
+ params.edx.w[0] = drive;
+ /* 'ME' 'MD' 'IS' 'K?' */
+ params.eax.w[1] = 0x454D;
+ params.ecx.w[1] = 0x444D;
+ params.edx.w[1] = 0x5349;
+ params.ebx.w[1] = 0x3F4B;
+
+ /* Perform the call */
+ __intcall(0x13, ¶ms, &results);
+
+ /* Check result */
+ found = (
+ /* '!M' 'EM' 'DI' 'SK' */
+ results.eax.w[1] == 0x4D21 &&
+ results.ecx.w[1] == 0x4D45 &&
+ results.edx.w[1] == 0x4944 &&
+ results.ebx.w[1] == 0x4B53
+ );
+
+ if (found)
+ return MK_PTR(results.es, results.edi.w[0]);
+
+ return NULL;
+ }
+
+static int scan_drives(void) {
+ int found, drive;
+ const s_mdi * mdi;
+
+ for (found = drive = 0; drive <= 0xFF; ++drive) {
+ mdi = installation_check(drive);
+ if (!mdi)
+ continue;
+
+ memdisk_info(mdi);
+ ++found;
+ continue;
+ }
+
+ return found;
+ }
+
+static int walk_safe_hooks(void) {
+ static const u_segoff * const int13 = (void *) M_INT13H;
+ const void * addr;
+ int found;
+ const s_safe_hook * hook;
+ const s_mdi * mdi;
+
+ /* INT 0x13 vector */
+ addr = MK_PTR(int13->seg_off.segment, int13->seg_off.offset);
+ found = 0;
+ while (addr) {
+ hook = is_safe_hook(addr);
+ if (!hook)
+ break;
+
+ mdi = is_memdisk_hook(hook);
+ if (mdi) {
+ memdisk_info(mdi);
+ ++found;
+ }
+
+ addr = MK_PTR(
+ hook->old_hook.seg_off.segment,
+ hook->old_hook.seg_off.offset
+ );
+ continue;
+ }
+ return found;
+ }
+
+static const s_safe_hook * is_safe_hook(const void * addr) {
+ static const char magic[] = "$INT13SF";
+ const s_safe_hook * const test = addr;
+
+ if (memcmp(test->signature, magic, sizeof magic - 1))
+ return NULL;
+
+ return test;
+ }
+
+static const s_mdi * is_memdisk_hook(const s_safe_hook * hook) {
+ static const char magic[] = "MEMDISK";
+ const s_mbft * mbft;
+
+ if (memcmp(hook->vendor, magic, sizeof magic - 1))
+ return NULL;
+
+ /* An mBFT is always aligned */
+ mbft = MK_PTR(hook->mbft >> 4, 0);
+ return &mbft->mdi;
+ }
+
+static int scan_mbfts(void) {
+ static const uint16_t * const free_base_mem = (void *) M_FREEBASEMEM;
+ static const void * const top = (void *) M_TOP;
+ const void * addr;
+ const s_mbft * mbft;
+ int found;
+
+ found = 0;
+ for (addr = MK_PTR(*free_base_mem << 4, 0); addr < top; addr += 1 << 4) {
+ if (!(mbft = is_mbft(addr)))
+ continue;
+
+ memdisk_info(&mbft->mdi);
+ ++found;
+ continue;
+ }
+
+ return found;
+ }
+
+static const s_mbft * is_mbft(const void * addr) {
+ static const char magic[] = "mBFT";
+ const s_mbft * const test = addr;
+ const uint8_t * ptr, * end;
+ uint8_t chksum;
+
+ if (memcmp(test->acpi.signature, magic, sizeof magic - 1))
+ return NULL;
+
+ if (test->acpi.length != sizeof *test)
+ return NULL;
+
+ end = (void *) (test + 1);
+ chksum = 0;
+ for (ptr = addr; ptr < end; ++ptr)
+ chksum += *ptr;
+ if (chksum)
+ return NULL;
+
+ /* Looks like it's an mBFT! */
+ return test;
+ }
+
+static int do_nothing(void) {
+ return 0;
+ }
+
+static void memdisk_info(const s_mdi * mdi) {
+ const char * cmdline;
+
+ if (!show_info)
+ return;
+
+ cmdline = MK_PTR(
+ mdi->cmdline.seg_off.segment,
+ mdi->cmdline.seg_off.offset
+ );
+ printf(
+ "Found MEMDISK version %u.%02u:\n"
+ " diskbuf == 0x%08X, disksize == %u sectors\n"
+ " bootloaderid == 0x%02X (%s),\n"
+ " cmdline: %s\n",
+ mdi->version_major,
+ mdi->version_minor,
+ mdi->diskbuf,
+ mdi->disksize,
+ mdi->bootloaderid,
+ bootloadername(mdi->bootloaderid),
+ cmdline
+ );
+ return;
+ }
+
+/* This function copyright H. Peter Anvin */
+static void boot_args(char **args)
+{
+ int len = 0, a = 0;
+ char **pp;
+ const char *p;
+ char c, *q, *str;
+
+ for (pp = args; *pp; pp++)
+ len += strlen(*pp) + 1;
+
+ q = str = alloca(len);
+ for (pp = args; *pp; pp++) {
+ p = *pp;
+ while ((c = *p++))
+ *q++ = c;
+ *q++ = ' ';
+ a = 1;
+ }
+ q -= a;
+ *q = '\0';
+
+ if (!str[0])
+ syslinux_run_default();
+ else
+ syslinux_run_command(str);
+}
+
+/* This function copyright H. Peter Anvin */
+static const char *bootloadername(uint8_t id)
+{
+ static const struct {
+ uint8_t id, mask;
+ const char *name;
+ } *lp, list[] = {
+ {0x00, 0xf0, "LILO"},
+ {0x10, 0xf0, "LOADLIN"},
+ {0x31, 0xff, "SYSLINUX"},
+ {0x32, 0xff, "PXELINUX"},
+ {0x33, 0xff, "ISOLINUX"},
+ {0x34, 0xff, "EXTLINUX"},
+ {0x30, 0xf0, "Syslinux family"},
+ {0x40, 0xf0, "Etherboot"},
+ {0x50, 0xf0, "ELILO"},
+ {0x70, 0xf0, "GrUB"},
+ {0x80, 0xf0, "U-Boot"},
+ {0xA0, 0xf0, "Gujin"},
+ {0xB0, 0xf0, "Qemu"},
+ {0x00, 0x00, "unknown"}
+ };
+
+ for (lp = list;; lp++) {
+ if (((id ^ lp->id) & lp->mask) == 0)
+ return lp->name;
+ }
+}
+
projects / platform / upstream / syslinux.git / commitdiff