The Tor Browser / file revision

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #include <stdio.h>

 #include <string.h>

 #include <signal.h>

 #include <unistd.h>

 #include <limits.h>

 #include <errno.h>

 #include <stdlib.h>

 #include <sys/time.h>

 #include <sys/wait.h>

 #include <sys/stat.h>

 #include "secrng.h"

 #include "secerr.h"

 #include "prerror.h"

 #include "prthread.h"

 #include "prprf.h"

 size_t RNG_FileUpdate(const char *fileName, size_t limit);

 /*

  * When copying data to the buffer we want the least signicant bytes

  * from the input since those bits are changing the fastest. The address

  * of least significant byte depends upon whether we are running on

  * a big-endian or little-endian machine.

  *

  * Does this mean the least signicant bytes are the most significant

  * to us? :-)

  */

 static size_t CopyLowBits(void *dst, size_t dstlen, void *src, size_t srclen)

 {

     union endianness {

 	PRInt32 i;

 	char c[4];

     } u;

     if (srclen <= dstlen) {

 	memcpy(dst, src, srclen);

 	return srclen;

     }

     u.i = 0x01020304;

     if (u.c[0] == 0x01) {

 	/* big-endian case */

 	memcpy(dst, (char*)src + (srclen - dstlen), dstlen);

     } else {

 	/* little-endian case */

 	memcpy(dst, src, dstlen);

     }

     return dstlen;

 }

 #ifdef SOLARIS

 #include <kstat.h>

 static const PRUint32 entropy_buf_len = 4096; /* buffer up to 4 KB */

 /* Buffer entropy data, and feed it to the RNG, entropy_buf_len bytes at a time.

  * Returns error if RNG_RandomUpdate fails. Also increments *total_fed

  * by the number of bytes successfully buffered.

  */

 static SECStatus BufferEntropy(char* inbuf, PRUint32 inlen,

                                 char* entropy_buf, PRUint32* entropy_buffered,

                                 PRUint32* total_fed)

 {

     PRUint32 tocopy = 0;

     PRUint32 avail = 0;

     SECStatus rv = SECSuccess;

     while (inlen) {

         avail = entropy_buf_len - *entropy_buffered;

         if (!avail) {

             /* Buffer is full, time to feed it to the RNG. */

             rv = RNG_RandomUpdate(entropy_buf, entropy_buf_len);

             if (SECSuccess != rv) {

                 break;

             }

             *entropy_buffered = 0;

             avail = entropy_buf_len;

         }

         tocopy = PR_MIN(avail, inlen);

         memcpy(entropy_buf + *entropy_buffered, inbuf, tocopy);

         *entropy_buffered += tocopy;

         inlen -= tocopy;

         inbuf += tocopy;

         *total_fed += tocopy;

     }

     return rv;

 }

 /* Feed kernel statistics structures and ks_data field to the RNG.

  * Returns status as well as the number of bytes successfully fed to the RNG.

  */

 static SECStatus RNG_kstat(PRUint32* fed)

 {

     kstat_ctl_t*    kc = NULL;

     kstat_t*        ksp = NULL;

     PRUint32        entropy_buffered = 0;

     char*           entropy_buf = NULL;

     SECStatus       rv = SECSuccess;

     PORT_Assert(fed);

     if (!fed) {

         return SECFailure;

     }

     *fed = 0;

     kc = kstat_open();

     PORT_Assert(kc);

     if (!kc) {

         return SECFailure;

     }

     entropy_buf = (char*) PORT_Alloc(entropy_buf_len);

     PORT_Assert(entropy_buf);

     if (entropy_buf) {

         for (ksp = kc->kc_chain; ksp != NULL; ksp = ksp->ks_next) {

             if (-1 == kstat_read(kc, ksp, NULL)) {

                 /* missing data from a single kstat shouldn't be fatal */

                 continue;

             }

             rv = BufferEntropy((char*)ksp, sizeof(kstat_t),

                                     entropy_buf, &entropy_buffered,

                                     fed);

             if (SECSuccess != rv) {

                 break;

