Adapt libthread_xu to use the new lwp kernel functions.

[dragonfly.git] / usr.sbin / usbd / usbd.c

/*
 * $NetBSD: usbd.c,v 1.4 1998/12/09 00:57:19 augustss Exp $
 * $FreeBSD: src/usr.sbin/usbd/usbd.c,v 1.29 2003/10/25 22:03:10 jmg Exp $
 * $DragonFly: src/usr.sbin/usbd/usbd.c,v 1.7 2005/12/05 01:23:23 swildner Exp $
 */

/*
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Lennart Augustsson (augustss@netbsd.org).
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *        This product includes software developed by the NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/* USBD creates 'threads' in the kernel, used for doing discovery when a
 * device has attached or detached. This functionality should be removed
 * once kernel threads have been added to the kernel.
 * It also handles the event queue, and executing commands based on those
 * events.
 *
 * See usbd(8).
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <ctype.h>
#include <signal.h>
#include <paths.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/linker.h>
#include <sys/module.h>
#include <sys/queue.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <regex.h>

#include <bus/usb/usb.h>

/* default name of configuration file
 */

#define CONFIGFILE      "/etc/usbd.conf"

/* the name of the device spitting out usb attach/detach events as well as
 * the prefix for the individual busses (used as a semi kernel thread).
 */
#define USBDEV          "/dev/usb"

/* Maximum number of USB busses expected to be in a system
 * XXX should be replaced by dynamic allocation.
 */
#define MAXUSBDEV       4

/* Sometimes a device does not respond in time for interrupt
 * driven explore to find it.  Therefore we run an exploration
 * at regular intervals to catch those.
 */
#define TIMEOUT         30

/* The wildcard used in actions for strings and integers
 */
#define WILDCARD_STRING NULL
#define WILDCARD_INT    -1


extern char *__progname;        /* name of program */

char *configfile = CONFIGFILE;  /* name of configuration file */

char *devs[MAXUSBDEV];          /* device names */
int fds[MAXUSBDEV];             /* file descriptors for USBDEV\d+ */
int ndevs = 0;                  /* number of entries in fds / devs */
int fd = -1;                    /* file descriptor for USBDEV */

int lineno;
int verbose = 0;                /* print message on what it is doing */

typedef struct event_name_s {
        int     type;           /* event number (from usb.h) */
        char    *name;
} event_name_t;

event_name_t event_names[] = {
        {USB_EVENT_CTRLR_ATTACH, "ctrlr-attach"},
        {USB_EVENT_CTRLR_DETACH, "ctrlr-detach"},
        {USB_EVENT_DRIVER_ATTACH, "driver-attach"},
        {USB_EVENT_DRIVER_DETACH, "driver-detach"},
        {USB_EVENT_DEVICE_ATTACH, "device-attach"},
        {USB_EVENT_DEVICE_DETACH, "device-detach"},
        {0, NULL}                       /* NULL indicates end of list, not 0 */
};

#define DEVICE_FIELD            0       /* descriptive field */

#define VENDOR_FIELD            1       /* selective fields */
#define PRODUCT_FIELD           2
#define RELEASE_FIELD           3
#define CLASS_FIELD             4
#define SUBCLASS_FIELD          5
#define PROTOCOL_FIELD          6
#define DEVNAME_FIELD           7

#define ATTACH_FIELD            8       /* command fields */
#define DETACH_FIELD            9


typedef struct action_s {
        char    *name;          /* descriptive string */

        int     vendor; /* selection criteria */
        int     product;
        int     release;
        int     class;
        int     subclass;
        int     protocol;
        char    *devname;
        regex_t devname_regex;

        char    *attach;        /* commands to execute */
        char    *detach;

        STAILQ_ENTRY(action_s) next;
} action_t;

STAILQ_HEAD(action_list, action_s) actions = STAILQ_HEAD_INITIALIZER(actions);

typedef struct action_match_s {
        action_t *action;
        char    *devname;
} action_match_t;


