/* $OpenBSD: environ.c,v 1.30 2026/02/23 08:45:27 nicm Exp $ */

/*
 * Copyright (c) 2009 Nicholas Marriott <nicholas.marriott@gmail.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
 * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>

#include <fnmatch.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "tmux.h"

/*
 * Environment - manipulate a set of environment variables.
 */

RB_HEAD(environ, environ_entry);
static int environ_cmp(struct environ_entry *, struct environ_entry *);
RB_GENERATE_STATIC(environ, environ_entry, entry, environ_cmp);

static int
environ_cmp(struct environ_entry *envent1, struct environ_entry *envent2)
{
        return (strcmp(envent1->name, envent2->name));
}

/* Initialise the environment. */
struct environ *
environ_create(void)
{
        struct environ  *env;

        env = xcalloc(1, sizeof *env);
        RB_INIT(env);

        return (env);
}

/* Free an environment. */
void
environ_free(struct environ *env)
{
        struct environ_entry    *envent, *envent1;

        if (env == NULL)
                return;

        RB_FOREACH_SAFE(envent, environ, env, envent1) {
                RB_REMOVE(environ, env, envent);
                free(envent->name);
                free(envent->value);
                free(envent);
        }
        free(env);
}

struct environ_entry *
environ_first(struct environ *env)
{
        return (RB_MIN(environ, env));
}

struct environ_entry *
environ_next(struct environ_entry *envent)
{
        return (RB_NEXT(environ, env, envent));
}

/* Copy one environment into another. */
void
environ_copy(struct environ *srcenv, struct environ *dstenv)
{
        struct environ_entry    *envent;

        RB_FOREACH(envent, environ, srcenv) {
                if (envent->value == NULL)
                        environ_clear(dstenv, envent->name);
                else {
                        environ_set(dstenv, envent->name, envent->flags,
                            "%s", envent->value);
                }
        }
}

/* Find an environment variable. */
struct environ_entry *
environ_find(struct environ *env, const char *name)
{
        struct environ_entry    envent;

        envent.name = (char *) name;
        return (RB_FIND(environ, env, &envent));
}

/* Set an environment variable. */
void
environ_set(struct environ *env, const char *name, int flags, const char *fmt,
    ...)
{
        struct environ_entry    *envent;
        va_list                  ap;

        va_start(ap, fmt);
        if ((envent = environ_find(env, name)) != NULL) {
                envent->flags = flags;
                free(envent->value);
                xvasprintf(&envent->value, fmt, ap);
        } else {
                envent = xmalloc(sizeof *envent);
                envent->name = xstrdup(name);
                envent->flags = flags;
                xvasprintf(&envent->value, fmt, ap);
                RB_INSERT(environ, env, envent);
        }
        va_end(ap);
}

/* Clear an environment variable. */
void
environ_clear(struct environ *env, const char *name)
{
        struct environ_entry    *envent;

        if ((envent = environ_find(env, name)) != NULL) {
                free(envent->value);
                envent->value = NULL;
        } else {
                envent = xmalloc(sizeof *envent);
                envent->name = xstrdup(name);
                envent->flags = 0;
                envent->value = NULL;
                RB_INSERT(environ, env, envent);
        }
}

/* Set an environment variable from a NAME=VALUE string. */
void
environ_put(struct environ *env, const char *var, int flags)
{
        char    *name, *value;

        value = strchr(var, '=');
        if (value == NULL)
                return;
        value++;

        name = xstrdup(var);
        name[strcspn(name, "=")] = '\0';

        environ_set(env, name, flags, "%s", value);
        free(name);
}

/* Unset an environment variable. */
void
environ_unset(struct environ *env, const char *name)
{
        struct environ_entry    *envent;

        if ((envent = environ_find(env, name)) == NULL)
                return;
        RB_REMOVE(environ, env, envent);
        free(envent->name);
        free(envent->value);
        free(envent);
}

/* Copy variables from a destination into a source environment. */
void
environ_update(struct options *oo, struct environ *src, struct environ *dst)
{
        struct environ_entry            *envent;
        struct environ_entry            *envent1;
        struct options_entry            *o;
        struct options_array_item       *a;
        union options_value             *ov;
        int                              found;

        o = options_get(oo, "update-environment");
        if (o == NULL)
                return;
        a = options_array_first(o);
        while (a != NULL) {
                ov = options_array_item_value(a);
                found = 0;
                RB_FOREACH_SAFE(envent, environ, src, envent1) {
                        if (fnmatch(ov->string, envent->name, 0) == 0) {
                                environ_set(dst, envent->name, 0, "%s", envent->value);
                                found = 1;
                        }
                }
                if (!found)
                        environ_clear(dst, ov->string);
                a = options_array_next(a);
        }
}

/* Push environment into the real environment - use after fork(). */
void
environ_push(struct environ *env)
{
        struct environ_entry    *envent;

        environ = xcalloc(1, sizeof *environ);
        RB_FOREACH(envent, environ, env) {
                if (envent->value != NULL &&
                    *envent->name != '\0' &&
                    (~envent->flags & ENVIRON_HIDDEN))
                        setenv(envent->name, envent->value, 1);
        }
}

/* Log the environment. */
void
environ_log(struct environ *env, const char *fmt, ...)
{
        struct environ_entry    *envent;
        va_list                  ap;
        char                    *prefix;

        va_start(ap, fmt);
        vasprintf(&prefix, fmt, ap);
        va_end(ap);

        RB_FOREACH(envent, environ, env) {
                if (envent->value != NULL && *envent->name != '\0') {
                        log_debug("%s%s=%s", prefix, envent->name,
                            envent->value);
                }
        }

        free(prefix);
}

/* Create initial environment for new child. */
struct environ *
environ_for_session(struct session *s, int no_TERM)
{
        struct environ  *env;
        const char      *value;
        int              idx;

        env = environ_create();
        environ_copy(global_environ, env);
        if (s != NULL)
                environ_copy(s->environ, env);

        if (!no_TERM) {
                value = options_get_string(global_options, "default-terminal");
                environ_set(env, "TERM", 0, "%s", value);
                environ_set(env, "TERM_PROGRAM", 0, "%s", "tmux");
                environ_set(env, "TERM_PROGRAM_VERSION", 0, "%s", getversion());
                environ_set(env, "COLORTERM", 0, "truecolor");
        }

        if (s != NULL)
                idx = s->id;
        else
                idx = -1;
        environ_set(env, "TMUX", 0, "%s,%ld,%d", socket_path, (long)getpid(),
            idx);

        return (env);
}