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FreeDOS/kernel/task.c

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/****************************************************************/
/* */
/* 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 "portab.h"
#include "globals.h"
#ifdef VERSION_STRINGS
static BYTE *RcsId =
"$Id: task.c 1563 2011-04-08 16:04:24Z bartoldeman $";
#endif
#define toupper(c) ((c) >= 'a' && (c) <= 'z' ? (c) + ('A' - 'a') : (c))
#define LOADNGO 0
#define LOAD 1
#define OVERLAY 3
#define LOAD_HIGH 0x80
/* static exe_header ExeHeader;
to save some bytes, both static and on stack,
we recycle SecPathBuffer TE */
#define ExeHeader (*(exe_header *)(SecPathName + 0))
#define TempExeBlock (*(exec_blk *)(SecPathName + sizeof(exe_header)))
#define Shell (SecPathName + sizeof(exe_header) + sizeof(exec_blk))
#ifdef __TURBOC__ /* this is a Borlandism and doesn't work elsewhere */
#if sizeof(SecPathName) < sizeof(exe_header) + sizeof(exec_blk) + NAMEMAX
#error No room in SecPathName to be recycled!
#endif
#endif
#define CHUNK 32256
#define MAXENV 32768u
#define ENV_KEEPFREE 83 /* keep unallocated by environment variables */
/* The '65' added to nEnvSize does not cover the additional stuff:
+ 2 bytes: number of strings
+ 80 bytes: maximum absolute filename
+ 1 byte: '\0'
-- 1999/04/21 ska */
intvec getvec(unsigned char intno)
{
intvec iv;
disable();
iv = *(intvec FAR *)MK_FP(0,4 * (intno));
enable();
return iv;
}
void setvec(unsigned char intno, intvec vector)
{
disable();
*(intvec FAR *)MK_FP(0,4 * intno) = vector;
enable();
}
ULONG SftGetFsize(int sft_idx)
{
sft FAR *s = idx_to_sft(sft_idx);
/* Get the SFT block that contains the SFT */
if (FP_OFF(s) == (size_t) -1)
return DE_INVLDHNDL;
return s->sft_size;
}
STATIC WORD SetverCompareFilename(BYTE FAR *m1, BYTE FAR *m2, COUNT c)
{
while (c--)
{
if (toupper(*m1) != toupper(*m2))
{
return *m1 - *m2;
}
m1 = m1 + 1; m2 = m2 + 1;
}
return 0;
}
STATIC UWORD SetverGetVersion(BYTE FAR *table, BYTE FAR *name)
{
BYTE FAR *len;
COUNT nlen;
if ((table != NULL) && (name != NULL))
{
nlen = fstrlen(name);
while (*(len = table) != 0)
{
if ((*len == nlen) && (SetverCompareFilename(name, table + 1, *len) == 0))
{
return *((UWORD FAR *)(table + *len + 1));
}
table = table + *len + 3;
}
}
return 0;
}
STATIC COUNT ChildEnv(exec_blk * exp, UWORD * pChildEnvSeg, char far * pathname)
{
BYTE FAR *pSrc;
BYTE FAR *pDest;
UWORD nEnvSize;
COUNT RetCode;
/* UWORD MaxEnvSize; not used -- 1999/04/21 ska */
psp FAR *ppsp = MK_FP(cu_psp, 0);
/* create a new environment for the process */
/* copy parent's environment if exec.env_seg == 0 */
pSrc = exp->exec.env_seg ?