/* the function returns 0 for failure, 1 for all arguments found and 2 for
 * arguments left over in trail.
 */
typedef int (*config_field_fn)(action_t *action, char *args, char **trail);

int set_device_field(action_t *action, char *args, char **trail);
int set_vendor_field(action_t *action, char *args, char **trail);
int set_product_field(action_t *action, char *args, char **trail);
int set_release_field(action_t *action, char *args, char **trail);
int set_class_field(action_t *action, char *args, char **trail);
int set_subclass_field(action_t *action, char *args, char **trail);
int set_protocol_field(action_t *action, char *args, char **trail);
int set_devname_field(action_t *action, char *args, char **trail);
int set_attach_field(action_t *action, char *args, char **trail);
int set_detach_field(action_t *action, char *args, char **trail);

/* the list of fields supported in an entry */
typedef struct config_field_s {
        int     event;
        char    *name;
        config_field_fn function;
} config_field_t;

config_field_t config_fields[] = {
        {DEVICE_FIELD,          "device",       set_device_field},

        {VENDOR_FIELD,          "vendor",       set_vendor_field},
        {PRODUCT_FIELD,         "product",      set_product_field},
        {RELEASE_FIELD,         "release",      set_release_field},
        {CLASS_FIELD,           "class",        set_class_field},
        {SUBCLASS_FIELD,        "subclass",     set_subclass_field},
        {PROTOCOL_FIELD,        "protocol",     set_protocol_field},
        {DEVNAME_FIELD,         "devname",      set_devname_field},

        {ATTACH_FIELD,          "attach",       set_attach_field},
        {DETACH_FIELD,          "detach",       set_detach_field},

        {0, NULL, NULL}         /* NULL is EOL marker, not the 0 */
};


/* prototypes for some functions */
void print_event(struct usb_event *event);
void print_action(action_t *action, int i);
void print_actions(void);
int  find_action(struct usb_device_info *devinfo, action_match_t *action_match);


void
usage(void)
{
        fprintf(stderr, "usage: %s [-d] [-v] [-t timeout] [-e] [-f dev]\n"
                        "           [-n] [-c config]\n",
                __progname);
        exit(1);
}


/* generic helper functions for the functions to set the fields of actions */
int
get_string(char *src, char **rdst, char **rsrc)
{
        /* Takes the first string from src, taking quoting into account.
         * rsrc (if not NULL) is set to the first byte not included in the
         * string returned in rdst.
         *
         * Input is:
         *   src = 'fir"st \'par"t       second part';
         * Returned is:
         *   *dst = 'hello \'world';
         *   if (rsrc != NULL)
         *     *rsrc = 'second part';
         *
         * Notice the fact that the single quote enclosed in double quotes is
         * returned. Also notice that before second part there is more than
         * one space, which is removed in rsrc.
         *
         * The string in src is not modified.
         */

        char *dst;              /* destination string */
        int i;                  /* index into src */
        int j;                  /* index into dst */
        int quoted = 0;         /* 1 for single, 2 for double quoted */

        dst = malloc(strlen(src)+1);    /* XXX allocation is too big, realloc?*/
        if (dst == NULL) {              /* should not happen, really */
                fprintf(stderr, "%s:%d: Out of memory\n", configfile, lineno);
                exit(2);
        }

        /* find the end of the current string. If quotes are found the search
         * continues until the corresponding quote is found.
         * So,
         *   hel'lo" "wor'ld
         * represents the string
         *   hello" "world
         * and not (hello world).
         */
        for (i = 0, j = 0; i < strlen(src); i++) {
                if (src[i] == '\'' && (quoted == 0 || quoted == 1)) {
                        quoted = (quoted? 0:1);
                } else if (src[i] == '"' && (quoted == 0 || quoted == 2)) {
                        quoted = (quoted? 0:2);
                } else if (isspace(src[i]) && !quoted) {
                        /* found a space outside quotes -> terminates src */
                        break;
                } else {
                        dst[j++] = src[i];      /* copy character */
                }
        }

        /* quotes being left open? */
        if (quoted) {
                fprintf(stderr, "%s:%d: Missing %s quote at end of '%s'\n",
                        configfile, lineno,
                        (quoted == 1? "single":"double"), src);
                exit(2);
        }

        /* skip whitespace for second part */
        for (/*i is set*/; i < strlen(src) && isspace(src[i]); i++)
                ;       /* nop */

        dst[j] = '\0';                  /* make sure it's NULL terminated */

        *rdst = dst;                    /* and return the pointers */
        if (rsrc != NULL)               /* if info wanted */
                *rsrc = &src[i];

        if (*dst == '\0') {             /* empty string */
                return 0;
        } else if (src[i] == '\0') {    /* completely used (1 argument) */
                return 1;
        } else {                        /* 2 or more args, *rsrc is rest */
                return 2;
        }
}

int
get_integer(char *src, int *dst, char **rsrc)
{
        char *endptr;

