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Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7// Has to be defined before including due to legacy Unices
8#define SYSLOG_NAMES 1
9
10#include <AK/DeprecatedString.h>
11#include <AK/StringBuilder.h>
12#include <stdio.h>
13#include <string.h>
14#include <syslog.h>
15#include <unistd.h>
16
17// This implementation doesn't talk to a syslog server. Any options related to
18// that are no-ops.
19
20extern "C" {
21
22// For implementation simplicity, we actually only use the re-entrant version
23// of each function, and the version that isn't just redirects with a static
24// struct to share.
25static struct syslog_data global_log_data = {
26 .ident = nullptr,
27 .logopt = 0,
28 .facility = LOG_USER,
29 .maskpri = LOG_UPTO(LOG_DEBUG)
30};
31
32// Used when ident is null, since syslog traditionally prints the program's
33// own name; the process name will always be the same unless we exec.
34static char program_name_buffer[256];
35static bool program_name_set = false;
36
37// Convenience function for initialization and checking what string to use
38// for the program name.
39static char const* get_syslog_ident(struct syslog_data* data)
40{
41 if (!program_name_set && data->ident == nullptr)
42 program_name_set = get_process_name(program_name_buffer, sizeof(program_name_buffer)) >= 0;
43
44 if (data->ident != nullptr)
45 return data->ident;
46 else if (program_name_set)
47 return program_name_buffer;
48
49 VERIFY_NOT_REACHED();
50}
51
52void openlog_r(char const* ident, int logopt, int facility, struct syslog_data* data)
53{
54 data->ident = ident;
55 data->logopt = logopt;
56 data->facility = facility;
57 // default value
58 data->maskpri = LOG_UPTO(LOG_DEBUG);
59 // would be where we connect to a daemon
60}
61
62void openlog(char const* ident, int logopt, int facility)
63{
64 openlog_r(ident, logopt, facility, &global_log_data);
65}
66
67void closelog_r(struct syslog_data* data)
68{
69 // would be where we disconnect from a daemon
70 // restore defaults
71 data->ident = nullptr;
72 data->logopt = 0;
73 data->facility = LOG_USER;
74 data->maskpri = LOG_UPTO(LOG_DEBUG);
75}
76
77void closelog(void)
78{
79 closelog_r(&global_log_data);
80}
81
82int setlogmask_r(int maskpri, struct syslog_data* data)
83{
84 // Remember, this takes the input of LOG_MASK/LOG_UPTO
85 int old_maskpri = data->maskpri;
86 data->maskpri = maskpri;
87 return old_maskpri;
88}
89
90int setlogmask(int maskpri)
91{
92 return setlogmask_r(maskpri, &global_log_data);
93}
94
95void syslog_r(int priority, struct syslog_data* data, char const* message, ...)
96{
97 va_list ap;
98 va_start(ap, message);
99 vsyslog_r(priority, data, message, ap);
100 va_end(ap);
101}
102
103void syslog(int priority, char const* message, ...)
104{
105 va_list ap;
106 va_start(ap, message);
107 vsyslog_r(priority, &global_log_data, message, ap);
108 va_end(ap);
109}
110
111void vsyslog_r(int priority, struct syslog_data* data, char const* message, va_list args)
112{
113 StringBuilder combined;
114
115 int real_priority = LOG_PRI(priority);
116 // Lots of parens, but it just extracts the priority from combo and masks.
117 if (!(data->maskpri & LOG_MASK(real_priority)))
118 return;
119
120 // Some metadata would be consumed by a syslog daemon, if we had one.
121 if (data->logopt & LOG_PID)
122 combined.appendff("{}[{}]: ", get_syslog_ident(data), getpid());
123 else
124 combined.appendff("{}: ", get_syslog_ident(data));
125
126 combined.appendvf(message, args);
127 auto combined_string = combined.to_deprecated_string();
128
129 if (data->logopt & LOG_CONS)
130 dbgputstr(combined_string.characters(), combined_string.length());
131 if (data->logopt & LOG_PERROR)
132 fputs(combined_string.characters(), stderr);
133}
134
135void vsyslog(int priority, char const* message, va_list args)
136{
137 vsyslog_r(priority, &global_log_data, message, args);
138}
139}