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-rw-r--r--lrmi.c871
1 files changed, 871 insertions, 0 deletions
diff --git a/lrmi.c b/lrmi.c
new file mode 100644
index 0000000..2f896df
--- /dev/null
+++ b/lrmi.c
@@ -0,0 +1,871 @@
+/*
+Linux Real Mode Interface - A library of DPMI-like functions for Linux.
+
+Copyright (C) 1998 by Josh Vanderhoof
+
+You are free to distribute and modify this file, as long as you
+do not remove this copyright notice and clearly label modified
+versions as being modified.
+
+This software has NO WARRANTY. Use it at your own risk.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/io.h>
+#include <asm/vm86.h>
+
+#ifdef USE_LIBC_VM86
+#include <sys/vm86.h>
+#endif
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "lrmi.h"
+
+#define REAL_MEM_BASE ((void *)0x10000)
+#define REAL_MEM_SIZE 0x10000
+#define REAL_MEM_BLOCKS 0x100
+
+struct mem_block
+ {
+ unsigned int size : 20;
+ unsigned int free : 1;
+ };
+
+static struct
+ {
+ int ready;
+ int count;
+ struct mem_block blocks[REAL_MEM_BLOCKS];
+ } mem_info = { 0 };
+
+static int
+real_mem_init(void)
+ {
+ void *m;
+ int fd_zero;
+
+ if (mem_info.ready)
+ return 1;
+
+ fd_zero = open("/dev/zero", O_RDONLY);
+ if (fd_zero == -1)
+ {
+ perror("open /dev/zero");
+ return 0;
+ }
+
+ m = mmap((void *)REAL_MEM_BASE, REAL_MEM_SIZE,
+ PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_FIXED | MAP_PRIVATE, fd_zero, 0);
+
+ if (m == (void *)-1)
+ {
+ perror("mmap /dev/zero");
+ close(fd_zero);
+ return 0;
+ }
+
+ mem_info.ready = 1;
+ mem_info.count = 1;
+ mem_info.blocks[0].size = REAL_MEM_SIZE;
+ mem_info.blocks[0].free = 1;
+
+ return 1;
+ }
+
+
+static void
+insert_block(int i)
+ {
+ memmove(
+ mem_info.blocks + i + 1,
+ mem_info.blocks + i,
+ (mem_info.count - i) * sizeof(struct mem_block));
+
+ mem_info.count++;
+ }
+
+static void
+delete_block(int i)
+ {
+ mem_info.count--;
+
+ memmove(
+ mem_info.blocks + i,
+ mem_info.blocks + i + 1,
+ (mem_info.count - i) * sizeof(struct mem_block));
+ }
+
+void *
+LRMI_alloc_real(int size)
+ {
+ int i;
+ char *r = (char *)REAL_MEM_BASE;
+
+ if (!mem_info.ready)
+ return NULL;
+
+ if (mem_info.count == REAL_MEM_BLOCKS)
+ return NULL;
+
+ size = (size + 15) & ~15;
+
+ for (i = 0; i < mem_info.count; i++)
+ {
+ if (mem_info.blocks[i].free && size < mem_info.blocks[i].size)
+ {
+ insert_block(i);
+
+ mem_info.blocks[i].size = size;
+ mem_info.blocks[i].free = 0;
+ mem_info.blocks[i + 1].size -= size;
+
+ return (void *)r;
+ }
+
+ r += mem_info.blocks[i].size;
+ }
+
+ return NULL;
+ }
+
+
+void
+LRMI_free_real(void *m)
+ {
+ int i;
+ char *r = (char *)REAL_MEM_BASE;
+
+ if (!mem_info.ready)
+ return;
+
+ i = 0;
+ while (m != (void *)r)
