/*
 * Copyright 2006-2015, Haiku, Inc.
 * Distributed under the terms of the MIT license.
 *
 * Author:
 *              Axel Dörfler, axeld@pinc-software.de
 */


#include <OS.h>
#include <fs_info.h>

#include <extended_system_info.h>
#include <extended_system_info_defs.h>
#include <syscalls.h>
#include <vfs_defs.h>
#include <kernel/util/KMessage.h>

#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


enum info_mode {
        kList,
        kFilterDevice,
        kFilterFile,
};

extern const char *__progname;


static const char *
open_mode_to_string(int openMode)
{
        switch (openMode & O_RWMASK) {
                case O_RDONLY:
                        return "R  ";
                case O_WRONLY:
                        return "  W";
                default:
                        return "R/W";
        }
}


static status_t
get_next_fd_info(team_id teamID, int32* cookie, fd_info* info)
{
        while (*cookie < 0) {
                *cookie = 0;

                // Fetch CWD before regular FDs.
                KMessage teamInfo;
                status_t error = get_extended_team_info(teamID, B_TEAM_INFO_BASIC, teamInfo);
                if (error != B_OK)
                        break;

                int32 cwdDevice = 0;
                int64 cwdDirectory = 0;
                if (teamInfo.FindInt32("cwd device", &cwdDevice) != B_OK
                        || teamInfo.FindInt64("cwd directory", &cwdDirectory) != B_OK) {
                        break;
                }

                info->number = AT_FDCWD;
                info->device = cwdDevice;
                info->node = cwdDirectory;
                info->open_mode = 0;
                return B_OK;
        }

        return _kern_get_next_fd_info(teamID, (uint32*)cookie, info, sizeof(fd_info));
}


void
print_fds(team_info &teamInfo)
{
        printf("Team: (%" B_PRId32 ") %s\n", teamInfo.team, teamInfo.args);

        int32 cookie = -1;
        fd_info info;

        while (get_next_fd_info(teamInfo.team, &cookie, &info) == B_OK) {
                printf("%5d  %s %" B_PRIdDEV ":%" B_PRIdINO "\n", info.number,
                        open_mode_to_string(info.open_mode), info.device, info.node);
        }
}


void
filter_device(team_info &teamInfo, dev_t device, bool brief)
{
        int32 cookie = -1;
        fd_info info;

        while (get_next_fd_info(teamInfo.team, &cookie, &info) == B_OK) {
                if (info.device != device)
                        continue;

                if (brief) {
                        printf("%5" B_PRId32 " %s\n", teamInfo.team, teamInfo.args);
                        break;
                }

                printf("%5" B_PRId32 " %4d  %3s  %" B_PRIdDEV ":%" B_PRIdINO " %s\n",
                        teamInfo.team, info.number, open_mode_to_string(info.open_mode),
                                info.device, info.node, teamInfo.args);
        }
}


void
filter_file(team_info &teamInfo, dev_t device, ino_t node, bool brief)
{
        int32 cookie = -1;
        fd_info info;

        while (get_next_fd_info(teamInfo.team, &cookie, &info) == B_OK) {
                if (info.device != device || info.node != node)
                        continue;

                if (brief) {
                        printf("%5" B_PRId32 " %s\n", teamInfo.team, teamInfo.args);
                        break;
                }

                printf("%5" B_PRId32 " %4d  %3s  %s\n", teamInfo.team, info.number,
                        open_mode_to_string(info.open_mode), teamInfo.args);
        }
}


void
usage(bool failure)
{
        printf("Usage: %s <id/pattern> or -[dD] <path-to-device> or -[fF] <file>\n"
                "  Shows info about the used file descriptors in the system.\n\n"
                "  -d\tOnly shows accesses to the given device\n"
                "  -D\tLikewise, but only shows the teams that access it\n"
                "  -f\tOnly shows accesses to the given file\n"
                "  -F\tLikewise, but only shows the teams that access it\n",
                __progname);

        exit(failure ? 1 : 0);
}


int
main(int argc, char **argv)
{
        const char *pattern = NULL;
        dev_t device = -1;
        ino_t node = -1;
        int32 id = -1;
        info_mode mode = kList;
        bool brief = false;

        // parse arguments

        if (argc == 2) {
                // filter output
                if (isdigit(argv[1][0]))
                        id = atol(argv[1]);
                else if (argv[1][0] == '-')
                        usage(!strcmp(argv[1], "--help"));
                else
                        pattern = argv[1];
        } else if (argc > 2) {
                if (!strcmp(argv[1], "-d") || !strcmp(argv[1], "-D")) {
                        // filter by device usage
                        device = dev_for_path(argv[2]);
                        if (device < 0) {
                                fprintf(stderr, "%s: could not find device: %s\n", __progname,
                                        strerror(errno));
                                return 1;
                        }
                        mode = kFilterDevice;
                        if (argv[1][1] == 'D')
                                brief = true;
                } else if (!strcmp(argv[1], "-f") || !strcmp(argv[1], "-F")) {
                        // filter by file usage
                        struct stat stat;
                        if (::stat(argv[2], &stat) < 0) {
                                fprintf(stderr, "%s: could not open file: %s\n", __progname,
                                        strerror(errno));
                                return 1;
                        }
                        device = stat.st_dev;
                        node = stat.st_ino;
                        mode = kFilterFile;
                        if (argv[1][1] == 'F')
                                brief = true;
                } else
                        usage(true);
        }

        // do the job!

        team_info info;
        int32 cookie = 0;

        while (get_next_team_info(&cookie, &info) == B_OK) {
                switch (mode) {
                        case kList:
                                if ((id != -1 && id != info.team)
                                        || (pattern != NULL && !strstr(info.args, pattern)))
                                        continue;
                                print_fds(info);
                                break;

                        case kFilterDevice:
                                filter_device(info, device, brief);
                                break;
                        case kFilterFile:
                                filter_file(info, device, node, brief);
                                break;
                }
        }

        return 0;
}