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
|
/**
* mds — A micro-display server
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* 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/>.
*/
#ifndef MDS_LIBMDSSERVER_UTIL_H
#define MDS_LIBMDSSERVER_UTIL_H
#include <stddef.h>
#include <stdint.h>
#include <sys/types.h>
/**
* Convert a client ID string into a client ID integer
*
* @param str The client ID string
* @return The client ID integer
*/
uint64_t parse_client_id(const char* str);
/**
* Read an environment variable, but handle it as undefined if empty
*
* @param var The environment variable's name
* @return The environment variable's value, `NULL` if empty or not defined
*/
char* getenv_nonempty(const char* var);
/**
* Prepare the server so that it can reexec into
* a newer version of the executed file.
*
* This is required for two reasons:
* 1: We cannot use argv[0] as PATH-resolution may
* cause it to reexec into another pathname, and
* maybe to wrong program. Additionally argv[0]
* may not even refer to the program, and chdir
* could also hinter its use.
* 2: The kernel appends ` (deleted)` to
* `/proc/self/exe` once it has been removed,
* so it cannot be replaced.
*
* The function will should be called immediately, it
* will store the content of `/proc/self/exe`.
*
* @return Zero on success, -1 on error
*/
int prepare_reexec(void);
/**
* Re-exec the server.
* This function only returns on failure.
*
* If `prepare_reexec` failed or has not been called,
* `argv[0]` will be used as a fallback.
*
* @param argc The number of elements in `argv`
* @param argv The command line arguments
* @param reexeced Whether the server has previously been re-exec:ed
*/
void reexec_server(int argc, char** argv, int reexeced);
/**
* Set up a signal trap.
* This function should only be used for common mds
* signals, and this function may choose to add
* additional behaviour depending on the signal, such
* as blocking other signals.
*
* @param signo The signal to trap
* @param function The function to run when the signal is caught
* @return Zero on success, -1 on error
*/
int xsigaction(int signo, void (*function)(int signo));
/**
* Send a message over a socket
*
* @param socket The file descriptor of the socket
* @param message The message to send
* @param length The length of the message
* @return The number of bytes that have been sent (even on error)
*/
size_t send_message(int socket, const char* message, size_t length);
/**
* A version of `atoi` that is strict about the syntax and bounds
*
* @param str The text to parse
* @param value Slot in which to store the value
* @param min The minimum accepted value
* @param max The maximum accepted value
* @return Zero on success, -1 on syntax error
*/
int strict_atoi(const char* str, int* value, int min, int max);
/**
* Send a buffer into a file and ignore interruptions
*
* @param fd The file descriptor
* @param buffer The buffer
* @param length The length of the buffer
* @return Zero on success, -1 on error
*/
int full_write(int fd, const char* buffer, size_t length);
/**
* Read a file completly and ignore interruptions
*
* @param fd The file descriptor
* @return The content of the file, you will need to free it. `NULL` on error.
*/
char* full_read(int fd);
/**
* Check whether a string begins with a specific string,
* where neither of the strings are necessarily NUL-terminated
*
* @param haystack The string that should start with the other string
* @param needle The string the first string should start with
* @param haystack_n The length of `haystack`
* @param needle_n The length of `needle`
* @return Whether the `haystack` begins with `needle`
*/
int startswith_n(const char* haystack, const char* needle, size_t haystack_n, size_t needle_n) __attribute__((pure));
/**
* Wrapper around `waitpid` that never returns on an interruption unless
* it is interrupted 100 times within the same second
*
* @param pid See description of `pid` in the documentation for `waitpid`
* @param pid See description of `status` in the documentation for `waitpid`
* @param pid See description of `options` in the documentation for `waitpid`
* @return See the documentation for `waitpid`
*/
pid_t uninterruptable_waitpid(pid_t pid, int* restrict status, int options);
#endif
|