+ {
+ r += mem_info.blocks[i].size;
+ i++;
+ if (i == mem_info.count)
+ return;
+ }
+
+ mem_info.blocks[i].free = 1;
+
+ if (i + 1 < mem_info.count && mem_info.blocks[i + 1].free)
+ {
+ mem_info.blocks[i].size += mem_info.blocks[i + 1].size;
+ delete_block(i + 1);
+ }
+
+ if (i - 1 >= 0 && mem_info.blocks[i - 1].free)
+ {
+ mem_info.blocks[i - 1].size += mem_info.blocks[i].size;
+ delete_block(i);
+ }
+ }
+
+
+#define DEFAULT_VM86_FLAGS (IF_MASK | IOPL_MASK)
+#define DEFAULT_STACK_SIZE 0x1000
+#define RETURN_TO_32_INT 255
+
+static struct
+ {
+ int ready;
+ unsigned short ret_seg, ret_off;
+ unsigned short stack_seg, stack_off;
+ struct vm86_struct vm;
+ } context = { 0 };
+
+
+static inline void
+set_bit(unsigned int bit, void *array)
+ {
+ unsigned char *a = array;
+
+ a[bit / 8] |= (1 << (bit % 8));
+ }
+
+
+static inline unsigned int
+get_int_seg(int i)
+ {
+ return *(unsigned short *)(i * 4 + 2);
+ }
+
+
+static inline unsigned int
+get_int_off(int i)
+ {
+ return *(unsigned short *)(i * 4);
+ }
+
+
+static inline void
+pushw(unsigned short i)
+ {
+ struct vm86_regs *r = &context.vm.regs;
+ r->esp -= 2;
+ *(unsigned short *)(((unsigned int)r->ss << 4) + r->esp) = i;
+ }
+
+
+int
+LRMI_init(void)
+ {
+ void *m;
+ int fd_mem;
+
+ if (context.ready)
+ return 1;
+
+ if (!real_mem_init())
+ return 0;
+
+ /*
+ Map the Interrupt Vectors (0x0 - 0x400) + BIOS data (0x400 - 0x502)
+ and the ROM (0xa0000 - 0x100000)
+ */
+ fd_mem = open("/dev/mem", O_RDWR);
+
+ if (fd_mem == -1)
+ {
+ perror("open /dev/mem");
+ return 0;
+ }
+
+ m = mmap((void *)0, 0x502,
+ PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_FIXED | MAP_PRIVATE, fd_mem, 0);
+
+ if (m == (void *)-1)
+ {
+ perror("mmap /dev/mem");
+ return 0;
+ }
+
+ m = mmap((void *)0xa0000, 0x100000 - 0xa0000,
+ PROT_READ | PROT_WRITE,
+ MAP_FIXED | MAP_SHARED, fd_mem, 0xa0000);
+
+ if (m == (void *)-1)
+ {
+ perror("mmap /dev/mem");
+ return 0;
+ }
+
+
+ /*
+ Allocate a stack
+ */
+ m = LRMI_alloc_real(DEFAULT_STACK_SIZE);
+
+ context.stack_seg = (unsigned int)m >> 4;
+ context.stack_off = DEFAULT_STACK_SIZE;
+
+ /*
+ Allocate the return to 32 bit routine
+ */
+ m = LRMI_alloc_real(2);
+
+ context.ret_seg = (unsigned int)m >> 4;
+ context.ret_off = (unsigned int)m & 0xf;
+
+ ((unsigned char *)m)[0] = 0xcd; /* int opcode */
+ ((unsigned char *)m)[1] = RETURN_TO_32_INT;
+
+ memset(&context.vm, 0, sizeof(context.vm));
+
+ /*
+ Enable kernel emulation of all ints except RETURN_TO_32_INT
+ */
+ memset(&context.vm.int_revectored, 0, sizeof(context.vm.int_revectored));
+ set_bit(RETURN_TO_32_INT, &context.vm.int_revectored);
+
+ context.ready = 1;
+
+ return 1;
+ }
+
+
+static void
+set_regs(struct LRMI_regs *r)