             }

             if (ksp->ks_data && ksp->ks_data_size>0 && ksp->ks_ndata>0) {

                 rv = BufferEntropy((char*)ksp->ks_data, ksp->ks_data_size,

                                         entropy_buf, &entropy_buffered,

                                         fed);

                 if (SECSuccess != rv) {

                     break;

                 }

             }

         }

         if (SECSuccess == rv && entropy_buffered) {

             /* Buffer is not empty, time to feed it to the RNG */

             rv = RNG_RandomUpdate(entropy_buf, entropy_buffered);

         }

         PORT_Free(entropy_buf);

     } else {

         rv = SECFailure;

     }

     if (kstat_close(kc)) {

         PORT_Assert(0);

         rv = SECFailure;

     }

     return rv;

 }

 #endif

 #if defined(SCO) || defined(UNIXWARE) || defined(BSDI) || defined(FREEBSD) \

     || defined(NETBSD) || defined(DARWIN) || defined(OPENBSD) \

     || defined(NTO) || defined(__riscos__)

 #include <sys/times.h>

 #define getdtablesize() sysconf(_SC_OPEN_MAX)

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     int ticks;

     struct tms buffer;

     ticks=times(&buffer);

     return CopyLowBits(buf, maxbytes, &ticks, sizeof(ticks));

 }

 static void

 GiveSystemInfo(void)

 {

     long si;

     /* 

      * Is this really necessary?  Why not use rand48 or something?

      */

     si = sysconf(_SC_CHILD_MAX);

     RNG_RandomUpdate(&si, sizeof(si));

     si = sysconf(_SC_STREAM_MAX);

     RNG_RandomUpdate(&si, sizeof(si));

     si = sysconf(_SC_OPEN_MAX);

     RNG_RandomUpdate(&si, sizeof(si));

 }

 #endif

 #if defined(__sun)

 #if defined(__svr4) || defined(SVR4)

 #include <sys/systeminfo.h>

 #define getdtablesize() sysconf(_SC_OPEN_MAX)

 static void

 GiveSystemInfo(void)

 {

     int rv;

     char buf[2000];

     rv = sysinfo(SI_MACHINE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_RELEASE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_HW_SERIAL, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

 }

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     hrtime_t t;

     t = gethrtime();

     if (t) {

 	return CopyLowBits(buf, maxbytes, &t, sizeof(t));

     }

     return 0;

 }

 #else /* SunOS (Sun, but not SVR4) */

 extern long sysconf(int name);

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     return 0;

 }

 static void

 GiveSystemInfo(void)

 {

     long si;

     /* This is not very good */

     si = sysconf(_SC_CHILD_MAX);

     RNG_RandomUpdate(&si, sizeof(si));

 }

 #endif

 #endif /* Sun */

 #if defined(__hpux)

 #include <sys/unistd.h>

 #define getdtablesize() sysconf(_SC_OPEN_MAX)

 #if defined(__ia64)

 #include <ia64/sys/inline.h>

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     PRUint64 t;

     t = _Asm_mov_from_ar(_AREG44);

     return CopyLowBits(buf, maxbytes, &t, sizeof(t));

 }

 #else

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     extern int ret_cr16();

     int cr16val;

     cr16val = ret_cr16();

     return CopyLowBits(buf, maxbytes, &cr16val, sizeof(cr16val));

 }

 #endif

 static void

 GiveSystemInfo(void)

 {

     long si;

     /* This is not very good */

     si = sysconf(_AES_OS_VERSION);

     RNG_RandomUpdate(&si, sizeof(si));

     si = sysconf(_SC_CPU_VERSION);

     RNG_RandomUpdate(&si, sizeof(si));

 }

 #endif /* HPUX */

 #if defined(OSF1)

 #include <sys/types.h>

 #include <sys/sysinfo.h>

 #include <sys/systeminfo.h>

 #include <c_asm.h>

 static void

 GiveSystemInfo(void)

 {

     char buf[BUFSIZ];

     int rv;

     int off = 0;

     rv = sysinfo(SI_MACHINE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_RELEASE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_HW_SERIAL, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

 }

 /*

  * Use the "get the cycle counter" instruction on the alpha.

