summaryrefslogtreecommitdiff
path: root/Userland/Utilities/man.cpp
blob: 08128c27bf9d2fe0d69761ada49583b90d8f5825 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
 * Copyright (c) 2019-2020, Sergey Bugaev <bugaevc@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/Assertions.h>
#include <AK/ByteBuffer.h>
#include <AK/String.h>
#include <LibCore/ArgsParser.h>
#include <LibCore/File.h>
#include <LibCore/System.h>
#include <LibMain/Main.h>
#include <LibMarkdown/Document.h>
#include <fcntl.h>
#include <spawn.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <unistd.h>

static ErrorOr<pid_t> pipe_to_pager(String const& command)
{
    char const* argv[] = { "sh", "-c", command.characters(), nullptr };

    auto stdout_pipe = TRY(Core::System::pipe2(O_CLOEXEC));

    posix_spawn_file_actions_t action;
    posix_spawn_file_actions_init(&action);
    posix_spawn_file_actions_adddup2(&action, stdout_pipe[0], STDIN_FILENO);

    pid_t pid;
    if ((errno = posix_spawnp(&pid, argv[0], &action, nullptr, const_cast<char**>(argv), environ))) {
        perror("posix_spawn");
        exit(1);
    }
    posix_spawn_file_actions_destroy(&action);

    TRY(Core::System::dup2(stdout_pipe[1], STDOUT_FILENO));
    TRY(Core::System::close(stdout_pipe[1]));
    TRY(Core::System::close(stdout_pipe[0]));
    return pid;
}

ErrorOr<int> serenity_main(Main::Arguments arguments)
{
    int view_width = 0;
    if (isatty(STDOUT_FILENO)) {
        struct winsize ws;
        if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == 0)
            view_width = ws.ws_col;
    }

    if (view_width == 0)
        view_width = 80;

    TRY(Core::System::pledge("stdio rpath exec proc"));
    TRY(Core::System::unveil("/usr/share/man", "r"));
    TRY(Core::System::unveil("/bin", "x"));
    TRY(Core::System::unveil(nullptr, nullptr));

    const char* section = nullptr;
    const char* name = nullptr;
    const char* pager = nullptr;

    Core::ArgsParser args_parser;
    args_parser.set_general_help("Read manual pages. Try 'man man' to get started.");
    args_parser.add_positional_argument(section, "Section of the man page", "section", Core::ArgsParser::Required::No);
    args_parser.add_positional_argument(name, "Name of the man page", "name");
    args_parser.add_option(pager, "Pager to pipe the man page to", "pager", 'P', "pager");
    args_parser.parse(arguments);

    auto make_path = [name](const char* section) {
        return String::formatted("/usr/share/man/man{}/{}.md", section, name);
    };
    if (!section) {
        const char* sections[] = {
            "1",
            "2",
            "3",
            "4",
            "5",
            "6",
            "7",
            "8"
        };
        for (auto s : sections) {
            String path = make_path(s);
            if (access(path.characters(), R_OK) == 0) {
                section = s;
                break;
            }
        }
        if (!section) {
            warnln("No man page for {}", name);
            exit(1);
        }
    }

    auto filename = make_path(section);

    String pager_command;
    if (pager)
        pager_command = pager;
    else
        pager_command = String::formatted("less -P 'Manual Page {}({}) line %l?e (END):.'", StringView(name).replace("'", "'\\''"), StringView(section).replace("'", "'\\''"));
    pid_t pager_pid = TRY(pipe_to_pager(pager_command));

    auto file = TRY(Core::File::open(filename, Core::OpenMode::ReadOnly));

    TRY(Core::System::pledge("stdio proc"));

    dbgln("Loading man page from {}", file->filename());
    auto buffer = file->read_all();
    auto source = String::copy(buffer);

    outln("{}({})\t\tSerenityOS manual", name, section);

    auto document = Markdown::Document::parse(source);
    VERIFY(document);

    String rendered = document->render_for_terminal(view_width);
    out("{}", rendered);

    // FIXME: Remove this wait, it shouldn't be necessary but Shell does not
    //        resume properly without it. This wait also breaks <C-z> backgrounding
    fclose(stdout);
    int wstatus;
    waitpid(pager_pid, &wstatus, 0);
    return 0;
}