MK_FP(exp->exec.env_seg, 0) : MK_FP(ppsp->ps_environ, 0);
#if 0
/* Every process requires an environment because of argv[0]
-- 1999/04/21 ska */
*/if (!pSrc) /* no environment to copy */
{
*pChildEnvSeg = 0;
return SUCCESS;
}
#endif
nEnvSize = 1;
/* This loop had not counted the very last '\0'
-- 1999/04/21 ska */
if (pSrc)
{ /* if no environment is available, one byte is required */
for (nEnvSize = 0;; nEnvSize++)
{
/* Test env size and abort if greater than max */
if (nEnvSize >= MAXENV - ENV_KEEPFREE)
return DE_INVLDENV;
if (*(UWORD FAR *) (pSrc + nEnvSize) == 0)
break;
}
nEnvSize += 2; /* account for trailing \0\0 */
}
/* allocate enough space for env + path */
if ((RetCode = DosMemAlloc((nEnvSize + ENV_KEEPFREE + 15)/16,
mem_access_mode, pChildEnvSeg,
NULL /*(UWORD FAR *) MaxEnvSize ska */ )) < 0)
return RetCode;
pDest = MK_FP(*pChildEnvSeg + 1, 0);
/* fill the new env and inform the process of its */
/* location throught the psp */
/* copy the environment */
if (pSrc)
{
fmemcpy(pDest, pSrc, nEnvSize);
pDest += nEnvSize;
}
else
*pDest++ = '\0'; /* create an empty environment */
/* initialize 'extra strings' count */
*((UWORD FAR *) pDest) = 1;
pDest += sizeof(UWORD) / sizeof(BYTE);
/* copy complete pathname */
if ((RetCode = truename(pathname, PriPathName, CDS_MODE_SKIP_PHYSICAL)) < SUCCESS)
{
return RetCode;
}
fstrcpy(pDest, PriPathName);
/* Theoretically one could either:
+ resize the already allocated block to best-fit behind the pathname, or
+ generate the filename into a temporary buffer to allocate only the
minimum required environment -- 1999/04/21 ska */
return SUCCESS;
}
/* The following code is 8086 dependant */
void new_psp(seg para, seg cur_psp)
{
psp FAR *p = MK_FP(para, 0);
fmemcpy(p, MK_FP(cur_psp, 0), sizeof(psp));
/* terminate address */
p->ps_isv22 = getvec(0x22);
/* break address */
p->ps_isv23 = getvec(0x23);
/* critical error address */
p->ps_isv24 = getvec(0x24);
/* RBIL is wrong on zeroing parent_psp, and in fact some
* progs (Alpha Waves game, https://github.com/stsp/fdpp/issues/112)
* won't work if its zeroed. */
#if 0
/* parent psp segment set to 0 (see RBIL int21/ah=26) */
p->ps_parent = 0;
#endif
/* default system version for int21/ah=30 */
p->ps_retdosver = (os_setver_minor << 8) + os_setver_major;
}
void child_psp(seg para, seg cur_psp, int psize)
{
psp FAR *p = MK_FP(para, 0);
psp FAR *q = MK_FP(cur_psp, 0);
int i;
new_psp(para, cur_psp);
/* Now for parent-child relationships */
/* parent psp segment */
p->ps_parent = cu_psp;
/* previous psp pointer */
p->ps_prevpsp = q;
/* Environment and memory useage parameters */
/* memory size in paragraphs */
p->ps_size = psize;
/* File System parameters */
/* maximum open files */
p->ps_maxfiles = 20;
fmemset(p->ps_files, 0xff, 20);
