/****************************************************************/
/* */
/* task.c */
/* */
/* Task Manager for DOS Processes */
/* */
/* Copyright (c) 1995 */
/* Pasquale J. Villani */
/* All Rights Reserved */
/* */
/* This file is part of DOS-C. */
/* */
/* DOS-C 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; either version */
/* 2, or (at your option) any later version. */
/* */
/* DOS-C is distributed in the hope that it will be useful, but */
/* WITHOUT ANY WARRANTY; without even the implied warranty of */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See */
/* the GNU General Public License for more details. */
/* */
/* You should have received a copy of the GNU General Public */
/* License along with DOS-C; see the file COPYING. If not, */
/* write to the Free Software Foundation, 675 Mass Ave, */
/* Cambridge, MA 02139, USA. */
/****************************************************************/
#include "../../hdr/portab.h"
#include "globals.h"
/* $Logfile: C:/dos-c/src/kernel/task.c_v $ */
#ifndef IPL
static BYTE *RcsId = "$Header: C:/dos-c/src/kernel/task.c_v 1.2 01 Sep 1995 17:54:22 patv $";
#endif
/*
* $Log: C:/dos-c/src/kernel/task.c_v $
*
* Rev 1.2 01 Sep 1995 17:54:22 patv
* First GPL release.
*
* Rev 1.1 30 Jul 1995 20:51:58 patv
* Eliminated version strings in ipl
*
* Rev 1.0 02 Jul 1995 8:34:06 patv
* Initial revision.
*/
#define LOADNGO 0
#define LOAD 1
#define OVERLAY 3
static exe_header header;
#define CHUNK 16384
#define MAXENV 32768
#ifndef PROTO
COUNT ChildEnv(exec_blk FAR *, UWORD *);
#else
COUNT ChildEnv();
#endif
#ifndef IPL
COUNT
ChildEnv (exec_blk FAR *exp, UWORD *pChildEnvSeg)
{
BYTE FAR *pSrc;
BYTE FAR *pDest;
UWORD nEnvSize;
COUNT RetCode;
UWORD MaxEnvSize;
/* create a new environment for the process */
if(exp -> exec.env_seg != 0)
{
for(nEnvSize = 0, pSrc = MK_FP(exp -> exec.env_seg,0); *pSrc != '\0'; )
{
while(*pSrc != '\0')
{
++pSrc;
++nEnvSize;
}
/* account for terminating null */
++nEnvSize;
++pSrc;
}
}
else
{
/** nEnvSize = 0; */
pChildEnvSeg = 0;
return SUCCESS;
}
/* Test env size and abort if greater than max */
if(nEnvSize >= MAXENV)
return DE_INVLDENV;
/* allocate enough space for env + path */
if((RetCode = DosMemAlloc(long2para(nEnvSize + 65), FIRST_FIT, (seg FAR *)pChildEnvSeg, (UWORD FAR *)MaxEnvSize)) < 0)
return RetCode;
else
pDest = MK_FP(*pChildEnvSeg + 1, 0);
/* fill the new env and inform the process of its */
/* location throught the psp */
for(pSrc = MK_FP(exp -> exec.env_seg,0); *pSrc != '\0'; )
{
fstrncpy(pDest, pSrc, BUFFERSIZE);
while(*pSrc != '\0')
++pSrc;
while(*pDest != '\0')
++pDest;
++pSrc;
++pDest;
}
*pDest = '\0';
return SUCCESS;
}
#endif
/* The following code is 8086 dependant */
VOID
new_psp (psp FAR *p, int psize)
{
REG COUNT i;
BYTE FAR *lpPspBuffer;
/* Clear out new psp first */
for(lpPspBuffer = p, i = 0; i < sizeof(psp) ; ++i)
*lpPspBuffer = 0;
/* initialize all entries and exits */
/* CP/M-like exit point */
p -> ps_exit = 0x20cb;
/* CP/M-like entry point - jump to special entry */
p -> ps_farcall= 0xea;
#ifndef IPL
p -> ps_reentry = int21_entry;
#endif
/* unix style call - 0xcd 0x21 0xcb (int 21, retf) */
p -> ps_unix[0] = 0xcd;
p -> ps_unix[1] = 0x21;
p -> ps_unix[2] = 0xcb;
