/*
 * 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.
 */

/*
 * synchronous svcadm logic
 */

#include <locale.h>
#include <libintl.h>
#include <libscf.h>
#include <libscf_priv.h>
#include <libuutil.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#include <errno.h>
#include <sys/stat.h>


/*
 * Definitions from svcadm.c.
 */
extern scf_handle_t *h;
extern ssize_t max_scf_fmri_sz;

extern void do_scfdie(int) __NORETURN;
extern int inst_get_state(scf_instance_t *, char *, const char *,
    scf_propertygroup_t **);
extern ssize_t get_astring_prop(const scf_propertygroup_t *, const char *,
    scf_property_t *, scf_value_t *, char *, size_t);
extern int get_bool_prop(scf_propertygroup_t *, const char *, uint8_t *);

#define scfdie()        do_scfdie(__LINE__)

int has_potential(scf_instance_t *, int);

/*
 * Determines if the specified instance is enabled, composing the
 * general and general_ovr property groups.  For simplicity, we map
 * most errors to "not enabled".
 */
int
is_enabled(scf_instance_t *inst)
{
        scf_propertygroup_t *pg;
        uint8_t bp;

        if ((pg = scf_pg_create(h)) == NULL)
                scfdie();

        if (scf_instance_get_pg(inst, SCF_PG_GENERAL_OVR, pg) == 0 &&
            get_bool_prop(pg, SCF_PROPERTY_ENABLED, &bp) == 0) {
                scf_pg_destroy(pg);
                return (bp);
        }

        if (scf_instance_get_pg(inst, SCF_PG_GENERAL, pg) == 0 &&
            get_bool_prop(pg, SCF_PROPERTY_ENABLED, &bp) == 0) {
                scf_pg_destroy(pg);
                return (bp);
        }

        scf_pg_destroy(pg);
        return (B_FALSE);
}

/*
 * Reads an astring property from a property group.  If the named
 * property doesn't exist, returns NULL.  The result of a successful
 * call should be freed.
 */
static char *
read_astring_prop(scf_propertygroup_t *pg, scf_value_t *val,
    scf_property_t *prop, const char *name)
{
        char *value;
        size_t value_sz;

        if (scf_pg_get_property(pg, name, prop) == -1) {
                switch (scf_error()) {
                case SCF_ERROR_NOT_FOUND:
                case SCF_ERROR_DELETED:
                        return (NULL);
                default:
                        scfdie();
                }
        }

        if (scf_property_get_value(prop, val) != 0) {
                switch (scf_error()) {
                case SCF_ERROR_DELETED:
                case SCF_ERROR_NOT_FOUND:
                case SCF_ERROR_CONSTRAINT_VIOLATED:
                        return (NULL);
                default:
                        scfdie();
                }
        }

        value_sz = scf_limit(SCF_LIMIT_MAX_VALUE_LENGTH);
        if ((value = malloc(value_sz)) == NULL)
                scfdie();

        if (scf_value_get_astring(val, value, value_sz) <= 0) {
                free(value);
                return (NULL);
        }

        return (value);
}

/*
 * Creates and returns an scf_iter for the values of the named
 * multi-value property.  Returns NULL on failure.
 */
static scf_iter_t *
prop_walk_init(scf_propertygroup_t *pg, const char *name)
{
        scf_iter_t *iter;
        scf_property_t *prop;

        if ((iter = scf_iter_create(h)) == NULL ||
            (prop = scf_property_create(h)) == NULL)
                scfdie();

        if (scf_pg_get_property(pg, name, prop) != 0) {
                switch (scf_error()) {
                case SCF_ERROR_NOT_FOUND:
                case SCF_ERROR_DELETED:
                        goto error;
                default:
                        scfdie();
                }
        }

        if (scf_iter_property_values(iter, prop) != 0) {
                if (scf_error() != SCF_ERROR_DELETED)
                        scfdie();
                goto error;
        }

        scf_property_destroy(prop);
        return (iter);
error:
        scf_property_destroy(prop);
        scf_iter_destroy(iter);
        return (NULL);
}

