/* Copyright 1987, 1998 The Open Group Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Except as contained in this notice, the name of The Open Group shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from The Open Group. Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts, Copyright 1994 Quarterdeck Office Systems. All Rights Reserved Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the names of Digital and Quarterdeck not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. DIGITAL AND QUARTERDECK DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #ifdef HAVE_DIX_CONFIG_H #include #endif #ifdef __CYGWIN__ #include #include /* Sigh... We really need a prototype for this to know it is stdcall, but #include-ing here is not a good idea... */ __stdcall unsigned long GetTickCount(void); #endif #if defined(WIN32) && !defined(__CYGWIN__) #include #endif #include #include #include #if !defined(WIN32) || !defined(__MINGW32__) #include #include #endif #include "misc.h" #include #define XSERV_t #define TRANS_SERVER #define TRANS_REOPEN #include #include "input.h" #include "dixfont.h" #include "osdep.h" #include "extension.h" #ifdef X_POSIX_C_SOURCE #define _POSIX_C_SOURCE X_POSIX_C_SOURCE #include #undef _POSIX_C_SOURCE #else #if defined(_POSIX_SOURCE) #include #else #define _POSIX_SOURCE #include #undef _POSIX_SOURCE #endif #endif #ifndef WIN32 #include #endif #if !defined(SYSV) && !defined(WIN32) #include #endif #include #include /* for isspace */ #include #include /* for malloc() */ #if defined(TCPCONN) || defined(STREAMSCONN) #ifndef WIN32 #include #endif #endif #include "opaque.h" #include "dixstruct.h" #include "xkbsrv.h" #include "picture.h" Bool noTestExtensions; #ifdef COMPOSITE Bool noCompositeExtension = FALSE; #endif #ifdef DAMAGE Bool noDamageExtension = FALSE; #endif #ifdef DBE Bool noDbeExtension = FALSE; #endif #ifdef DPMSExtension Bool noDPMSExtension = FALSE; #endif #ifdef GLXEXT Bool noGlxExtension = FALSE; #endif #ifdef SCREENSAVER Bool noScreenSaverExtension = FALSE; #endif #ifdef MITSHM Bool noMITShmExtension = FALSE; #endif #ifdef RANDR Bool noRRExtension = FALSE; #endif Bool noRenderExtension = FALSE; #ifdef XCSECURITY Bool noSecurityExtension = FALSE; #endif #ifdef RES Bool noResExtension = FALSE; #endif #ifdef XF86BIGFONT Bool noXFree86BigfontExtension = FALSE; #endif #ifdef XFreeXDGA Bool noXFree86DGAExtension = FALSE; #endif #ifdef XF86DRI Bool noXFree86DRIExtension = FALSE; #endif #ifdef XF86VIDMODE Bool noXFree86VidModeExtension = FALSE; #endif #ifdef XFIXES Bool noXFixesExtension = FALSE; #endif #ifdef PANORAMIX /* Xinerama is disabled by default unless enabled via +xinerama */ Bool noPanoramiXExtension = TRUE; #endif #ifdef XSELINUX Bool noSELinuxExtension = FALSE; int selinuxEnforcingState = SELINUX_MODE_DEFAULT; #endif #ifdef XV Bool noXvExtension = FALSE; #endif #ifdef DRI2 Bool noDRI2Extension = FALSE; #endif Bool noGEExtension = FALSE; #define X_INCLUDE_NETDB_H #include #include Bool CoreDump; #ifdef PANORAMIX Bool PanoramiXExtensionDisabledHack = FALSE; #endif int auditTrailLevel = 1; char *SeatId = NULL; sig_atomic_t inSignalContext = FALSE; #ifdef _MSC_VER static HANDLE s_hSmartScheduleTimer = NULL; static HANDLE s_hSmartScheduleTimerQueue = NULL; #endif #if defined(SVR4) || defined(__linux__) || defined(CSRG_BASED) #define HAS_SAVED_IDS_AND_SETEUID #endif OsSigHandlerPtr OsSignal(int sig, OsSigHandlerPtr handler) { #ifdef X_NOT_POSIX return signal(sig, handler); #else struct sigaction act, oact; sigemptyset(&act.sa_mask); if (handler != SIG_IGN) sigaddset(&act.sa_mask, sig); act.sa_flags = 0; act.sa_handler = handler; if (sigaction(sig, &act, &oact)) perror("sigaction"); return oact.sa_handler; #endif } /* * Explicit support for a server lock file like the ones used for UUCP. * For architectures with virtual terminals that can run more than one * server at a time. This keeps the servers from stomping on each other * if the user forgets to give them different display numbers. */ #define LOCK_DIR "/tmp" #define LOCK_TMP_PREFIX "/.tX" #define LOCK_PREFIX "/.X" #define LOCK_SUFFIX "-lock" #ifdef _MSC_VER #define LockFile szLockFile #endif static Bool StillLocking = FALSE; static char LockFile[PATH_MAX]; static Bool nolock = FALSE; /* * LockServer -- * Check if the server lock file exists. If so, check if the PID * contained inside is valid. If so, then die. Otherwise, create * the lock file containing the PID. */ void LockServer(void) { #if defined(WIN32) && !defined(__CYGWIN__) char MutexName[100]; sprintf(MutexName, "Global\\VcXsrv_Mutex_%d\n", getpid()); if (!CreateMutex(NULL,TRUE,MutexName) || GetLastError()== ERROR_ALREADY_EXISTS) { FatalError("Server is already active for display %d\n", atoi(display)); } #else char tmp[PATH_MAX], pid_str[12]; int lfd, i, haslock, l_pid, t; const char *tmppath = LOCK_DIR; int len; char port[20]; if (nolock) return; /* * Path names */ snprintf(port, sizeof(port), "%d", atoi(display)); len = strlen(LOCK_PREFIX) > strlen(LOCK_TMP_PREFIX) ? strlen(LOCK_PREFIX) : strlen(LOCK_TMP_PREFIX); len += strlen(tmppath) + strlen(port) + strlen(LOCK_SUFFIX) + 1; if (len > sizeof(LockFile)) FatalError("Display name `%s' is too long\n", port); (void) sprintf(tmp, "%s" LOCK_TMP_PREFIX "%s" LOCK_SUFFIX, tmppath, port); (void) sprintf(LockFile, "%s" LOCK_PREFIX "%s" LOCK_SUFFIX, tmppath, port); /* * Create a temporary file containing our PID. Attempt three times * to create the file. */ StillLocking = TRUE; i = 0; do { i++; lfd = open(tmp, O_CREAT | O_EXCL | O_WRONLY, 0644); if (lfd < 0) sleep(2); else break; } while (i < 3); if (lfd < 0) { unlink(tmp); i = 0; do { i++; lfd = open(tmp, O_CREAT | O_EXCL | O_WRONLY, 0644); if (lfd < 0) sleep(2); else break; } while (i < 3); } if (lfd < 0) FatalError("Could not create lock file in %s\n", tmp); snprintf(pid_str, sizeof(pid_str), "%10ld\n", (long) getpid()); (void) write(lfd, pid_str, 11); (void) fchmod(lfd, 0444); (void) close(lfd); /* * OK. Now the tmp file exists. Try three times to move it in place * for the lock. */ i = 0; haslock = 0; while ((!haslock) && (i++ < 3)) { haslock = (link(tmp, LockFile) == 0); if (haslock) { /* * We're done. */ break; } else { /* * Read the pid from the existing file */ lfd = open(LockFile, O_RDONLY | O_NOFOLLOW); if (lfd < 0) { unlink(tmp); FatalError("Can't read lock file %s\n", LockFile); } pid_str[0] = '\0'; if (read(lfd, pid_str, 11) != 11) { /* * Bogus lock file. */ unlink(LockFile); close(lfd); continue; } pid_str[11] = '\0'; sscanf(pid_str, "%d", &l_pid); close(lfd); /* * Now try to kill the PID to see if it exists. */ errno = 0; t = kill(l_pid, 0); if ((t < 0) && (errno == ESRCH)) { /* * Stale lock file. */ unlink(LockFile); continue; } else if (((t < 0) && (errno == EPERM)) || (t == 0)) { /* * Process is still active. */ unlink(tmp); FatalError ("Server is already active for display %s\n%s %s\n%s\n", port, "\tIf this server is no longer running, remove", LockFile, "\tand start again."); } } } unlink(tmp); if (!haslock) FatalError("Could not create server lock file: %s\n", LockFile); StillLocking = FALSE; #endif } /* * UnlockServer -- * Remove the server lock file. */ void UnlockServer(void) { if (nolock) return; if (!StillLocking) { (void) unlink(LockFile); } } /* Force connections to close on SIGHUP from init */ void AutoResetServer(int sig) { int olderrno = errno; dispatchException |= DE_RESET; isItTimeToYield = TRUE; errno = olderrno; } /* Force connections to close and then exit on SIGTERM, SIGINT */ void GiveUp(int sig) { int olderrno = errno; dispatchException |= DE_TERMINATE; isItTimeToYield = TRUE; errno = olderrno; } #if (defined WIN32 && defined __MINGW32__) || defined(__CYGWIN__) CARD32 GetTimeInMillis(void) { return GetTickCount(); } #else CARD32 GetTimeInMillis(void) { struct timeval tv; #ifdef MONOTONIC_CLOCK struct timespec tp; static clockid_t clockid; if (!clockid) { #ifdef CLOCK_MONOTONIC_COARSE if (clock_getres(CLOCK_MONOTONIC_COARSE, &tp) == 0 && (tp.tv_nsec / 1000) <= 1000 && clock_gettime(CLOCK_MONOTONIC_COARSE, &tp) == 0) clockid = CLOCK_MONOTONIC_COARSE; else #endif if (clock_gettime(CLOCK_MONOTONIC, &tp) == 0) clockid = CLOCK_MONOTONIC; else clockid = ~0L; } if (clockid != ~0L && clock_gettime(clockid, &tp) == 0) return (tp.tv_sec * 1000) + (tp.tv_nsec / 1000000L); #endif X_GETTIMEOFDAY(&tv); return (tv.tv_sec * 1000) + (tv.tv_usec / 1000); } #endif void AdjustWaitForDelay(pointer waitTime, unsigned long newdelay) { static struct timeval delay_val; struct timeval **wt = (struct timeval **) waitTime; unsigned long olddelay; if (*wt == NULL) { delay_val.tv_sec = newdelay / 1000; delay_val.tv_usec = 1000 * (newdelay % 1000); *wt = &delay_val; } else { olddelay = (*wt)->tv_sec * 1000 + (*wt)->tv_usec / 1000; if (newdelay < olddelay) { (*wt)->tv_sec = newdelay / 1000; (*wt)->tv_usec = 1000 * (newdelay % 1000); } } } void UseMsg(void) { ErrorF("Usage...\nVcxsrv [:] [option]\n\n"); ErrorF(":display-number\n\tVcxsrv runs as the given display-number, which defaults to 0.\n"); ErrorF("\tTo run multiple instances, use unique display-numbers.\n\n"); ErrorF("-a # default pointer acceleration (factor)\n"); ErrorF("-ac disable access control restrictions\n"); ErrorF("-audit int set audit trail level\n"); ErrorF("-auth file select authorization file\n"); ErrorF("-br create root window with black background\n"); ErrorF("+bs enable any backing store support\n"); ErrorF("-bs disable any backing store support\n"); ErrorF("-cc int default color visual class\n"); ErrorF("-nocursor disable the cursor\n"); ErrorF("-core generate core dump on fatal error\n"); #ifdef _MSC_VER ErrorF("-dpi [auto|int] screen resolution set to native or this dpi\n"); #else ErrorF("-dpi int screen resolution in dots per inch\n"); #endif #ifdef DPMSExtension ErrorF("-dpms disables VESA DPMS monitor control\n"); #endif ErrorF ("-deferglyphs [none|all|16] defer loading of [no|all|16-bit] glyphs\n"); ErrorF("-f # bell base (0-100)\n"); ErrorF("-fc string cursor font\n"); ErrorF("-fn string default font name\n"); ErrorF("-fp string default font path\n"); ErrorF("-help prints message with these options\n"); ErrorF("-I ignore all remaining arguments\n"); #ifdef RLIMIT_DATA ErrorF("-ld int limit data space to N Kb\n"); #endif #ifdef RLIMIT_NOFILE ErrorF("-lf int limit number of open files to N\n"); #endif #ifdef RLIMIT_STACK ErrorF("-ls int limit stack space to N Kb\n"); #endif ErrorF("-nolock disable the locking mechanism\n"); ErrorF("-nolisten string don't listen on protocol\n"); ErrorF("-noreset don't reset after last client exists\n"); ErrorF("-background [none] create root window with no background\n"); ErrorF("-reset reset after last client exists\n"); ErrorF("-pn accept failure to listen on all ports\n"); ErrorF("-nopn reject failure to listen on all ports\n"); ErrorF("-r turns off auto-repeat\n"); ErrorF("r turns on auto-repeat \n"); ErrorF("-render [default|mono|gray|color] set render color alloc policy\n"); ErrorF("-retro start with classic stipple\n"); ErrorF("-seat string seat to run on\n"); ErrorF("-t # default pointer threshold (pixels/t)\n"); ErrorF("-terminate terminate at server reset\n"); ErrorF("-to # connection time out\n"); ErrorF("-tst disable testing extensions\n"); ErrorF("-wm WhenMapped default backing-store\n"); ErrorF("-wr create root window with white background\n"); #ifdef PANORAMIX ErrorF("+xinerama Enable XINERAMA extension\n"); ErrorF("-xinerama Disable XINERAMA extension\n"); #endif ErrorF ("-dumbSched Disable smart scheduling, enable old behavior\n"); ErrorF("-schedInterval int Set scheduler interval in msec\n"); ErrorF("+extension name Enable extension\n"); ErrorF("-extension name Disable extension\n"); #ifdef XDMCP XdmcpUseMsg(); #endif XkbUseMsg(); ddxUseMsg(); } /* This function performs a rudimentary sanity check * on the display name passed in on the command-line, * since this string is used to generate filenames. * It is especially important that the display name * not contain a "/" and not start with a "-". * --kvajk */ static int VerifyDisplayName(const char *d) { if (d == (char *) 0) return 0; /* null */ if (*d == '\0') return 0; /* empty */ if (*d == '-') return 0; /* could be confused for an option */ if (*d == '.') return 0; /* must not equal "." or ".." */ if (strchr(d, '/') != (char *) 0) return 0; /* very important!!! */ return 1; } /* * This function parses the command line. Handles device-independent fields * and allows ddx to handle additional fields. It is not allowed to modify * argc or any of the strings pointed to by argv. */ void ProcessCommandLine(int argc, char *argv[]) { int i, skip; defaultKeyboardControl.autoRepeat = TRUE; #ifdef NO_PART_NET PartialNetwork = FALSE; #else PartialNetwork = TRUE; #endif for (i = 1; i < argc; i++) { /* call ddx first, so it can peek/override if it wants */ if ((skip = ddxProcessArgument(argc, argv, i))) { i += (skip - 1); } else if (argv[i][0] == ':') { /* initialize display */ display = argv[i]; display++; if (!VerifyDisplayName(display)) { ErrorF("Bad display name: %s\n", display); UseMsg(); FatalError("Bad display name, exiting: %s\n", display); } } else if (strcmp(argv[i], "-a") == 0) { if (++i < argc) defaultPointerControl.num = atoi(argv[i]); else UseMsg(); } else if (strcmp(argv[i], "-ac") == 0) { defeatAccessControl = TRUE; } else if (strcmp(argv[i], "-audit") == 0) { if (++i < argc) auditTrailLevel = atoi(argv[i]); else UseMsg(); } else if (strcmp(argv[i], "-auth") == 0) { if (++i < argc) InitAuthorization(argv[i]); else UseMsg(); } else if (strcmp(argv[i], "-br") == 0); /* default */ else if (strcmp(argv[i], "+bs") == 0) enableBackingStore = TRUE; else if (strcmp(argv[i], "-bs") == 0) disableBackingStore = TRUE; else if (strcmp(argv[i], "-cc") == 0) { if (++i < argc) defaultColorVisualClass = atoi(argv[i]); else UseMsg(); } else if (strcmp(argv[i], "-core") == 0) { #if !defined(WIN32) || !defined(__MINGW32__) struct rlimit core_limit; getrlimit(RLIMIT_CORE, &core_limit); core_limit.rlim_cur = core_limit.rlim_max; setrlimit(RLIMIT_CORE, &core_limit); #endif CoreDump = TRUE; } else if (strcmp(argv[i], "-nocursor") == 0) { EnableCursor = FALSE; } else if (strcmp(argv[i], "-dpi") == 0) { if (++i < argc) #ifdef _MSC_VER { if (strcmp(argv[i], "auto") == 0) { HDC hdc = GetDC(NULL); if (hdc) { int dpiY = GetDeviceCaps(hdc, LOGPIXELSY); monitorResolution = dpiY; ReleaseDC(NULL, hdc); } } else if (isdigit(*argv[i])) /* Naively prevent a crash if not numeric */ monitorResolution = atoi(argv[i]); } #else monitorResolution = atoi(argv[i]); #endif else UseMsg(); } else if (strcmp(argv[i], "-displayfd") == 0) { if (++i < argc) { displayfd = atoi(argv[i]); display = NULL; nolock = TRUE; } else UseMsg(); } #ifdef DPMSExtension else if (strcmp(argv[i], "dpms") == 0) /* ignored for compatibility */ ; else if (strcmp(argv[i], "-dpms") == 0) DPMSDisabledSwitch = TRUE; #endif else if (strcmp(argv[i], "-deferglyphs") == 0) { if (++i >= argc || !ParseGlyphCachingMode(argv[i])) UseMsg(); } else if (strcmp(argv[i], "-f") == 0) { if (++i < argc) defaultKeyboardControl.bell = atoi(argv[i]); else UseMsg(); } else if (strcmp(argv[i], "-fc") == 0) { if (++i < argc) defaultCursorFont = argv[i]; else UseMsg(); } else if (strcmp(argv[i], "-fn") == 0) { if (++i < argc) defaultTextFont = argv[i]; else UseMsg(); } else if (strcmp(argv[i], "-fp") == 0) { if (++i < argc) { defaultFontPath = argv[i]; } else UseMsg(); } else if (strcmp(argv[i], "-help") == 0) { UseMsg(); exit(0); } else if ((skip = XkbProcessArguments(argc, argv, i)) != 0) { if (skip > 0) i += skip - 1; else UseMsg(); } #ifdef RLIMIT_DATA else if (strcmp(argv[i], "-ld") == 0) { if (++i < argc) { limitDataSpace = atoi(argv[i]); if (limitDataSpace > 0) limitDataSpace *= 1024; } else UseMsg(); } #endif #ifdef RLIMIT_NOFILE else if (strcmp(argv[i], "-lf") == 0) { if (++i < argc) limitNoFile = atoi(argv[i]); else UseMsg(); } #endif #ifdef RLIMIT_STACK else if (strcmp(argv[i], "-ls") == 0) { if (++i < argc) { limitStackSpace = atoi(argv[i]); if (limitStackSpace > 0) limitStackSpace *= 1024; } else UseMsg(); } #endif else if (strcmp(argv[i], "-nolock") == 0) { #if !defined(WIN32) && !defined(__CYGWIN__) if (getuid() != 0) ErrorF ("Warning: the -nolock option can only be used by root\n"); else #endif nolock = TRUE; } else if (strcmp(argv[i], "-nolisten") == 0) { if (++i < argc) { if (_XSERVTransNoListen(argv[i])) ErrorF("Failed to disable listen for %s transport", argv[i]); } else UseMsg(); } else if (strcmp(argv[i], "-noreset") == 0) { dispatchExceptionAtReset = 0; } else if (strcmp(argv[i], "-reset") == 0) { dispatchExceptionAtReset = DE_RESET; } else if (strcmp(argv[i], "-p") == 0) { if (++i < argc) defaultScreenSaverInterval = ((CARD32) atoi(argv[i])) * MILLI_PER_MIN; else UseMsg(); } else if (strcmp(argv[i], "-pogo") == 0) { dispatchException = DE_TERMINATE; } else if (strcmp(argv[i], "-pn") == 0) PartialNetwork = TRUE; else if (strcmp(argv[i], "-nopn") == 0) PartialNetwork = FALSE; else if (strcmp(argv[i], "r") == 0) defaultKeyboardControl.autoRepeat = TRUE; else if (strcmp(argv[i], "-r") == 0) defaultKeyboardControl.autoRepeat = FALSE; else if (strcmp(argv[i], "-retro") == 0) party_like_its_1989 = TRUE; else if (strcmp(argv[i], "-s") == 0) { if (++i < argc) defaultScreenSaverTime = ((CARD32) atoi(argv[i])) * MILLI_PER_MIN; else UseMsg(); } else if (strcmp(argv[i], "-seat") == 0) { if (++i < argc) SeatId = argv[i]; else UseMsg(); } else if (strcmp(argv[i], "-t") == 0) { if (++i < argc) defaultPointerControl.threshold = atoi(argv[i]); else UseMsg(); } else if (strcmp(argv[i], "-terminate") == 0) { dispatchExceptionAtReset = DE_TERMINATE; } else if (strcmp(argv[i], "-to") == 0) { if (++i < argc) TimeOutValue = ((CARD32) atoi(argv[i])) * MILLI_PER_SECOND; else UseMsg(); } else if (strcmp(argv[i], "-tst") == 0) { noTestExtensions = TRUE; } else if (strcmp(argv[i], "-wm") == 0) defaultBackingStore = WhenMapped; else if (strcmp(argv[i], "-wr") == 0) whiteRoot = TRUE; else if (strcmp(argv[i], "-background") == 0) { if (++i < argc) { if (!strcmp(argv[i], "none")) bgNoneRoot = TRUE; else UseMsg(); } } else if (strcmp(argv[i], "-maxbigreqsize") == 0) { if (++i < argc) { long reqSizeArg = atol(argv[i]); /* Request size > 128MB does not make much sense... */ if (reqSizeArg > 0L && reqSizeArg < 128L) { maxBigRequestSize = (reqSizeArg * 1048576L) - 1L; } else { UseMsg(); } } else { UseMsg(); } } #ifdef PANORAMIX else if (strcmp(argv[i], "+xinerama") == 0) { noPanoramiXExtension = FALSE; } else if (strcmp(argv[i], "-xinerama") == 0) { noPanoramiXExtension = TRUE; } else if (strcmp(argv[i], "-disablexineramaextension") == 0) { PanoramiXExtensionDisabledHack = TRUE; } #endif else if (strcmp(argv[i], "-I") == 0) { /* ignore all remaining arguments */ break; } else if (strncmp(argv[i], "tty", 3) == 0) { /* init supplies us with this useless information */ } #ifdef XDMCP else if ((skip = XdmcpOptions(argc, argv, i)) != i) { i = skip - 1; } #endif else if (strcmp(argv[i], "-dumbSched") == 0) { SmartScheduleDisable = TRUE; } else if (strcmp(argv[i], "-schedInterval") == 0) { if (++i < argc) { SmartScheduleInterval = atoi(argv[i]); SmartScheduleSlice = SmartScheduleInterval; } else UseMsg(); } else if (strcmp(argv[i], "-schedMax") == 0) { if (++i < argc) { SmartScheduleMaxSlice = atoi(argv[i]); } else UseMsg(); } else if (strcmp(argv[i], "-render") == 0) { if (++i < argc) { int policy = PictureParseCmapPolicy(argv[i]); if (policy != PictureCmapPolicyInvalid) PictureCmapPolicy = policy; else UseMsg(); } else UseMsg(); } else if (strcmp(argv[i], "+extension") == 0) { if (++i < argc) { if (!EnableDisableExtension(argv[i], TRUE)) EnableDisableExtensionError(argv[i], TRUE); } else UseMsg(); } else if (strcmp(argv[i], "-extension") == 0) { if (++i < argc) { if (!EnableDisableExtension(argv[i], FALSE)) EnableDisableExtensionError(argv[i], FALSE); } else UseMsg(); } else { ErrorF("Unrecognized option: %s\n", argv[i]); UseMsg(); FatalError("Unrecognized option: %s\n", argv[i]); } } } /* Implement a simple-minded font authorization scheme. The authorization name is "hp-hostname-1", the contents are simply the host name. */ int set_font_authorizations(char **authorizations, int *authlen, pointer client) { #define AUTHORIZATION_NAME "hp-hostname-1" #if defined(TCPCONN) || defined(STREAMSCONN) static char *result = NULL; static char *p = NULL; if (p == NULL) { char hname[1024], *hnameptr; unsigned int len; #if defined(IPv6) && defined(AF_INET6) struct addrinfo hints, *ai = NULL; #else struct hostent *host; #ifdef XTHREADS_NEEDS_BYNAMEPARAMS _Xgethostbynameparams hparams; #endif #endif gethostname(hname, 1024); #if defined(IPv6) && defined(AF_INET6) memset(&hints, 0, sizeof(hints)); hints.ai_flags = AI_CANONNAME; if (getaddrinfo(hname, NULL, &hints, &ai) == 0) { hnameptr = ai->ai_canonname; } else { hnameptr = hname; } #else host = _XGethostbyname(hname, hparams); if (host == NULL) hnameptr = hname; else hnameptr = host->h_name; #endif len = strlen(hnameptr) + 1; result = malloc(len + sizeof(AUTHORIZATION_NAME) + 4); p = result; *p++ = sizeof(AUTHORIZATION_NAME) >> 8; *p++ = sizeof(AUTHORIZATION_NAME) & 0xff; *p++ = (len) >> 8; *p++ = (len & 0xff); memmove(p, AUTHORIZATION_NAME, sizeof(AUTHORIZATION_NAME)); p += sizeof(AUTHORIZATION_NAME); memmove(p, hnameptr, len); p += len; #if defined(IPv6) && defined(AF_INET6) if (ai) { freeaddrinfo(ai); } #endif } *authlen = p - result; *authorizations = result; return 1; #else /* TCPCONN */ return 0; #endif /* TCPCONN */ } void * Xalloc(unsigned long amount) { /* * Xalloc used to return NULL when large amount of memory is requested. In * order to catch the buggy callers this warning has been added, slated to * removal by anyone who touches this code (or just looks at it) in 2011. * * -- Mikhail Gusarov */ if ((long) amount <= 0) ErrorF("Warning: Xalloc: " "requesting unpleasantly large amount of memory: %lu bytes.\n", amount); return malloc(amount); } void * XNFalloc(unsigned long amount) { void *ptr = malloc(amount); if (!ptr) FatalError("Out of memory"); return ptr; } void * Xcalloc(unsigned long amount) { return calloc(1, amount); } void * XNFcalloc(unsigned long amount) { void *ret = calloc(1, amount); if (!ret) FatalError("XNFcalloc: Out of memory"); return ret; } void * Xrealloc(void *ptr, unsigned long amount) { /* * Xrealloc used to return NULL when large amount of memory is requested. In * order to catch the buggy callers this warning has been added, slated to * removal by anyone who touches this code (or just looks at it) in 2011. * * -- Mikhail Gusarov */ if ((long) amount <= 0) ErrorF("Warning: Xrealloc: " "requesting unpleasantly large amount of memory: %lu bytes.\n", amount); return realloc(ptr, amount); } void * XNFrealloc(void *ptr, unsigned long amount) { void *ret = realloc(ptr, amount); if (!ret) FatalError("XNFrealloc: Out of memory"); return ret; } void Xfree(void *ptr) { free(ptr); } char * Xstrdup(const char *s) { if (s == NULL) return NULL; return strdup(s); } char * XNFstrdup(const char *s) { char *ret; if (s == NULL) return NULL; ret = strdup(s); if (!ret) FatalError("XNFstrdup: Out of memory"); return ret; } void SmartScheduleStopTimer(void) { #ifdef _MSC_VER if (SmartScheduleDisable) return; DeleteTimerQueueTimer(s_hSmartScheduleTimerQueue, s_hSmartScheduleTimer, NULL); s_hSmartScheduleTimer=NULL; #else struct itimerval timer; if (SmartScheduleDisable) return; timer.it_interval.tv_sec = 0; timer.it_interval.tv_usec = 0; timer.it_value.tv_sec = 0; timer.it_value.tv_usec = 0; (void) setitimer(ITIMER_REAL, &timer, 0); #endif } #ifdef _MSC_VER static VOID CALLBACK SmartScheduleTimer( PVOID lpParameter, BOOLEAN TimerOrWaitFired) #else static void SmartScheduleTimer (int sig) #endif { SmartScheduleTime += SmartScheduleInterval; } void SmartScheduleStartTimer(void) { #ifdef _MSC_VER if (SmartScheduleDisable) return; if (!CreateTimerQueueTimer( &s_hSmartScheduleTimer, s_hSmartScheduleTimerQueue, SmartScheduleTimer, NULL , SmartScheduleInterval, SmartScheduleInterval, WT_EXECUTEONLYONCE|WT_EXECUTEINPERSISTENTTHREAD)) { DWORD Error=GetLastError(); ErrorF("Error starting timer, smart scheduling disabled: 0x%x (%d)\n",Error,Error); CloseHandle(s_hSmartScheduleTimer); SmartScheduleDisable = TRUE; return; } #else struct itimerval timer; if (SmartScheduleDisable) return; timer.it_interval.tv_sec = 0; timer.it_interval.tv_usec = SmartScheduleInterval * 1000; timer.it_value.tv_sec = 0; timer.it_value.tv_usec = SmartScheduleInterval * 1000; setitimer(ITIMER_REAL, &timer, 0); #endif } void SmartScheduleInit(void) { #ifdef _MSC_VER if (SmartScheduleDisable) return; s_hSmartScheduleTimerQueue = CreateTimerQueue(); if (!s_hSmartScheduleTimerQueue) { DWORD Error=GetLastError(); ErrorF("Error creating timer, smart scheduling disabled: 0x%x (%d)\n",Error,Error); SmartScheduleDisable = TRUE; } #else struct sigaction act; if (SmartScheduleDisable) return; memset((char *) &act, 0, sizeof(struct sigaction)); /* Set up the timer signal function */ act.sa_handler = SmartScheduleTimer; sigemptyset(&act.sa_mask); sigaddset(&act.sa_mask, SIGALRM); if (sigaction(SIGALRM, &act, 0) < 0) { perror("sigaction for smart scheduler"); SmartScheduleDisable = TRUE; } #endif } #ifdef SIG_BLOCK static sigset_t PreviousSignalMask; static int BlockedSignalCount; #endif void OsBlockSignals(void) { #ifdef SIG_BLOCK if (BlockedSignalCount++ == 0) { sigset_t set; #ifdef SIGIO OsBlockSIGIO(); #endif sigemptyset(&set); sigaddset(&set, SIGALRM); sigaddset(&set, SIGVTALRM); #ifdef SIGWINCH sigaddset(&set, SIGWINCH); #endif sigaddset(&set, SIGTSTP); sigaddset(&set, SIGTTIN); sigaddset(&set, SIGTTOU); sigaddset(&set, SIGCHLD); sigprocmask(SIG_BLOCK, &set, &PreviousSignalMask); } #endif } #ifdef SIG_BLOCK static sig_atomic_t sigio_blocked; #endif /** * returns zero if this call caused SIGIO to be blocked now, non-zero if it * was already blocked by a previous call to this function. */ int OsBlockSIGIO(void) { #ifdef SIGIO #ifdef SIG_BLOCK if (sigio_blocked++ == 0) { sigset_t set, old; int ret; sigemptyset(&set); sigaddset(&set, SIGIO); sigprocmask(SIG_BLOCK, &set, &old); ret = sigismember(&old, SIGIO); return ret; } else #endif return 1; #else return 1; #endif } void OsReleaseSIGIO(void) { #ifdef SIGIO #ifdef SIG_BLOCK if (--sigio_blocked == 0) { sigset_t set; sigemptyset(&set); sigaddset(&set, SIGIO); sigprocmask(SIG_UNBLOCK, &set, NULL); } else if (sigio_blocked < 0) { BUG_WARN(sigio_blocked < 0); sigio_blocked = 0; } #endif #endif } void OsReleaseSignals(void) { #ifdef SIG_BLOCK if (--BlockedSignalCount == 0) { sigprocmask(SIG_SETMASK, &PreviousSignalMask, 0); OsReleaseSIGIO(); } #endif } void OsResetSignals(void) { #ifdef SIG_BLOCK while (BlockedSignalCount > 0) OsReleaseSignals(); #ifdef SIGIO while (sigio_blocked > 0) OsReleaseSIGIO(); #endif #endif } /* * Pending signals may interfere with core dumping. Provide a * mechanism to block signals when aborting. */ void OsAbort(void) { #ifndef __APPLE__ OsBlockSignals(); #endif abort(); } #if !defined(WIN32) /* * "safer" versions of system(3), popen(3) and pclose(3) which give up * all privs before running a command. * * This is based on the code in FreeBSD 2.2 libc. * * XXX It'd be good to redirect stderr so that it ends up in the log file * as well. As it is now, xkbcomp messages don't end up in the log file. */ int System(const char *command) { int pid, p; void (*csig) (int); int status; if (!command) return 1; csig = signal(SIGCHLD, SIG_DFL); if (csig == SIG_ERR) { perror("signal"); return -1; } DebugF("System: `%s'\n", command); switch (pid = fork()) { case -1: /* error */ p = -1; case 0: /* child */ if (setgid(getgid()) == -1) _exit(127); if (setuid(getuid()) == -1) _exit(127); execl("/bin/sh", "sh", "-c", command, (char *) NULL); _exit(127); default: /* parent */ do { p = waitpid(pid, &status, 0); } while (p == -1 && errno == EINTR); } if (signal(SIGCHLD, csig) == SIG_ERR) { perror("signal"); return -1; } return p == -1 ? -1 : status; } static struct pid { struct pid *next; FILE *fp; int pid; } *pidlist; OsSigHandlerPtr old_alarm = NULL; /* XXX horrible awful hack */ pointer Popen(const char *command, const char *type) { struct pid *cur; FILE *iop; int pdes[2], pid; if (command == NULL || type == NULL) return NULL; if ((*type != 'r' && *type != 'w') || type[1]) return NULL; if ((cur = malloc(sizeof(struct pid))) == NULL) return NULL; if (pipe(pdes) < 0) { free(cur); return NULL; } /* Ignore the smart scheduler while this is going on */ old_alarm = OsSignal(SIGALRM, SIG_IGN); if (old_alarm == SIG_ERR) { close(pdes[0]); close(pdes[1]); free(cur); perror("signal"); return NULL; } switch (pid = fork()) { case -1: /* error */ close(pdes[0]); close(pdes[1]); free(cur); if (OsSignal(SIGALRM, old_alarm) == SIG_ERR) perror("signal"); return NULL; case 0: /* child */ if (setgid(getgid()) == -1) _exit(127); if (setuid(getuid()) == -1) _exit(127); if (*type == 'r') { if (pdes[1] != 1) { /* stdout */ dup2(pdes[1], 1); close(pdes[1]); } close(pdes[0]); } else { if (pdes[0] != 0) { /* stdin */ dup2(pdes[0], 0); close(pdes[0]); } close(pdes[1]); } execl("/bin/sh", "sh", "-c", command, (char *) NULL); _exit(127); } /* Avoid EINTR during stdio calls */ OsBlockSignals(); /* parent */ if (*type == 'r') { iop = fdopen(pdes[0], type); close(pdes[1]); } else { iop = fdopen(pdes[1], type); close(pdes[0]); } cur->fp = iop; cur->pid = pid; cur->next = pidlist; pidlist = cur; DebugF("Popen: `%s', fp = %p\n", command, iop); return iop; } /* fopen that drops privileges */ pointer Fopen(const char *file, const char *type) { FILE *iop; #ifndef