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xserver/Xext/xf86bigfont.c

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/*
* BIGFONT extension for sharing font metrics between clients (if possible)
* and for transmitting font metrics to clients in a compressed form.
*
* Copyright (c) 1999-2000 Bruno Haible
* Copyright (c) 1999-2000 The XFree86 Project, Inc.
*/
/* THIS IS NOT AN X CONSORTIUM STANDARD */
/*
* Big fonts suffer from the following: All clients that have opened a
* font can access the complete glyph metrics array (the XFontStruct member
* `per_char') directly, without going through a macro. Moreover these
* glyph metrics are ink metrics, i.e. are not redundant even for a
* fixed-width font. For a Unicode font, the size of this array is 768 KB.
*
* Problems: 1. It eats a lot of memory in each client. 2. All this glyph
* metrics data is piped through the socket when the font is opened.
*
* This extension addresses these two problems for local clients, by using
* shared memory. It also addresses the second problem for non-local clients,
* by compressing the data before transmit by a factor of nearly 6.
*
* If you use this extension, your OS ought to nicely support shared memory.
* This means: Shared memory should be swappable to the swap, and the limits
* should be high enough (SHMMNI at least 64, SHMMAX at least 768 KB,
* SHMALL at least 48 MB). It is a plus if your OS allows shmat() calls
* on segments that have already been marked "removed", because it permits
* these segments to be cleaned up by the OS if the X server is killed with
* signal SIGKILL.
*
* This extension is transparently exploited by Xlib (functions XQueryFont,
* XLoadQueryFont).
*/
#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif
#include <sys/types.h>
#ifdef HAS_SHM
#if defined(linux) && (!defined(__GNU_LIBRARY__) || __GNU_LIBRARY__ < 2)
/* libc4 does not define __GNU_LIBRARY__, libc5 defines __GNU_LIBRARY__ as 1 */
/* Linux libc4 and libc5 only (because glibc doesn't include kernel headers):
Linux 2.0.x and 2.2.x define SHMLBA as PAGE_SIZE, but forget to define
PAGE_SIZE. It is defined in <asm/page.h>. */
#include <asm/page.h>
#endif
#ifdef SVR4
#include <sys/sysmacros.h>
#endif
#if defined(__CYGWIN__)
#include <sys/param.h>
#include <sys/sysmacros.h>
#endif
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#endif
#include <X11/X.h>
#include <X11/Xproto.h>
#include "misc.h"
#include "os.h"
#include "dixstruct.h"
#include "gcstruct.h"
#include "dixfontstr.h"
#include "extnsionst.h"
#include "extinit.h"
#include "protocol-versions.h"
#include <X11/extensions/xf86bigfproto.h>
#include "xf86bigfontsrv.h"
static void XF86BigfontResetProc(ExtensionEntry * /* extEntry */
);
#ifdef HAS_SHM
/* A random signature, transmitted to the clients so they can verify that the
shared memory segment they are attaching to was really established by the
X server they are talking to. */
static CARD32 signature;
/* Index for additional information stored in a FontRec's devPrivates array. */
static int FontShmdescIndex;
static unsigned int pagesize;
static Bool badSysCall = FALSE;
#if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__CYGWIN__) || defined(__DragonFly__)
#include <sys/signal.h>
static void
SigSysHandler(int signo)
{
badSysCall = TRUE;
}
static Bool
CheckForShmSyscall(void)
{
void (*oldHandler) (int);
int shmid = -1;
/* If no SHM support in the kernel, the bad syscall will generate SIGSYS */
oldHandler = signal(SIGSYS, SigSysHandler);
badSysCall = FALSE;
shmid = shmget(IPC_PRIVATE, 4096, IPC_CREAT);
if (shmid != -1) {
/* Successful allocation - clean up */
shmctl(shmid, IPC_RMID, NULL);
}
else {
/* Allocation failed */
badSysCall = TRUE;
}
signal(SIGSYS, oldHandler);
return !badSysCall;
}
#define MUST_CHECK_FOR_SHM_SYSCALL
#endif
#endif
/* ========== Management of shared memory segments ========== */
#ifdef HAS_SHM
#ifdef __linux__
/* On Linux, shared memory marked as "removed" can still be attached.