/*
 * Reads the next value from the multi-value property using the
 * scf_iter obtained by prop_walk_init, and places it in the buffer
 * pointed to by fmri.  Returns -1 on failure, 0 when done, and non-0
 * when returning a value.
 */
static int
prop_walk_step(scf_iter_t *iter, char *fmri, size_t len)
{
        int r;
        scf_value_t *val;

        if ((val = scf_value_create(h)) == NULL)
                scfdie();

        r = scf_iter_next_value(iter, val);
        if (r == 0)
                goto out;
        if (r == -1) {
                if (scf_error() != SCF_ERROR_DELETED)
                        scfdie();
                goto out;
        }
        if (scf_value_get_astring(val, fmri, len) <= 0) {
                r = -1;
                goto out;
        }

out:
        scf_value_destroy(val);
        return (r);
}

/*
 * Determines if a file dependency is satisfied, taking into account
 * whether it is an exclusion dependency or not.  If we can't access
 * the file, we err on the side of caution and assume the dependency
 * isn't satisfied.
 */
static int
file_has_potential(char *fmri, int exclude)
{
        const char *path;
        struct stat st;

        int good = exclude ? B_FALSE : B_TRUE;

        if (scf_parse_file_fmri(fmri, NULL, &path) != 0)
                return (good);

        if (stat(path, &st) == 0)
                return (good);

        if (errno == EACCES) {
                uu_warn(gettext("Unable to access \"%s\".\n"), path);
                return (B_FALSE);
        }

        return (!good);
}

/*
 * Determines if a dependency on a service instance is satisfiable.
 * Returns 0 if not, 1 if it is, or 2 if it is an optional or exclude
 * dependency and the service only "weakly" satisfies (i.e. is disabled
 * or is in maintenance state).
 */
static int
inst_has_potential(scf_instance_t *inst, int enabled, int optional, int exclude)
{
        char state[MAX_SCF_STATE_STRING_SZ];

        if (!enabled)
                return ((optional || exclude) ? 2 : 0);

        /*
         * Normally we would return a positive value on failure;
         * relying on startd to place the service in maintenance.  But
         * if we can't read a service's state, we have to assume it is
         * out to lunch.
         */
        if (inst_get_state(inst, state, NULL, NULL) != 0)
                return (0);

        /*
         * Optional dependencies which are offline always have a possibility of
         * coming online.
         */
        if (optional && strcmp(state, SCF_STATE_STRING_OFFLINE) == 0)
                return (2);

        if (strcmp(state, SCF_STATE_STRING_MAINT) == 0) {
                /*
                 * Enabled services in maintenance state satisfy
                 * optional-all dependencies.
                 */
                return ((optional || exclude) ? 2 : 0);
        }

        /*
         * We're enabled and not in maintenance.
         */
        if (exclude)
                return (0);

        if (strcmp(state, SCF_STATE_STRING_ONLINE) == 0 ||
            strcmp(state, SCF_STATE_STRING_DEGRADED) == 0)
                return (1);

        return (has_potential(inst, B_FALSE));
}

/*
 * Determines if a dependency on an fmri is satisfiable, handling the
 * separate cases for file, service, and instance fmris.  Returns false
 * if not, or true if it is.  Takes into account if the dependency is
 * an optional or exclusive one.
 */
static int
fmri_has_potential(char *fmri, int isfile, int optional, int exclude,
    int restarter)
{
        scf_instance_t *inst;
        scf_service_t *svc;
        scf_iter_t *iter;
        int good = exclude ? B_FALSE : B_TRUE;
        int enabled;
        int r, result;
        int optbad;

        assert(!optional || !exclude);

        if (isfile)
                return (file_has_potential(fmri, exclude));

        if ((inst = scf_instance_create(h)) == NULL ||
            (svc = scf_service_create(h)) == NULL ||
            (iter = scf_iter_create(h)) == NULL)
                scfdie();

        if (scf_handle_decode_fmri(h, fmri, NULL, NULL, inst, NULL, NULL,
            SCF_DECODE_FMRI_EXACT) == 0) {
                enabled = is_enabled(inst);
                result =
                    (inst_has_potential(inst, enabled, optional, exclude) != 0);
                goto out;
        }

