libdhcpsvc/private/confopt.c

/*
 * 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.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * This module contains the functions implementing the interface to the
 * /etc/inet/dhcpsvc.conf DHCP service configuration file.
 */

#include <thread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <alloca.h>
#include <string.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <dhcp_svc_confkey.h>
#include <dhcp_svc_confopt.h>
#include <dhcp_svc_private.h>

/*
 * Finds the parameter called key, and returns a reference to it.  Returns
 * NULL if not found or an error occurred.
 */
static dhcp_confopt_t *
find_dhcp_confopt(dhcp_confopt_t *ddp, const char *key)
{
    unsigned int    i;

    if (ddp == NULL || key == NULL)
        return (NULL);

    for (i = 0; ddp[i].co_type != DHCP_END; i++) {
        if (ddp[i].co_type == DHCP_KEY &&
            strcasecmp(ddp[i].co_key, key) == 0)
            return (&ddp[i]);
    }
    return (NULL);
}

/*
 * Adds a dhcp_confopt_t to the ddpp table. If the table is NULL, one is
 * created. The table is terminated by a NULL entry.  The key and value
 * arguments are copied, not referenced directly.  No check is done to see
 * if the parameter already exists.  Returns 0 for success, nonzero
 * otherwise.
 */
int
add_dsvc_conf(dhcp_confopt_t **ddpp, const char *key, const char *value)
{
    dhcp_confopt_t      *ndp, tdp;
    unsigned int        i;

    if (ddpp == NULL || key == NULL || value == NULL) {
        errno = EINVAL;
        return (-1);
    }

    tdp.co_key = strdup(key);
    tdp.co_type = DHCP_KEY;
    tdp.co_value = strdup(value);
    if (tdp.co_key == NULL || tdp.co_value == NULL) {
        free(tdp.co_key);
        free(tdp.co_value);
        errno = ENOMEM;
        return (-1);
    }

    for (i = 0; *ddpp && (*ddpp)[i].co_key != NULL; i++)
        ;

    ndp = realloc(*ddpp, (i + 2) * sizeof (dhcp_confopt_t));
    if (ndp == NULL) {
        free(tdp.co_key);
        free(tdp.co_value);
        errno = ENOMEM;
        return (-1);
    }

    ndp[i] = tdp;
    (void) memset(&ndp[i + 1], 0, sizeof (dhcp_confopt_t));
    *ddpp = ndp;

    return (0);
}

/*
 * Reads the contents of the configuration file into a dynamically
 * allocated array of dhcp_confopt_t records.  A zeroed element marks the
 * end of the array.  Blank lines are ignored.  Caller is responsible for
 * freeing ddp.
 */
int
read_dsvc_conf(dhcp_confopt_t **ddpp)
{
    struct stat sb;
    int     dd;
    int     error;
    unsigned int    entry;
    char        *cp, *dp, *eol, *value;
    dhcp_confopt_t  confopt, *tdp, *ddp = NULL;
    char        conf[MAXPATHLEN];

    if (ddpp == NULL) {
        errno = EINVAL;
        return (-1);
    }

    (void) snprintf(conf, sizeof (conf), "%s" DHCP_CONFOPT_FILE,
        DHCP_CONFOPT_ROOT);

    if ((dd = open(conf, O_RDONLY)) == -1)
        return (-1);
    if (fstat(dd, &sb) == -1) {
        error = errno;
        (void) close(dd);
        errno = error;
        return (-1);
    }

    dp = alloca(sb.st_size);
    if (read(dd, dp, sb.st_size) != sb.st_size) {
        error = errno;
        (void) close(dd);
        errno = error;
        return (-1);
    }
    (void) close(dd);

    for (entry = 0, cp = dp; cp < &dp[sb.st_size]; cp = eol + 1) {
        eol = strchr(cp, '\n');
        if (eol == NULL)        /* done parsing file */
            break;
        if (eol == cp)          /* blank line -- skip */
            continue;
        *eol = '\0';

        if (*cp == '#') {
            confopt.co_type = DHCP_COMMENT;
            confopt.co_comment = strdup(cp + 1);
            if (confopt.co_comment == NULL)
                goto nomem;
        } else {
            value = strchr(cp, '=');
            if (value == NULL)
                continue;
            *value = '\0';

            confopt.co_type = DHCP_KEY;
            confopt.co_key = strdup(cp);
            if (confopt.co_key == NULL)
                goto nomem;

            confopt.co_value = strdup(value + 1);
            if (confopt.co_value == NULL) {
                free(confopt.co_key);
                goto nomem;
            }
        }

        /* always allocate a spare slot for the zeroed entry */
        tdp = realloc(ddp, (entry + 2) * sizeof (dhcp_confopt_t));
        if (tdp == NULL)
            goto nomem;

        tdp[entry] = confopt;
        (void) memset(&tdp[entry + 1], 0, sizeof (dhcp_confopt_t));
        ddp = tdp;
        entry++;
    }

    if (ddp == NULL)
        return (-1);

