Restructured the RNG source and add support for loadable

random modules.

1 files changed, 754 insertions, 0 deletions

diff --git a/cipher/rndunix.c b/cipher/rndunix.c
new file mode 100644
index 000000000..530971723
--- /dev/null
+++ b/cipher/rndunix.c
@@ -0,0 +1,754 @@
+/****************************************************************************
+ *									    *
+ *   BeOS Randomness-Gathering Code					    *
+ *   Copyright Peter Gutmann, Paul Kendall, and Chris Wedgwood 1996-1998    *
+ *									    *
+ ****************************************************************************/
+
+/* General includes */
+
+#include <config.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#ifdef	HAVE_GETHRTIME
+  #include <sys/times.h>
+#endif
+#ifdef HAVE_GETTIMEOFDAY
+  #include <sys/times.h>
+#endif
+#ifdef HAVE_GETRUSAGE
+  #include <sys/resource.h>
+#endif
+
+/* OS-specific includes */
+
+#ifdef __osf__
+  /* Somewhere in the morass of system-specific cruft which OSF/1 pulls in
+   * via the following includes are various endianness defines, so we
+   * undefine the cryptlib ones, which aren't really needed for this module
+   * anyway */
+#undef BIG_ENDIAN
+#undef LITTLE_ENDIAN
+#endif				/* __osf__ */
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <pwd.h>
+#ifndef __QNX__
+#include <sys/errno.h>
+#include <sys/ipc.h>
+#endif				/* __QNX__ */
+#include <sys/time.h>		/* SCO and SunOS need this before resource.h */
+#ifndef __QNX__
+#include <sys/resource.h>
+#endif				/* __QNX__ */
+#ifdef _AIX
+#include <sys/select.h>
+#endif				/* _AIX */
+#ifndef __QNX__
+#include <sys/shm.h>
+#include <sys/signal.h>
+#endif				/* __QNX__ */
+#include <sys/stat.h>
+#include <sys/types.h>		/* Verschiedene komische Typen */
+#if defined( __hpux ) && ( OS_VERSION == 9 )
+#include <vfork.h>
+#endif				/* __hpux 9.x, after that it's in unistd.h */
+#include <sys/wait.h>
+/* #include <kitchensink.h> */
+#include <errno.h>
+
+#include "types.h"  /* for byte and u32 typedefs */
+#include "g10lib.h"
+#ifndef IS_MODULE
+#include "dynload.h"
+#endif
+
+typedef enum { FALSE=0, TRUE } BOOLEAN;
+typedef unsigned char BYTE;
+
+#define DEBUG_RANDOM  1
+#define DEBUG_RANDOM_VERBOSE  1
+
+/* The structure containing information on random-data sources.  Each
+ * record contains the source and a relative estimate of its usefulness
+ * (weighting) which is used to scale the number of kB of output from the
+ * source (total = data_bytes / usefulness).  Usually the weighting is in the
+ * range 1-3 (or 0 for especially useless sources), resulting in a usefulness
+ * rating of 1...3 for each kB of source output (or 0 for the useless
+ * sources).
+ *
+ * If the source is constantly changing (certain types of network statistics
+ * have this characteristic) but the amount of output is small, the weighting
+ * is given as a negative value to indicate that the output should be treated
+ * as if a minimum of 1K of output had been obtained.  If the source produces
+ * a lot of output then the scale factor is fractional, resulting in a
+ * usefulness rating of < 1 for each kB of source output.
+ *
+ * In order to provide enough randomness to satisfy the requirements for a
+ * slow poll, we need to accumulate at least 20 points of usefulness (a
+ * typical system should get about 30 points).
+ *
+ * Some potential options are missed out because of special considerations.
+ * pstat -i and pstat -f can produce amazing amounts of output (the record
+ * is 600K on an Oracle server) which floods the buffer and doesn't yield
+ * anything useful (apart from perhaps increasing the entropy of the vmstat
+ * output a bit), so we don't bother with this.  pstat in general produces
+ * quite a bit of output, but it doesn't change much over time, so it gets
+ * very low weightings.  netstat -s produces constantly-changing output but
+ * also produces quite a bit of it, so it only gets a weighting of 2 rather
+ * than 3.  The same holds for netstat -in, which gets 1 rather than 2.