Nice feature, because the kernel will automatically free the associated
storage when the server and all clients are gone. */
#define EARLY_REMOVE
#endif
typedef struct _ShmDesc {
struct _ShmDesc *next;
struct _ShmDesc **prev;
int shmid;
char *attach_addr;
} ShmDescRec, *ShmDescPtr;
static ShmDescPtr ShmList = (ShmDescPtr) NULL;
static ShmDescPtr
shmalloc(unsigned int size)
{
ShmDescPtr pDesc;
int shmid;
char *addr;
#ifdef MUST_CHECK_FOR_SHM_SYSCALL
if (pagesize == 0)
return (ShmDescPtr) NULL;
#endif
/* On some older Linux systems, the number of shared memory segments
system-wide is 127. In Linux 2.4, it is 4095.
Therefore there is a tradeoff to be made between allocating a
shared memory segment on one hand, and allocating memory and piping
the glyph metrics on the other hand. If the glyph metrics size is
small, we prefer the traditional way. */
if (size < 3500)
return (ShmDescPtr) NULL;
pDesc = malloc(sizeof(ShmDescRec));
if (!pDesc)
return (ShmDescPtr) NULL;
size = (size + pagesize - 1) & -pagesize;
shmid = shmget(IPC_PRIVATE, size, S_IWUSR | S_IRUSR | S_IRGRP | S_IROTH);
if (shmid == -1) {
ErrorF(XF86BIGFONTNAME " extension: shmget() failed, size = %u, %s\n",
size, strerror(errno));
free(pDesc);
return (ShmDescPtr) NULL;
}
if ((addr = shmat(shmid, 0, 0)) == (char *) -1) {
ErrorF(XF86BIGFONTNAME " extension: shmat() failed, size = %u, %s\n",
size, strerror(errno));
shmctl(shmid, IPC_RMID, (void *) 0);
free(pDesc);
return (ShmDescPtr) NULL;
}
#ifdef EARLY_REMOVE
shmctl(shmid, IPC_RMID, (void *) 0);
#endif
pDesc->shmid = shmid;
pDesc->attach_addr = addr;
if (ShmList)
ShmList->prev = &pDesc->next;
pDesc->next = ShmList;
pDesc->prev = &ShmList;
ShmList = pDesc;
return pDesc;
}
static void
shmdealloc(ShmDescPtr pDesc)
{
#ifndef EARLY_REMOVE
shmctl(pDesc->shmid, IPC_RMID, (void *) 0);
#endif
shmdt(pDesc->attach_addr);
if (pDesc->next)
pDesc->next->prev = pDesc->prev;
*pDesc->prev = pDesc->next;
free(pDesc);
}
#endif
/* Called when a font is closed. */
void
XF86BigfontFreeFontShm(FontPtr pFont)
{
#ifdef HAS_SHM
ShmDescPtr pDesc;
/* If during shutdown of the server, XF86BigfontCleanup() has already
* called shmdealloc() for all segments, we don't need to do it here.
*/
if (!ShmList)
return;
pDesc = (ShmDescPtr) FontGetPrivate(pFont, FontShmdescIndex);
if (pDesc)
shmdealloc(pDesc);
#endif
}
/* Called upon fatal signal. */
void
XF86BigfontCleanup(void)
{
#ifdef HAS_SHM
while (ShmList)
shmdealloc(ShmList);
#endif
}
/* Called when a server generation dies. */
static void
XF86BigfontResetProc(ExtensionEntry * extEntry)
{
/* This function is normally called from CloseDownExtensions(), called
* from main(). It will be followed by a call to FreeAllResources(),
* which will call XF86BigfontFreeFontShm() for each font. Thus it
* appears that we do not need to do anything in this function. --
* But I prefer to write robust code, and not keep shared memory lying
* around when it's not needed any more. (Someone might close down the
* extension without calling FreeAllResources()...)
