[Dosemu-cvs] dosemu/src/dosext/dpmi msdos.c,1.18,1.19
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[Dosemu-cvs] dosemu/src/dosext/dpmi msdos.c,1.18,1.19
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From: Stas S. <st...@us...> - 2004-05-29 14:31:21
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Update of /cvsroot/dosemu/dosemu/src/dosext/dpmi In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv8967 Modified Files: msdos.c Log Message: - Rewrote old_dos_terminate() as per suggestions in bug #909015 - Disable fix-NULL-deref code as per suggestion in RFE #937984 Index: msdos.c =================================================================== RCS file: /cvsroot/dosemu/dosemu/src/dosext/dpmi/msdos.c,v retrieving revision 1.18 retrieving revision 1.19 diff -u -d -r1.18 -r1.19 --- msdos.c 2 Apr 2004 21:45:29 -0000 1.18 +++ msdos.c 29 May 2004 14:31:11 -0000 1.19 @@ -83,68 +83,9 @@ DPMI_CLIENT.ems_frame_mapped = 0; } -static int old_dos_terminate(struct sigcontext_struct *scp) -{ - REG(cs) = DPMI_CLIENT.CURRENT_PSP; - REG(eip) = 0x100; - if (in_win31) { - int i; - unsigned short parent_seg; - unsigned short parent_off; -#if 0 - /* is seems that winos2 uses a PSP that not allocate via dos, */ - /* so we can\'t let dos to free it. just restore some DOS int */ - /* vectors and return. */ - - /* restore terminate address address */ - ((unsigned long *)0)[0x22] = - *(unsigned long *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa); - /* restore Ctrl-Break address */ - ((unsigned long *)0)[0x23] = - *(unsigned long *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xe); - /* restore critical error address */ - ((unsigned long *)0)[0x24] = - *(unsigned long *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0x12); -#endif - /*DTA_over_1MB = 0;*/ - parent_off = *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa); - parent_seg = *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa+2); -#if 0 - return 1; -#else - -#if 1 - /* find the code selector */ - for (i=0; i < MAX_SELECTORS; i++) - if (Segments[i].used && - (Segments[i].type & MODIFY_LDT_CONTENTS_CODE) && - (Segments[i].base_addr == (unsigned long)(parent_seg << 4)) && - (Segments[i].limit > parent_off)) - break; - if (i>=MAX_SELECTORS) { - error("DPMI: WARNING !!! invalid terminate address found in PSP\n"); - return 1; - } else - _cs = (i << 3)|7; - _eip = parent_off; -#endif - /* set parent\'s PSP to itself, so dos won\'t free memory */ - /* I believe winkernel puts the selector of parent psp there */ - *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0x16) = DPMI_CLIENT.CURRENT_PSP; - - /* put our return address there */ - *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa) = - DPMI_OFF + HLT_OFF(DPMI_return_from_dosint) + 0x21; - *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa+2) = DPMI_SEG; - return 0; -#endif - } - return 0; -} - /* DOS selector is a selector whose base address is less than 0xffff0 */ /* and para. aligned. */ -static int inline in_dos_space(unsigned short sel, unsigned long off) +static int in_dos_space(unsigned short sel, unsigned long off) { unsigned long base = Segments[sel >> 3].base_addr; @@ -159,6 +100,56 @@ return 1; } +static void old_dos_terminate(struct sigcontext_struct *scp, int i) +{ + unsigned short psp_seg_sel; + unsigned char *ptr; + + D_printf("DPMI: old_dos_terminate, int=%#x\n", i); + + REG(cs) = DPMI_CLIENT.CURRENT_PSP; + REG(eip) = 0x100; + +#if 0 + _eip = *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa); + _cs = ConvertSegmentToCodeDescriptor( + *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa+2)); +#endif + + /* put our return address there */ + *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa) = + DPMI_OFF + HLT_OFF(DPMI_return_from_dosint) + i; + *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa+2) = DPMI_SEG; + + psp_seg_sel = *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0x16); + ptr = (char *)SEG2LINEAR(psp_seg_sel); + if (ptr[0] != 0xCD || ptr[1] != 0x20) { + unsigned short psp_seg = DPMI_CLIENT.CURRENT_PSP; + D_printf("DPMI: Trying PSP sel=%#x, V=%i, d=%i, l=%#lx\n", + psp_seg_sel, ValidAndUsedSelector(psp_seg_sel), + in_dos_space(psp_seg_sel, 0), GetSegmentLimit(psp_seg_sel)); + if (ValidAndUsedSelector(psp_seg_sel) && in_dos_space(psp_seg_sel, 0) && + GetSegmentLimit(psp_seg_sel) >= 0xff) { + ptr = (char *)GetSegmentBaseAddress(psp_seg_sel); + D_printf("DPMI: Trying PSP sel=%#x, addr=%p\n", psp_seg_sel, ptr); + if ((!(((int)ptr) & 0x0f)) && ptr[0] == 0xCD && ptr[1] == 0x20) { + psp_seg = ((int)ptr) >> 4; + D_printf("DPMI: parent PSP sel=%#x, seg=%#x\n", + psp_seg_sel, psp_seg); + } + } else { + D_printf("DPMI: using current PSP as parent!\n"); + } + *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0x16) = psp_seg; + } else { + D_printf("DPMI: parent PSP seg=%#x\n", psp_seg_sel); + } + + /* And update our PSP pointer */ + DPMI_CLIENT.CURRENT_PSP = + *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0x16); +} + /* * DANG_BEGIN_FUNCTION msdos_pre_extender * @@ -253,7 +244,8 @@ INT15_SAVED_REGS = *scp; return 0; case 0x20: /* DOS terminate */ - return old_dos_terminate(scp); + old_dos_terminate(scp, intr); + return 0; case 0x21: if (in_dos_21) dbug_printf("DPMI: int21 AX=%#04x called recursively " @@ -347,7 +339,9 @@ in_dos_21++; return 0; case 0x00: /* DOS terminate */ - return old_dos_terminate(scp); + old_dos_terminate(scp, intr); + in_dos_21++; + return 0; case 0x09: /* Print String */ { int i; @@ -872,13 +866,6 @@ case 0x21: in_dos_21--; switch (S_HI(ax)) { - case 0x00: - in_dos_21++; - /* restore terminate address */ - *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa) = S_LWORD(eip); - *(unsigned short *)((char *)(DPMI_CLIENT.CURRENT_PSP<<4) + 0xa+2) = - GetSegmentBaseAddress(S_REG(cs))>>4; - break; case 0x09: /* print String */ case 0x1a: /* set DTA */ DPMI_CLIENT.stack_frame.edx = S_REG(edx); @@ -1585,8 +1572,9 @@ unsigned long len; D_printf("DPMI: msdos_fault, err=%#lx\n",_err); - if ((_err & 0xffff) == 0) { /* not a selector error */ + /* Why should we "fix" the NULL dereferences? */ +#if 0 char fixed = 0; unsigned char * csp; @@ -1663,6 +1651,9 @@ break; } return fixed; +#else + return 0; +#endif } /* now it is a invalid selector error, try to fix it if it is */ |