+ *
+ * Some binaries are stored in different locations on different systems so
+ * alternative paths are given for them.  The code sorts out which one to
+ * run by itself, once it finds an exectable somewhere it moves on to the
+ * next source.  The sources are arranged roughly in their order of
+ * usefulness, occasionally sources which provide a tiny amount of
+ * relatively useless data are placed ahead of ones which provide a large
+ * amount of possibly useful data because another 100 bytes can't hurt, and
+ * it means the buffer won't be swamped by one or two high-output sources.
+ * All the high-output sources are clustered towards the end of the list
+ * for this reason.  Some binaries are checked for in a certain order, for
+ * example under Slowaris /usr/ucb/ps understands aux as an arg, but the
+ * others don't.  Some systems have conditional defines enabling alternatives
+ * to commands which don't understand the usual options but will provide
+ * enough output (in the form of error messages) to look like they're the
+ * real thing, causing alternative options to be skipped (we can't check the
+ * return either because some commands return peculiar, non-zero status even
+ * when they're working correctly).
+ *
+ * In order to maximise use of the buffer, the code performs a form of run-
+ * length compression on its input where a repeated sequence of bytes is
+ * replaced by the occurrence count mod 256.  Some commands output an awful
+ * lot of whitespace, this measure greatly increases the amount of data we
+ * can fit in the buffer.
+ *
+ * When we scale the weighting using the SC() macro, some preprocessors may
+ * give a division by zero warning for the most obvious expression
+ * 'weight ? 1024 / weight : 0' (and gcc 2.7.2.2 dies with a division by zero
+ * trap), so we define a value SC_0 which evaluates to zero when fed to
+ * '1024 / SC_0' */
+
+#define SC( weight )	( 1024 / weight )	/* Scale factor */
+#define SC_0			16384	/* SC( SC_0 ) evalutes to 0 */
+
+static struct RI {
+    const char *path;		/* Path to check for existence of source */
+    const char *arg;		/* Args for source */
+    const int usefulness;	/* Usefulness of source */
+    FILE *pipe; 		/* Pipe to source as FILE * */
+    int pipeFD; 		/* Pipe to source as FD */
+    pid_t pid;			/* pid of child for waitpid() */
+    int length; 		/* Quantity of output produced */
+    const BOOLEAN hasAlternative;	/* Whether source has alt.location */
+} dataSources[] = {
+
+    {	"/bin/vmstat", "-s", SC(-3), NULL, 0, 0, 0, TRUE    },
+    {	"/usr/bin/vmstat", "-s", SC(-3), NULL, 0, 0, 0, FALSE},
+    {	"/bin/vmstat", "-c", SC(-3), NULL, 0, 0, 0, TRUE     },
+    {	"/usr/bin/vmstat", "-c", SC(-3), NULL, 0, 0, 0, FALSE},
+    {	"/usr/bin/pfstat", NULL, SC(-2), NULL, 0, 0, 0, FALSE},
+    {	"/bin/vmstat", "-i", SC(-2), NULL, 0, 0, 0, TRUE     },
+    {	"/usr/bin/vmstat", "-i", SC(-2), NULL, 0, 0, 0, FALSE},
+    {	"/usr/ucb/netstat", "-s", SC(2), NULL, 0, 0, 0, TRUE },
+    {	"/usr/bin/netstat", "-s", SC(2), NULL, 0, 0, 0, TRUE },
+    {	"/usr/sbin/netstat", "-s", SC(2), NULL, 0, 0, 0, TRUE},
+    {	"/usr/etc/netstat", "-s", SC(2), NULL, 0, 0, 0, FALSE},
+    {	"/usr/bin/nfsstat", NULL, SC(2), NULL, 0, 0, 0, FALSE},
+    {	"/usr/ucb/netstat", "-m", SC(-1), NULL, 0, 0, 0, TRUE  },
+    {	"/usr/bin/netstat", "-m", SC(-1), NULL, 0, 0, 0, TRUE  },
+    {	"/usr/sbin/netstat", "-m", SC(-1), NULL, 0, 0, 0, TRUE },