+ {
+ context.vm.regs.edi = r->edi;
+ context.vm.regs.esi = r->esi;
+ context.vm.regs.ebp = r->ebp;
+ context.vm.regs.ebx = r->ebx;
+ context.vm.regs.edx = r->edx;
+ context.vm.regs.ecx = r->ecx;
+ context.vm.regs.eax = r->eax;
+ context.vm.regs.eflags = DEFAULT_VM86_FLAGS;
+ context.vm.regs.es = r->es;
+ context.vm.regs.ds = r->ds;
+ context.vm.regs.fs = r->fs;
+ context.vm.regs.gs = r->gs;
+ }
+
+
+static void
+get_regs(struct LRMI_regs *r)
+ {
+ r->edi = context.vm.regs.edi;
+ r->esi = context.vm.regs.esi;
+ r->ebp = context.vm.regs.ebp;
+ r->ebx = context.vm.regs.ebx;
+ r->edx = context.vm.regs.edx;
+ r->ecx = context.vm.regs.ecx;
+ r->eax = context.vm.regs.eax;
+ r->flags = context.vm.regs.eflags;
+ r->es = context.vm.regs.es;
+ r->ds = context.vm.regs.ds;
+ r->fs = context.vm.regs.fs;
+ r->gs = context.vm.regs.gs;
+ }
+
+#define DIRECTION_FLAG (1 << 10)
+
+static void
+em_ins(int size)
+ {
+ unsigned int edx, edi;
+
+ edx = context.vm.regs.edx & 0xffff;
+ edi = context.vm.regs.edi & 0xffff;
+ edi += (unsigned int)context.vm.regs.ds << 4;
+
+ if (context.vm.regs.eflags & DIRECTION_FLAG)
+ {
+ if (size == 4)
+ asm volatile ("std; insl; cld"
+ : "=D" (edi) : "d" (edx), "0" (edi));
+ else if (size == 2)
+ asm volatile ("std; insw; cld"
+ : "=D" (edi) : "d" (edx), "0" (edi));
+ else
+ asm volatile ("std; insb; cld"
+ : "=D" (edi) : "d" (edx), "0" (edi));
+ }
+ else
+ {
+ if (size == 4)
+ asm volatile ("cld; insl"
+ : "=D" (edi) : "d" (edx), "0" (edi));
+ else if (size == 2)
+ asm volatile ("cld; insw"
+ : "=D" (edi) : "d" (edx), "0" (edi));
+ else
+ asm volatile ("cld; insb"
+ : "=D" (edi) : "d" (edx), "0" (edi));
+ }
+
+ edi -= (unsigned int)context.vm.regs.ds << 4;
+
+ context.vm.regs.edi &= 0xffff0000;
+ context.vm.regs.edi |= edi & 0xffff;
+ }
+
+static void
+em_rep_ins(int size)
+ {
+ unsigned int ecx, edx, edi;
+
+ ecx = context.vm.regs.ecx & 0xffff;
+ edx = context.vm.regs.edx & 0xffff;
+ edi = context.vm.regs.edi & 0xffff;
+ edi += (unsigned int)context.vm.regs.ds << 4;
+
+ if (context.vm.regs.eflags & DIRECTION_FLAG)
+ {
+ if (size == 4)
+ asm volatile ("std; rep; insl; cld"
+ : "=D" (edi), "=c" (ecx)
+ : "d" (edx), "0" (edi), "1" (ecx));
+ else if (size == 2)
+ asm volatile ("std; rep; insw; cld"
+ : "=D" (edi), "=c" (ecx)
+ : "d" (edx), "0" (edi), "1" (ecx));
+ else
+ asm volatile ("std; rep; insb; cld"
+ : "=D" (edi), "=c" (ecx)
+ : "d" (edx), "0" (edi), "1" (ecx));
+ }
+ else
+ {
+ if (size == 4)
+ asm volatile ("cld; rep; insl"
+ : "=D" (edi), "=c" (ecx)
+ : "d" (edx), "0" (edi), "1" (ecx));
+ else if (size == 2)
+ asm volatile ("cld; rep; insw"
+ : "=D" (edi), "=c" (ecx)
+ : "d" (edx), "0" (edi), "1" (ecx));
+ else