/* Now for parent-child relationships */
/* parent psp segment */
p -> ps_parent = DOS_PSP;
/* previous psp pointer */
p -> ps_prevpsp = (BYTE FAR *)-1;
#ifndef IPL
/* Environment and memory useage parameters */
/* memory size in paragraphs */
p -> ps_size = psize;
/* environment paragraph */
p -> ps_environ = 0;
/* process dta */
p -> ps_dta = (BYTE FAR *)(&p -> ps_cmd_count);
/* terminate address */
p -> ps_isv22 = int22_handler;
/* break address */
p -> ps_isv23 = int23_handler;
/* critical error address */
p -> ps_isv24 = int24_handler;
#endif
/* File System parameters */
/* user stack pointer - int 21 */
p -> ps_stack = (BYTE FAR *)-1;
/* file table - 0xff is unused */
for(i = 0; i < 20; i++)
p -> ps_files[i] = 0xff;
/* initialize stdin, stdout, etc */
p -> ps_files[STDIN] = 0; /* stdin */
p -> ps_files[STDOUT] = 1; /* stdout */
p -> ps_files[STDERR] = 2; /* stderr */
p -> ps_files[STDAUX] = 3; /* stdaux */
p -> ps_files[STDPRN] = 4; /* stdprn */
/* maximum open files */
p -> ps_maxfiles = 20;
/* open file table pointer */
p -> ps_filetab = p -> ps_files;
/* first command line argument */
p -> ps_fcb1.fcb_drive = 1;
/* second command line argument */
p -> ps_fcb2.fcb_drive = 2;
/* local command line */
p -> ps_cmd_count = 0; /* command tail */
p -> ps_cmd[0] = 0; /* command tail */
}
#ifndef IPL
static COUNT
DosComLoader (BYTE FAR *namep, exec_blk FAR *exp, COUNT mode)
{
COUNT rc, env_size, nread;
UWORD mem;
UWORD env, asize;
BYTE FAR *sp, FAR *dp;
psp FAR *p;
mcb FAR *mp;
iregs FAR *irp;
LONG com_size;
if(mode != OVERLAY)
{
if((rc = ChildEnv(exp, &env)) != SUCCESS)
return rc;
}
else
mem = exp -> load.load_seg;
/* Allocate our memory and pass back any errors */
if((rc = DosMemAlloc(0, LARGEST, (seg FAR *)&mem, (UWORD FAR *)&asize)) < 0)
{
if(env != 0)
DosMemFree(env);
return rc;
}
else
{
mp = MK_FP(mem, 0);
++mem;
}
/* Now load the executable */
/* If file not found - error */
/* NOTE - this is fatal because we lost it in transit */
/* from DosExec! */
if((rc = dos_open(namep, 0)) < 0)
fatal("(DosComLoader) com file lost in transit");
/* do it in 32K chunks */
sp = MK_FP(mem, sizeof(psp));
for(com_size = 65536l, nread = 0; com_size > 0; )
{
nread = dos_read(rc, sp, CHUNK);
sp += nread;
com_size -= nread;
if(nread < CHUNK)
break;
}
dos_close(rc);
if(mode == OVERLAY)
return SUCCESS;
/* point to the PSP so we can build it */
p = MK_FP(mem, 0);
new_psp(p, mem + asize);
/* clone the file table */
if(InDOS > 0)
{
psp FAR *q;
REG COUNT i;
q = MK_FP(cu_psp, 0);
for(i = 0; i < 20; i++)
{
REG COUNT ret;
if(q -> ps_files[i] != 0xff
&& ((ret = CloneHandle(q -> ps_files[i])) >= 0))
p -> ps_files[i] = ret;
else
p -> ps_files[i] = 0xff;
}
}
p -> ps_environ = env == 0 ? 0 : env + 1;
/* complete the psp by adding the command line */
p -> ps_cmd_count = exp -> exec.cmd_line -> ctCount;
fbcopy(exp -> exec.cmd_line -> ctBuffer, p -> ps_cmd,
p -> ps_cmd_count > 127 ? 127 : p -> ps_cmd_count);
/* stick a new line on the end for safe measure */
p -> ps_cmd[p -> ps_cmd_count] = '\r';
/* identify the mcb as this functions' */
/* use the file name less extension - left adjusted and */
/* space filled */
mp -> m_psp = mem + 1;
for(asize = 0; asize < 8; asize++)
{
if(namep[asize] != '.')