+    {	"/usr/etc/netstat", "-m", SC(-1), NULL, 0, 0, 0, FALSE },
+    {	"/bin/netstat",     "-in", SC(-1), NULL, 0, 0, 0, TRUE },
+    {	"/usr/ucb/netstat", "-in", SC(-1), NULL, 0, 0, 0, TRUE },
+    {	"/usr/bin/netstat", "-in", SC(-1), NULL, 0, 0, 0, TRUE },
+    {	"/usr/sbin/netstat", "-in", SC(-1), NULL, 0, 0, 0, TRUE},
+    {	"/usr/etc/netstat", "-in", SC(-1), NULL, 0, 0, 0, FALSE},
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.7.1.0",
+				    SC(-1), NULL, 0, 0, 0, FALSE }, /* UDP in */
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.7.4.0",
+				    SC(-1), NULL, 0, 0, 0, FALSE },  /* UDP out */
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.4.3.0",
+				    SC(-1), NULL, 0, 0, 0, FALSE }, /* IP ? */
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.6.10.0",
+				    SC(-1), NULL, 0, 0, 0, FALSE }, /* TCP ? */
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.6.11.0",
+				    SC(-1), NULL, 0, 0, 0, FALSE }, /* TCP ? */
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.6.13.0",
+				    SC(-1), NULL, 0, 0, 0, FALSE }, /* TCP ? */
+    {	"/usr/bin/mpstat", NULL, SC(1), NULL, 0, 0, 0, FALSE     },
+    {	"/usr/bin/w", NULL, SC(1), NULL, 0, 0, 0, TRUE           },
+    {	"/usr/bsd/w", NULL, SC(1), NULL, 0, 0, 0, FALSE          },
+    {	"/usr/bin/df", NULL, SC(1), NULL, 0, 0, 0, TRUE          },
+    {	"/bin/df", NULL, SC(1), NULL, 0, 0, 0, FALSE             },
+    {	"/usr/sbin/portstat", NULL, SC(1), NULL, 0, 0, 0, FALSE  },
+    {	"/usr/bin/iostat", NULL, SC(SC_0), NULL, 0, 0, 0, FALSE  },
+    {	"/usr/bin/uptime", NULL, SC(SC_0), NULL, 0, 0, 0, TRUE   },
+    {	"/usr/bsd/uptime", NULL, SC(SC_0), NULL, 0, 0, 0, FALSE  },
+    {	"/bin/vmstat", "-f", SC(SC_0), NULL, 0, 0, 0, TRUE       },
+    {	"/usr/bin/vmstat", "-f", SC(SC_0), NULL, 0, 0, 0, FALSE  },
+    {	"/bin/vmstat", NULL, SC(SC_0), NULL, 0, 0, 0, TRUE       },
+    {	"/usr/bin/vmstat", NULL, SC(SC_0), NULL, 0, 0, 0, FALSE  },
+    {	"/usr/ucb/netstat", "-n", SC(0.5), NULL, 0, 0, 0, TRUE   },
+    {	"/usr/bin/netstat", "-n", SC(0.5), NULL, 0, 0, 0, TRUE   },
+    {	"/usr/sbin/netstat", "-n", SC(0.5), NULL, 0, 0, 0, TRUE  },
+    {	"/usr/etc/netstat", "-n", SC(0.5), NULL, 0, 0, 0, FALSE  },
+#if defined( __sgi ) || defined( __hpux )
+    {	"/bin/ps", "-el", SC(0.3), NULL, 0, 0, 0, TRUE           },
+#endif				/* __sgi || __hpux */
+    {	"/usr/ucb/ps", "aux", SC(0.3), NULL, 0, 0, 0, TRUE       },
+    {	"/usr/bin/ps", "aux", SC(0.3), NULL, 0, 0, 0, TRUE       },
+    {	"/bin/ps", "aux", SC(0.3), NULL, 0, 0, 0, FALSE          },
+    {	"/usr/bin/ipcs", "-a", SC(0.5), NULL, 0, 0, 0, TRUE      },
+    {	"/bin/ipcs", "-a", SC(0.5), NULL, 0, 0, 0, FALSE         },
+    /* Unreliable source, depends on system usage */
+    {	"/etc/pstat", "-p", SC(0.5), NULL, 0, 0, 0, TRUE         },
+    {	"/bin/pstat", "-p", SC(0.5), NULL, 0, 0, 0, FALSE        },
+    {	"/etc/pstat", "-S", SC(0.2), NULL, 0, 0, 0, TRUE         },
+    {	"/bin/pstat", "-S", SC(0.2), NULL, 0, 0, 0, FALSE        },
+    {	"/etc/pstat", "-v", SC(0.2), NULL, 0, 0, 0, TRUE         },
+    {	"/bin/pstat", "-v", SC(0.2), NULL, 0, 0, 0, FALSE        },
+    {	"/etc/pstat", "-x", SC(0.2), NULL, 0, 0, 0, TRUE         },
+    {	"/bin/pstat", "-x", SC(0.2), NULL, 0, 0, 0, FALSE        },
+    {	"/etc/pstat", "-t", SC(0.1), NULL, 0, 0, 0, TRUE         },
+    {	"/bin/pstat", "-t", SC(0.1), NULL, 0, 0, 0, FALSE        },
+    /* pstat is your friend */
+    {	"/usr/bin/last", "-n 50", SC(0.3), NULL, 0, 0, 0, TRUE   },
