libzonecfg/common/getzoneent.c

	getzoneent.c revision 087719fdb025870aa55ae7d42f46547e050208ec
/*
 * 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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*
 * This module contains functions used for reading and writing the index file.
 * setzoneent() opens the file.  getzoneent() parses the file, doing the usual
 * skipping of comment lines, etc., and using gettok() to deal with the ":"
 * delimiters.  endzoneent() closes the file.  putzoneent() updates the file,
 * adding, deleting or modifying lines, locking and unlocking appropriately.
 */

#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>
#include <libzonecfg.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <assert.h>
#include "zonecfg_impl.h"


#define _PATH_TMPFILE   ZONE_CONFIG_ROOT "/zonecfg.XXXXXX"

/*
 * gettok() is a helper function for parsing the index file, used to split
 * the lines by their ":" delimiters.  Note that an entry may contain a ":"
 * inside double quotes; this should only affect the zonepath, as zone names
 * do not allow such characters, and zone states do not have them either.
 * Same with double-quotes themselves: they are not allowed in zone names,
 * and do not occur in zone states, and in theory should never occur in a
 * zonepath since zonecfg does not support a method for escaping them.
 */

static char *
gettok(char **cpp)
{
    char *cp = *cpp, *retv;
    boolean_t quoted = B_FALSE;

    if (cp == NULL)
        return ("");
    if (*cp == '"') {
        quoted = B_TRUE;
        cp++;
    }
    retv = cp;
    if (quoted) {
        while (*cp != '\0' && *cp != '"')
            cp++;
        if (*cp == '"')
            *cp++ = '\0';
    }
    while (*cp != '\0' && *cp != ':')
        cp++;
    if (*cp == '\0') {
        *cpp = NULL;
    } else {
        *cp++ = '\0';
        *cpp = cp;
    }
    return (retv);
}

char *
getzoneent(FILE *cookie)
{
    struct zoneent *ze;
    char *name;

    if ((ze = getzoneent_private(cookie)) == NULL)
        return (NULL);
    name = strdup(ze->zone_name);
    free(ze);
    return (name);
}

struct zoneent *
getzoneent_private(FILE *cookie)
{
    char *cp, buf[MAX_INDEX_LEN], *p;
    struct zoneent *ze;

    if (cookie == NULL)
        return (NULL);

    if ((ze = malloc(sizeof (struct zoneent))) == NULL)
        return (NULL);

    for (;;) {
        if (fgets(buf, sizeof (buf), cookie) == NULL) {
            free(ze);
            return (NULL);
        }
        if ((cp = strpbrk(buf, "\r\n")) == NULL) {
            /* this represents a line that's too long */
            continue;
        }
        *cp = '\0';
        cp = buf;
        if (*cp == '#') {
            /* skip comment lines */
            continue;
        }
        p = gettok(&cp);
        if (p == NULL || *p == '\0' || strlen(p) > ZONENAME_MAX) {
            /*
             * empty or very long zone names are not allowed
             */
            continue;
        }
        (void) strlcpy(ze->zone_name, p, ZONENAME_MAX);

        p = gettok(&cp);
        if (p == NULL || *p == '\0') {
            /* state field should not be empty */
            continue;
        }
        errno = 0;
        if (strcmp(p, ZONE_STATE_STR_CONFIGURED) == 0) {
            ze->zone_state = ZONE_STATE_CONFIGURED;
        } else if (strcmp(p, ZONE_STATE_STR_INCOMPLETE) == 0) {
            ze->zone_state = ZONE_STATE_INCOMPLETE;
        } else if (strcmp(p, ZONE_STATE_STR_INSTALLED) == 0) {
            ze->zone_state = ZONE_STATE_INSTALLED;
        } else
            continue;

        p = gettok(&cp);
        if (strlen(p) > MAXPATHLEN) {
            /* very long paths are not allowed */
            continue;
        }
        if (p == NULL) {
            /* empty paths accepted for backwards compatibility */
            p = "";
        }
        (void) strlcpy(ze->zone_path, p, MAXPATHLEN);