*/
XF86BigfontCleanup();
}
/* ========== Handling of extension specific requests ========== */
static int
ProcXF86BigfontQueryVersion(ClientPtr client)
{
xXF86BigfontQueryVersionReply reply;
REQUEST_SIZE_MATCH(xXF86BigfontQueryVersionReq);
reply = (xXF86BigfontQueryVersionReply) {
.type = X_Reply,
.sequenceNumber = client->sequence,
.length = 0,
.majorVersion = SERVER_XF86BIGFONT_MAJOR_VERSION,
.minorVersion = SERVER_XF86BIGFONT_MINOR_VERSION,
.uid = geteuid(),
.gid = getegid(),
#ifdef HAS_SHM
.signature = signature,
.capabilities = (client->local && !client->swapped)
? XF86Bigfont_CAP_LocalShm : 0
#else
.signature = 0,
.capabilities = 0
#endif
};
if (client->swapped) {
swaps(&reply.sequenceNumber);
swapl(&reply.length);
swaps(&reply.majorVersion);
swaps(&reply.minorVersion);
swapl(&reply.uid);
swapl(&reply.gid);
swapl(&reply.signature);
}
WriteToClient(client, sizeof(xXF86BigfontQueryVersionReply), &reply);
return Success;
}
static void
swapCharInfo(xCharInfo * pCI)
{
swaps(&pCI->leftSideBearing);
swaps(&pCI->rightSideBearing);
swaps(&pCI->characterWidth);
swaps(&pCI->ascent);
swaps(&pCI->descent);
swaps(&pCI->attributes);
}
/* static CARD32 hashCI (xCharInfo *p); */
#define hashCI(p) \
(CARD32)(((p->leftSideBearing << 27) + (p->leftSideBearing >> 5) + \
(p->rightSideBearing << 23) + (p->rightSideBearing >> 9) + \
(p->characterWidth << 16) + \
(p->ascent << 11) + (p->descent << 6)) ^ p->attributes)
static int
ProcXF86BigfontQueryFont(ClientPtr client)
{
FontPtr pFont;
REQUEST(xXF86BigfontQueryFontReq);
CARD32 stuff_flags;
xCharInfo *pmax;
xCharInfo *pmin;
int nCharInfos;
int shmid;
#ifdef HAS_SHM
ShmDescPtr pDesc = NULL;
#else
#define pDesc 0
#endif
xCharInfo *pCI;
CARD16 *pIndex2UniqIndex;
CARD16 *pUniqIndex2Index;
CARD32 nUniqCharInfos;
#if 0
REQUEST_SIZE_MATCH(xXF86BigfontQueryFontReq);
#else
switch (client->req_len) {
case 2: /* client with version 1.0 libX11 */
stuff_flags = (client->local &&
!client->swapped ? XF86Bigfont_FLAGS_Shm : 0);
break;
case 3: /* client with version 1.1 libX11 */
stuff_flags = stuff->flags;
break;
default:
return BadLength;
}
#endif
if (dixLookupFontable(&pFont, stuff->id, client, DixGetAttrAccess) !=
Success)
return BadFont; /* procotol spec says only error is BadFont */
pmax = FONTINKMAX(pFont);
pmin = FONTINKMIN(pFont);
nCharInfos =
(pmax->rightSideBearing == pmin->rightSideBearing
&& pmax->leftSideBearing == pmin->leftSideBearing
&& pmax->descent == pmin->descent
&& pmax->ascent == pmin->ascent
&& pmax->characterWidth == pmin->characterWidth)
? 0 : N2dChars(pFont);
shmid = -1;
pCI = NULL;
pIndex2UniqIndex = NULL;
pUniqIndex2Index = NULL;
nUniqCharInfos = 0;
if (nCharInfos > 0) {
#ifdef HAS_SHM
if (!badSysCall)
pDesc = (ShmDescPtr) FontGetPrivate(pFont, FontShmdescIndex);
if (pDesc) {
pCI = (xCharInfo *) pDesc->attach_addr;
if (stuff_flags & XF86Bigfont_FLAGS_Shm)