        /* Converts str to a number. If one argument was found in
         * str, 1 is returned and *dst is set to the value of the integer.
         * If 2 or more arguments were presented, 2 is returned,
         * *dst is set to the converted value and rsrc, if not null, points
         * at the start of the next argument (whitespace skipped).
         * Else 0 is returned and nothing else is valid.
         */

        if (src == NULL || *src == '\0')        /* empty src */
                return(0);

        *dst = (int) strtol(src, &endptr, 0);

        /* skip over whitespace of second argument */
        while (isspace(*endptr))
                endptr++;

        if (rsrc)
                *rsrc = endptr;

        if (isspace(*endptr)) {         /* partial match, 2 or more arguments */
                return(2);
        } else if (*endptr == '\0') {   /* full match, 1 argument */
                return(1);
        } else {                        /* invalid src, no match */
                return(0);
        }
}

/* functions to set the fields of the actions appropriately */
int
set_device_field(action_t *action, char *args, char **trail)
{
        return(get_string(args, &action->name, trail));
}
int
set_vendor_field(action_t *action, char *args, char **trail)
{
        return(get_integer(args, &action->vendor, trail));
}
int
set_product_field(action_t *action, char *args, char **trail)
{
        return(get_integer(args, &action->product, trail));
}
int
set_release_field(action_t *action, char *args, char **trail)
{
        return(get_integer(args, &action->release, trail));
}
int
set_class_field(action_t *action, char *args, char **trail)
{
        return(get_integer(args, &action->class, trail));
}
int
set_subclass_field(action_t *action, char *args, char **trail)
{
        return(get_integer(args, &action->subclass, trail));
}
int
set_protocol_field(action_t *action, char *args, char **trail)
{
        return(get_integer(args, &action->protocol, trail));
}
int
set_devname_field(action_t *action, char *args, char **trail)
{
        int match = get_string(args, &action->devname, trail);
        int len;
        int error;
        char *string;
#       define ERRSTR_SIZE      100
        char errstr[ERRSTR_SIZE];

        if (match == 0)
                return(0);

        len = strlen(action->devname);
        string = malloc(len + 15);
        if (string == NULL)
                return(0);

        bcopy(action->devname, string+7, len);  /* make some space for */
        bcopy("[[:<:]]", string, 7);            /*   beginning of word */
        bcopy("[[:>:]]", string+7+len, 7);      /*   and end of word   */
        string[len + 14] = '\0';

        error = regcomp(&action->devname_regex, string, REG_NOSUB|REG_EXTENDED);
        if (error) {
                errstr[0] = '\0';
                regerror(error, &action->devname_regex, errstr, ERRSTR_SIZE);
                fprintf(stderr, "%s:%d: %s\n", configfile, lineno, errstr);
                return(0);
        }

        return(match);
}
int
set_attach_field(action_t *action, char *args, char **trail)
{
        return(get_string(args, &action->attach, trail));
}
int
set_detach_field(action_t *action, char *args, char **trail)
{
        return(get_string(args, &action->detach, trail));
}


void
read_configuration(void)
{
        FILE *file;             /* file descriptor */
        char *line;             /* current line */
        char *linez;            /* current line, NULL terminated */
        char *field;            /* first part, the field name */
        char *args;             /* second part, arguments */
        char *trail;            /* remaining part after parsing, should be '' */
        size_t len;             /* length of current line */
        int i,j;                /* loop counters */
        action_t *action = NULL;        /* current action */

        file = fopen(configfile, "r");
        if (file == NULL) {
                fprintf(stderr, "%s: Could not open for reading, %s\n",
                        configfile, strerror(errno));
                exit(2);
        }

        for (lineno = 1; /* nop */;lineno++) {
        
                line = fgetln(file, &len);
                if (line == NULL) {
                        if (feof(file))                 /* EOF */
                                break;
                        if (ferror(file)) {
                                fprintf(stderr, "%s:%d: Could not read, %s\n",
                                        configfile, lineno, strerror(errno));
                                exit(2);
                        }
                }