        break;
    }

    return (ze);
}

FILE *
setzoneent(void)
{
    return (fopen(ZONE_INDEX_FILE, "r"));
}

void
endzoneent(FILE *cookie)
{
    if (cookie != NULL)
        (void) fclose(cookie);
}

static int
lock_index_file(int *lock_fd)
{
    struct flock lock;

    if ((mkdir(ZONE_SNAPSHOT_ROOT, S_IRWXU) == -1) && errno != EEXIST)
        return (Z_LOCKING_FILE);
    *lock_fd = open(ZONE_INDEX_LOCK_FILE, O_CREAT|O_RDWR, 0644);
    if (*lock_fd < 0)
        return (Z_LOCKING_FILE);

    lock.l_type = F_WRLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = 0;
    lock.l_len = 0;

    if (fcntl(*lock_fd, F_SETLKW, &lock) == -1)
        return (Z_LOCKING_FILE);

    return (Z_OK);
}

static int
unlock_index_file(int lock_fd)
{
    struct flock lock;

    lock.l_type = F_UNLCK;
    lock.l_whence = SEEK_SET;
    lock.l_start = 0;
    lock.l_len = 0;

    if (fcntl(lock_fd, F_SETLK, &lock) == -1)
        return (Z_UNLOCKING_FILE);

    if (close(lock_fd) == -1)
        return (Z_UNLOCKING_FILE);

    return (Z_OK);
}

/*
 * This function adds or removes a zone name et al. to the index file.
 *
 * If ze->zone_state is < 0, it means leave the
 * existing value unchanged; this is only meaningful when operation ==
 * PZE_MODIFY (i.e., it's bad on PZE_ADD and a no-op on PZE_REMOVE).
 *
 * A zero-length ze->zone_path means leave the existing value
 * unchanged; this is only meaningful when operation == PZE_MODIFY
 * (i.e., it's bad on PZE_ADD and a no-op on PZE_REMOVE).
 *
 * A zero-length ze->zone_newname means leave the existing name
 * unchanged; otherwise the zone is renamed to zone_newname.  This is
 * only meaningful when operation == PZE_MODIFY.
 *
 * Locking and unlocking is done via the functions above.
 * The file itself is not modified in place; rather, a copy is made which
 * is modified, then the copy is atomically renamed back to the main file.
 */
int
putzoneent(struct zoneent *ze, zoneent_op_t operation)
{
    FILE *index_file, *tmp_file;
    char *tmp_file_name, buf[MAX_INDEX_LEN], orig_buf[MAX_INDEX_LEN];
    char zone[ZONENAME_MAX + 1];        /* name plus newline */
    char line[MAX_INDEX_LEN];
    int tmp_file_desc, lock_fd, err;
    boolean_t exists = B_FALSE, need_quotes;
    char *cp, *p;

    assert(ze != NULL);
    if (operation == PZE_ADD &&
        (ze->zone_state < 0 || strlen(ze->zone_path) == 0))
        return (Z_INVAL);

    if (operation != PZE_MODIFY && strlen(ze->zone_newname) != 0)
        return (Z_INVAL);

    if ((err = lock_index_file(&lock_fd)) != Z_OK)
        return (err);
    tmp_file_name = strdup(_PATH_TMPFILE);
    if (tmp_file_name == NULL) {
        (void) unlock_index_file(lock_fd);
        return (Z_NOMEM);
    }
    tmp_file_desc = mkstemp(tmp_file_name);
    if (tmp_file_desc == -1) {
        (void) unlink(tmp_file_name);
        free(tmp_file_name);
        (void) unlock_index_file(lock_fd);
        return (Z_TEMP_FILE);
    }
    if ((tmp_file = fdopen(tmp_file_desc, "w")) == NULL) {
        (void) close(tmp_file_desc);
        (void) unlink(tmp_file_name);
        free(tmp_file_name);
        (void) unlock_index_file(lock_fd);
        return (Z_MISC_FS);
    }
    if ((index_file = fopen(ZONE_INDEX_FILE, "r")) == NULL) {
        (void) fclose(tmp_file);
        (void) unlink(tmp_file_name);
        free(tmp_file_name);
        (void) unlock_index_file(lock_fd);
        return (Z_MISC_FS);
    }