+ asm volatile ("cld; rep; insb"
+ : "=D" (edi), "=c" (ecx)
+ : "d" (edx), "0" (edi), "1" (ecx));
+ }
+
+ edi -= (unsigned int)context.vm.regs.ds << 4;
+
+ context.vm.regs.edi &= 0xffff0000;
+ context.vm.regs.edi |= edi & 0xffff;
+
+ context.vm.regs.ecx &= 0xffff0000;
+ context.vm.regs.ecx |= ecx & 0xffff;
+ }
+
+static void
+em_outs(int size)
+ {
+ unsigned int edx, esi;
+
+ edx = context.vm.regs.edx & 0xffff;
+ esi = context.vm.regs.esi & 0xffff;
+ esi += (unsigned int)context.vm.regs.ds << 4;
+
+ if (context.vm.regs.eflags & DIRECTION_FLAG)
+ {
+ if (size == 4)
+ asm volatile ("std; outsl; cld"
+ : "=S" (esi) : "d" (edx), "0" (esi));
+ else if (size == 2)
+ asm volatile ("std; outsw; cld"
+ : "=S" (esi) : "d" (edx), "0" (esi));
+ else
+ asm volatile ("std; outsb; cld"
+ : "=S" (esi) : "d" (edx), "0" (esi));
+ }
+ else
+ {
+ if (size == 4)
+ asm volatile ("cld; outsl"
+ : "=S" (esi) : "d" (edx), "0" (esi));
+ else if (size == 2)
+ asm volatile ("cld; outsw"
+ : "=S" (esi) : "d" (edx), "0" (esi));
+ else
+ asm volatile ("cld; outsb"
+ : "=S" (esi) : "d" (edx), "0" (esi));
+ }
+
+ esi -= (unsigned int)context.vm.regs.ds << 4;
+
+ context.vm.regs.esi &= 0xffff0000;
+ context.vm.regs.esi |= esi & 0xffff;
+ }
+
+static void
+em_rep_outs(int size)
+ {
+ unsigned int ecx, edx, esi;
+
+ ecx = context.vm.regs.ecx & 0xffff;
+ edx = context.vm.regs.edx & 0xffff;
+ esi = context.vm.regs.esi & 0xffff;
+ esi += (unsigned int)context.vm.regs.ds << 4;
+
+ if (context.vm.regs.eflags & DIRECTION_FLAG)
+ {
+ if (size == 4)
+ asm volatile ("std; rep; outsl; cld"
+ : "=S" (esi), "=c" (ecx)
+ : "d" (edx), "0" (esi), "1" (ecx));
+ else if (size == 2)
+ asm volatile ("std; rep; outsw; cld"
+ : "=S" (esi), "=c" (ecx)
+ : "d" (edx), "0" (esi), "1" (ecx));
+ else
+ asm volatile ("std; rep; outsb; cld"
+ : "=S" (esi), "=c" (ecx)
+ : "d" (edx), "0" (esi), "1" (ecx));
+ }
+ else
+ {
+ if (size == 4)
+ asm volatile ("cld; rep; outsl"
+ : "=S" (esi), "=c" (ecx)
+ : "d" (edx), "0" (esi), "1" (ecx));
+ else if (size == 2)
+ asm volatile ("cld; rep; outsw"
+ : "=S" (esi), "=c" (ecx)
+ : "d" (edx), "0" (esi), "1" (ecx));
+ else
+ asm volatile ("cld; rep; outsb"
+ : "=S" (esi), "=c" (ecx)
+ : "d" (edx), "0" (esi), "1" (ecx));
+ }
+
+ esi -= (unsigned int)context.vm.regs.ds << 4;
+
+ context.vm.regs.esi &= 0xffff0000;
+ context.vm.regs.esi |= esi & 0xffff;
+
+ context.vm.regs.ecx &= 0xffff0000;
+ context.vm.regs.ecx |= ecx & 0xffff;
+ }
+
+static void
+em_inbl(unsigned char literal)
+ {
+ context.vm.regs.eax = inb(literal) & 0xff;
+ }
+
+static void
+em_inb(void)
+ {
+ asm volatile ("inb (%w1), %b0"
+ : "=a" (context.vm.regs.eax)
+ : "d" (context.vm.regs.edx), "0" (context.vm.regs.eax));
+ }
+
+static void