HAS_SAVED_IDS_AND_SETEUID struct pid *cur; int pdes[2], pid; if (file == NULL || type == NULL) return NULL; if ((*type != 'r' && *type != 'w') || type[1]) return NULL; if ((cur = malloc(sizeof(struct pid))) == NULL) return NULL; if (pipe(pdes) < 0) { free(cur); return NULL; } switch (pid = fork()) { case -1: /* error */ close(pdes[0]); close(pdes[1]); free(cur); return NULL; case 0: /* child */ if (setgid(getgid()) == -1) _exit(127); if (setuid(getuid()) == -1) _exit(127); if (*type == 'r') { if (pdes[1] != 1) { /* stdout */ dup2(pdes[1], 1); close(pdes[1]); } close(pdes[0]); } else { if (pdes[0] != 0) { /* stdin */ dup2(pdes[0], 0); close(pdes[0]); } close(pdes[1]); } execl("/bin/cat", "cat", file, (char *) NULL); _exit(127); } /* Avoid EINTR during stdio calls */ OsBlockSignals(); /* parent */ if (*type == 'r') { iop = fdopen(pdes[0], type); close(pdes[1]); } else { iop = fdopen(pdes[1], type); close(pdes[0]); } cur->fp = iop; cur->pid = pid; cur->next = pidlist; pidlist = cur; DebugF("Fopen(%s), fp = %p\n", file, iop); return iop; #else int ruid, euid; ruid = getuid(); euid = geteuid(); if (seteuid(ruid) == -1) { return NULL; } iop = fopen(file, type); if (seteuid(euid) == -1) { fclose(iop); return NULL; } return iop; #endif /* HAS_SAVED_IDS_AND_SETEUID */ } int Pclose(pointer iop) { struct pid *cur, *last; int pstat; int pid; DebugF("Pclose: fp = %p\n", iop); fclose(iop); for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next) if (cur->fp == iop) break; if (cur == NULL) return -1; do { pid = waitpid(cur->pid, &pstat, 0); } while (pid == -1 && errno == EINTR); if (last == NULL) pidlist = cur->next; else last->next = cur->next; free(cur); /* allow EINTR again */ OsReleaseSignals(); if (old_alarm && OsSignal(SIGALRM, old_alarm) == SIG_ERR) { perror("signal"); return -1; } return pid == -1 ? -1 : pstat; } int Fclose(pointer iop) { #ifdef HAS_SAVED_IDS_AND_SETEUID return fclose(iop); #else return Pclose(iop); #endif } #endif /* !WIN32 */ #ifdef WIN32 #include const char * Win32TempDir() { static char buffer[PATH_MAX]; if (GetTempPath(sizeof(buffer), buffer)) { int len; buffer[sizeof(buffer) - 1] = 0; len = strlen(buffer); if (len > 0) if (buffer[len - 1] == '\\') buffer[len - 1] = 0; return buffer; } if (getenv("TEMP") != NULL) return getenv("TEMP"); else if (getenv("TMP") != NULL) return getenv("TEMP"); else return "/tmp"; } int System(const char *cmdline) { STARTUPINFO si; PROCESS_INFORMATION pi; DWORD dwExitCode; char *cmd = strdup(cmdline); ZeroMemory(&si, sizeof(si)); si.cb = sizeof(si); ZeroMemory(&pi, sizeof(pi)); if (!CreateProcess(NULL, cmd, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) { LPVOID buffer; if (!FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR) & buffer, 0, NULL)) { ErrorF("[xkb] Starting '%s' failed!\n", cmdline); } else { ErrorF("[xkb] Starting '%s' failed: %s", cmdline, (char *) buffer); LocalFree(buffer); } free(cmd); return -1; } /* Wait until child process exits. */ WaitForSingleObject(pi.hProcess, INFINITE); GetExitCodeProcess(pi.hProcess, &dwExitCode); /* Close process and thread handles. */ CloseHandle(pi.hProcess); CloseHandle(pi.hThread); free(cmd); return dwExitCode; } #endif /* * CheckUserParameters: check for long command line arguments and long * environment variables. By default, these checks are only done when * the server's euid != ruid. In 3.3.x, these checks were done in an * external wrapper utility. */ /* Consider LD* variables insecure? */ #ifndef _MSC_VER #ifndef REMOVE_ENV_LD #define REMOVE_ENV_LD 1 #endif /* Remove long environment variables? */ #ifndef REMOVE_LONG_ENV #define REMOVE_LONG_ENV 1 #endif #endif /* * Disallow stdout or stderr as pipes? It's possible to block the X server * when piping stdout+stderr to a pipe. * * Don't enable this because it looks like it's going to cause problems. */ #ifndef NO_OUTPUT_PIPES #define NO_OUTPUT_PIPES 0 #endif /* Check args and env only if running setuid (euid == 0 && euid != uid) ? */ #ifndef CHECK_EUID #ifndef WIN32 #define CHECK_EUID 1 #else #define CHECK_EUID 0 #endif #endif /* * Maybe the locale can be faked to make isprint(3) report that everything * is printable? Avoid it by default. */ #ifndef USE_ISPRINT #define USE_ISPRINT 0 #endif #define MAX_ARG_LENGTH 128 #define MAX_ENV_LENGTH 2048 #define MAX_ENV_PATH_LENGTH 2048 /* Limit for *PATH and TERMCAP */ #if USE_ISPRINT #include #define checkPrintable(c) isprint(c) #else #define checkPrintable(c) (((c) & 0x7f) >= 0x20 && ((c) & 0x7f) != 0x7f) #endif enum BadCode { NotBad = 0, UnsafeArg, ArgTooLong, UnprintableArg, EnvTooLong, OutputIsPipe, InternalError }; #if defined(VENDORSUPPORT) #define BUGADDRESS VENDORSUPPORT #elif defined(BUILDERADDR) #define BUGADDRESS BUILDERADDR #else #define BUGADDRESS "xorg@freedesktop.org" #endif void CheckUserParameters(int argc, char **argv, char **envp) { enum BadCode bad = NotBad; int i = 0, j; char *a, *e = NULL; #if CHECK_EUID