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Simplify swapInDisks function

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After introducing shared_ptr, previous implementation of this function
confused Clang static analyzer into reporting a false-positive "use
after free".

Also, do small cleanup in lines touching diskSwap array.
This commit is contained in:
Patryk Obara 2019-12-18 17:00:54 +01:00 • committed by Patryk Obara
parent 5f282f6015
commit 8f81eb199a
1 changed files with 41 additions and 43 deletions
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84
src/ints/bios_disk.cpp
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@ -16,19 +16,20 @@
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "bios_disk.h"
#include <algorithm>
#include <cassert>
#include <utility>
#include "dosbox.h"
#include "callback.h"
#include "bios.h"
#include "bios_disk.h"
#include "regs.h"
#include "mem.h"
#include "dos_inc.h" /* for Drives[] */
#include "../dos/drives.h"
#include "mapper.h"
diskGeo DiskGeometryList[] = {
{ 160, 8, 1, 40, 0},
{ 180, 9, 1, 40, 0},
@ -99,34 +100,33 @@ void incrementFDD(void) {
CMOS_SetRegister(0x14, (Bit8u)(equipment&0xff));
}
void swapInDisks(void) {
bool allNull = true;
Bit32s diskcount = 0;
Bit32s swapPos = swapPosition;
Bit32s i;
/* Check to make sure that there is at least one setup image */
for(i=0;i<MAX_SWAPPABLE_DISKS;i++) {
if(diskSwap[i]) {
allNull = false;
template<typename T, size_t N>
static size_t disk_array_prefix_size(const std::array<T, N> &images) {
size_t num = 0;
for (const auto &disk : images) {
if (!disk)
break;
}
num++;
}
return num;
}
/* No disks setup... fail */
if (allNull) return;
void swapInDisks(void) {
const size_t boot_disks_num = disk_array_prefix_size(diskSwap);
if (boot_disks_num == 0)
return;
/* If only one disk is loaded, this loop will load the same disk in dive A and drive B */
while(diskcount<2) {
if(diskSwap[swapPos]) {
LOG_MSG("Loaded disk %d from swaplist position %d - \"%s\"", diskcount, swapPos, diskSwap[swapPos]->diskname);
imageDiskList[diskcount] = diskSwap[swapPos];
diskcount++;
}
swapPos++;
if(swapPos >= MAX_SWAPPABLE_DISKS)
swapPos=0;
}
assert(swapPosition < boot_disks_num);
const unsigned int pos_1 = swapPosition;
const unsigned int pos_2 = (swapPosition + 1) % boot_disks_num;
imageDiskList[0] = diskSwap[pos_1];
LOG_MSG("Loaded disk A from swaplist position %u - \"%s\"",
pos_1, diskSwap[pos_1]->diskname);
imageDiskList[1] = diskSwap[pos_2];
LOG_MSG("Loaded disk B from swaplist position %u - \"%s\"",
pos_2, diskSwap[pos_2]->diskname);
}
bool getSwapRequest(void) {
@ -304,18 +304,20 @@ static bool driveInactive(Bit8u driveNum) {
return false;
}
template<typename T, size_t N>
static bool has_image(const std::array<T, N> &arr) {
auto to_bool = [](const T &x) { return bool(x); };
return std::any_of(std::begin(arr), std::end(arr), to_bool);
}
static Bitu INT13_DiskHandler(void) {
Bit16u segat, bufptr;
Bit8u sectbuf[512];
Bit8u drivenum;
Bitu i,t;
Bitu t;
last_drive = reg_dl;
drivenum = GetDosDriveNumber(reg_dl);
bool any_images = false;
for(i = 0;i < MAX_DISK_IMAGES;i++) {
if(imageDiskList[i]) any_images=true;
}
const bool any_images = has_image(imageDiskList);
// unconditionally enable the interrupt flag
CALLBACK_SIF(true);
@ -391,7 +393,7 @@ static Bitu INT13_DiskHandler(void) {
segat = SegValue(es);
bufptr = reg_bx;
for(i=0;i<reg_al;i++) {
for (Bitu i = 0; i < reg_al; i++) {
last_status = imageDiskList[drivenum]->Read_Sector((Bit32u)reg_dh, (Bit32u)(reg_ch | ((reg_cl & 0xc0)<< 2)), (Bit32u)((reg_cl & 63)+i), sectbuf);
if((last_status != 0x00) || (killRead)) {
LOG_MSG("Error in disk read");
@ -409,30 +411,26 @@ static Bitu INT13_DiskHandler(void) {
CALLBACK_SCF(false);
break;
case 0x3: /* Write sectors */
if(driveInactive(drivenum)) {
reg_ah = 0xff;
CALLBACK_SCF(true);
return CBRET_NONE;
}
}
bufptr = reg_bx;
for(i=0;i<reg_al;i++) {
for (Bitu i = 0; i < reg_al; i++) {
for(t=0;t<imageDiskList[drivenum]->getSectSize();t++) {
sectbuf[t] = real_readb(SegValue(es),bufptr);
bufptr++;
}
last_status = imageDiskList[drivenum]->Write_Sector((Bit32u)reg_dh, (Bit32u)(reg_ch | ((reg_cl & 0xc0) << 2)), (Bit32u)((reg_cl & 63) + i), &sectbuf[0]);
if(last_status != 0x00) {
CALLBACK_SCF(true);
CALLBACK_SCF(true);
return CBRET_NONE;
}
}
}
reg_ah = 0x00;
CALLBACK_SCF(false);
break;
break;
case 0x04: /* Verify sectors */
if (reg_al==0) {
reg_ah = 0x01;