  * The low 32 bits completely turn over in less than a minute.

  * The high 32 bits are some non-counter gunk that changes sometimes.

  */

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     unsigned long t;

     t = asm("rpcc %v0");

     return CopyLowBits(buf, maxbytes, &t, sizeof(t));

 }

 #endif /* Alpha */

 #if defined(_IBMR2)

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     return 0;

 }

 static void

 GiveSystemInfo(void)

 {

     /* XXX haven't found any yet! */

 }

 #endif /* IBM R2 */

 #if defined(LINUX)

 #include <sys/sysinfo.h>

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     return 0;

 }

 static void

 GiveSystemInfo(void)

 {

 #ifndef NO_SYSINFO

     struct sysinfo si;

     if (sysinfo(&si) == 0) {

 	RNG_RandomUpdate(&si, sizeof(si));

     }

 #endif

 }

 #endif /* LINUX */

 #if defined(NCR)

 #include <sys/utsname.h>

 #include <sys/systeminfo.h>

 #define getdtablesize() sysconf(_SC_OPEN_MAX)

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     return 0;

 }

 static void

 GiveSystemInfo(void)

 {

     int rv;

     char buf[2000];

     rv = sysinfo(SI_MACHINE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_RELEASE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_HW_SERIAL, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

 }

 #endif /* NCR */

 #if defined(sgi)

 #include <fcntl.h>

 #undef PRIVATE

 #include <sys/mman.h>

 #include <sys/syssgi.h>

 #include <sys/immu.h>

 #include <sys/systeminfo.h>

 #include <sys/utsname.h>

 #include <wait.h>

 static void

 GiveSystemInfo(void)

 {

     int rv;

     char buf[4096];

     rv = syssgi(SGI_SYSID, &buf[0]);

     if (rv > 0) {

 	RNG_RandomUpdate(buf, MAXSYSIDSIZE);

     }

 #ifdef SGI_RDUBLK

     rv = syssgi(SGI_RDUBLK, getpid(), &buf[0], sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, sizeof(buf));

     }

 #endif /* SGI_RDUBLK */

     rv = syssgi(SGI_INVENT, SGI_INV_READ, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, sizeof(buf));

     }

     rv = sysinfo(SI_MACHINE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_RELEASE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_HW_SERIAL, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

 }

 static size_t GetHighResClock(void *buf, size_t maxbuf)

 {

     unsigned phys_addr, raddr, cycleval;

     static volatile unsigned *iotimer_addr = NULL;

     static int tries = 0;

     static int cntr_size;

     int mfd;

     long s0[2];

     struct timeval tv;

 #ifndef SGI_CYCLECNTR_SIZE

 #define SGI_CYCLECNTR_SIZE      165     /* Size user needs to use to read CC */

 #endif

     if (iotimer_addr == NULL) {

 	if (tries++ > 1) {

 	    /* Don't keep trying if it didn't work */

 	    return 0;

 	}

 	/*

 	** For SGI machines we can use the cycle counter, if it has one,

 	** to generate some truly random numbers

 	*/

 	phys_addr = syssgi(SGI_QUERY_CYCLECNTR, &cycleval);

 	if (phys_addr) {

 	    int pgsz = getpagesize();

 	    int pgoffmask = pgsz - 1;

 	    raddr = phys_addr & ~pgoffmask;

 	    mfd = open("/dev/mmem", O_RDONLY);

 	    if (mfd < 0) {

 		return 0;

 	    }

 	    iotimer_addr = (unsigned *)

 		mmap(0, pgoffmask, PROT_READ, MAP_PRIVATE, mfd, (int)raddr);

 	    if (iotimer_addr == (void*)-1) {

 		close(mfd);

 		iotimer_addr = NULL;

 		return 0;

 	    }

 	    iotimer_addr = (unsigned*)

 		((__psint_t)iotimer_addr | (phys_addr & pgoffmask));

 	    /*

 	     * The file 'mfd' is purposefully not closed.