/* open file table pointer */
p->ps_filetab = p->ps_files;
/* clone the file table -- 0xff is unused */
for (i = 0; i < 20; i++)
if (CloneHandle(i) >= 0)
p->ps_files[i] = q->ps_filetab[i];
/* first command line argument */
p->ps_fcb1.fcb_drive = 0;
fmemset(p->ps_fcb1.fcb_fname, ' ', FNAME_SIZE + FEXT_SIZE);
/* second command line argument */
p->ps_fcb2.fcb_drive = 0;
fmemset(p->ps_fcb2.fcb_fname, ' ', FNAME_SIZE + FEXT_SIZE);
/* local command line */
p->ps_cmd.ctCount = 0;
p->ps_cmd.ctBuffer[0] = 0xd; /* command tail */
}
STATIC UWORD patchPSP(UWORD pspseg, UWORD envseg, exec_blk FAR * exb,
BYTE FAR * fnam)
{
psp FAR *psp;
mcb FAR *pspmcb;
int i;
BYTE FAR *np;
UWORD fakever;
pspmcb = MK_FP(pspseg, 0);
++pspseg;
psp = MK_FP(pspseg, 0);
/* complete the psp by adding the command line and FCBs */
fmemcpy(&psp->ps_cmd, exb->exec.cmd_line, sizeof(CommandTail));
if (FP_OFF(exb->exec.fcb_1) != 0xffff)
{
fmemcpy(&psp->ps_fcb1, exb->exec.fcb_1, 16);
fmemcpy(&psp->ps_fcb2, exb->exec.fcb_2, 16);
}
/* identify the mcb as this functions' */
pspmcb->m_psp = pspseg;
/* Patch in environment segment, if present, also adjust its MCB */
if (envseg)
{
((mcb FAR *) MK_FP(envseg, 0))->m_psp = pspseg;
envseg++;
}
psp->ps_environ = envseg;
/* use the file name less extension - left adjusted and */
np = fnam;
for (;;)
{
switch (*fnam++)
{
case '\0':
goto set_name;
case ':':
case '/':
case '\\':
np = fnam;
}
}
set_name:
for (i = 0; i < 8 && np[i] != '.' && np[i] != '\0'; i++)
{
pspmcb->m_name[i] = toupper(np[i]);
}
if (i < 8)
pspmcb->m_name[i] = '\0';
if ((fakever = SetverGetVersion(setverPtr, np)) != 0)
{
psp->ps_retdosver = fakever;
}
/* return value: AX value to be passed based on FCB values */
return (get_cds1(psp->ps_fcb1.fcb_drive) ? 0 : 0xff) |
(get_cds1(psp->ps_fcb2.fcb_drive) ? 0 : 0xff00);
}
STATIC int load_transfer(UWORD ds, exec_blk *exp, UWORD fcbcode, COUNT mode)
{
psp FAR *p = MK_FP(ds, 0);
psp FAR *q = MK_FP(cu_psp, 0);
/* Transfer control to the executable */
p->ps_parent = cu_psp;
p->ps_prevpsp = q;
q->ps_stack = (BYTE FAR *)user_r;
user_r->FLAGS &= ~FLG_CARRY;
cu_psp = ds;
/* process dta */
dta = &p->ps_cmd;
if (mode == LOADNGO)
{
iregs FAR *irp;
/* build the user area on the stack */
irp = (iregs FAR *)(exp->exec.stack - sizeof(iregs));
/* start allocating REGs (as in MS-DOS - some demos expect them so --LG) */
/* see http://www.beroset.com/asm/showregs.asm */
irp->DX = irp->ES = irp->DS = ds;
irp->CS = FP_SEG(exp->exec.start_addr);
irp->SI = irp->IP = FP_OFF(exp->exec.start_addr);
irp->DI = FP_OFF(exp->exec.stack);
irp->BP = 0x91e; /* this is more or less random but some programs
expect 0x9 in the high byte of BP!! */
irp->AX = irp->BX = fcbcode;
irp->CX = 0xFF;
irp->FLAGS = 0x200;
if (InDOS)
--InDOS;
exec_user(irp, 1);
/* We should never be here