mp -> m_name[asize] = namep[asize];
else
break;
}
for(; asize < 8; asize++)
mp -> m_name[asize] = ' ';
/* build the user area on the stack */
irp = MK_FP(mem, (0xfffe - sizeof(iregs)));
/* start allocating REGs */
irp -> ES = irp -> DS = mem;
irp -> CS = mem;
irp -> IP = 0x100;
irp -> AX = 0xffff; /* for now, until fcb code is in */
irp -> BX =
irp -> CX =
irp -> DX =
irp -> SI =
irp -> DI =
irp -> BP = 0;
irp -> FLAGS = 0;
/* Transfer control to the executable */
p -> ps_parent = cu_psp;
p -> ps_prevpsp = (BYTE FAR *)MK_FP(cu_psp, 0);
p -> ps_stack = (BYTE FAR *)user_r;
switch(mode)
{
case LOADNGO:
cu_psp = mem;
dta = p -> ps_dta;
exec_user(irp);
/* We should never be here */
fatal("KERNEL RETURNED!!!");
break;
case LOAD:
exp -> exec.stack = (BYTE FAR *)irp;
exp -> exec.start_addr = MK_FP(irp -> CS, irp -> IP);
return SUCCESS;
}
}
VOID
return_user (void)
{
psp FAR *p, FAR *q;
REG COUNT i;
/* Close all files */
for(i = 0; i < 20; i++)
DosClose(i);
/* restore parent */
p = MK_FP(cu_psp, 0);
/* When process returns - restore the isv */
setvec(0x22, p -> ps_isv22);
setvec(0x23, p -> ps_isv23);
setvec(0x24, p -> ps_isv24);
/* And free all process memory if not a TSR return */
if(!tsr)
{
if(p -> ps_environ != (UWORD)0)
DosMemFree(--p -> ps_environ);
DosMemFree(--cu_psp);
}
cu_psp = p -> ps_parent;
q = MK_FP(cu_psp,0);
dta = q -> ps_dta;
exec_user(p -> ps_stack);
}
#endif
static COUNT
DosExeLoader (BYTE FAR *namep, exec_blk FAR *exp, COUNT mode)
{
COUNT rc, env_size, i, nBytesRead;
UWORD mem, env, asize, start_seg;
ULONG image_size;
ULONG image_offset;
BYTE FAR *sp, FAR * dp;
psp FAR *p;
mcb FAR *mp;
iregs FAR *irp;
UWORD reloc[2];
seg FAR *spot;
LONG exe_size;
#ifdef IPL
BYTE szNameBuffer[64];
#endif
#ifndef IPL
/* Clone the environement and create a memory arena */
if(mode != OVERLAY)
{
if((rc = ChildEnv(exp, &env)) != SUCCESS)
return rc;
}
else
mem = exp -> load.load_seg;
#endif
/* compute image offset from the header */
#ifdef IPL
fscopy(namep, (BYTE FAR *)szNameBuffer);
printf("\nEXE loader loading: %s", szNameBuffer);
#endif
image_offset = (ULONG)header.exHeaderSize * 16l;
/* compute image size by removing the offset from the */
/* number pages scaled to bytes plus the remainder and */
/* the psp */
/* First scale the size */
image_size = (ULONG)(header.exPages) * 512l;
#if 0
/* remove the offset */
image_size -= image_offset;
/* add in the remainder bytes */
if(header.exExtraBytes != 0)
image_size -= (ULONG)(512 - header.exExtraBytes);
#endif
/* and finally add in the psp size */
if(mode != OVERLAY)
image_size += (ULONG)long2para((LONG)sizeof(psp));
#ifndef IPL
if(mode != OVERLAY)
{
/* Now find out how many paragraphs are available */
if((rc = DosMemLargest((seg FAR *)&asize)) != SUCCESS)
return rc;
else
{
exe_size = (LONG)long2para(image_size) + header.exMinAlloc + long2para((LONG)sizeof(psp));
if(exe_size > asize)