 	     */

 	    cntr_size = syssgi(SGI_CYCLECNTR_SIZE);

 	    if (cntr_size < 0) {

 		struct utsname utsinfo;

 		/* 

 		 * We must be executing on a 6.0 or earlier system, since the

 		 * SGI_CYCLECNTR_SIZE call is not supported.

 		 * 

 		 * The only pre-6.1 platforms with 64-bit counters are

 		 * IP19 and IP21 (Challenge, PowerChallenge, Onyx).

 		 */

 		uname(&utsinfo);

 		if (!strncmp(utsinfo.machine, "IP19", 4) ||

 		    !strncmp(utsinfo.machine, "IP21", 4))

 			cntr_size = 64;

 		else

 			cntr_size = 32;

 	    }

 	    cntr_size /= 8;	/* Convert from bits to bytes */

 	}

     }

     s0[0] = *iotimer_addr;

     if (cntr_size > 4)

 	s0[1] = *(iotimer_addr + 1);

     memcpy(buf, (char *)&s0[0], cntr_size);

     return CopyLowBits(buf, maxbuf, &s0, cntr_size);

 }

 #endif

 #if defined(sony)

 #include <sys/systeminfo.h>

 #define getdtablesize() sysconf(_SC_OPEN_MAX)

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     return 0;

 }

 static void

 GiveSystemInfo(void)

 {

     int rv;

     char buf[2000];

     rv = sysinfo(SI_MACHINE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_RELEASE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_HW_SERIAL, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

 }

 #endif /* sony */

 #if defined(sinix)

 #include <sys/systeminfo.h>

 #include <sys/times.h>

 int gettimeofday(struct timeval *, struct timezone *);

 int gethostname(char *, int);

 #define getdtablesize() sysconf(_SC_OPEN_MAX)

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     int ticks;

     struct tms buffer;

     ticks=times(&buffer);

     return CopyLowBits(buf, maxbytes, &ticks, sizeof(ticks));

 }

 static void

 GiveSystemInfo(void)

 {

     int rv;

     char buf[2000];

     rv = sysinfo(SI_MACHINE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_RELEASE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_HW_SERIAL, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

 }

 #endif /* sinix */

 #ifdef BEOS

 #include <be/kernel/OS.h>

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     bigtime_t bigtime; /* Actually a int64 */

     bigtime = real_time_clock_usecs();

     return CopyLowBits(buf, maxbytes, &bigtime, sizeof(bigtime));

 }

 static void

 GiveSystemInfo(void)

 {

     system_info *info = NULL;

     PRInt32 val;

     get_system_info(info);

     if (info) {

         val = info->boot_time;

         RNG_RandomUpdate(&val, sizeof(val));

         val = info->used_pages;

         RNG_RandomUpdate(&val, sizeof(val));

         val = info->used_ports;

         RNG_RandomUpdate(&val, sizeof(val));

         val = info->used_threads;

         RNG_RandomUpdate(&val, sizeof(val));

         val = info->used_teams;

         RNG_RandomUpdate(&val, sizeof(val));

     }

 }

 #endif /* BEOS */

 #if defined(nec_ews)

 #include <sys/systeminfo.h>

 #define getdtablesize() sysconf(_SC_OPEN_MAX)

 static size_t

 GetHighResClock(void *buf, size_t maxbytes)

 {

     return 0;

 }

 static void

 GiveSystemInfo(void)

 {

     int rv;

     char buf[2000];

     rv = sysinfo(SI_MACHINE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_RELEASE, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

     rv = sysinfo(SI_HW_SERIAL, buf, sizeof(buf));

     if (rv > 0) {

 	RNG_RandomUpdate(buf, rv);