+#ifdef __sgi
+    {	"/usr/bsd/last", "-50", SC(0.3), NULL, 0, 0, 0, FALSE    },
+#endif				/* __sgi */
+#ifdef __hpux
+    {	"/etc/last", "-50", SC(0.3), NULL, 0, 0, 0, FALSE        },
+#endif				/* __hpux */
+    {	"/usr/bsd/last", "-n 50", SC(0.3), NULL, 0, 0, 0, FALSE  },
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.5.1.0",
+				SC(0.1), NULL, 0, 0, 0, FALSE }, /* ICMP ? */
+    {	"/usr/sbin/snmp_request", "localhost public get 1.3.6.1.2.1.5.3.0",
+				SC(0.1), NULL, 0, 0, 0, FALSE }, /* ICMP ? */
+    {	"/etc/arp", "-a", SC(0.1), NULL, 0, 0, 0, TRUE  },
+    {	"/usr/etc/arp", "-a", SC(0.1), NULL, 0, 0, 0, TRUE  },
+    {	"/usr/bin/arp", "-a", SC(0.1), NULL, 0, 0, 0, TRUE  },
+    {	"/usr/sbin/arp", "-a", SC(0.1), NULL, 0, 0, 0, FALSE },
+    {	"/usr/sbin/ripquery", "-nw 1 127.0.0.1",
+				SC(0.1), NULL, 0, 0, 0, FALSE },
+    {	"/bin/lpstat", "-t", SC(0.1), NULL, 0, 0, 0, TRUE     },
+    {	"/usr/bin/lpstat", "-t", SC(0.1), NULL, 0, 0, 0, TRUE },
+    {	"/usr/ucb/lpstat", "-t", SC(0.1), NULL, 0, 0, 0, FALSE },
+    {	"/usr/bin/tcpdump", "-c 5 -efvvx", SC(1), NULL, 0, 0, 0, FALSE },
+    /* This is very environment-dependant.  If network traffic is low, it'll
+     * probably time out before delivering 5 packets, which is OK because
+     * it'll probably be fixed stuff like ARP anyway */
+    {	"/usr/sbin/advfsstat", "-b usr_domain",
+				SC(SC_0), NULL, 0, 0, 0, FALSE},
+    {	"/usr/sbin/advfsstat", "-l 2 usr_domain",
+				SC(0.5), NULL, 0, 0, 0, FALSE},
+    {	"/usr/sbin/advfsstat", "-p usr_domain",
+				SC(SC_0), NULL, 0, 0, 0, FALSE},
+    /* This is a complex and screwball program.  Some systems have things
+     * like rX_dmn, x = integer, for RAID systems, but the statistics are
+     * pretty dodgy */
+#if 0
+    /* The following aren't enabled since they're somewhat slow and not very
+     * unpredictable, however they give an indication of the sort of sources
+     * you can use (for example the finger might be more useful on a
+     * firewalled internal network) */
+    {	"/usr/bin/finger", "@ml.media.mit.edu", SC(0.9), NULL, 0, 0, 0, FALSE },
+    {	"/usr/local/bin/wget", "-O - http://lavarand.sgi.com/block.html",
+				SC(0.9), NULL, 0, 0, 0, FALSE },
+    {	"/bin/cat", "/usr/spool/mqueue/syslog", SC(0.9), NULL, 0, 0, 0, FALSE },
+#endif				/* 0 */
+    {	NULL, NULL, 0, NULL, 0, 0, 0, FALSE }
+};
+
+/* Variables to manage the child process which fills the buffer */
+
+static pid_t gathererProcess = 0;   /* The child process which fills the
+				     * buffer */
+static BYTE *gathererBuffer;	/* Shared buffer for gathering random noise */
+static int gathererMemID;	/* ID for shared memory */
+static int gathererBufSize;	/* Size of the shared memory buffer */
+static uid_t gathererID = (uid_t) - 1;	/* Gatherers user ID */
+
+/* The struct at the start of the shared memory buffer used to communicate
+ * information from the child to the parent */
+
+typedef struct {
+    int usefulness;		/* Usefulness of data in buffer */
+    int noBytes;		/* No.of bytes in buffer */
+} GATHERER_INFO;
+
+/* Under SunOS popen() doesn't record the pid of the child process.  When
+ * pclose() is called, instead of calling waitpid() for the correct child, it
+ * calls wait() repeatedly until the right child is reaped.  The problem is
+ * that this reaps any other children that happen to have died at that
+ * moment, and when their pclose() comes along, the process hangs forever.
