/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 * Copyright 2017 Nexenta Systems, Inc.
 */

#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <ftw.h>
#include <string.h>
#include <thread.h>
#include <synch.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/modctl.h>
#include <strings.h>

#include <libdevinfo.h>
#include "libdevid.h"

/*
 * Get Device Id from an open file descriptor
 */
int
devid_get(int fd, ddi_devid_t *devidp)
{
        int             len = 0;
        dev_t           dev;
        struct stat     statb;
        ddi_devid_t     mydevid;

        if (fstat(fd, &statb) != 0)
                return (-1);

        /* If not char or block device, then error */
        if (!S_ISCHR(statb.st_mode) && !S_ISBLK(statb.st_mode))
                return (-1);

        /* Get the device id size */
        dev = statb.st_rdev;
        if (modctl(MODSIZEOF_DEVID, dev, &len) != 0)
                return (-1);

        /* Allocate space to return device id */
        if ((mydevid = (ddi_devid_t)malloc(len)) == NULL)
                return (-1);

        /* Get the device id */
        if (modctl(MODGETDEVID, dev, len, mydevid) != 0) {
                free(mydevid);
                return (-1);
        }

        /* Return the device id copy */
        *devidp = mydevid;
        return (0);
}

/*
 * Get the minor name
 */
int
devid_get_minor_name(int fd, char **minor_namep)
{
        int             len = 0;
        dev_t           dev;
        int             spectype;
        char            *myminor_name;
        struct stat     statb;

        if (fstat(fd, &statb) != 0)
                return (-1);

        /* If not a char or block device, then return an error */
        if (!S_ISCHR(statb.st_mode) && !S_ISBLK(statb.st_mode))
                return (-1);

        spectype = statb.st_mode & S_IFMT;
        dev = statb.st_rdev;

        /* Get the minor name size */
        if (modctl(MODSIZEOF_MINORNAME, dev, spectype, &len) != 0)
                return (-1);

        /* Allocate space for the minor name */
        if ((myminor_name = (char *)malloc(len)) == NULL)
                return (-1);

        /* Get the minor name */
        if (modctl(MODGETMINORNAME, dev, spectype, len, myminor_name) != 0) {
                free(myminor_name);
                return (-1);
        }

        /* return the minor name copy */
        *minor_namep = myminor_name;
        return (0);
}

char *
devid_str_from_path(const char *path)
{
        int             fd;
        ddi_devid_t     devid;
        char            *minor, *ret = NULL;

        if ((fd = open(path, O_RDONLY)) < 0)
                return (NULL);

        if (devid_get(fd, &devid) == 0) {
                if (devid_get_minor_name(fd, &minor) != 0)
                        minor = NULL;
                ret = devid_str_encode(devid, minor);
                if (minor != NULL)
                        devid_str_free(minor);
                devid_free(devid);
        }
        (void) close(fd);

        return (ret);
}

/* list element of devid_nmlist_t information */
struct nmlist {
        struct nmlist   *nl_next;
        char            *nl_devname;
        dev_t           nl_dev;
};

/* add list element to end of nmlist headed by *nlhp */
struct nmlist *
nmlist_add(struct nmlist **nlhp, char *path)
{
        struct stat     statb;
        dev_t           dev;
        struct nmlist   *nl;

        /* stat and get the devt for char or block */
        if ((stat(path, &statb) == 0) &&
            (S_ISCHR(statb.st_mode) || S_ISBLK(statb.st_mode)))
                dev = statb.st_rdev;
        else
                dev = NODEV;

        /* find the end of the list */
        for (; (nl = *nlhp) != NULL; nlhp = &nl->nl_next)
                ;

        /* allocate and initialize new entry */
        if ((nl = malloc(sizeof (*nl))) == NULL)
                return (NULL);

        if ((nl->nl_devname = strdup(path)) == NULL) {
                free(nl);
                return (NULL);
        }
        nl->nl_next = NULL;
        nl->nl_dev = dev;

        /* link new entry at end */
        *nlhp = nl;
        return (nl);
}

/* information needed by devlink_callback to call nmlist_add */
struct devlink_cbinfo {
        struct nmlist   **cbi_nlhp;
        char            *cbi_search_path;
        int             cbi_error;
};

/* di_devlink callback to add a /dev entry to nmlist */
static int
devlink_callback(di_devlink_t dl, void *arg)
{
        struct devlink_cbinfo   *cbip = (struct devlink_cbinfo *)arg;
        char                    *devpath = (char *)di_devlink_path(dl);

        if (strncmp(devpath, cbip->cbi_search_path,
            strlen(cbip->cbi_search_path)) == 0) {
                if (nmlist_add(cbip->cbi_nlhp, devpath) == NULL) {
                        cbip->cbi_error = 1;
                        return (DI_WALK_TERMINATE);
                }
        }
        return (DI_WALK_CONTINUE);
}

/*
 * Resolve /dev names to DI_PRIMARY_LINK, DI_SECONDARY_LINK, or both.
 * The default is to resolve to just the DI_PRIMARY_LINK.
 */
int                     devid_deviceid_to_nmlist_link = DI_PRIMARY_LINK;

/*
 * Options for the devid_deviceid_to_nmlist implementation:
 *
 *   DEVICEID_NMLIST_SLINK -    reduce overhead by reuse the previous
 *                              di_devlink_init.
 */
#define DEVICEID_NMLIST_SLINK   1
int                     devid_deviceid_to_nmlist_flg = 0;
static di_devlink_handle_t devid_deviceid_to_nmlist_dlh = NULL; /* SLINK */

