source: mainline/uspace/app/bdsh/cmds/builtins/cd/cd.c

/*
 * Copyright (c) 2008 Tim Post
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <stdlib.h>
#include <str.h>
#include <errno.h>
#include <vfs/vfs.h>

#include "util.h"
#include "errors.h"
#include "entry.h"
#include "cmds.h"
#include "cd.h"

static const char *cmdname = "cd";

/*
 * Previous directory variables.
 *
 * Declaring them static to avoid many "== NULL" checks.
 * PATH_MAX is not that big to cause any problems with memory overhead.
 */
static char previous_directory[PATH_MAX] = "";
static char previous_directory_tmp[PATH_MAX];
static bool previous_directory_valid = true;
static bool previous_directory_set = false;

static errno_t chdir_and_remember(const char *new_dir)
{

        errno_t rc = vfs_cwd_get(previous_directory_tmp, PATH_MAX);
        previous_directory_valid = (rc == EOK);
        previous_directory_set = true;

        rc = vfs_cwd_set(new_dir);
        if (rc != EOK)
                return rc;

        str_cpy(previous_directory, PATH_MAX, previous_directory_tmp);
        return EOK;
}

void help_cmd_cd(unsigned int level)
{
        if (level == HELP_SHORT) {
                printf("`%s' changes the current working directory.\n", cmdname);
        } else {
                printf(
                    "  %s <directory>\n"
                    "  Change directory to <directory>, e.g `%s /sbin'\n",
                    cmdname, cmdname);
        }

        return;
}

/* This is a very rudamentary 'cd' command. It is not 'link smart' (yet) */

int cmd_cd(char **argv, cliuser_t *usr)
{
        int argc;
        errno_t rc = EOK;

        argc = cli_count_args(argv);

        /* Handle cd -- -. Override to switch to a directory named '-' */
        bool hyphen_override = false;
        char *target_directory = argv[1];
        if (argc == 3) {
                if (!str_cmp(argv[1], "--")) {
                        hyphen_override = true;
                        argc--;
                        target_directory = argv[2];
                }
        }

        /*
         * We don't yet play nice with whitespace, a getopt implementation should
         * protect "quoted\ destination" as a single argument. Its not our job to
         * look for && || or redirection as the tokenizer should have done that
         * (currently, it does not)
         */

        if (argc > 2) {
                cli_error(CL_EFAIL, "Too many arguments to `%s'", cmdname);
                return CMD_FAILURE;
        }

        if (argc < 2) {
                printf("%s - no directory specified. Try `help %s extended'\n",
                    cmdname, cmdname);
                return CMD_FAILURE;
        }

        /* We have the correct # of arguments */
        // TODO: handle tidle (~) expansion? */

        /* Handle 'cd -' first. */
        if (!str_cmp(target_directory, "-") && !hyphen_override) {
                if (!previous_directory_valid) {
                        cli_error(CL_EFAIL, "Cannot switch to previous directory");
                        return CMD_FAILURE;
                }
                if (!previous_directory_set) {
                        cli_error(CL_EFAIL, "No previous directory to switch to");
                        return CMD_FAILURE;
                }
                char *prev_dup = str_dup(previous_directory);
                if (prev_dup == NULL) {
                        cli_error(CL_ENOMEM, "Cannot switch to previous directory");
                        return CMD_FAILURE;
                }
                rc = chdir_and_remember(prev_dup);
                free(prev_dup);
        } else {
                rc = chdir_and_remember(target_directory);
        }

        if (rc == 0) {
                cli_set_prompt(usr);
                return CMD_SUCCESS;
        } else {
                switch (rc) {
                case ENOMEM:
                        cli_error(CL_EFAIL, "Destination path too long");
                        break;
                case ENOENT:
                        cli_error(CL_ENOENT, "Invalid directory `%s'", target_directory);
                        break;
                default:
                        cli_error(CL_EFAIL, "Unable to change to `%s'", target_directory);
                        break;
                }
        }

        return CMD_FAILURE;
}