shmid = pDesc->shmid;
}
else {
if (stuff_flags & XF86Bigfont_FLAGS_Shm && !badSysCall)
pDesc = shmalloc(nCharInfos * sizeof(xCharInfo)
+ sizeof(CARD32));
if (pDesc) {
pCI = (xCharInfo *) pDesc->attach_addr;
shmid = pDesc->shmid;
}
else {
#endif
pCI = malloc(nCharInfos * sizeof(xCharInfo));
if (!pCI)
return BadAlloc;
#ifdef HAS_SHM
}
#endif
/* Fill nCharInfos starting at pCI. */
{
xCharInfo *prCI = pCI;
int ninfos = 0;
int ncols = pFont->info.lastCol - pFont->info.firstCol + 1;
int row;
for (row = pFont->info.firstRow;
row <= pFont->info.lastRow && ninfos < nCharInfos; row++) {
unsigned char chars[512];
xCharInfo *tmpCharInfos[256];
unsigned long count;
int col;
unsigned long i;
i = 0;
for (col = pFont->info.firstCol;
col <= pFont->info.lastCol; col++) {
chars[i++] = row;
chars[i++] = col;
}
(*pFont->get_metrics) (pFont, ncols, chars, TwoD16Bit,
&count, tmpCharInfos);
for (i = 0; i < count && ninfos < nCharInfos; i++) {
*prCI++ = *tmpCharInfos[i];
ninfos++;
}
}
}
#ifdef HAS_SHM
if (pDesc && !badSysCall) {
*(CARD32 *) (pCI + nCharInfos) = signature;
if (!FontSetPrivate(pFont, FontShmdescIndex, pDesc)) {
shmdealloc(pDesc);
return BadAlloc;
}
}
}
#endif
if (shmid == -1) {
/* Cannot use shared memory, so remove-duplicates the xCharInfos
using a temporary hash table. */
/* Note that CARD16 is suitable as index type, because
nCharInfos <= 0x10000. */
CARD32 hashModulus;
CARD16 *pHash2UniqIndex;
CARD16 *pUniqIndex2NextUniqIndex;
CARD32 NextIndex;
CARD32 NextUniqIndex;
CARD16 *tmp;
CARD32 i, j;
hashModulus = 67;
if (hashModulus > nCharInfos + 1)
hashModulus = nCharInfos + 1;
tmp = malloc((4 * nCharInfos + 1) * sizeof(CARD16));
if (!tmp) {
if (!pDesc)
free(pCI);
return BadAlloc;
}
pIndex2UniqIndex = tmp;
/* nCharInfos elements */
pUniqIndex2Index = tmp + nCharInfos;
/* max. nCharInfos elements */
pUniqIndex2NextUniqIndex = tmp + 2 * nCharInfos;
/* max. nCharInfos elements */
pHash2UniqIndex = tmp + 3 * nCharInfos;
/* hashModulus (<= nCharInfos+1) elements */
/* Note that we can use 0xffff as end-of-list indicator, because
even if nCharInfos = 0x10000, 0xffff can not occur as valid
entry before the last element has been inserted. And once the
last element has been inserted, we don't need the hash table
any more. */
for (j = 0; j < hashModulus; j++)
pHash2UniqIndex[j] = (CARD16) (-1);
NextUniqIndex = 0;
for (NextIndex = 0; NextIndex < nCharInfos; NextIndex++) {
xCharInfo *p = &pCI[NextIndex];
CARD32 hashCode = hashCI(p) % hashModulus;
for (i = pHash2UniqIndex[hashCode];
i != (CARD16) (-1); i = pUniqIndex2NextUniqIndex[i]) {
j = pUniqIndex2Index[i];
if (pCI[j].leftSideBearing == p->leftSideBearing
&& pCI[j].rightSideBearing == p->rightSideBearing
&& pCI[j].characterWidth == p->characterWidth
&& pCI[j].ascent == p->ascent
&& pCI[j].descent == p->descent
&& pCI[j].attributes == p->attributes)
break;
}