fatal("KERNEL RETURNED!!!"); */
}
/* mode == LOAD */
exp->exec.stack -= 2;
*((UWORD FAR *)(exp->exec.stack)) = fcbcode;
return SUCCESS;
}
/* Now find out how many paragraphs are available
considering a threshold, trying HIGH then LOW */
STATIC int ExecMemLargest(UWORD *asize, UWORD threshold)
{
int rc;
if (mem_access_mode & 0x80)
{
mem_access_mode &= ~0x80;
mem_access_mode |= 0x40;
rc = DosMemLargest(asize);
mem_access_mode &= ~0x40;
/* less memory than the .COM/.EXE file has:
try low memory first */
if (rc != SUCCESS || *asize < threshold)
rc = DosMemLargest(asize);
mem_access_mode |= 0x80;
}
else
rc = DosMemLargest(asize);
return (*asize < threshold ? DE_NOMEM : rc);
}
STATIC int ExecMemAlloc(UWORD size, seg *para, UWORD *asize)
{
/* We can still get an error on first fit if the above */
/* returned size was a best fit case */
/* ModeLoadHigh = 80 = try high, then low */
int rc = DosMemAlloc(size, mem_access_mode, para, asize);
if (rc != SUCCESS)
{
if (rc == DE_NOMEM)
{
rc = DosMemAlloc(0, LARGEST, para, asize);
if ((mem_access_mode & 0x80) && (rc != SUCCESS))
{
mem_access_mode &= ~0x80;
rc = DosMemAlloc(0, LARGEST, para, asize);
mem_access_mode |= 0x80;
}
}
}
else
{
/* with no error, we got exactly what we asked for */
*asize = size;
}
/* This should never happen, but ... */
if (rc == SUCCESS && *asize < size)
{
DosMemFree(*para);
return DE_NOMEM;
}
return rc;
}
COUNT DosComLoader(BYTE FAR * namep, exec_blk * exp, COUNT mode, COUNT fd)
{
UWORD mem;
UWORD env, asize = 0;
{
UWORD com_size;
{
ULONG com_size_long = SftGetFsize(fd);
/* maximally 64k - 256 bytes stack -
256 bytes psp */
com_size = ((UWORD)min(com_size_long, 0xfe00u) >> 4) + 0x10;
}
if ((mode & 0x7f) != OVERLAY)
{
COUNT rc;
UBYTE UMBstate = uppermem_link;
UBYTE orig_mem_access = mem_access_mode;
if (mode & 0x80)
{
mem_access_mode |= 0x80;
DosUmbLink(1); /* link in UMBs */
}
rc = ChildEnv(exp, &env, namep);
/* COMFILES will always be loaded in largest area. is that true TE */
/* yes, see RBIL, int21/ah=48 -- Bart */
if (rc == SUCCESS)
rc = ExecMemLargest(&asize, com_size);
if (rc == SUCCESS)
/* Allocate our memory and pass back any errors */
rc = ExecMemAlloc(asize, &mem, &asize);
if (rc != SUCCESS)
DosMemFree(env);
if (mode & 0x80)
{
DosUmbLink(UMBstate); /* restore link state */
mem_access_mode = orig_mem_access;
mode &= 0x7f;
}
if (rc != SUCCESS)
return rc;
++mem;
}
else
mem = exp->load.load_seg;
}
#ifdef DEBUG
printf("DosComLoader. Loading '%S' at %04x\n", namep, mem);
#endif
/* Now load the executable */
{
BYTE FAR *sp;
if (mode == OVERLAY) /* memory already allocated */
sp = MK_FP(mem, 0);
else /* test the filesize against the allocated memory */
sp = MK_FP(mem, sizeof(psp));
/* MS DOS always only loads the very first 64KB - sizeof(psp) bytes.