        if (scf_handle_decode_fmri(h, fmri, NULL, svc, NULL, NULL, NULL,
            SCF_DECODE_FMRI_EXACT) != 0) {
                /*
                 * If we are checking a restarter dependency, a bad
                 * or nonexistent service will never be noticed.
                 */
                result = restarter ? B_FALSE : good;
                goto out;
        }

        if (scf_iter_service_instances(iter, svc) != 0) {
                if (scf_error() != SCF_ERROR_DELETED)
                        scfdie();
                result = good;
                goto out;
        }

        optbad = 0;
        for (;;) {
                r = scf_iter_next_instance(iter, inst);
                if (r == 0) {
                        result = exclude || (optional && !optbad);
                        goto out;
                }
                if (r == -1) {
                        if (scf_error() != SCF_ERROR_DELETED)
                                scfdie();
                        result = good;
                        goto out;
                }

                enabled = is_enabled(inst);
                r = inst_has_potential(inst, enabled, optional, exclude);

                /*
                 * Exclusion dependencies over services map to
                 * require-none for its instances.
                 */
                if (exclude)
                        r = (r == 0);

                if (r == 1) {
                        /*
                         * Remember, if this is an exclusion dependency
                         * (which means we are here because there
                         * exists an instance which wasn't satisfiable
                         * in that regard), good means bad.
                         */
                        result = good;
                        goto out;
                }

                if (optional && r == 0)
                        optbad = 1;
        }

out:
        scf_instance_destroy(inst);
        scf_service_destroy(svc);
        scf_iter_destroy(iter);
        return (result);
}

static int
eval_require_any(scf_iter_t *iter, char *value, size_t value_sz, int isfile)
{
        int r, empty = B_TRUE;

        for (;;) {
                /*
                 * For reasons unknown, an empty require_any dependency
                 * group is considered by startd to be satisfied.
                 * This insanity fortunately doesn't extend to
                 * dependencies on services with no instances.
                 */
                if ((r = prop_walk_step(iter, value, value_sz)) <= 0)
                        return ((r == 0 && empty) ? B_TRUE : r);
                if (fmri_has_potential(value, isfile, B_FALSE, B_FALSE,
                    B_FALSE))
                        return (1);
                empty = B_FALSE;
        }
}

static int
eval_all(scf_iter_t *iter, char *value, size_t value_sz,
    int isfile, int optional, int exclude)
{
        int r;

        for (;;) {
                if ((r = prop_walk_step(iter, value, value_sz)) <= 0)
                        return ((r == 0) ? 1 : r);
                if (!fmri_has_potential(value, isfile, optional, exclude,
                    B_FALSE))
                        return (0);
        }
}

static int
eval_require_all(scf_iter_t *iter, char *value, size_t value_sz, int isfile)
{
        return (eval_all(iter, value, value_sz, isfile, B_FALSE, B_FALSE));
}

static int
eval_optional_all(scf_iter_t *iter, char *value, size_t value_sz, int isfile)
{
        return (eval_all(iter, value, value_sz, isfile, B_TRUE, B_FALSE));
}

static int
eval_exclude_all(scf_iter_t *iter, char *value, size_t value_sz, int isfile)
{
        return (eval_all(iter, value, value_sz, isfile, B_FALSE, B_TRUE));
}

/*
 * Examines the state and health of an instance's restarter and
 * dependencies, and determines the impact of both on the instance's
 * ability to be brought on line.  A true return value indicates that
 * instance appears to be a likely candidate for the online club.
 * False indicates that there is no hope for the instance.
 */
int
has_potential(scf_instance_t *inst, int restarter_only)
{
        scf_snapshot_t *snap;
        scf_iter_t *iter, *viter = NULL;
        scf_propertygroup_t *pg;
        scf_property_t *prop;
        scf_value_t *val;
        char *type = NULL, *grouping = NULL;
        char *value;
        size_t value_sz;
        int result = B_TRUE, r;
        int isfile;

        value_sz = scf_limit(SCF_LIMIT_MAX_VALUE_LENGTH);
        if ((iter = scf_iter_create(h)) == NULL ||
            (snap = scf_snapshot_create(h)) == NULL ||
            (pg = scf_pg_create(h)) == NULL ||
            (val = scf_value_create(h)) == NULL ||
            (prop = scf_property_create(h)) == NULL ||
            (value = malloc(value_sz)) == NULL)
                scfdie();