+em_inw(void)
+ {
+ asm volatile ("inw (%w1), %w0"
+ : "=a" (context.vm.regs.eax)
+ : "d" (context.vm.regs.edx), "0" (context.vm.regs.eax));
+ }
+
+static void
+em_inl(void)
+ {
+ asm volatile ("inl (%w1), %0"
+ : "=a" (context.vm.regs.eax)
+ : "d" (context.vm.regs.edx));
+ }
+
+static void
+em_outbl(unsigned char literal)
+ {
+ outb(context.vm.regs.eax & 0xff, literal);
+ }
+
+static void
+em_outb(void)
+ {
+ asm volatile ("outb %b0, (%w1)"
+ : : "a" (context.vm.regs.eax),
+ "d" (context.vm.regs.edx));
+ }
+
+static void
+em_outw(void)
+ {
+ asm volatile ("outw %w0, (%w1)"
+ : : "a" (context.vm.regs.eax),
+ "d" (context.vm.regs.edx));
+ }
+
+static void
+em_outl(void)
+ {
+ asm volatile ("outl %0, (%w1)"
+ : : "a" (context.vm.regs.eax),
+ "d" (context.vm.regs.edx));
+ }
+
+static int
+emulate(void)
+ {
+ unsigned char *insn;
+ struct
+ {
+ unsigned int size : 1;
+ unsigned int rep : 1;
+ } prefix = { 0, 0 };
+ int i = 0;
+
+ insn = (unsigned char *)((unsigned int)context.vm.regs.cs << 4);
+ insn += context.vm.regs.eip;
+
+ while (1)
+ {
+ if (insn[i] == 0x66)
+ {
+ prefix.size = 1 - prefix.size;
+ i++;
+ }
+ else if (insn[i] == 0xf3)
+ {
+ prefix.rep = 1;
+ i++;
+ }
+ else if (insn[i] == 0xf0 || insn[i] == 0xf2
+ || insn[i] == 0x26 || insn[i] == 0x2e
+ || insn[i] == 0x36 || insn[i] == 0x3e
+ || insn[i] == 0x64 || insn[i] == 0x65
+ || insn[i] == 0x67)
+ {
+ /* these prefixes are just ignored */
+ i++;
+ }
+ else if (insn[i] == 0x6c)
+ {
+ if (prefix.rep)
+ em_rep_ins(1);
+ else
+ em_ins(1);
+ i++;
+ break;
+ }
+ else if (insn[i] == 0x6d)
+ {
+ if (prefix.rep)
+ {
+ if (prefix.size)
+ em_rep_ins(4);
+ else
+ em_rep_ins(2);
+ }
+ else
+ {
+ if (prefix.size)
+ em_ins(4);
+ else
+ em_ins(2);
+ }
+ i++;
+ break;
+ }
+ else if (insn[i] == 0x6e)
+ {
+ if (prefix.rep)
+ em_rep_outs(1);
+ else
+ em_outs(1);
+ i++;
+ break;
+ }
+ else if (insn[i] == 0x6f)
+ {
+ if (prefix.rep)
+ {
+ if (prefix.size)
+ em_rep_outs(4);
+ else
+ em_rep_outs(2);
+ }
+ else
+ {
+ if (prefix.size)
+ em_outs(4);
+ else
+ em_outs(2);
+ }
+ i++;
+ break;
+ }
+ else if (insn[i] == 0xe4)
+ {
+ em_inbl(insn[i + 1]);
+ i += 2;
+ break;
+ }
+ else if (insn[i] == 0xe6)
+ {
+ em_outbl(insn[i + 1]);
+ i += 2;
+ break;
+ }
+ else if (insn[i] == 0xec)
+ {
+ em_inb();
+ i++;
+ break;
+ }
+ else if (insn[i] == 0xed)
+ {
+ if (prefix.size)
+ em_inl();
+ else
+ em_inw();
+ i++;
+ break;
+ }
+ else if (insn[i] == 0xee)
+ {
+ em_outb();
+ i++;
+ break;
+ }
+ else if (insn[i] == 0xef)
+ {
+ if (prefix.size)
+ em_outl();
+ else
+ em_outw();
+
+ i++;
+ break;
+ }
+ else
+ return 0;
+ }
+
+ context.vm.regs.eip += i;
+ return 1;
+ }
+
+
+/*
+ I don't know how to make sure I get the right vm86() from libc.
