1 /* ----------------------------------------------------------------------- * 2 * 3 * Copyright 2010 Gert Hulselmans - All Rights Reserved 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, 8 * Boston MA 02110-1301, USA; either version 2 of the License, or 9 * (at your option) any later version; incorporated herein by reference. 10 * 11 * ----------------------------------------------------------------------- */ 12 13 /* 14 * ifplop.c 15 * 16 * This COM32 module detects if the PLoP Boot Manager was used to boot a CDROM 17 * drive or USB drive, by checking for the presence of the PLoP INT13h hook. 18 * 19 * Usage: ifplop.c32 [<plop_detected>] -- [<plop_not_detected>] 20 * Examples: ifplop.c32 menu.c32 another.cfg -- plpbt hiddenusb usb1=2 21 * You need to remove the ".bin" extension of the plpbt.bin file 22 * if you use it this way. 23 * ifplop.c32 plop_detected -- plop_not_detected 24 * 25 * A possible config file could be: 26 * 27 * =========================================================================== 28 * DEFAULT plopcheck 29 * 30 * # Check for the presence of PLoP (run by default) 31 * # When PLoP INT13h hook is found, run the first command (plop_detected) 32 * # When PLoP INT13h hook isn't found, run the second command (plop_not_detected) 33 * LABEL plopcheck 34 * COM32 ifplop.c32 35 * APPEND plop_detected -- plop_not_detected 36 * 37 * # When PLoP INT13h hook was found, boot the menu system. 38 * # PLoP can have added USB 2.0 speed, so the entries we want to boot 39 * # will be read from disk much faster (supposing that we have a BIOS 40 * # that only supports USB 1.1 speed, but a mobo with USB 2.0 controllers). 41 * LABEL plop_detected 42 * COM32 menu.c32 43 * APPEND another.cfg 44 * 45 * # PLoP INT13h hook wasn't found, so we boot PLoP, so it can add USB 2.0 support 46 * # When using "LINUX plpbt.bin", you don't need to remove the .bin extension. 47 * LABEL plop_not_detected 48 * LINUX plpbt.bin 49 * APPEND hiddenusb usb1=2 50 * 51 * =========================================================================== 52 * 53 * Why is/can this module be useful? 54 * 55 * You may want to boot PLoP by default from Syslinux when you boot from your 56 * USB stick/drive: 57 * 1. PLoP can upgrade USB 1.1 speed offered by the BIOS to USB 2.0 speed 58 * if you have USB 2.0 controllers on your mobo. 59 * 2. Some BIOSes only can access the first 128GiB (137GB) on USB drives, while 60 * internal hard drives don't necessarily suffer from this 128GiB problem. 61 * Using PLoPs USB capabilities, you can access the whole drive. 62 * 63 * When you select the "USB" entry in PLoP, it will boot your USB stick/drive 64 * again and it will boot PLoP again when you have set booting PLoP as DEFAULT 65 * boot option in your Syslinux configuration file. 66 * 67 * By using ifplop.c32 you can specify which action you want to do the second 68 * time your USB stick/drive is booted. So you can load another config file or 69 * boot a large hard disk image or whatever you want. 70 * 71 * PLoP Boot Manager website: http://www.plop.at/en/bootmanager.html 72 */ 73 74 #include <com32.h> 75 #include <stdlib.h> 76 #include <stdio.h> 77 #include <string.h> 78 #include <alloca.h> 79 #include <console.h> 80 #include <syslinux/boot.h> 81 82 static bool plop_INT13h_check(void) 83 { 84 com32sys_t inregs, outregs; 85 86 /* Prepare the register set */ 87 memset(&inregs, 0, sizeof inregs); 88 89 /* 90 * Check if PLoP already has booted a CDROM or USB drive by checking 91 * for the presence of the PLoP INT13h hook. 92 * 93 * The following assembly code (NASM) can detect the PLoP INT13h hook: 94 * 95 * mov eax,'PoLP' ; Reverse of 'PLoP' 96 * mov ebp,'DKHC' ; Reverse of 'CHKD' 97 * int 13h 98 * cmp eax,' sey' ; Reverse of 'yes ' 99 * jz plop_INT13h_active 100 */ 101 102 inregs.eax.l = 0x504c6f50; /* "PLoP" */ 103 inregs.ebp.l = 0x43484b44; /* "CHKD" */ 104 105 __intcall(0x13, &inregs, &outregs); 106 107 /* eax will contain "yes " if PLoP INT13h hook is available */ 108 if (outregs.eax.l == 0x79657320) 109 return true; 110 111 return false; 112 } 113 114 /* XXX: this really should be librarized */ 115 static void boot_args(char **args) 116 { 117 int len = 0, a = 0; 118 char **pp; 119 const char *p; 120 char c, *q, *str; 121 122 for (pp = args; *pp; pp++) 123 len += strlen(*pp) + 1; 124 125 q = str = alloca(len); 126 for (pp = args; *pp; pp++) { 127 p = *pp; 128 while ((c = *p++)) 129 *q++ = c; 130 *q++ = ' '; 131 a = 1; 132 } 133 q -= a; 134 *q = '\0'; 135 136 if (!str[0]) 137 syslinux_run_default(); 138 else 139 syslinux_run_command(str); 140 } 141 142 int main(int argc, char *argv[]) 143 { 144 char **args[2]; 145 int arg = 0; 146 147 if (argc) 148 arg++; 149 args[0] = &argv[arg]; 150 args[1] = NULL; 151 while (arg < argc) { 152 if (!strcmp(argv[arg], "--")) { 153 argv[arg] = NULL; 154 args[1] = &argv[arg + 1]; 155 break; 156 } 157 arg++; 158 } 159 if (args[1] != NULL) { 160 boot_args(plop_INT13h_check()? args[0] : args[1]); 161 } else { 162 fprintf(stderr, 163 "Usage: ifplop.c32 [<plop_detected>] -- [<plop_not_detected>]\n" 164 "Example: ifplop.c32 menu.c32 another.cfg -- plpbt hiddenusb usb1=2\n"); 165 } 166 167 return 0; 168 } 169