+ * The fix is to use a wrapper for popen()/pclose() which saves the pid in
+ * the dataSources structure (code adapted from GNU-libc's popen() call).
+ *
+ * Aut viam inveniam aut faciam */
+
+static FILE *
+my_popen(struct RI *entry)
+{
+
+    int pipedes[2];
+    FILE *stream;
+
+    /* Create the pipe */
+    if (pipe(pipedes) < 0)
+	return (NULL);
+
+    /* Fork off the child ("vfork() is like an OS orgasm.  All OS's want to
+     * do it, but most just end up faking it" - Chris Wedgwood).  If your OS
+     * supports it, you should try to use vfork() here because it's somewhat
+     * more efficient */
+#if defined( sun ) || defined( __ultrix__ ) || defined( __osf__ ) || \
+	defined(__hpux)
+    entry->pid = vfork();
+#else				/*  */
+    entry->pid = fork();
+#endif				/* Unixen which have vfork() */
+    if (entry->pid == (pid_t) - 1) {
+	/* The fork failed */
+	close(pipedes[0]);
+	close(pipedes[1]);
+	return (NULL);
+    }
+
+    if (entry->pid == (pid_t) 0) {
+	struct passwd *passwd;
+
+	/* We are the child.  Make the read side of the pipe be stdout */
+	if (dup2(pipedes[STDOUT_FILENO], STDOUT_FILENO) < 0)
+	    exit(127);
+
+	/* Now that everything is set up, give up our permissions to make
+	 * sure we don't read anything sensitive.  If the getpwnam() fails,
+	 * we default to -1, which is usually nobody */
+	if (gathererID == (uid_t) - 1 && \
+	    (passwd = getpwnam("nobody")) != NULL)
+	    gathererID = passwd->pw_uid;
+
+	setuid(gathererID);
+
+	/* Close the pipe descriptors */
+	close(pipedes[STDIN_FILENO]);
+	close(pipedes[STDOUT_FILENO]);
+
+	/* Try and exec the program */
+	execl(entry->path, entry->path, entry->arg, NULL);
+
+	/* Die if the exec failed */
+	exit(127);
+    }
+
+    /* We are the parent.  Close the irrelevant side of the pipe and open
+     * the relevant side as a new stream.  Mark our side of the pipe to
+     * close on exec, so new children won't see it */
+    close(pipedes[STDOUT_FILENO]);
+
+    fcntl(pipedes[STDIN_FILENO], F_SETFD, FD_CLOEXEC);
+
+    stream = fdopen(pipedes[STDIN_FILENO], "r");
+
+    if (stream == NULL) {
+	int savedErrno = errno;
+
+	/* The stream couldn't be opened or the child structure couldn't be
+	 * allocated.  Kill the child and close the other side of the pipe */
+	kill(entry->pid, SIGKILL);
+	if (stream == NULL)
+	    close(pipedes[STDOUT_FILENO]);
+	else
+	    fclose(stream);
+
+	waitpid(entry->pid, NULL, 0);
+
+	entry->pid = 0;
+	errno = savedErrno;
+	return (NULL);
+    }
+
+    return (stream);
+}
+
+static int
+my_pclose(struct RI *entry)
+{
+    int status = 0;
+
+    if (fclose(entry->pipe))
+	return (-1);
+
+    /* We ignore the return value from the process because some programs
+     * return funny values which would result in the input being discarded
+     * even if they executed successfully.  This isn't a problem because the
+     * result data size threshold will filter out any programs which exit
+     * with a usage message without producing useful output */
+    if (waitpid(entry->pid, NULL, 0) != entry->pid)
+	status = -1;
+
+    entry->pipe = NULL;
+    entry->pid = 0;
+    return (status);
+}
+
+
+/* Unix slow poll (without special support for Linux)
+ *
+ * If a few of the randomness sources create a large amount of output then
+ * the slowPoll() stops once the buffer has been filled (but before all the
+ * randomness sources have been sucked dry) so that the 'usefulness' factor