    /*
     * We need to quote a path which contains a ":"; this should only
     * affect the zonepath, as zone names do not allow such characters,
     * and zone states do not have them either.  Same with double-quotes
     * themselves: they are not allowed in zone names, and do not occur
     * in zone states, and in theory should never occur in a zonepath
     * since zonecfg does not support a method for escaping them.
     */
    need_quotes = (strchr(ze->zone_path, ':') != NULL);

    (void) snprintf(line, sizeof (line), "%s:%s:%s%s%s\n", ze->zone_name,
        zone_state_str(ze->zone_state), need_quotes ? "\"" : "",
        ze->zone_path, need_quotes ? "\"" : "");
    for (;;) {
        if (fgets(buf, sizeof (buf), index_file) == NULL) {
            if (operation == PZE_ADD && !exists)
                (void) fputs(line, tmp_file);
            break;
        }
        (void) strlcpy(orig_buf, buf, sizeof (orig_buf));

        if ((cp = strpbrk(buf, "\r\n")) == NULL) {
            /* this represents a line that's too long */
            continue;
        }
        *cp = '\0';
        cp = buf;
        if (*cp == '#') {
            /* skip comment lines */
            (void) fputs(orig_buf, tmp_file);
            continue;
        }
        p = gettok(&cp);
        if (p == NULL || *p == '\0' || strlen(p) > ZONENAME_MAX) {
            /*
             * empty or very long zone names are not allowed
             */
            continue;
        }
        (void) strlcpy(zone, p, ZONENAME_MAX);

        if (strcmp(zone, ze->zone_name) == 0) {
            exists = B_TRUE;        /* already there */
            if (operation == PZE_ADD) {
                /* can't add same zone */
                goto error;
            } else if (operation == PZE_MODIFY) {
                char tmp_state[ZONE_STATE_MAXSTRLEN + 1];
                char *tmp_name;

                if (ze->zone_state >= 0 &&
                    strlen(ze->zone_path) > 0) {
                    /* use specified values */
                    (void) fputs(line, tmp_file);
                    continue;
                }
                /* use existing value for state */
                p = gettok(&cp);
                if (p == NULL || *p == '\0') {
                    /* state field should not be empty */
                    goto error;
                }
                (void) strlcpy(tmp_state,
                    (ze->zone_state < 0) ? p :
                    zone_state_str(ze->zone_state),
                    sizeof (tmp_state));

                p = gettok(&cp);

                /*
                 * If a new name is supplied, use it.
                 */
                if (strlen(ze->zone_newname) != 0)
                    tmp_name = ze->zone_newname;
                else
                    tmp_name = ze->zone_name;

                (void) fprintf(tmp_file, "%s:%s:%s%s%s\n",
                    tmp_name, tmp_state,
                    need_quotes ? "\"" : "",
                    (strlen(ze->zone_path) == 0) ? p :
                    ze->zone_path, need_quotes ? "\"" : "");
            }
            /* else if (operation == PZE_REMOVE) { no-op } */
        } else {
            (void) fputs(orig_buf, tmp_file);
        }
    }

    (void) fclose(index_file);
    if (fclose(tmp_file) != 0) {
        (void) unlink(tmp_file_name);
        free(tmp_file_name);
        (void) unlock_index_file(lock_fd);
        return (Z_MISC_FS);
    }
    (void) chmod(tmp_file_name, 0644);
    if (rename(tmp_file_name, ZONE_INDEX_FILE) == -1) {
        (void) unlink(tmp_file_name);
        free(tmp_file_name);
        (void) unlock_index_file(lock_fd);
        if (errno == EACCES)
            return (Z_ACCES);
        return (Z_MISC_FS);
    }
    free(tmp_file_name);
    if (unlock_index_file(lock_fd) != Z_OK)
        return (Z_UNLOCKING_FILE);
    return (Z_OK);
error:
    (void) fclose(index_file);
    (void) fclose(tmp_file);
    (void) unlink(tmp_file_name);
    free(tmp_file_name);
    if (unlock_index_file(lock_fd) != Z_OK)
        return (Z_UNLOCKING_FILE);
    return (Z_UPDATING_INDEX);
}