                /* skip initial spaces */
                while (len > 0 && isspace(*line)) {
                        line++;
                        len--;
                }

                if (len == 0)           /* empty line */
                        continue;
                if (line[0] == '#')     /* comment line */
                        continue;

                /* make a NULL terminated copy of the string */
                linez = malloc(len+1);
                if (linez == NULL) {
                        fprintf(stderr, "%s:%d: Out of memory\n",
                                configfile, lineno);
                        exit(2);
                }
                strncpy(linez, line, len);
                linez[len] = '\0';

                /* find the end of the current word (is field), that's the
                 * start of the arguments
                 */
                field = linez;
                args = linez;
                while (*args != '\0' && !isspace(*args))
                        args++;

                /* If arguments is not the empty string, NULL terminate the
                 * field and move the argument pointer to the first character
                 * of the arguments.
                 * If arguments is the empty string field and arguments both
                 * are terminated (strlen(field) >= 0, strlen(arguments) == 0).
                 */
                if (*args != '\0') {
                        *args = '\0';
                        args++;
                }

                /* Skip initial spaces */
                while (*args != '\0' && isspace(*args))
                        args++;

                /* Cut off trailing whitespace */
                for (i = 0, j = 0; args[i] != '\0'; i++)
                        if (!isspace(args[i]))
                                j = i+1;
                args[j] = '\0';

                /* We now have the field and the argument separated into
                 * two strings that are NULL terminated
                 */

                /* If the field is 'device' we have to start a new action. */
                if (strcmp(field, "device") == 0) {
                        /* Allocate a new action and set defaults */
                        action = malloc(sizeof(*action));
                        if (action == NULL) {
                                fprintf(stderr, "%s:%d: Out of memory\n",
                                        configfile, lineno);
                                exit(2);
                        }
                        memset(action, 0, sizeof(*action));
                        action->product = WILDCARD_INT;
                        action->vendor = WILDCARD_INT;
                        action->release = WILDCARD_INT;
                        action->class = WILDCARD_INT;
                        action->subclass = WILDCARD_INT;
                        action->protocol = WILDCARD_INT;
                        action->devname = WILDCARD_STRING;

                        /* Add it to the end of the list to preserve order */
                        STAILQ_INSERT_TAIL(&actions, action, next);
                }

                if (action == NULL) {
                        line[len] = '\0';       /* XXX zero terminate */
                        fprintf(stderr, "%s:%d: Doesn't start with 'device' "
                                "but '%s'\n", configfile, lineno, field);
                        exit(2);
                }
                
                for (i = 0; config_fields[i].name  ; i++) {
                        /* does the field name match? */
                        if (strcmp(config_fields[i].name, field) == 0) {
                                /* execute corresponding set-field function */
                                if ((config_fields[i].function)(action, args,
                                                                &trail)
                                    != 1) {
                                        fprintf(stderr,"%s:%d: "
                                                "Syntax error in '%s'\n",
                                                configfile, lineno, linez);
                                        exit(2);
                                }
                                break;
                        }
                }
                if (config_fields[i].name == NULL) {    /* Reached end of list*/
                        fprintf(stderr, "%s:%d: Unknown field '%s'\n",
                                configfile, lineno, field);
                        exit(2);
                }
        }

        fclose(file);

        if (verbose >= 2)
                print_actions();
}


void
print_event(struct usb_event *event)
{
        int i;
        struct timespec *timespec = &event->ue_time;
        struct usb_device_info *devinfo = &event->u.ue_device;

        printf("%s: ", __progname);
        for (i = 0; event_names[i].name != NULL; i++) {
                if (event->ue_type == event_names[i].type) {
                        printf("%s event", event_names[i].name);
                        break;
                }
        }
        if (event_names[i].name == NULL)
                printf("unknown event %d", event->ue_type);

        if (event->ue_type == USB_EVENT_DEVICE_ATTACH ||
            event->ue_type == USB_EVENT_DEVICE_DETACH) {
                devinfo = &event->u.ue_device;

                printf(" at %ld.%09ld, %s, %s:\n",
                        timespec->tv_sec, timespec->tv_nsec,
                        devinfo->udi_product, devinfo->udi_vendor);

                printf("  vndr=0x%04x prdct=0x%04x rlse=0x%04x "
                       "clss=0x%04x subclss=0x%04x prtcl=0x%04x\n",
                       devinfo->udi_vendorNo, devinfo->udi_productNo,
                       devinfo->udi_releaseNo,
                       devinfo->udi_class, devinfo->udi_subclass, devinfo->udi_protocol);

                if (devinfo->udi_devnames[0][0] != '\0') {
                        char c = ' ';