     }

 }

 #endif /* nec_ews */

 size_t RNG_GetNoise(void *buf, size_t maxbytes)

 {

     struct timeval tv;

     int n = 0;

     int c;

     n = GetHighResClock(buf, maxbytes);

     maxbytes -= n;

     (void)gettimeofday(&tv, 0);

     c = CopyLowBits((char*)buf+n, maxbytes, &tv.tv_usec, sizeof(tv.tv_usec));

     n += c;

     maxbytes -= c;

     c = CopyLowBits((char*)buf+n, maxbytes, &tv.tv_sec, sizeof(tv.tv_sec));

     n += c;

     return n;

 }

 #define SAFE_POPEN_MAXARGS	10	/* must be at least 2 */

 /*

  * safe_popen is static to this module and we know what arguments it is

  * called with. Note that this version only supports a single open child

  * process at any time.

  */

 static pid_t safe_popen_pid;

 static struct sigaction oldact;

 static FILE *

 safe_popen(char *cmd)

 {

     int p[2], fd, argc;

     pid_t pid;

     char *argv[SAFE_POPEN_MAXARGS + 1];

     FILE *fp;

     static char blank[] = " \t";

     static struct sigaction newact;

     if (pipe(p) < 0)

 	return 0;

     fp = fdopen(p[0], "r");

     if (fp == 0) {

 	close(p[0]);

 	close(p[1]);

 	return 0;

     }

     /* Setup signals so that SIGCHLD is ignored as we want to do waitpid */

     newact.sa_handler = SIG_DFL;

     newact.sa_flags = 0;

     sigfillset(&newact.sa_mask);

     sigaction (SIGCHLD, &newact, &oldact);

     pid = fork();

     switch (pid) {

       int ndesc;

       case -1:

 	fclose(fp); /* this closes p[0], the fd associated with fp */

 	close(p[1]);

 	sigaction (SIGCHLD, &oldact, NULL);

 	return 0;

       case 0:

 	/* dup write-side of pipe to stderr and stdout */

 	if (p[1] != 1) dup2(p[1], 1);

 	if (p[1] != 2) dup2(p[1], 2);

 	/* 

 	 * close the other file descriptors, except stdin which we

 	 * try reassociating with /dev/null, first (bug 174993)

 	 */

 	if (!freopen("/dev/null", "r", stdin))

 	    close(0);

 	ndesc = getdtablesize();

 	for (fd = PR_MIN(65536, ndesc); --fd > 2; close(fd));

 	/* clean up environment in the child process */

 	putenv("PATH=/bin:/usr/bin:/sbin:/usr/sbin:/etc:/usr/etc");

 	putenv("SHELL=/bin/sh");

 	putenv("IFS= \t");

 	/*

 	 * The caller may have passed us a string that is in text

 	 * space. It may be illegal to modify the string

 	 */

 	cmd = strdup(cmd);

 	/* format argv */

 	argv[0] = strtok(cmd, blank);

 	argc = 1;

 	while ((argv[argc] = strtok(0, blank)) != 0) {

 	    if (++argc == SAFE_POPEN_MAXARGS) {

 		argv[argc] = 0;

 		break;

 	    }

 	}

 	/* and away we go */

 	execvp(argv[0], argv);

 	exit(127);

 	break;

       default:

 	close(p[1]);

 	break;

     }

     /* non-zero means there's a cmd running */

     safe_popen_pid = pid;

     return fp;

 }

 static int

 safe_pclose(FILE *fp)

 {

     pid_t pid;

     int status = -1, rv;

     if ((pid = safe_popen_pid) == 0)

 	return -1;

     safe_popen_pid = 0;

     fclose(fp);

     /* yield the processor so the child gets some time to exit normally */

     PR_Sleep(PR_INTERVAL_NO_WAIT);

     /* if the child hasn't exited, kill it -- we're done with its output */

     while ((rv = waitpid(pid, &status, WNOHANG)) == -1 && errno == EINTR)