#define DEVICEID_NMLIST_NRETRY  10

/*
 * Convert the specified devid/minor_name into a devid_nmlist_t array
 * with names that resolve into /devices or /dev depending on search_path.
 *
 * The man page indicates that:
 *
 *     This function traverses the file tree, starting at search_path.
 *
 * This is not true, we reverse engineer the paths relative to
 * the specified search path to avoid attaching all devices.
 */
int
devid_deviceid_to_nmlist(char *search_path, ddi_devid_t devid, char *minor_name,
    devid_nmlist_t **retlist)
{
        char                    *cp;
        int                     dev;
        char                    *paths = NULL;
        char                    *path;
        int                     lens;
        di_devlink_handle_t     dlh = NULL;
        int                     ret = -1;
        struct devlink_cbinfo   cbi;
        struct nmlist           *nlh = NULL;
        struct nmlist           *nl;
        devid_nmlist_t          *rl;
        int                     nret;
        int                     nagain = 0;
        int                     err = 0;

        *retlist = NULL;

        /* verify valid search path starts with "/devices" or "/dev" */
        if ((strcmp(search_path, "/devices") == 0) ||
            (strncmp(search_path, "/devices/", 9) == 0))
                dev = 0;
        else if ((strcmp(search_path, "/dev") == 0) ||
            (strncmp(search_path, "/dev/", 5) == 0))
                dev = 1;
        else {
                errno = EINVAL;
                return (-1);
        }


        /* translate devid/minor_name to /devices paths */
again:  if (modctl(MODDEVID2PATHS, devid, minor_name, 0, &lens, NULL) != 0)
                goto out;
        if ((paths = (char *)malloc(lens)) == NULL)
                goto out;
        if (modctl(MODDEVID2PATHS, devid, minor_name, 0, &lens, paths) != 0) {
                if ((errno == EAGAIN) && (nagain++ < DEVICEID_NMLIST_NRETRY)) {
                        free(paths);
                        paths = NULL;
                        goto again;
                }
                goto out;
        }

        /*
         * initialize for /devices path to /dev path translation. To reduce
         * overhead we reuse the last snapshot if DEVICEID_NMLIST_SLINK is set.
         */
        if (dev) {
                dlh = devid_deviceid_to_nmlist_dlh;
                if (dlh &&
                    !(devid_deviceid_to_nmlist_flg & DEVICEID_NMLIST_SLINK)) {
                        (void) di_devlink_fini(&dlh);
                        dlh = devid_deviceid_to_nmlist_dlh = NULL;
                }
                if ((dlh == NULL) &&
                    ((dlh = di_devlink_init(NULL, 0)) == NULL))
                                goto out;
        }

        /*
         * iterate over all the devtspectype resolutions of the devid and
         * convert them into the appropriate path form and add items to return
         * to the nmlist list;
         */
        for (path = paths; *path; path += strlen(path) + 1) {
                if (dev) {
                        /* add /dev entries */
                        cbi.cbi_nlhp = &nlh;
                        cbi.cbi_search_path = search_path;
                        cbi.cbi_error = 0;

                        (void) di_devlink_walk(dlh, NULL, path,
                            devid_deviceid_to_nmlist_link,
                            (void *)&cbi, devlink_callback);
                        if (cbi.cbi_error)
                                goto out;
                } else {
                        /* add /devices entry */
                        cp = malloc(strlen("/devices") + strlen(path) + 1);
                        (void) strcpy(cp, "/devices");
                        (void) strcat(cp, path);
                        if (strncmp(cp, search_path,
                            strlen(search_path)) == 0) {
                                if (nmlist_add(&nlh, cp) == NULL) {
                                        free(cp);
                                        goto out;
                                }
                        }
                        free(cp);
                }
        }

        /* convert from nmlist to retlist array */
        for (nl = nlh, nret = 0; nl; nl = nl->nl_next)
                nret++;
        if (nret == 0) {
                err = ENODEV;
                goto out;
        }
        if ((*retlist = calloc(nret + 1, sizeof (devid_nmlist_t))) == NULL) {
                err = ENOMEM;
                goto out;
        }
        for (nl = nlh, rl = *retlist; nl; nl = nl->nl_next, rl++) {
                rl->devname = nl->nl_devname;
                rl->dev = nl->nl_dev;
        }
        rl->devname = NULL;
        rl->dev = NODEV;

        ret = 0;

out:
        while ((nl = nlh) != NULL) {    /* free the nmlist */
                nlh = nl->nl_next;
                free(nl);
        }
        if (paths)
                free(paths);
        if (dlh) {
                if ((ret == 0) &&
                    (devid_deviceid_to_nmlist_flg & DEVICEID_NMLIST_SLINK))
                        devid_deviceid_to_nmlist_dlh = dlh;
                else
                        (void) di_devlink_fini(&dlh);
        }
        if (ret && *retlist)
                free(*retlist);
        if (ret && err != 0)
                errno = err;
        return (ret);
}

/*
 * Free Device Id Name List
 */
void
devid_free_nmlist(devid_nmlist_t *list)
{
        devid_nmlist_t *p = list;

        if (list == NULL)
                return;

        /* Free all the device names */
        while (p->devname != NULL) {
                free(p->devname);
                p++;
        }

        /* Free the array */
        free(list);
}