                        printf("  device names:");
                        for (i = 0; i < USB_MAX_DEVNAMES; i++) {
                                if (devinfo->udi_devnames[i][0] == '\0')
                                        break;

                                printf("%c%s", c, devinfo->udi_devnames[i]);
                                c = ',';
                        }
                }
        } else if (event->ue_type == USB_EVENT_CTRLR_ATTACH ||
            event->ue_type == USB_EVENT_CTRLR_DETACH) {
                printf(" bus=%d", &event->u.ue_ctrlr.ue_bus);
        } else if (event->ue_type == USB_EVENT_DRIVER_ATTACH ||
            event->ue_type == USB_EVENT_DRIVER_DETACH) {
                printf(" cookie=%u devname=%s",
                    &event->u.ue_driver.ue_cookie.cookie,
                    &event->u.ue_driver.ue_devname);
        }
        printf("\n");
}

void
print_action(action_t *action, int i)
{
        if (action == NULL)
                return;

        printf("%s: action %d: %s\n",
                __progname, i,
                (action->name? action->name:""));
        if (action->product != WILDCARD_INT ||
            action->vendor != WILDCARD_INT ||
            action->release != WILDCARD_INT ||
            action->class != WILDCARD_INT ||
            action->subclass != WILDCARD_INT ||
            action->protocol != WILDCARD_INT)
                printf(" ");
        if (action->vendor != WILDCARD_INT)
                printf(" vndr=0x%04x", action->vendor);
        if (action->product != WILDCARD_INT)
                printf(" prdct=0x%04x", action->product);
        if (action->release != WILDCARD_INT)
                printf(" rlse=0x%04x", action->release);
        if (action->class != WILDCARD_INT)
                printf(" clss=0x%04x", action->class);
        if (action->subclass != WILDCARD_INT)
                printf(" subclss=0x%04x", action->subclass);
        if (action->protocol != WILDCARD_INT)
                printf(" prtcl=0x%04x", action->protocol);
        if (action->vendor != WILDCARD_INT ||
            action->product != WILDCARD_INT ||
            action->release != WILDCARD_INT ||
            action->class != WILDCARD_INT ||
            action->subclass != WILDCARD_INT ||
            action->protocol != WILDCARD_INT)
                printf("\n");
        if (action->devname != WILDCARD_STRING)
                printf("  devname: %s\n", action->devname);

        if (action->attach != NULL)
                printf("  attach='%s'\n",
                        action->attach);
        if (action->detach != NULL)
                printf("  detach='%s'\n",
                        action->detach);
}

void
print_actions(void)
{
        int i = 0;
        action_t *action;

        STAILQ_FOREACH(action, &actions, next)
                print_action(action, ++i);

        printf("%s: %d action%s\n", __progname, i, (i == 1? "":"s"));
}


int
match_devname(action_t *action, struct usb_device_info *devinfo)
{
        int i;
        regmatch_t match;
        int error;

        for (i = 0; i < USB_MAX_DEVNAMES; i++) {
                if (devinfo->udi_devnames[i][0] == '\0')
                        break;

                error = regexec(&action->devname_regex, devinfo->udi_devnames[i],
                                1, &match, 0);
                if (error == 0) {
                        if (verbose >= 2)
                                printf("%s: %s matches %s\n", __progname,
                                        devinfo->udi_devnames[i], action->devname);
                        return(i);
                }
        }
        
        return(-1);
}


int
find_action(struct usb_device_info *devinfo, action_match_t *action_match)
{
        action_t *action;
        char *devname = NULL;
        int match = -1;