 	;

     if (rv == 0) {

 	kill(pid, SIGKILL);

 	while ((rv = waitpid(pid, &status, 0)) == -1 && errno == EINTR)

 	    ;

     }

     /* Reset SIGCHLD signal hander before returning */

     sigaction(SIGCHLD, &oldact, NULL);

     return status;

 }

 #ifdef DARWIN

 #include <TargetConditionals.h>

 #if !TARGET_OS_IPHONE

 #include <crt_externs.h>

 #endif

 #endif

 /* Fork netstat to collect its output by default. Do not unset this unless

  * another source of entropy is available

  */

 #define DO_NETSTAT 1

 void RNG_SystemInfoForRNG(void)

 {

     FILE *fp;

     char buf[BUFSIZ];

     size_t bytes;

     const char * const *cp;

     char *randfile;

 #ifdef DARWIN

 #if TARGET_OS_IPHONE

     /* iOS does not expose a way to access environ. */

     char **environ = NULL;

 #else

     char **environ = *_NSGetEnviron();

 #endif

 #else

     extern char **environ;

 #endif

 #ifdef BEOS

     static const char * const files[] = {

 	"/boot/var/swap",

 	"/boot/var/log/syslog",

 	"/boot/var/tmp",

 	"/boot/home/config/settings",

 	"/boot/home",

 	0

     };

 #else

     static const char * const files[] = {

 	"/etc/passwd",

 	"/etc/utmp",

 	"/tmp",

 	"/var/tmp",

 	"/usr/tmp",

 	0

     };

 #endif

 #if defined(BSDI)

     static char netstat_ni_cmd[] = "netstat -nis";

 #else

     static char netstat_ni_cmd[] = "netstat -ni";

 #endif

     GiveSystemInfo();

     bytes = RNG_GetNoise(buf, sizeof(buf));

     RNG_RandomUpdate(buf, bytes);

     /*

      * Pass the C environment and the addresses of the pointers to the

      * hash function. This makes the random number function depend on the

      * execution environment of the user and on the platform the program

      * is running on.

      */

     if (environ != NULL) {

         cp = (const char * const *) environ;

         while (*cp) {

 	    RNG_RandomUpdate(*cp, strlen(*cp));

 	    cp++;

         }

         RNG_RandomUpdate(environ, (char*)cp - (char*)environ);

     }

     /* Give in system information */

     if (gethostname(buf, sizeof(buf)) == 0) {

 	RNG_RandomUpdate(buf, strlen(buf));

     }

     GiveSystemInfo();

     /* grab some data from system's PRNG before any other files. */

     bytes = RNG_FileUpdate("/dev/urandom", SYSTEM_RNG_SEED_COUNT);

     /* If the user points us to a random file, pass it through the rng */

     randfile = getenv("NSRANDFILE");

     if ( ( randfile != NULL ) && ( randfile[0] != '\0') ) {

 	char *randCountString = getenv("NSRANDCOUNT");

 	int randCount = randCountString ? atoi(randCountString) : 0;

 	if (randCount != 0) {

 	    RNG_FileUpdate(randfile, randCount);

 	} else {

 	    RNG_FileForRNG(randfile);

 	}

     }

     /* pass other files through */

     for (cp = files; *cp; cp++)

 	RNG_FileForRNG(*cp);

 /*

  * Bug 100447: On BSD/OS 4.2 and 4.3, we have problem calling safe_popen

  * in a pthreads environment.  Therefore, we call safe_popen last and on

  * BSD/OS we do not call safe_popen when we succeeded in getting data

  * from /dev/urandom.

  *

  * Bug 174993: On platforms providing /dev/urandom, don't fork netstat

  * either, if data has been gathered successfully.

  */

 #if defined(BSDI) || defined(FREEBSD) || defined(NETBSD) \

     || defined(OPENBSD) || defined(DARWIN) || defined(LINUX) \

     || defined(HPUX)

     if (bytes)

         return;

 #endif

 #ifdef SOLARIS

 /*

  * On Solaris, NSS may be initialized automatically from libldap in

  * applications that are unaware of the use of NSS. safe_popen forks, and

  * sometimes creates issues with some applications' pthread_atfork handlers.