    *ddpp = ddp;
    return (0);

nomem:
    if (ddp != NULL)
        free_dsvc_conf(ddp);

    errno = ENOMEM;
    return (-1);
}

/*
 * If the requested parameter exists, replace its value with the new
 * value. If it doesn't exist, then add the parameter with the new value.
 * Returns 0 for success, -1 otherwise (errno is set).
 */
int
replace_dsvc_conf(dhcp_confopt_t **ddpp, const char *key, const char *value)
{
    dhcp_confopt_t  *tdp;
    int     err;

    if (ddpp == NULL || key == NULL || value == NULL) {
        errno = EINVAL;
        return (-1);
    }
    if ((tdp = find_dhcp_confopt(*ddpp, key)) != NULL) {
        char    *valp;

        if ((valp = strdup(value)) == NULL)
            return (-1); /* NOMEM */

        if (tdp->co_value != NULL)
            free(tdp->co_value);

        tdp->co_value = valp;

        errno = 0;
        err = 0;
    } else
        err = (add_dsvc_conf(ddpp, key, value) == 0) ? 0 : -1;

    return (err);
}

/*
 * Writes ddp array to the configuration file.  If the configuration file
 * already exists, its contents are replaced with the contents of the ddp
 * array.  If the configuration file does not exist, it is created using
 * the identity of the caller (euid/egid) with the permission bits
 * specified by the mode argument (and modified by the umask).  Caller is
 * responsible for freeing the array.
 */
int
write_dsvc_conf(dhcp_confopt_t *ddp, mode_t mode)
{
    int     tdd;
    ssize_t     bytes;
    size_t      i, size;
    char        *tmpbuf;
    char        tmpconf[MAXPATHLEN], conf[MAXPATHLEN];

    if (ddp == NULL) {
        errno = EINVAL;
        return (-1);
    }

    /* guess at final file size */
    for (i = 0, size = 0; ddp[i].co_type != DHCP_END; i++) {
        if (ddp[i].co_type == DHCP_KEY) {
            size += strlen(ddp[i].co_key) + 1; /* include = */
            size += strlen(ddp[i].co_value) + 1; /* include \n */
        } else
            size += strlen(ddp[i].co_comment) + 2; /* inc # + \n */
    }

    if (size == 0) {
        errno = EINVAL;
        return (-1);
    }

    (void) snprintf(conf, sizeof (conf), "%s" DHCP_CONFOPT_FILE,
        DHCP_CONFOPT_ROOT);
    (void) snprintf(tmpconf, sizeof (tmpconf),
        "%s" DHCP_CONFOPT_FILE ".%ld.%u", DHCP_CONFOPT_ROOT, getpid(),
        thr_self());

    if ((tdd = open(tmpconf, O_CREAT | O_EXCL | O_WRONLY, mode)) < 0)
        return (-1);

    tmpbuf = alloca(size);
    for (i = 0; ddp[i].co_type != DHCP_END; i++) {
        if (ddp[i].co_type == DHCP_KEY)
            (void) snprintf(tmpbuf, size, "%s=%s\n", ddp[i].co_key,
                ddp[i].co_value);
        else
            (void) snprintf(tmpbuf, size, "#%s\n",
                ddp[i].co_comment);

        bytes = write(tdd, tmpbuf, strlen(tmpbuf));

        /* Nuke the file if we can't successfully update it */
        if (bytes != strlen(tmpbuf)) {
            (void) close(tdd);
            (void) unlink(tmpconf);
            return (-1);
        }
    }
    (void) close(tdd);

    /* Move new file into place */
    if (rename(tmpconf, conf) < 0) {
        (void) unlink(tmpconf);
        return (-1);
    }

    return (0);
}

/*
 * Frees the memory associated with the ddp array.
 */
void
free_dsvc_conf(dhcp_confopt_t *ddp)
{
    unsigned int    i;

    if (ddp == NULL)
        return;

    for (i = 0; ddp[i].co_type != DHCP_END; i++) {
        if (ddp[i].co_type == DHCP_KEY) {
            free(ddp[i].co_key);
            free(ddp[i].co_value);
        } else
            free(ddp[i].co_comment);
    }
    free(ddp);
}

/*
 * Deletes the configuration file.
 */
int
delete_dsvc_conf(void)
{
    char confpath[MAXPATHLEN];

    (void) snprintf(confpath, sizeof (confpath), "%s" DHCP_CONFOPT_FILE,
        DHCP_CONFOPT_ROOT);
    return (unlink(confpath));
}

/*
 * Return a copy of the value portion of the named key.  Caller is
 * responsible for freeing value when they're finished using it.  Returns 0
 * for success, -1 otherwise (errno is set).
 */
int
query_dsvc_conf(dhcp_confopt_t *ddp, const char *key, char **value)
{
    dhcp_confopt_t  *tdp;

    if (key == NULL || value == NULL) {
        errno = EINVAL;
        return (-1);
    }
    if ((tdp = find_dhcp_confopt(ddp, key)) != NULL) {
        *value = strdup(tdp->co_value);
        if (*value == NULL) {
            errno = ENOMEM;
            return (-1);
        }
        errno = 0;
        return (0);
    }
    errno = ENOENT;
    *value = NULL;
    return (-1);
}

/*
 * Given a dhcp_confopt_t structure, fill in a dsvc_datastore_t.
 * Data is copied from dhcp_confopt_t structure.
 */
int
confopt_to_datastore(dhcp_confopt_t *ddp, dsvc_datastore_t *dsp)
{
    dhcp_confopt_t  *tdp;

    if (ddp == NULL || dsp == NULL)
        return (DSVC_INVAL);

    tdp = find_dhcp_confopt(ddp, DSVC_CK_CONVER);
    if (tdp == NULL || tdp->co_value == NULL)
        return (DSVC_BAD_CONVER);
    dsp->d_conver = atoi(tdp->co_value);

    if (query_dsvc_conf(ddp, DSVC_CK_RESOURCE, &dsp->d_resource) == -1)
        return (DSVC_BAD_RESOURCE);

    if (query_dsvc_conf(ddp, DSVC_CK_PATH, &dsp->d_location) == -1) {
        free(dsp->d_resource);
        return (DSVC_BAD_PATH);
    }

    /*
     * RESOURCE_CONFIG is optional - underlying service will complain
     * if it isn't right.
     */
    (void) query_dsvc_conf(ddp, DSVC_CK_RESOURCE_CONFIG, &dsp->d_config);

    return (DSVC_SUCCESS);
}