-- 1999/04/21 ska */
/* rewind to start */
SftSeek(fd, 0, 0);
/* read everything, but at most 64K - sizeof(PSP) */
/* lpproj: some device drivers (not exe) are larger than 0xff00bytes... */
DosRWSft(fd, (mode == OVERLAY) ? 0xfffeU : 0xff00U, sp, XFR_READ);
DosCloseSft(fd, FALSE);
}
if (mode == OVERLAY)
return SUCCESS;
{
UWORD fcbcode;
psp FAR *p;
/* point to the PSP so we can build it */
setvec(0x22, (intvec)MK_FP(user_r->CS, user_r->IP));
child_psp(mem, cu_psp, mem + asize);
fcbcode = patchPSP(mem - 1, env, exp, namep);
/* set asize to end of segment */
if (asize > 0x1000)
asize = 0x1000;
if (asize < 0x11)
return DE_NOMEM;
asize -= 0x11;
/* CP/M compatibility--size of first segment for .COM files
while preserving the far call to 0:00c0 +
copy in HMA at ffff:00d0 */
p = MK_FP(mem, 0);
p->ps_reentry = MK_FP(0xc - asize, asize << 4);
asize <<= 4;
asize += 0x10e;
exp->exec.stack = MK_FP(mem, asize);
exp->exec.start_addr = MK_FP(mem, 0x100);
*((UWORD FAR *) MK_FP(mem, asize)) = (UWORD) 0;
load_transfer(mem, exp, fcbcode, mode);
}
return SUCCESS;
}
VOID return_user(void)
{
psp FAR *p; psp FAR * q;
REG COUNT i;
iregs FAR *irp;
/* long j;*/
/* 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 */
network_redirector(REM_PROCESS_END);
/* might be a good idea to do that after closing
but doesn't help NET either TE */
if (!tsr && p->ps_parent != cu_psp)
{
network_redirector(REM_CLOSEALL);
for (i = 0; i < p->ps_maxfiles; i++)
{
DosClose(i);
}
FcbCloseAll();
FreeProcessMem(cu_psp);
}
cu_psp = p->ps_parent;
q = MK_FP(cu_psp, 0);
irp = (iregs FAR *) q->ps_stack;
irp->CS = FP_SEG(p->ps_isv22);
irp->IP = FP_OFF(p->ps_isv22);
irp->FLAGS = 0x200; /* clear trace and carry flags, set interrupt flag */
if (InDOS)
--InDOS;
exec_user((iregs FAR *) q->ps_stack, 0);
}
COUNT DosExeLoader(BYTE FAR * namep, exec_blk * exp, COUNT mode, COUNT fd)
{
UWORD mem, env, start_seg, asize = 0;
UWORD exe_size;
{
UWORD image_size;
/* compute image size by removing the offset from the */
/* number pages scaled to bytes plus the remainder and */
/* the psp */
#if 0
if (ExeHeader.exPages >= 2048)
return DE_INVLDDATA; /* we're not able to get >=1MB in dos memory */
#else
/* TurboC++ 3 BOSS NE stub: image > 1 MB but load only "X mod 1 MB" */
/* ExeHeader.exPages &= 0x7ff; */ /* just let << 5 do the clipping! */
#endif
/* First scale the size and remove the offset */
image_size = (ExeHeader.exPages << 5) - ExeHeader.exHeaderSize;
/* We should not attempt to allocate
memory if we are overlaying the current process, because the new
process will simply re-use the block we already have allocated.
Jun 11, 2000 - rbc */
if ((mode & 0x7f) != OVERLAY)
{
UBYTE UMBstate = uppermem_link;
UBYTE orig_mem_access = mem_access_mode;
COUNT rc;
/* and finally add in the psp size */
image_size += sizeof(psp) / 16; /* TE 03/20/01 */
exe_size = image_size + ExeHeader.exMinAlloc;
/* Some ancient NE programs set exMinAlloc to 0xffff to signify
that they should not be run as normal MZ programs at all. Check
for this and similar conditions. -- 2019/11/05 tkchia */
if (exe_size < image_size)
return DE_NOMEM;
/* Clone the environement and create a memory arena */
if (mode & 0x80)
{
DosUmbLink(1); /* link in UMBs */
mem_access_mode |= 0x80;
}
rc = ChildEnv(exp, &env, namep);
if (rc == SUCCESS)
/* Now find out how many paragraphs are available */
rc = ExecMemLargest(&asize, exe_size);
exe_size = image_size + ExeHeader.exMaxAlloc;
/* second test is for overflow (avoiding longs) --
exMaxAlloc can be high */
if (exe_size > asize || exe_size < image_size)
exe_size = asize;
/* TE if ExeHeader.exMinAlloc == ExeHeader.exMaxAlloc == 0,
DOS will allocate the largest possible memory area
and load the image as high as possible into it.