  * We always have /dev/urandom on Solaris 9 and above as an entropy source,

  * and for Solaris 8 we have the libkstat interface, so we don't need to

  * fork netstat.

  */

 #undef DO_NETSTAT

     if (!bytes) {

         /* On Solaris 8, /dev/urandom isn't available, so we use libkstat. */

         PRUint32 kstat_bytes = 0;

         if (SECSuccess != RNG_kstat(&kstat_bytes)) {

             PORT_Assert(0);

         }

         bytes += kstat_bytes;

         PORT_Assert(bytes);

     }

 #endif

 #ifdef DO_NETSTAT

     fp = safe_popen(netstat_ni_cmd);

     if (fp != NULL) {

 	while ((bytes = fread(buf, 1, sizeof(buf), fp)) > 0)

 	    RNG_RandomUpdate(buf, bytes);

 	safe_pclose(fp);

     }

 #endif

 }

 #define TOTAL_FILE_LIMIT 1000000	/* one million */

 size_t RNG_FileUpdate(const char *fileName, size_t limit)

 {

     FILE *        file;

     int           fd;

     int           bytes;

     size_t        fileBytes = 0;

     struct stat   stat_buf;

     unsigned char buffer[BUFSIZ];

     static size_t totalFileBytes = 0;

     /* suppress valgrind warnings due to holes in struct stat */

     memset(&stat_buf, 0, sizeof(stat_buf));

     if (stat((char *)fileName, &stat_buf) < 0)

 	return fileBytes;

     RNG_RandomUpdate(&stat_buf, sizeof(stat_buf));

     file = fopen(fileName, "r");

     if (file != NULL) {

 	/* Read from the underlying file descriptor directly to bypass stdio

 	 * buffering and avoid reading more bytes than we need from

 	 * /dev/urandom. NOTE: we can't use fread with unbuffered I/O because

 	 * fread may return EOF in unbuffered I/O mode on Android.

 	 *

 	 * Moreover, we read into a buffer of size BUFSIZ, so buffered I/O

 	 * has no performance advantage. */

 	fd = fileno(file);

 	/* 'file' was just opened, so this should not fail. */

 	PORT_Assert(fd != -1);

 	while (limit > fileBytes) {

 	    bytes = PR_MIN(sizeof buffer, limit - fileBytes);

 	    bytes = read(fd, buffer, bytes);

 	    if (bytes <= 0)

 		break;

 	    RNG_RandomUpdate(buffer, bytes);

 	    fileBytes      += bytes;

 	    totalFileBytes += bytes;

 	    /* after TOTAL_FILE_LIMIT has been reached, only read in first

 	    ** buffer of data from each subsequent file.

 	    */

 	    if (totalFileBytes > TOTAL_FILE_LIMIT) 

 		break;

 	}

 	fclose(file);

     }

     /*

      * Pass yet another snapshot of our highest resolution clock into

      * the hash function.

      */

     bytes = RNG_GetNoise(buffer, sizeof(buffer));

     RNG_RandomUpdate(buffer, bytes);

     return fileBytes;

 }

 void RNG_FileForRNG(const char *fileName)

 {

     RNG_FileUpdate(fileName, TOTAL_FILE_LIMIT);

 }

 void ReadSingleFile(const char *fileName)

 {

     FILE *        file;

     unsigned char buffer[BUFSIZ];

     file = fopen(fileName, "rb");

     if (file != NULL) {

 	while (fread(buffer, 1, sizeof(buffer), file) > 0)

 	    ;

 	fclose(file);

     } 

 }

 #define _POSIX_PTHREAD_SEMANTICS

 #include <dirent.h>

 PRBool

 ReadFileOK(char *dir, char *file)

 {

     struct stat   stat_buf;

     char filename[PATH_MAX];

     int count = snprintf(filename, sizeof filename, "%s/%s",dir, file);

     if (count <= 0) {

 	return PR_FALSE; /* name too long, can't read it anyway */

     }

     if (stat(filename, &stat_buf) < 0)

 	return PR_FALSE; /* can't stat, probably can't read it then as well */

     return S_ISREG(stat_buf.st_mode) ? PR_TRUE : PR_FALSE;

 }

 /*

  * read one file out of either /etc or the user's home directory.