if (geteuid() == 0 && getuid() != geteuid()) #endif { /* Check each argv[] */ for (i = 1; i < argc; i++) { if (strcmp(argv[i], "-fp") == 0) { i++; /* continue with next argument. skip the length check */ if (i >= argc) break; } else { if (strlen(argv[i]) > MAX_ARG_LENGTH) { bad = ArgTooLong; break; } } a = argv[i]; while (*a) { if (checkPrintable(*a) == 0) { bad = UnprintableArg; break; } a++; } if (bad) break; } if (!bad) { /* Check each envp[] */ for (i = 0; envp[i]; i++) { /* Check for bad environment variables and values */ #if REMOVE_ENV_LD while (envp[i] && (strncmp(envp[i], "LD", 2) == 0)) { for (j = i; envp[j]; j++) { envp[j] = envp[j + 1]; } } #endif if (envp[i] && (strlen(envp[i]) > MAX_ENV_LENGTH)) { #if REMOVE_LONG_ENV for (j = i; envp[j]; j++) { envp[j] = envp[j + 1]; } i--; #else char *eq; int len; eq = strchr(envp[i], '='); if (!eq) continue; len = eq - envp[i]; e = strndup(envp[i], len); if (!e) { bad = InternalError; break; } if (len >= 4 && (strcmp(e + len - 4, "PATH") == 0 || strcmp(e, "TERMCAP") == 0)) { if (strlen(envp[i]) > MAX_ENV_PATH_LENGTH) { bad = EnvTooLong; break; } else { free(e); } } else { bad = EnvTooLong; break; } #endif } } } #if NO_OUTPUT_PIPES if (!bad) { struct stat buf; if (fstat(fileno(stdout), &buf) == 0 && S_ISFIFO(buf.st_mode)) bad = OutputIsPipe; if (fstat(fileno(stderr), &buf) == 0 && S_ISFIFO(buf.st_mode)) bad = OutputIsPipe; } #endif } switch (bad) { case NotBad: return; case UnsafeArg: ErrorF("Command line argument number %d is unsafe\n", i); break; case ArgTooLong: ErrorF("Command line argument number %d is too long\n", i); break; case UnprintableArg: ErrorF("Command line argument number %d contains unprintable" " characters\n", i); break; case EnvTooLong: ErrorF("Environment variable `%s' is too long\n", e); break; case OutputIsPipe: ErrorF("Stdout and/or stderr is a pipe\n"); break; case InternalError: ErrorF("Internal Error\n"); break; default: ErrorF("Unknown error\n"); break; } FatalError("X server aborted because of unsafe environment\n"); } /* * CheckUserAuthorization: check if the user is allowed to start the * X server. This usually means some sort of PAM checking, and it is * usually only done for setuid servers (uid != euid). */ #ifdef USE_PAM #include #include #include #endif /* USE_PAM */ void CheckUserAuthorization(void) { #ifdef USE_PAM static struct pam_conv conv = { misc_conv, NULL }; pam_handle_t *pamh = NULL; struct passwd *pw; int retval; if (getuid() != geteuid()) { pw = getpwuid(getuid()); if (pw == NULL) FatalError("getpwuid() failed for uid %d\n", getuid()); retval = pam_start("xserver", pw->pw_name, &conv, &pamh); if (retval != PAM_SUCCESS) FatalError("pam_start() failed.\n" "\tMissing or mangled PAM config file or module?\n"); retval = pam_authenticate(pamh, 0); if (retval != PAM_SUCCESS) { pam_end(pamh, retval); FatalError("PAM authentication failed, cannot start X server.\n" "\tPerhaps you do not have console ownership?\n"); } retval = pam_acct_mgmt(pamh, 0); if (retval != PAM_SUCCESS) { pam_end(pamh, retval); FatalError("PAM authentication failed, cannot start X server.\n" "\tPerhaps you do not have console ownership?\n"); } /* this is not a session, so do not do session management */ pam_end(pamh, PAM_SUCCESS); } #endif } /* * Tokenize a string into a NULL terminated array of strings. Always returns * an allocated array unless an error occurs. */ char ** xstrtokenize(const char *str, const char *separators) { char **list, **nlist; char *tok, *tmp; unsigned num = 0, n; if (!str) return NULL; list = calloc(1, sizeof(*list)); if (!list) return NULL; tmp = strdup(str); if (!tmp) goto error; for (tok = strtok(tmp, separators); tok; tok = strtok(NULL, separators)) { nlist = realloc(list, (num + 2) * sizeof(*list)); if (!nlist) goto error; list = nlist; list[num] = strdup(tok); if (!list[num]) goto error; list[++num] = NULL; } free(tmp); return list; error: free(tmp); for (n = 0; n < num; n++) free(list[n]); free(list); return NULL; } /* Format a number into a string in a signal safe manner. The string should be * at least 21 characters in order to handle all uint64_t values. */ void FormatUInt64(uint64_t num, char *string) { uint64_t divisor; int len; int i; for (len = 1, divisor = 10; len < 20 && num / divisor; len++, divisor *= 10); for (i = len, divisor = 1; i > 0; i--, divisor *= 10) string[i - 1] = '0' + ((num / divisor) % 10); string[len] = '\0'; } /* Format a number into a hexadecimal string in a signal safe manner. The string * should be at least 17 characters in order to handle all uint64_t values. */ void FormatUInt64Hex(uint64_t num, char *string) { uint64_t divisor; int len; int i; for (len = 1, divisor = 0x10; len < 16 && num / divisor; len++, divisor *= 0x10); for (i = len, divisor = 1; i > 0; i--, divisor *= 0x10) { int val = (num / divisor) % 0x10; if (val < 10) string[i - 1] = '0' + val; else string[i - 1] = 'a' + val - 10; } string[len] = '\0'; }