discovered (and after that found in RBIL), when testing NET */
if ((ExeHeader.exMinAlloc | ExeHeader.exMaxAlloc) == 0)
exe_size = asize;
/* Allocate our memory and pass back any errors */
if (rc == SUCCESS)
rc = ExecMemAlloc(exe_size, &mem, &asize);
if (rc != SUCCESS)
DosMemFree(env);
if (mode & 0x80)
{
mem_access_mode = orig_mem_access; /* restore old situation */
DosUmbLink(UMBstate); /* restore link state */
}
if (rc != SUCCESS)
return rc;
mode &= 0x7f; /* forget about high loading from now on */
#ifdef DEBUG
printf("DosExeLoader. Loading '%S' at %04x\n", namep, mem);
#endif
/* memory found large enough - continue processing */
++mem;
/* /// Added open curly brace and "else" clause. We should not attempt
to allocate memory if we are overlaying the current process, because
the new process will simply re-use the block we already have allocated.
This was causing execl() to fail in applications which use it to
overlay (replace) the current exe file with a new one.
Jun 11, 2000 - rbc */
}
else /* !!OVERLAY */
{
mem = exp->load.load_seg;
}
/* Now load the executable */
/* offset to start of image */
if (SftSeek(fd, ExeHeader.exHeaderSize * 16UL, 0) != SUCCESS)
{
if (mode != OVERLAY)
{
DosMemFree(--mem);
DosMemFree(env);
}
return DE_INVLDDATA;
}
/* create the start seg for later computations */
start_seg = mem;
exe_size = image_size;
if (mode != OVERLAY)
{
exe_size -= sizeof(psp) / 16;
start_seg += sizeof(psp) / 16;
if (exe_size > 0 && (ExeHeader.exMinAlloc | ExeHeader.exMaxAlloc) == 0)
{
mcb FAR *mp = MK_FP(mem - 1, 0);
/* then the image should be placed as high as possible */
start_seg += mp->m_size - image_size;
}
}
}
/* read in the image in 32256 chunks */
{
int nBytesRead, toRead = CHUNK;
seg sp = start_seg;
while (1)
{
if (exe_size < CHUNK/16)
toRead = exe_size*16;
nBytesRead = (int)DosRWSft(fd, toRead, MK_FP(sp, 0), XFR_READ);
if (nBytesRead < toRead || exe_size <= CHUNK/16)
break;
sp += CHUNK/16;
exe_size -= CHUNK/16;
}
}
{ /* relocate the image for new segment */
COUNT i;
UWORD reloc[2];
seg FAR *spot;
SftSeek(fd, ExeHeader.exRelocTable, 0);
for (i = 0; i < ExeHeader.exRelocItems; i++)
{
if (DosRWSft
(fd, sizeof(reloc), (VOID FAR *) & reloc[0], XFR_READ) != sizeof(reloc))
{
if (mode != OVERLAY)
{
DosMemFree(--mem);
DosMemFree(env);
}
return DE_INVLDDATA;
}
if (mode == OVERLAY)
{
spot = MK_FP(reloc[1] + mem, reloc[0]);
*spot += exp->load.reloc;
}
else
{
/* spot = MK_FP(reloc[1] + mem + 0x10, reloc[0]); */
spot = MK_FP(reloc[1] + start_seg, reloc[0]);
*spot += start_seg;
}
}
}
/* and finally close the file */
DosCloseSft(fd, FALSE);
/* exit here for overlay */
if (mode == OVERLAY)
return SUCCESS;
{
UWORD fcbcode;
/* point to the PSP so we can build it */
setvec(0x22, (intvec)MK_FP(user_r->CS, user_r->IP));
child_psp(mem, cu_psp, mem + asize);