+ The one I want is syscall # 113 (vm86old() in libc 5, vm86() in glibc)
+ which should be declared as "int vm86(struct vm86_struct *);" in
+ <sys/vm86.h>.
+
+ This just does syscall 113 with inline asm, which should work
+ for both libc's (I hope).
+*/
+#if !defined(USE_LIBC_VM86)
+static int
+lrmi_vm86(struct vm86_struct *vm)
+ {
+ int r;
+#if 1
+ asm volatile (
+ "pushl %%ebx\n\t"
+ "movl %2, %%ebx\n\t"
+ "int $0x80\n\t"
+ "popl %%ebx"
+ : "=a" (r)
+ : "0" (113), "r" (vm));
+#else
+ asm volatile (
+ "int $0x80"
+ : "=a" (r)
+ : "0" (113), "b" (vm));
+#endif
+ return r;
+ }
+#else
+#define lrmi_vm86 vm86
+#endif
+
+static int
+run_vm86(void)
+ {
+ unsigned int vret;
+
+ while (1)
+ {
+ vret = lrmi_vm86(&context.vm);
+
+ if (VM86_TYPE(vret) == VM86_INTx)
+ {
+ unsigned int v = VM86_ARG(vret);
+
+ if (v == RETURN_TO_32_INT)
+ return 1;
+
+ pushw(context.vm.regs.eflags);
+ pushw(context.vm.regs.cs);
+ pushw(context.vm.regs.eip);
+
+ context.vm.regs.cs = get_int_seg(v);
+ context.vm.regs.eip = get_int_off(v);
+ context.vm.regs.eflags &= ~(VIF_MASK | TF_MASK);
+
+ continue;
+ }
+
+ if (VM86_TYPE(vret) != VM86_UNKNOWN)
+ break;
+
+ if (!emulate())
+ break;
+ }
+
+ return 0;
+ }
+
+
+int
+LRMI_call(struct LRMI_regs *r)
+ {
+ unsigned int vret;
+
+ memset(&context.vm.regs, 0, sizeof(context.vm.regs));
+
+ set_regs(r);
+
+ context.vm.regs.cs = r->cs;
+ context.vm.regs.eip = r->ip;
+
+ if (r->ss == 0 && r->sp == 0)
+ {
+ context.vm.regs.ss = context.stack_seg;
+ context.vm.regs.esp = context.stack_off;
+ }
+ else
+ {
+ context.vm.regs.ss = r->ss;
+ context.vm.regs.esp = r->sp;
+ }
+
+ pushw(context.ret_seg);
+ pushw(context.ret_off);
+
+ vret = run_vm86();
+
+ get_regs(r);
+
+ return vret;
+ }
+
+
+int
+LRMI_int(int i, struct LRMI_regs *r)
+ {
+ unsigned int vret;
+ unsigned int seg, off;
+
+ seg = get_int_seg(i);
+ off = get_int_off(i);
+
+ /*
+ If the interrupt is in regular memory, it's probably
+ still pointing at a dos TSR (which is now gone).
+ */
+ if (seg < 0xa000 || (seg << 4) + off >= 0x100000)
+ {
+#ifdef ORIGINAL_LRMI_CODE_THAT_GOT_IFDEFED_OUT
+ fprintf(stderr, "Int 0x%x is not in rom (%04x:%04x)\n", i, seg, off);
+#endif
+ return 0;
+ }
+
+ memset(&context.vm.regs, 0, sizeof(context.vm.regs));
+
+ set_regs(r);
+
+ context.vm.regs.cs = seg;
+ context.vm.regs.eip = off;
+
+ if (r->ss == 0 && r->sp == 0)
+ {
+ context.vm.regs.ss = context.stack_seg;
+ context.vm.regs.esp = context.stack_off;
+ }
+ else
+ {
+ context.vm.regs.ss = r->ss;
+ context.vm.regs.esp = r->sp;
+ }
+
+ pushw(DEFAULT_VM86_FLAGS);
+ pushw(context.ret_seg);
+ pushw(context.ret_off);
+
+ vret = run_vm86();
+
+ get_regs(r);
+
+ return vret;
+ }
+