return DE_NOMEM;
else if(((LONG)long2para(image_size) + header.exMaxAlloc + long2para((LONG)sizeof(psp))) < asize)
exe_size = (LONG)long2para(image_size) + header.exMaxAlloc + long2para((LONG)sizeof(psp));
else
exe_size = asize;
}
/* Allocate our memory and pass back any errors */
/* We can still get an error on first fit if the above */
/* returned size was a bet fit case */
if((rc = DosMemAlloc((seg)exe_size, FIRST_FIT, (seg FAR *)&mem, (UWORD FAR *)&asize)) < 0)
{
if(rc == DE_NOMEM)
{
if((rc = DosMemAlloc(0, LARGEST, (seg FAR *)&mem, (UWORD FAR *)&asize)) < 0)
{
if(env != 0)
DosMemFree(env);
return rc;
}
/* This should never happen, but ... */
if(asize < exe_size)
{
if(env != 0)
DosMemFree(env);
DosMemFree(mem);
return rc;
}
}
else
{
if(env != 0)
DosMemFree(env);
return rc;
}
}
else
/* with no error, we got exactly what we asked for */
asize = exe_size;
}
#else
mem = KERNSEG;
#endif
#ifndef IPL
if(mode != OVERLAY)
{
#endif
/* memory found large enough - continue processing */
mp = MK_FP(mem, 0);
++mem;
#ifndef IPL
}
else
mem = exp -> load.load_seg;
#endif
#ifdef IPL
printf(".");
#endif
/* create the start seg for later computations */
if(mode == OVERLAY)
start_seg = mem;
else
start_seg = mem + long2para((LONG)sizeof(psp));
/* Now load the executable */
/* If file not found - error */
/* NOTE - this is fatal because we lost it in transit */
/* from DosExec! */
if((rc = dos_open(namep, 0)) < 0)
fatal("(DosExeLoader) exe file lost in transit");
#ifdef IPL
printf(".");
#endif
/* offset to start of image */
if (dos_lseek(rc, image_offset, 0) != image_offset)
{
#ifndef IPL
if(mode != OVERLAY)
{
DosMemFree(--mem);
if(env != 0)
DosMemFree(env);
}
#endif
return DE_INVLDDATA;
}
#ifdef IPL
printf(".");
#endif
/* read in the image in 32K chunks */
if(mode != OVERLAY)
exe_size = image_size - long2para((LONG)sizeof(psp));
else
exe_size = image_size;
sp = MK_FP(start_seg, 0x0);
while(exe_size > 0)
{
nBytesRead = dos_read((COUNT)rc, (VOID FAR *)sp, (COUNT)(exe_size < CHUNK ? exe_size : CHUNK));
sp = add_far((VOID FAR *)sp, (ULONG)CHUNK);
exe_size -= nBytesRead;
if(nBytesRead == 0 || exe_size <= 0)
break;
#ifdef IPL
printf(".");
#endif
}
#if 0
/* Error if we did not read the entire image */
if(exe_size != 0)
fatal("Broken exe loader (exe_size != 0)");
#endif
/* relocate the image for new segment */
dos_lseek(rc, (LONG)header.exRelocTable, 0);
for (i=0; i < header.exRelocItems; i++)
{
if (dos_read(rc, (VOID FAR *)&reloc[0], sizeof(reloc)) != sizeof(reloc))
{
return DE_INVLDDATA;
}
if(mode == OVERLAY)
{
spot = MK_FP(reloc[1] + mem, reloc[0]);
*spot = *spot + exp -> load.reloc;
}
else
{
/* spot = MK_FP(reloc[1] + mem + 0x10, reloc[0]);*/
spot = MK_FP(reloc[1] + start_seg, reloc[0]);
*spot = *spot + start_seg;
}
}
#ifdef IPL
printf(".");
#endif
/* and finally close the file */
dos_close(rc);
/* exit here for overlay */