        /*
         * First we check our restarter as an implicit dependency.
         */
        if (scf_instance_get_pg_composed(inst, NULL, SCF_PG_GENERAL, pg) != 0)
                scfdie();

        r = get_astring_prop(pg, SCF_PROPERTY_RESTARTER, prop, val, value,
            value_sz);
        if (r == -ENOENT) {
                (void) strlcpy(value, SCF_SERVICE_STARTD, value_sz);
        } else if (r < 0 || r > max_scf_fmri_sz) {
                /*
                 * Normally we would return true and let the restarter
                 * tell our caller there is a problem by changing the
                 * instance's state, but that's not going to happen if
                 * the restarter is invalid.
                 */
                result = B_FALSE;
                goto out;
        }

        if (!fmri_has_potential(value, B_FALSE, B_FALSE, B_FALSE, B_TRUE)) {
                result = B_FALSE;
                goto out;
        }

        if (restarter_only)
                goto out;

        /*
         * Now we check explicit dependencies.
         */
        if (scf_instance_get_snapshot(inst, "running", snap) != 0) {
                if (scf_error() != SCF_ERROR_NOT_FOUND)
                        scfdie();
                scf_snapshot_destroy(snap);
                snap = NULL;
        }

        if (scf_iter_instance_pgs_typed_composed(iter, inst, snap,
            SCF_GROUP_DEPENDENCY) != 0) {
                if (scf_error() != SCF_ERROR_DELETED)
                        scfdie();
                goto out;
        }

        for (;;) {
                r = scf_iter_next_pg(iter, pg);
                if (r == 0)
                        break;
                if (r == -1) {
                        if (scf_error() != SCF_ERROR_DELETED)
                                scfdie();
                        goto out;
                }

                if ((grouping = read_astring_prop(pg, val, prop,
                    SCF_PROPERTY_GROUPING)) == NULL)
                        goto out;

                if ((type = read_astring_prop(pg, val, prop,
                    SCF_PROPERTY_TYPE)) == NULL)
                        goto out;

                if (strcmp(type, "path") == 0) {
                        isfile = B_TRUE;
                } else if (strcmp(type, "service") == 0) {
                        isfile = B_FALSE;
                } else {
                        free(type);
                        goto out;
                }
                free(type);

                if ((viter = prop_walk_init(pg, SCF_PROPERTY_ENTITIES)) == NULL)
                        goto out;

                if (strcmp(grouping, SCF_DEP_REQUIRE_ALL) == 0) {
                        r = eval_require_all(viter, value, value_sz, isfile);
                } else if (strcmp(grouping, SCF_DEP_REQUIRE_ANY) == 0) {
                        r = eval_require_any(viter, value, value_sz, isfile);
                } else if (strcmp(grouping, SCF_DEP_EXCLUDE_ALL) == 0) {
                        r = eval_exclude_all(viter, value, value_sz, isfile);
                } else if (strcmp(grouping, SCF_DEP_OPTIONAL_ALL) == 0) {
                        r = eval_optional_all(viter, value, value_sz, isfile);
                } else {
                        scf_iter_destroy(viter);
                        free(grouping);
                        grouping = NULL;
                        goto out;
                }

                scf_iter_destroy(viter);
                free(grouping);
                grouping = NULL;

                if (r == 0) {
                        result = B_FALSE;
                        goto out;
                } else if (r == -1) {
                        goto out;
                }
        }

out:
        free(value);
        scf_property_destroy(prop);
        scf_value_destroy(val);
        scf_pg_destroy(pg);
        if (snap != NULL)
                scf_snapshot_destroy(snap);
        if (grouping != NULL)
                free(grouping);
        scf_iter_destroy(iter);
        return (result);
}