if (i != (CARD16) (-1)) {
/* Found *p at Index j, UniqIndex i */
pIndex2UniqIndex[NextIndex] = i;
}
else {
/* Allocate a new entry in the Uniq table */
if (hashModulus <= 2 * NextUniqIndex
&& hashModulus < nCharInfos + 1) {
/* Time to increate hash table size */
hashModulus = 2 * hashModulus + 1;
if (hashModulus > nCharInfos + 1)
hashModulus = nCharInfos + 1;
for (j = 0; j < hashModulus; j++)
pHash2UniqIndex[j] = (CARD16) (-1);
for (i = 0; i < NextUniqIndex; i++)
pUniqIndex2NextUniqIndex[i] = (CARD16) (-1);
for (i = 0; i < NextUniqIndex; i++) {
j = pUniqIndex2Index[i];
p = &pCI[j];
hashCode = hashCI(p) % hashModulus;
pUniqIndex2NextUniqIndex[i] =
pHash2UniqIndex[hashCode];
pHash2UniqIndex[hashCode] = i;
}
p = &pCI[NextIndex];
hashCode = hashCI(p) % hashModulus;
}
i = NextUniqIndex++;
pUniqIndex2NextUniqIndex[i] = pHash2UniqIndex[hashCode];
pHash2UniqIndex[hashCode] = i;
pUniqIndex2Index[i] = NextIndex;
pIndex2UniqIndex[NextIndex] = i;
}
}
nUniqCharInfos = NextUniqIndex;
/* fprintf(stderr, "font metrics: nCharInfos = %d, nUniqCharInfos = %d, hashModulus = %d\n", nCharInfos, nUniqCharInfos, hashModulus); */
}
}
{
int nfontprops = pFont->info.nprops;
int rlength = sizeof(xXF86BigfontQueryFontReply)
+ nfontprops * sizeof(xFontProp)
+ (nCharInfos > 0 && shmid == -1
? nUniqCharInfos * sizeof(xCharInfo)
+ (nCharInfos + 1) / 2 * 2 * sizeof(CARD16)
: 0);
xXF86BigfontQueryFontReply *reply = calloc(1, rlength);
char *p;
if (!reply) {
if (nCharInfos > 0) {
if (shmid == -1)
free(pIndex2UniqIndex);
if (!pDesc)
free(pCI);
}
return BadAlloc;
}
reply->type = X_Reply;
reply->length = bytes_to_int32(rlength - sizeof(xGenericReply));
reply->sequenceNumber = client->sequence;
reply->minBounds = pFont->info.ink_minbounds;
reply->maxBounds = pFont->info.ink_maxbounds;
reply->minCharOrByte2 = pFont->info.firstCol;
reply->maxCharOrByte2 = pFont->info.lastCol;
reply->defaultChar = pFont->info.defaultCh;
reply->nFontProps = pFont->info.nprops;
reply->drawDirection = pFont->info.drawDirection;
reply->minByte1 = pFont->info.firstRow;
reply->maxByte1 = pFont->info.lastRow;
reply->allCharsExist = pFont->info.allExist;
reply->fontAscent = pFont->info.fontAscent;
reply->fontDescent = pFont->info.fontDescent;
reply->nCharInfos = nCharInfos;
reply->nUniqCharInfos = nUniqCharInfos;
reply->shmid = shmid;
reply->shmsegoffset = 0;
if (client->swapped) {
swaps(&reply->sequenceNumber);
swapl(&reply->length);
swapCharInfo(&reply->minBounds);
swapCharInfo(&reply->maxBounds);
swaps(&reply->minCharOrByte2);
swaps(&reply->maxCharOrByte2);
swaps(&reply->defaultChar);
swaps(&reply->nFontProps);
swaps(&reply->fontAscent);
swaps(&reply->fontDescent);
swapl(&reply->nCharInfos);
swapl(&reply->nUniqCharInfos);
swapl(&reply->shmid);
swapl(&reply->shmsegoffset);
}
p = (char *) &reply[1];
{
FontPropPtr pFP;
xFontProp *prFP;
int i;