  * fileToRead tells which file to read.

  *

  * return 1 if it's time to reset the fileToRead (no more files to read).

  */

 int ReadOneFile(int fileToRead)

 {

     char *dir = "/etc";

     DIR *fd = opendir(dir);

     int resetCount = 0;

 #ifdef SOLARIS

      /* grumble, Solaris does not define struct dirent to be the full length */

     typedef union {

 	unsigned char space[sizeof(struct dirent) + MAXNAMELEN];

 	struct dirent dir;

     } dirent_hack;

     dirent_hack entry, firstEntry;

 #define entry_dir entry.dir

 #else

     struct dirent entry, firstEntry;

 #define entry_dir entry

 #endif

     int i, error = -1;

     if (fd == NULL) {

 	dir = getenv("HOME");

 	if (dir) {

 	    fd = opendir(dir);

 	}

     }

     if (fd == NULL) {

 	return 1;

     }

     for (i=0; i <= fileToRead; i++) {

 	struct dirent *result = NULL;

 	do {

 	    error = readdir_r(fd, &entry_dir, &result);

 	} while (error == 0 && result != NULL  &&

 					!ReadFileOK(dir,&result->d_name[0]));

 	if (error != 0 || result == NULL)  {

 	    resetCount = 1; /* read to the end, start again at the beginning */

 	    if (i != 0) {

 		/* ran out of entries in the directory, use the first one */

 	 	entry = firstEntry;

 	 	error = 0;

 	 	break;

 	    }

 	    /* if i== 0, there were no readable entries in the directory */

 	    break;

 	}

 	if (i==0) {

 	    /* save the first entry in case we run out of entries */

 	    firstEntry = entry;

 	}

     }

     if (error == 0) {

 	char filename[PATH_MAX];

 	int count = snprintf(filename, sizeof filename, 

 				"%s/%s",dir, &entry_dir.d_name[0]);

 	if (count >= 1) {

 	    ReadSingleFile(filename);

 	}

     } 

     closedir(fd);

     return resetCount;

 }

 /*

  * do something to try to introduce more noise into the 'GetNoise' call

  */

 static void rng_systemJitter(void)

 {

    static int fileToRead = 1;

    if (ReadOneFile(fileToRead)) {

 	fileToRead = 1;

    } else {

 	fileToRead++;

    }

 }

 size_t RNG_SystemRNG(void *dest, size_t maxLen)

 {

     FILE *file;

     int fd;

     int bytes;

     size_t fileBytes = 0;

     unsigned char *buffer = dest;

     file = fopen("/dev/urandom", "r");

     if (file == NULL) {

 	return rng_systemFromNoise(dest, maxLen);

     }

     /* Read from the underlying file descriptor directly to bypass stdio

      * buffering and avoid reading more bytes than we need from /dev/urandom.

      * NOTE: we can't use fread with unbuffered I/O because fread may return

      * EOF in unbuffered I/O mode on Android.

      */

     fd = fileno(file);

     /* 'file' was just opened, so this should not fail. */

     PORT_Assert(fd != -1);

     while (maxLen > fileBytes) {

 	bytes = maxLen - fileBytes;

 	bytes = read(fd, buffer, bytes);

 	if (bytes <= 0)

 	    break;

 	fileBytes += bytes;

 	buffer += bytes;

     }

     fclose(file);

     if (fileBytes != maxLen) {

 	PORT_SetError(SEC_ERROR_NEED_RANDOM);  /* system RNG failed */

 	fileBytes = 0;

     }

     return fileBytes;

 }