if(mode == OVERLAY)
return SUCCESS;
/* point to the PSP so we can build it */
p = MK_FP(mem, 0);
new_psp(p, mem + asize);
#ifndef IPL
/* clone the file table */
if(InDOS > 0)
{
psp FAR *q;
q = MK_FP(cu_psp, 0);
for(i = 0; i < 20; i++)
{
REG COUNT ret;
if(q -> ps_files[i] != 0xff
&& ((ret = CloneHandle(q -> ps_files[i])) >= 0))
p -> ps_files[i] = ret;
else
p -> ps_files[i] = 0xff;
}
}
p -> ps_environ = env == 0 ? 0 : env + 1;
#else
p -> ps_environ = 0;
#endif
/* complete the psp by adding the command line */
p -> ps_cmd_count = exp -> exec.cmd_line -> ctCount;
fbcopy(exp -> exec.cmd_line -> ctBuffer, p -> ps_cmd,
p -> ps_cmd_count > 127 ? 127 : p -> ps_cmd_count);
/* stick a new line on the end for safe measure */
p -> ps_cmd[p -> ps_cmd_count] = '\r';
/* identify the mcb as this functions' */
/* use the file name less extension - left adjusted and */
/* space filled */
mp -> m_psp = mem + 1;
for(i = 0; i < 8; i++)
{
if(namep[i] != '.')
mp -> m_name[i] = namep[i];
else
break;
}
for(; i < 8; i++)
mp -> m_name[i] = ' ';
/* build the user area on the stack */
irp = MK_FP(header.exInitSS + start_seg, ((header.exInitSP - sizeof(iregs)) & 0xffff));
#ifdef IPL
printf(".\n");
#endif
/* start allocating REGs */
/* Note: must match es & ds memory segment */
irp -> ES = irp -> DS = mem;
irp -> CS = header.exInitCS + start_seg;
irp -> IP = header.exInitIP;
irp -> AX = 0xffff; /* for now, until fcb code is in */
#ifdef IPL
irp -> BX = BootDrive;
irp -> CX = NumFloppies;
#else
irp -> BX =
irp -> CX =
#endif
irp -> DX =
irp -> SI =
irp -> DI =
irp -> BP = 0;
irp -> FLAGS = 0;
/* Transfer control to the executable */
p -> ps_parent = cu_psp;
p -> ps_prevpsp = (BYTE FAR *)MK_FP(cu_psp, 0);
p -> ps_stack = (BYTE FAR *)user_r;
#ifdef IPL
printf("Starting kernel ...\n");
#endif
switch(mode)
{
case LOADNGO:
cu_psp = mem;
dta = p -> ps_dta;
exec_user(irp);
/* We should never be here */
fatal("KERNEL RETURNED!!!");
break;
#ifndef IPL
case LOAD:
exp -> exec.stack = (BYTE FAR *)irp;
exp -> exec.start_addr = MK_FP(irp -> CS, irp -> IP);
return SUCCESS;
#endif
}
}
COUNT
DosExec (COUNT mode, exec_blk FAR *ep, BYTE FAR *lp)
{
COUNT rc, nNumRead;
/* If file not found - free ram and return error */
#ifdef IPL
printf(".");
#endif
if((rc = dos_open(lp, 0)) < 0)
return DE_FILENOTFND;
if((nNumRead = dos_read(rc, (VOID FAR *)&header, sizeof(exe_header)))
!= sizeof(exe_header))
{
#ifdef IPL
printf("Internal IPL error - Read failure (read %d != %d)",
nNumRead, sizeof(exe_header));
#endif
return DE_INVLDDATA;
}
dos_close(rc);
#ifdef IPL
printf(".");
#endif
if(header.exSignature != MAGIC)
#ifndef IPL
return DosComLoader(lp, ep, mode);
#else
{
char szFileName[32];
fmemcpy((BYTE FAR *)szFileName, lp);
printf("\nFile: %s (MAGIC = %04x)", szFileName, header.exSignature);
fatal("IPL can't load .com files!");
}
#endif
else
return DosExeLoader(lp, ep, mode);
}
