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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
/***
This file is part of snapcast
Copyright (C) 2014-2024 Johannes Pohl
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
***/
// prototype/interface header file
#include "daemon.hpp"
// local headers
#include "common/snap_exception.hpp"
#include "common/str_compat.hpp"
#include "common/utils/file_utils.hpp"
// standard headers
#include <cstdlib>
#include <cstring>
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <syslog.h>
#include <unistd.h>
Daemon::Daemon(const std::string& user, const std::string& group, const std::string& pidfile)
: pidFilehandle_(-1), user_(user), group_(group), pidfile_(pidfile)
{
if (pidfile.empty() || pidfile.find('/') == std::string::npos)
throw SnapException("invalid pid file \"" + pidfile + "\"");
}
Daemon::~Daemon()
{
if (pidFilehandle_ != -1)
close(pidFilehandle_);
}
void Daemon::daemonize()
{
std::string pidfileDir(pidfile_.substr(0, pidfile_.find_last_of('/')));
utils::file::mkdirRecursive(pidfileDir.c_str(), S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH);
/// Ensure only one copy
pidFilehandle_ = open(pidfile_.c_str(), O_RDWR | O_CREAT, 0644);
if (pidFilehandle_ == -1)
{
/// Couldn't open lock file
throw SnapException("Could not open PID lock file \"" + pidfile_ + "\"");
}
auto user_uid = static_cast<uid_t>(-1);
auto user_gid = static_cast<gid_t>(-1);
// std::string user_name;
// #ifdef FREEBSD
// bool had_group = false;
// #endif
if (!user_.empty())
{
struct passwd* pwd = getpwnam(user_.c_str());
if (pwd == nullptr)
throw SnapException("no such user \"" + user_ + "\"");
user_uid = pwd->pw_uid;
user_gid = pwd->pw_gid;
// user_name = strdup(user_.c_str());
/// this is needed by libs such as arts
setenv("HOME", pwd->pw_dir, 1);
}
if (!group_.empty())
{
const struct group* grp = getgrnam(group_.c_str());
if (grp == nullptr)
throw SnapException("no such group \"" + group_ + "\"");
user_gid = grp->gr_gid;
// #ifdef FREEBSD
// had_group = true;
// #endif
}
if (chown(pidfile_.c_str(), user_uid, user_gid) == -1)
{
/// Couldn't open lock file
throw SnapException("Could not chown PID lock file \"" + pidfile_ + "\"");
}
/// set gid
if (user_gid != static_cast<gid_t>(-1) && user_gid != getgid() && setgid(user_gid) == -1)
throw SnapException("Failed to set group " + cpt::to_string(static_cast<int>(user_gid)));
// #if defined(FREEBSD) && !defined(MACOS)
// #ifdef FREEBSD
/// init supplementary groups
/// (must be done before we change our uid)
/// no need to set the new user's supplementary groups if we are already this user
// if (!had_group && user_uid != getuid() && initgroups(user_name, user_gid) == -1)
// throw SnapException("Failed to set supplementary groups of user \"" + user + "\"");
// #endif
/// set uid
if (user_uid != static_cast<uid_t>(-1) && user_uid != getuid() && setuid(user_uid) == -1)
throw SnapException("Failed to set user " + user_);
/// Our process ID and Session ID
pid_t pid, sid;
/// Fork off the parent process
pid = fork();
if (pid < 0)
exit(EXIT_FAILURE);
/// If we got a good PID, then we can exit the parent process.
if (pid > 0)
exit(EXIT_SUCCESS);
/// Change the file mode mask
umask(0);
/// Open any logs here
/// Create a new SID for the child process
sid = setsid();
if (sid < 0)
{
/// Log the failure
exit(EXIT_FAILURE);
}
/// Change the current working directory
if ((chdir("/")) < 0)
{
/// Log the failure
exit(EXIT_FAILURE);
}
/// Try to lock file
if (lockf(pidFilehandle_, F_TLOCK, 0) == -1)
throw SnapException("Could not lock PID lock file \"" + pidfile_ + "\". Is the daemon already running?");
char str[10];
/// Get and format PID
sprintf(str, "%d\n", getpid());
/// write pid to lockfile
if (write(pidFilehandle_, str, strlen(str)) != static_cast<int>(strlen(str)))
throw SnapException("Could not write PID to lock file \"" + pidfile_ + "\"");
/// Close out the standard file descriptors
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);
}
|