        STAILQ_FOREACH(action, &actions, next) {
                if ((action->vendor == WILDCARD_INT ||
                     action->vendor == devinfo->udi_vendorNo) &&
                    (action->product == WILDCARD_INT ||
                     action->product == devinfo->udi_productNo) &&
                    (action->release == WILDCARD_INT ||
                     action->release == devinfo->udi_releaseNo) &&
                    (action->class == WILDCARD_INT ||
                     action->class == devinfo->udi_class) &&
                    (action->subclass == WILDCARD_INT ||
                     action->subclass == devinfo->udi_subclass) &&
                    (action->protocol == WILDCARD_INT ||
                     action->protocol == devinfo->udi_protocol) &&
                    (action->devname == WILDCARD_STRING ||
                     (match = match_devname(action, devinfo)) != -1)) {
                        /* found match !*/

                        /* Find a devname for pretty printing. Either
                         * the matched one or otherwise, if there is only
                         * one devname for that device, use that.
                         */
                        if (match >= 0)
                                devname = devinfo->udi_devnames[match];
                        else if (devinfo->udi_devnames[0][0] != '\0' &&
                                 devinfo->udi_devnames[1][0] == '\0')
                                /* if we have exactly 1 device name */
                                devname = devinfo->udi_devnames[0];

                        if (verbose) {
                                printf("%s: Found action '%s' for %s, %s",
                                        __progname, action->name,
                                        devinfo->udi_product, devinfo->udi_vendor);
                                if (devname)
                                        printf(" at %s", devname);
                                printf("\n");
                        }

                        action_match->action = action;
                        action_match->devname = devname;

                        return(1);
                }
        }

        return(0);
}

void
execute_command(char *cmd)
{
        pid_t pid;
        struct sigaction ign, intact, quitact;
        sigset_t newsigblock, oldsigblock;
        int status;
        int i;

        if (verbose)
                printf("%s: Executing '%s'\n", __progname, cmd);
        if (cmd == NULL)
                return;

        /* The code below is directly taken from the system(3) call.
         * Added to it is the closing of open file descriptors.
         */
        /*
         * Ignore SIGINT and SIGQUIT, block SIGCHLD. Remember to save
         * existing signal dispositions.
         */
        ign.sa_handler = SIG_IGN;
        sigemptyset(&ign.sa_mask);
        ign.sa_flags = 0;
        sigaction(SIGINT, &ign, &intact);
        sigaction(SIGQUIT, &ign, &quitact);
        sigemptyset(&newsigblock);
        sigaddset(&newsigblock, SIGCHLD);
        sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
        pid = fork();
        if (pid == -1) {
                fprintf(stderr, "%s: fork failed, %s\n",
                        __progname, strerror(errno));
        } else if (pid == 0) {
                /* child here */

                /* close all open file handles for USBDEV\d* devices */
                for (i = 0; i < ndevs; i++)
                        close(fds[i]);          /* USBDEV\d+ */
                close(fd);                      /* USBDEV */

                /* Restore original signal dispositions and exec the command. */
                sigaction(SIGINT, &intact, NULL);
                sigaction(SIGQUIT,  &quitact, NULL);
                sigprocmask(SIG_SETMASK, &oldsigblock, NULL);

                execl(_PATH_BSHELL, "sh", "-c", cmd, (char *)NULL);

                /* should only be reached in case of error */
                exit(127);
        } else {
                /* parent here */
                do {
                        pid = waitpid(pid, &status, 0);
                } while (pid == -1 && errno == EINTR);
        }
        sigaction(SIGINT, &intact, NULL);
        sigaction(SIGQUIT,  &quitact, NULL);
        sigprocmask(SIG_SETMASK, &oldsigblock, NULL);

        if (pid == -1) {
                fprintf(stderr, "%s: waitpid returned: %s\n",
                        __progname, strerror(errno));
        } else if (pid == 0) {
                fprintf(stderr, "%s: waitpid returned 0 ?!\n",
                        __progname);
        } else {
                if (status == -1) {
                        fprintf(stderr, "%s: Could not start '%s'\n",
                                __progname, cmd);
                } else if (status == 127) {
                        fprintf(stderr, "%s: Shell failed for '%s'\n",
                                __progname, cmd);
                } else if (WIFEXITED(status) && WEXITSTATUS(status)) {
                        fprintf(stderr, "%s: '%s' returned %d\n",
                                __progname, cmd, WEXITSTATUS(status));
                } else if (WIFSIGNALED(status)) {
                        fprintf(stderr, "%s: '%s' caught signal %d\n",
                                __progname, cmd, WTERMSIG(status));
                } else if (verbose >= 2) {
                        printf("%s: '%s' is ok\n", __progname, cmd);
                }
        }
}

