ls.c

/* Copyright (c) 2008, Tim Post <tinkertim@gmail.com>
 * 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.
 *
 * Neither the name of the original program's authors nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
 */

/* NOTE:
 * This is a bit of an ugly hack, working around the absence of fstat / etc.
 * As more stuff is completed and exposed in libc, this will improve */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <dirent.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <str.h>
#include <sort.h>

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

/* Various values that can be returned by ls_scope() */
#define LS_BOGUS 0
#define LS_FILE  1
#define LS_DIR   2

struct dir_elem_t {
        char *name;
        struct stat s;
};

static const char *cmdname = "ls";

static struct option const long_options[] = {
        { "help", no_argument, 0, 'h' },
        { "unsort", no_argument, 0, 'u' },
        { 0, 0, 0, 0 }
};

static void ls_print(struct dir_elem_t *de)
{
        if (de->s.is_file)
                printf("%-40s\t%llu\n", de->name, (long long) de->s.size);
        else if (de->s.is_directory)
                printf("%-40s\t<dir>\n", de->name);
        else
                printf("%-40s\n", de->name);
}


static int ls_cmp(void *a, void *b, void *arg)
{
        struct dir_elem_t *da = a;
        struct dir_elem_t *db = b;
        
        if ((da->s.is_directory && db->s.is_file) ||
            ((da->s.is_directory == db->s.is_directory) &&
            str_cmp(da->name, db->name) < 0))
                return -1;
        else
                return 1;
}

static void ls_scan_dir(const char *d, DIR *dirp, int sort)
{
        int alloc_blocks = 20;
        int i;
        int nbdirs = 0;
        int rc;
        int len;
        char *buff;
        struct dir_elem_t *tmp;
        struct dir_elem_t *tosort;
        struct dirent *dp;
        
        if (!dirp)
                return;

        buff = (char *) malloc(PATH_MAX);
        if (!buff) {
                cli_error(CL_ENOMEM, "ls: failed to scan %s", d);
                return;
        }
        
        tosort = (struct dir_elem_t *) malloc(alloc_blocks * sizeof(*tosort));
        if (!tosort) {
                cli_error(CL_ENOMEM, "ls: failed to scan %s", d);
                free(buff);
                return;
        }
        
        while ((dp = readdir(dirp))) {
                if (nbdirs + 1 > alloc_blocks) {
                        alloc_blocks += alloc_blocks;
                        
                        tmp = (struct dir_elem_t *) realloc(tosort,
                            alloc_blocks * sizeof(struct dir_elem_t));
                        if (!tmp) {
                                cli_error(CL_ENOMEM, "ls: failed to scan %s", d);
                                goto out;
                        }
                        tosort = tmp;
                }
                
                /* fill the name field */
                tosort[nbdirs].name = (char *) malloc(str_length(dp->d_name) + 1);
                if (!tosort[nbdirs].name) {
                        cli_error(CL_ENOMEM, "ls: failed to scan %s", d);
                        goto out;
                }
                
                str_cpy(tosort[nbdirs].name, str_length(dp->d_name) + 1, dp->d_name);
                len = snprintf(buff, PATH_MAX - 1, "%s/%s", d, tosort[nbdirs].name);
                buff[len] = '\0';

                rc = stat(buff, &tosort[nbdirs++].s);
                if (rc != 0) {
                        printf("ls: skipping bogus node %s\n", buff);
                        printf("rc=%d\n", rc);
                        goto out;
                }
        }
        
        if (sort) {
                if (!qsort(&tosort[0], nbdirs, sizeof(struct dir_elem_t),
                    ls_cmp, NULL)) {
                        printf("Sorting error.\n");
                }
        }
        
        for (i = 0; i < nbdirs; i++)
                ls_print(&tosort[i]);
        
out:
        for(i = 0; i < nbdirs; i++)
                free(tosort[i].name);
        free(tosort);
        free(buff);
}

void help_cmd_ls(unsigned int level)
{
        if (level == HELP_SHORT) {
                printf("`%s' lists files and directories.\n", cmdname);
        } else {
                help_cmd_ls(HELP_SHORT);
                printf(
                "Usage:  %s [options] [path]\n"
                "If not path is given, the current working directory is used.\n"
                "Options:\n"
                "  -h, --help       A short option summary\n"
                "  -u, --unsort     Do not sort directory entries\n",
                cmdname);
        }

        return;
}

int cmd_ls(char **argv)
{
        unsigned int argc;
        struct dir_elem_t de;
        DIR *dirp;
        int c, opt_ind;
        int sort = 1;

        argc = cli_count_args(argv);
        
        for (c = 0, optind = 0, opt_ind = 0; c != -1;) {
                c = getopt_long(argc, argv, "hu", long_options, &opt_ind);
                switch (c) {
                case 'h':
                        help_cmd_ls(HELP_LONG);
                        return CMD_SUCCESS;
                case 'u':
                        sort = 0;
                        break;
                }
        }
        
        argc -= optind;
        
        de.name = (char *) malloc(PATH_MAX);
        if (!de.name) {
                cli_error(CL_ENOMEM, "%s: ", cmdname);
                return CMD_FAILURE;
        }
        memset(de.name, 0, sizeof(PATH_MAX));
        
        if (argc == 0)
                getcwd(de.name, PATH_MAX);
        else
                str_cpy(de.name, PATH_MAX, argv[optind]);
        
        if (stat(de.name, &de.s)) {
                cli_error(CL_ENOENT, de.name);
                free(de.name);
                return CMD_FAILURE;
        }

        if (de.s.is_file) {
                ls_print(&de);
        } else {
                dirp = opendir(de.name);
                if (!dirp) {
                        /* May have been deleted between scoping it and opening it */
                        cli_error(CL_EFAIL, "Could not stat %s", de.name);
                        free(de.name);
                        return CMD_FAILURE;
                }
                ls_scan_dir(de.name, dirp, sort);
                closedir(dirp);
        }

        free(de.name);

        return CMD_SUCCESS;
}

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