fcbcode = patchPSP(mem - 1, env, exp, namep);
exp->exec.stack =
MK_FP(ExeHeader.exInitSS + start_seg, ExeHeader.exInitSP);
exp->exec.start_addr =
MK_FP(ExeHeader.exInitCS + start_seg, ExeHeader.exInitIP);
/* Transfer control to the executable */
load_transfer(mem, exp, fcbcode, mode);
}
return SUCCESS;
}
/* mode = LOAD or EXECUTE
ep = EXE block
lp = filename to load (string)
leb = local copy of exe block
*/
COUNT DosExec(COUNT mode, exec_blk FAR * ep, BYTE FAR * lp)
{
COUNT rc;
COUNT fd;
if ((mode & 0x7f) > 3 || (mode & 0x7f) == 2)
return DE_INVLDFMT;
fmemcpy(&TempExeBlock, ep, sizeof(exec_blk));
/* If file not found - free ram and return error */
if (IsDevice(lp) || /* we don't want to execute C:>NUL */
(fd = (short)DosOpenSft(lp, O_LEGACY | O_OPEN | O_RDONLY, 0)) < 0)
{
return DE_FILENOTFND;
}
rc = (int)DosRWSft(fd, sizeof(exe_header), (BYTE FAR *)&ExeHeader, XFR_READ);
if (rc == sizeof(exe_header) &&
(ExeHeader.exSignature == MAGIC || ExeHeader.exSignature == OLD_MAGIC))
{
rc = DosExeLoader(lp, &TempExeBlock, mode, fd);
}
else if (rc != 0)
{
rc = DosComLoader(lp, &TempExeBlock, mode, fd);
}
DosCloseSft(fd, FALSE);
if (mode == LOAD && rc == SUCCESS)
fmemcpy(ep, &TempExeBlock, sizeof(exec_blk));
return rc;
}
#include "config.h" /* config structure definition */
/* start process 0 (the shell) */
VOID ASMCFUNC P_0(struct config FAR *Config)
{
BYTE *tailp, *endp;
exec_blk exb;
UBYTE mode = Config->cfgP_0_startmode;
/* build exec block and save all parameters here as init part will vanish! */
exb.exec.fcb_1 = exb.exec.fcb_2 = (fcb FAR *)-1L;
exb.exec.env_seg = DOS_PSP + 8;
fstrcpy(Shell, MK_FP(FP_SEG(Config), Config->cfgInit));
/* join name and tail */
fstrcpy(Shell + strlen(Shell), MK_FP(FP_SEG(Config), Config->cfgInitTail));
endp = Shell + strlen(Shell);
for ( ; ; ) /* endless shell load loop - reboot or shut down to exit it! */
{
BYTE *p;
/* if there are no parameters, point to end without "\r\n" */
if((tailp = strchr(Shell,'\t')) == NULL &&
(tailp = strchr(Shell, ' ')) == NULL)
tailp = endp - 2;
/* shift tail to right by 2 to make room for '\0', ctCount */
for (p = endp - 1; p >= tailp; p--)
*(p + 2) = *p;
/* terminate name and tail */
*tailp = *(endp + 2) = '\0';
/* ctCount: just past '\0' do not count the "\r\n" */
exb.exec.cmd_line = (CommandTail *)(tailp + 1);
exb.exec.cmd_line->ctCount = endp - tailp - 2;
#ifdef DEBUG
printf("Process 0 starting: %s%s\n\n", Shell, tailp + 2);
#endif
res_DosExec(mode, &exb, Shell);
put_string("Bad or missing Command Interpreter: "); /* failure _or_ exit */
put_string(Shell);
put_string(tailp + 2);
put_string(" Enter the full shell command line: ");
endp = Shell + res_read(STDIN, Shell, NAMEMAX);
*endp = '\0'; /* terminate string for strchr */
}
}
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