+ * remains below the threshold.  For this reason the gatherer buffer has to
+ * be fairly sizeable on moderately loaded systems.  This is something of a
+ * bug since the usefulness should be influenced by the amount of output as
+ * well as the source type */
+
+#define DEVRANDOM_BITS		1024
+#define SHARED_BUFSIZE		49152	/* Usually about 25K are filled */
+
+static void
+slowPoll(void)
+{
+    GATHERER_INFO *gathererInfo;
+    BOOLEAN moreSources;
+    struct timeval tv;
+    fd_set fds;
+#if defined( __hpux )
+    size_t maxFD = 0;
+    int pageSize = 4096;	/* PHUX doesn't have getpagesize() */
+#elif defined( _M_XENIX ) || defined( __aux )
+    int maxFD = 0, pageSize = 4096;	/* Nor do others, but they
+					 * get fd right */
+#else				/*  */
+    int maxFD = 0, pageSize = getpagesize();
+#endif				/* OS-specific brokenness */
+    int bufPos, i, usefulness = 0;
+
+    /* Make sure we don't start more than one slow poll at a time */
+    if (gathererProcess) {
+	g10_log_debug( "already in slowPoll\n");
+	return;
+    }
+
+    /* Set up the shared memory */
+    gathererBufSize = (SHARED_BUFSIZE / pageSize) * (pageSize + 1);
+
+    if ((gathererMemID = shmget(IPC_PRIVATE, gathererBufSize,
+				IPC_CREAT | 0600)) == -1) {
+	g10_log_debug("shmget failed: %s\n", strerror(errno) );
+	return; 		/* Something broke */
+    }
+
+    if ((gathererBuffer = (BYTE *) shmat(gathererMemID, NULL, 0)) == (BYTE *) - 1) {
+	g10_log_debug("shmat failed: %s\n", strerror(errno) );
+	return; 		/* Something broke */
+    }
+
+    /* Fork off the gatherer, the parent process returns to the caller */
+    if ((gathererProcess = fork()) || (gathererProcess == -1)) {
+	g10_log_debug("gatherer pid = %d\n", gathererProcess );
+	return; 		/* Error/parent process returns */
+    }
+
+
+    fclose(stderr);		/* Arrghh!!  It's Stuart code!! */
+
+    /* Reset the SIGC(H)LD handler to the system default.  This is necessary
+     * because if the program which cryptlib is a part of installs its own
+     * SIGC(H)LD handler, it will end up reaping the cryptlib children before
+     * cryptlib can.  As a result, my_pclose() will call waitpid() on a
+     * process which has already been reaped by the installed handler and
+     * return an error, so the read data won't be added to the randomness
+     * pool.  There are two types of SIGC(H)LD naming, the SysV SIGCLD and
+     * the BSD/Posix SIGCHLD, so we need to handle either possibility */
+#ifdef SIGCLD
+    signal(SIGCLD, SIG_DFL);
+#else				/*  */
+    signal(SIGCHLD, SIG_DFL);
+
+#endif				/* SIGCLD */
+
+    /* Fire up each randomness source */
+    FD_ZERO(&fds);
+    for (i = 0; dataSources[i].path != NULL; i++) {
+	/* Since popen() is a fairly heavy function, we check to see whether
+	 * the executable exists before we try to run it */
+	if (access(dataSources[i].path, X_OK)) {
+#ifdef DEBUG_RANDOM_VERBOSE
+	    printf("%s not present%s\n", dataSources[i].path,
+	      dataSources[i].hasAlternative ? ", has alternatives" : "");
+#endif				/* DEBUG_RANDOM */
+	    dataSources[i].pipe = NULL;
+	}
+	else
+	    dataSources[i].pipe = my_popen(&dataSources[i]);
+
+	if (dataSources[i].pipe != NULL) {
+	    dataSources[i].pipeFD = fileno(dataSources[i].pipe);
+	    if (dataSources[i].pipeFD > maxFD)
+		maxFD = dataSources[i].pipeFD;
+	    fcntl(dataSources[i].pipeFD, F_SETFL, O_NONBLOCK);
+	    FD_SET(dataSources[i].pipeFD, &fds);
+	    dataSources[i].length = 0;
+