void
process_event_queue(int fd)
{
        struct usb_event event;
        int error;
        int len;
        action_match_t action_match;

        for (;;) {
                len = read(fd, &event, sizeof(event));
                if (len == -1) {
                        if (errno == EWOULDBLOCK) {
                                /* no more events */
                                break;
                        } else {
                                fprintf(stderr,"%s: Could not read event, %s\n",
                                        __progname, strerror(errno));
                                exit(1);
                        }
                }
                if (len == 0)
                        break;
                if (len != sizeof(event)) {
                        fprintf(stderr, "partial read on %s\n", USBDEV);
                        exit(1);
                }

                /* we seem to have gotten a valid event */

                if (verbose)
                        print_event(&event);

                /* handle the event appropriately */
                switch (event.ue_type) {
                case USB_EVENT_CTRLR_ATTACH:
                        if (verbose)
                                printf("USB_EVENT_CTRLR_ATTACH\n");
                        break;
                case USB_EVENT_CTRLR_DETACH:
                        if (verbose)
                                printf("USB_EVENT_CTRLR_DETACH\n");
                        break;
                case USB_EVENT_DEVICE_ATTACH:
                case USB_EVENT_DEVICE_DETACH:
                        if (find_action(&event.u.ue_device, &action_match) == 0)
                                /* nothing found */
                                break;

                        if (verbose >= 2)
                                print_action(action_match.action, 0);

                        if (action_match.devname) {
                                if (verbose >= 2)
                                        printf("%s: Setting DEVNAME='%s'\n",
                                                __progname, action_match.devname);

                                error = setenv("DEVNAME", action_match.devname, 1);
                                if (error)
                                        fprintf(stderr, "%s: setenv(\"DEVNAME\", \"%s\",1) failed, %s\n",
                                                __progname, action_match.devname, strerror(errno));
                        }

                        if (USB_EVENT_IS_ATTACH(event.ue_type) &&
                            action_match.action->attach) 
                                execute_command(action_match.action->attach);
                        if (USB_EVENT_IS_DETACH(event.ue_type) &&
                            action_match.action->detach)
                                execute_command(action_match.action->detach);
                        break;
                case USB_EVENT_DRIVER_ATTACH:
                        if (verbose)
                                printf("USB_EVENT_DRIVER_ATTACH\n");
                        break;
                case USB_EVENT_DRIVER_DETACH:
                        if (verbose)
                                printf("USB_EVENT_DRIVER_DETACH\n");
                        break;
                default:
                        printf("Unknown USB event %d\n", event.ue_type);
                }
        }       
}


int
main(int argc, char **argv)
{
        int error, i;
        int ch;                 /* getopt option */
        int debug = 0;          /* print debugging output */
        int explore_once = 0;   /* don't do only explore */
        int handle_events = 1;  /* do handle the event queue */
        int maxfd;              /* maximum fd in use */
        char buf[50];           /* for creation of the filename */
        fd_set r,w;
        int itimeout = TIMEOUT; /* timeout for select */
        struct timeval tv;

        if (modfind(USB_UHUB) < 0) {
                if (kldload(USB_KLD) < 0 || modfind(USB_UHUB) < 0) {
                        perror(USB_KLD ": Kernel module not available");
                        return 1;
                }
        }

        while ((ch = getopt(argc, argv, "c:def:nt:v")) != -1) {
                switch(ch) {
                case 'c':
                        configfile = strdup(optarg);
                        if (configfile == NULL) {
                                fprintf(stderr, "strdup returned NULL\n");
                                return 1;
                        }
                        break;
                case 'd':
                        debug++;
                        break;
                case 'e':
                        explore_once = 1;
                        break;
                case 'f':
                        if (ndevs < MAXUSBDEV)
                                devs[ndevs++] = optarg;
                        break;
                case 'n':
                        handle_events = 0;
                        break;
                case 't':
                        itimeout = atoi(optarg);
                        break;
                case 'v':
                        verbose++;
                        break;
                case '?':
                default:
                        usage();
                }
        }
        argc -= optind;
        argv += optind;