for (i = 0, pFP = pFont->info.props, prFP = (xFontProp *) p;
i < nfontprops; i++, pFP++, prFP++) {
prFP->name = pFP->name;
prFP->value = pFP->value;
if (client->swapped) {
swapl(&prFP->name);
swapl(&prFP->value);
}
}
p = (char *) prFP;
}
if (nCharInfos > 0 && shmid == -1) {
xCharInfo *pci;
CARD16 *ps;
int i, j;
pci = (xCharInfo *) p;
for (i = 0; i < nUniqCharInfos; i++, pci++) {
*pci = pCI[pUniqIndex2Index[i]];
if (client->swapped)
swapCharInfo(pci);
}
ps = (CARD16 *) pci;
for (j = 0; j < nCharInfos; j++, ps++) {
*ps = pIndex2UniqIndex[j];
if (client->swapped) {
swaps(ps);
}
}
}
WriteToClient(client, rlength, reply);
free(reply);
if (nCharInfos > 0) {
if (shmid == -1)
free(pIndex2UniqIndex);
if (!pDesc)
free(pCI);
}
return Success;
}
}
static int
ProcXF86BigfontDispatch(ClientPtr client)
{
REQUEST(xReq);
switch (stuff->data) {
case X_XF86BigfontQueryVersion:
return ProcXF86BigfontQueryVersion(client);
case X_XF86BigfontQueryFont:
return ProcXF86BigfontQueryFont(client);
default:
return BadRequest;
}
}
static int
SProcXF86BigfontQueryVersion(ClientPtr client)
{
REQUEST(xXF86BigfontQueryVersionReq);
swaps(&stuff->length);
return ProcXF86BigfontQueryVersion(client);
}
static int
SProcXF86BigfontQueryFont(ClientPtr client)
{
REQUEST(xXF86BigfontQueryFontReq);
swaps(&stuff->length);
REQUEST_SIZE_MATCH(xXF86BigfontQueryFontReq);
swapl(&stuff->id);
return ProcXF86BigfontQueryFont(client);
}
static int
SProcXF86BigfontDispatch(ClientPtr client)
{
REQUEST(xReq);
switch (stuff->data) {
case X_XF86BigfontQueryVersion:
return SProcXF86BigfontQueryVersion(client);
case X_XF86BigfontQueryFont:
return SProcXF86BigfontQueryFont(client);
default:
return BadRequest;
}
}
void
XFree86BigfontExtensionInit(void)
{
if (AddExtension(XF86BIGFONTNAME,
XF86BigfontNumberEvents,
XF86BigfontNumberErrors,
ProcXF86BigfontDispatch,
SProcXF86BigfontDispatch,
XF86BigfontResetProc, StandardMinorOpcode)) {
#ifdef HAS_SHM
#ifdef MUST_CHECK_FOR_SHM_SYSCALL
/*
* Note: Local-clients will not be optimized without shared memory
* support. Remote-client optimization does not depend on shared
* memory support. Thus, the extension is still registered even
* when shared memory support is not functional.
*/
if (!CheckForShmSyscall()) {
ErrorF(XF86BIGFONTNAME
" extension local-client optimization disabled due to lack of shared memory support in the kernel\n");
return;
}
#endif
srand((unsigned int) time(NULL));
signature = ((unsigned int) (65536.0 / (RAND_MAX + 1.0) * rand()) << 16)
+ (unsigned int) (65536.0 / (RAND_MAX + 1.0) * rand());
/* fprintf(stderr, "signature = 0x%08X\n", signature); */
FontShmdescIndex = AllocateFontPrivateIndex();
#if !defined(CSRG_BASED) && !defined(__CYGWIN__)
pagesize = SHMLBA;
#else
#ifdef _SC_PAGESIZE
pagesize = sysconf(_SC_PAGESIZE);
#else
pagesize = getpagesize();
#endif
#endif
#endif
}
}
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