+	    /* If there are alternatives for this command, don't try and
+	     * execute them */
+	    while (dataSources[i].hasAlternative) {
+#ifdef DEBUG_RANDOM_VERBOSE
+		printf("Skipping %s\n", dataSources[i + 1].path);
+#endif				/* DEBUG_RANDOM */
+		i++;
+	    }
+	}
+    }
+
+    gathererInfo = (GATHERER_INFO *) gathererBuffer;
+    bufPos = sizeof(GATHERER_INFO);	/* Start of buf.has status
+					 * info */
+
+    /* Suck all the data we can get from each of the sources */
+    moreSources = TRUE;
+    while (moreSources && bufPos <= gathererBufSize) {
+	/* Wait for data to become available from any of the sources, with a
+	 * timeout of 10 seconds.  This adds even more randomness since data
+	 * becomes available in a nondeterministic fashion.  Kudos to HP's QA
+	 * department for managing to ship a select() which breaks its own
+	 * prototype */
+	tv.tv_sec = 10;
+	tv.tv_usec = 0;
+
+#if defined( __hpux ) && ( OS_VERSION == 9 )
+	if (select(maxFD + 1, (int *)&fds, NULL, NULL, &tv) == -1)
+#else				/*  */
+	if (select(maxFD + 1, &fds, NULL, NULL, &tv) == -1)
+#endif				/* __hpux */
+	    break;
+
+	/* One of the sources has data available, read it into the buffer */
+	for (i = 0; dataSources[i].path != NULL; i++) {
+	    if( dataSources[i].pipe && FD_ISSET(dataSources[i].pipeFD, &fds)) {
+		size_t noBytes;
+
+		if ((noBytes = fread(gathererBuffer + bufPos, 1,
+				     gathererBufSize - bufPos,
+				     dataSources[i].pipe)) == 0) {
+		    if (my_pclose(&dataSources[i]) == 0) {
+			int total = 0;
+
+			/* Try and estimate how much entropy we're getting
+			 * from a data source */
+			if (dataSources[i].usefulness)
+			    if (dataSources[i].usefulness < 0)
+				total = (dataSources[i].length + 999)
+					/ -dataSources[i].usefulness;
+			    else
+				total = dataSources[i].length
+					/ dataSources[i].usefulness;
+#ifdef DEBUG_RANDOM
+		   printf("%s %s contributed %d bytes (compressed), "
+			       "usefulness = %d\n", dataSources[i].path,
+			       (dataSources[i].arg != NULL) ?
+				       dataSources[i].arg : "",
+				      dataSources[i].length, total);
+#endif				/* DEBUG_RANDOM */
+			if( dataSources[i].length )
+			    usefulness += total;
+		    }
+		    dataSources[i].pipe = NULL;
+		}
+		else {
+		    int currPos = bufPos;
+		    int endPos = bufPos + noBytes;
+
+		    /* Run-length compress the input byte sequence */
+		    while (currPos < endPos) {
+			int ch = gathererBuffer[currPos];
+
+			/* If it's a single byte, just copy it over */
+			if (ch != gathererBuffer[currPos + 1]) {
+			    gathererBuffer[bufPos++] = ch;
+			    currPos++;
+			}
+			else {
+			    int count = 0;
+
+			    /* It's a run of repeated bytes, replace them
+			     * with the byte count mod 256 */
+			    while ((ch == gathererBuffer[currPos])
+				    && currPos < endPos) {
+				count++;
+				currPos++;
+			    }
+			    gathererBuffer[bufPos++] = count;
+			    noBytes -= count - 1;
+			}
+		    }
+
+		    /* Remember the number of (compressed) bytes of input we
+		     * obtained */
+		    dataSources[i].length += noBytes;
+		}
+	    }
+	}
+
+	/* Check if there is more input available on any of the sources */
+	moreSources = FALSE;
+	FD_ZERO(&fds);
+	for (i = 0; dataSources[i].path != NULL; i++) {
+	    if (dataSources[i].pipe != NULL) {
+		FD_SET(dataSources[i].pipeFD, &fds);
+		moreSources = TRUE;
+	    }
+	}
+    }
+
+    gathererInfo->usefulness = usefulness;