        maxfd = 0;
        if (ndevs == 0) {
                /* open all the USBDEVS\d+ devices */
                for (i = 0; i < MAXUSBDEV; i++) {
                        sprintf(buf, "%s%d", USBDEV, i);
                        fds[ndevs] = open(buf, O_RDWR);
                        if (fds[ndevs] >= 0) {
                                devs[ndevs] = strdup(buf);
                                if (devs[ndevs] == NULL) {
                                        fprintf(stderr, "strdup returned NULL\n");
                                        return 1;
                                }
                                if (verbose)
                                        printf("%s: opened %s\n", 
                                               __progname, devs[ndevs]);
                                if (fds[ndevs] > maxfd)
                                        maxfd = fds[ndevs];
                                ndevs++;
                        } else if (errno != ENXIO && errno != ENOENT) {
                                /* there was an error, on a device that does
                                 * exist (device is configured)
                                 */
                                fprintf(stderr, "%s: Could not open %s, %s\n",
                                        __progname, buf, strerror(errno));
                                exit(1);
                        }
                }
        } else {
                /* open all the files specified with -f */
                for (i = 0; i < ndevs; i++) {
                        fds[i] = open(devs[i], O_RDWR);
                        if (fds[i] < 0) {
                                fprintf(stderr, "%s: Could not open %s, %s\n",
                                        __progname, devs[i], strerror(errno));
                                exit(1);
                        } else {
                                if (verbose)
                                        printf("%s: opened %s\n", 
                                               __progname, devs[i]);
                                if (fds[i] > maxfd)
                                        maxfd = fds[i];
                        }
                }
        }

        if (ndevs == 0) {
                fprintf(stderr, "No USB host controllers found\n");
                exit(1);
        }


        /* Do the explore once and exit */
        if (explore_once) {
                for (i = 0; i < ndevs; i++) {
                        error = ioctl(fds[i], USB_DISCOVER);
                        if (error < 0) {
                                fprintf(stderr, "%s: ioctl(%s, USB_DISCOVER) "
                                        "failed, %s\n",
                                        __progname, devs[i], strerror(errno));
                                exit(1);
                        }
                }
                exit(0);
        }

        if (handle_events) {
                if (verbose)
                        printf("%s: reading configuration file %s\n",
                                __progname, configfile);
                read_configuration();

                fd = open(USBDEV, O_RDONLY | O_NONBLOCK);
                if (fd < 0) {
                        fprintf(stderr, "%s: Could not open %s, %s\n",
                                __progname, USBDEV, strerror(errno));
                        exit(1);
                }
                if (verbose)
                        printf("%s: opened %s\n", __progname, USBDEV);
                if (fd > maxfd)
                        maxfd = fd;

                process_event_queue(fd);        /* dequeue the initial events */
        }

        /* move to the background */
        if (!debug)
                daemon(0, 0);

        /* start select on all the open file descriptors */
        for (;;) {
                FD_ZERO(&r);
                FD_ZERO(&w);
                if (handle_events)
                        FD_SET(fd, &r);         /* device USBDEV */
                for (i = 0; i < ndevs; i++)
                        FD_SET(fds[i], &w);     /* device USBDEV\d+ */
                tv.tv_usec = 0;
                tv.tv_sec = itimeout;
                error = select(maxfd+1, &r, &w, 0, itimeout ? &tv : 0);
                if (error < 0) {
                        fprintf(stderr, "%s: Select failed, %s\n",
                                __progname, strerror(errno));
                        exit(1);
                }

                /* USBDEV\d+ devices have signaled change, do a usb_discover */
                for (i = 0; i < ndevs; i++) {
                        if (error == 0 || FD_ISSET(fds[i], &w)) {
                                if (verbose >= 2)
                                        printf("%s: doing %sdiscovery on %s\n", 
                                               __progname,
                                               (error? "":"timeout "), devs[i]);
                                if (ioctl(fds[i], USB_DISCOVER) < 0) {
                                        fprintf(stderr, "%s: ioctl(%s, "
                                                "USB_DISCOVER) failed, %s\n",
                                                __progname, devs[i],
                                                strerror(errno));
                                        exit(1);
                                }
                        }
                }

                /* check the event queue */
                if (handle_events && (FD_ISSET(fd, &r) || error == 0)) {
                        if (verbose >= 2)
                                printf("%s: processing event queue %son %s\n",
                                        __progname,
                                       (error? "":"due to timeout "), USBDEV);
                        process_event_queue(fd);
                }
        }
}