+    gathererInfo->noBytes = bufPos;
+
+#ifdef DEBUG_RANDOM
+    printf("Got %d bytes, usefulness = %d\n", bufPos, usefulness);
+#endif				/* DEBUG_RANDOM */
+
+    /* Child MUST exit here */
+    exit(0);
+}
+
+
+static void
+fast_poll( void (*add)(const void*, size_t, int) )
+{
+  #if HAVE_GETHRTIME
+    {	hrtime_t tv;
+	tv = gethrtime();
+	(*add)( &tv, sizeof(tv), 1 );
+    }
+  #elif HAVE_GETTIMEOFDAY
+    {	struct timeval tv;
+	if( gettimeofday( &tv, NULL ) )
+	    BUG();
+	(*add)( &tv.tv_sec, sizeof(tv.tv_sec), 1 );
+	(*add)( &tv.tv_usec, sizeof(tv.tv_usec), 1 );
+    }
+  #else /* use times */
+    {	struct tms buf;
+	times( &buf );
+	(*add)( &buf, sizeof buf, 1 );
+    }
+  #endif
+  #ifdef HAVE_GETRUSAGE
+    {	struct rusage buf;
+	if( getrusage( RUSAGE_SELF, &buf ) )
+	    BUG();
+	(*add)( &buf, sizeof buf, 1 );
+	memset( &buf, 0, sizeof buf );
+    }
+  #endif
+}
+
+
+
+static int
+gather_random( byte *buffer, size_t *r_length, int level )
+{
+    GATHERER_INFO gathererInfo;
+    int status;
+    size_t n;
+    size_t length = *r_length;
+
+    slowPoll();
+    assert( gathererProcess );
+    /* Wait for the gathering process to finish, add the randomness it's
+     * gathered, and detach the shared memory */
+    waitpid(gathererProcess, &status, 0);   /* Should prob.check status */
+
+    gathererInfo = *(GATHERER_INFO *)gathererBuffer;
+    n = gathererInfo.noBytes;
+    if( n > length )
+	n = length;
+    memcpy( buffer, gathererBuffer, n );
+
+    memset(gathererBuffer, 0, gathererBufSize);
+    shmdt(gathererBuffer);
+    shmctl(gathererMemID, IPC_RMID, NULL);
+    gathererProcess = 0;
+
+    *r_length = n;
+    if( gathererInfo.usefulness > 30 )
+	return 100;
+    else if ( gathererInfo.usefulness )
+	return gathererInfo.usefulness * 100 / 30;
+    else
+	return 0;
+}
+
+
+
+#ifndef IS_MODULE
+static
+#endif
+const char * const gnupgext_version = "RNDUNIX ($Revision$)";
+
+
+static struct {
+    int class;
+    int version;
+    void *func;
+} func_table[] = {
+    { 40, 1, gather_random },
+    { 41, 1, fast_poll },
+};
+
+/****************
+ * Enumerate the names of the functions together with informations about
+ * this function. Set sequence to an integer with a initial value of 0 and
+ * do not change it.
+ * If what is 0 all kind of functions are returned.
+ * Return values: class := class of function:
+ *			   10 = message digest algorithm info function
+ *			   11 = integer with available md algorithms
+ *			   20 = cipher algorithm info function
+ *			   21 = integer with available cipher algorithms
+ *			   30 = public key algorithm info function
+ *			   31 = integer with available pubkey algorithms
+ *			   40 = get read_random_source() function
+ *			   41 = get fast_random_poll function
+ *		  version = interface version of the function/pointer
+ *			    (currently this is 1 for all functions)
+ */
+
+#ifndef IS_MODULE
+static
+#endif
+void *
+gnupgext_enum_func( int what, int *sequence, int *class, int *vers )
+{
+    void *ret;
+    int i = *sequence;
+
+    do {
+	if ( i >= DIM(func_table) || i < 0 ) {
+	    return NULL;
+	}
+	*class = func_table[i].class;
+	*vers  = func_table[i].version;
+	ret = func_table[i].func;
+	i++;
+    } while ( what && what != *class );
+
+    *sequence = i;
+    return ret;
+}
+
+#ifndef IS_MODULE
+void
+rndunix_constructor(void)
+{
+    register_internal_cipher_extension( gnupgext_version,
+					gnupgext_enum_func );
+}
+#endif
+
+