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1 | /* |
2 | * Copyright (c) 2015 Nicira, Inc. | |
3 | * | |
4 | * Licensed under the Apache License, Version 2.0 (the "License"); | |
5 | * you may not use this file except in compliance with the License. | |
6 | * You may obtain a copy of the License at: | |
7 | * | |
8 | * http://www.apache.org/licenses/LICENSE-2.0 | |
9 | * | |
10 | * Unless required by applicable law or agreed to in writing, software | |
11 | * distributed under the License is distributed on an "AS IS" BASIS, | |
12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
13 | * See the License for the specific language governing permissions and | |
14 | * limitations under the License. | |
15 | */ | |
16 | #include "syslog-direct.h" | |
17 | ||
18 | #include <config.h> | |
19 | ||
20 | #include <string.h> | |
21 | #include <unistd.h> | |
22 | ||
23 | #include "compiler.h" | |
3e8a2ad1 | 24 | #include "openvswitch/dynamic-string.h" |
fe089c0d AA |
25 | #include "socket-util.h" |
26 | #include "syslog-provider.h" | |
27 | #include "util.h" | |
28 | ||
29 | #define FACILITY_MASK 0x03f8 | |
30 | ||
31 | static void syslog_direct_open(struct syslogger *this, int facility); | |
32 | static void syslog_direct_log(struct syslogger *this, int pri, | |
33 | const char *msg); | |
34 | ||
35 | static struct syslog_class syslog_direct_class = { | |
36 | syslog_direct_open, | |
37 | syslog_direct_log, | |
38 | }; | |
39 | ||
40 | struct syslog_direct { | |
41 | struct syslogger parent; | |
42 | int fd; /* Negative number in error case. Otherwise, socket. */ | |
43 | int facility; | |
44 | }; | |
45 | ||
46 | ||
47 | /* This function creates object that directly interacts with syslog over | |
48 | * UDP or Unix domain socket specified in 'method'. */ | |
49 | struct syslogger * | |
50 | syslog_direct_create(const char *method) | |
51 | { | |
52 | struct syslog_direct *this = xmalloc(sizeof *this); | |
53 | ||
54 | this->parent.class = &syslog_direct_class; | |
55 | this->parent.prefix = "<%B>"; | |
56 | ||
57 | /* socket is created from here (opposed to syslog_direct_open()) | |
58 | * so that deadlocks would be avoided. The problem is that these | |
59 | * functions that create socket might call VLOG() */ | |
60 | if (!strncmp(method, "udp:", 4)) { | |
61 | inet_open_active(SOCK_DGRAM, &method[4], 514, NULL, &this->fd, 0); | |
62 | } else if (!strncmp(method, "unix:", 5)) { | |
63 | this->fd = make_unix_socket(SOCK_DGRAM, true, NULL, &method[5]); | |
64 | } else { | |
65 | this->fd = -1; | |
66 | } | |
67 | ||
68 | return &this->parent; | |
69 | } | |
70 | ||
71 | static void | |
72 | syslog_direct_open(struct syslogger *this, int facility) | |
73 | { | |
74 | struct syslog_direct *this_ = (struct syslog_direct*) this; | |
75 | ||
76 | this_->facility = facility; | |
77 | } | |
78 | ||
79 | static void | |
80 | syslog_direct_log(struct syslogger *this, int pri, const char *msg) | |
81 | { | |
82 | static size_t max_len = SIZE_MAX; /* max message size we have discovered | |
83 | * to be able to send() without failing | |
84 | * with EMSGSIZE. */ | |
85 | ||
86 | struct syslog_direct *this_ = (struct syslog_direct*) this; | |
87 | struct ds ds = DS_EMPTY_INITIALIZER; | |
88 | const char *wire_msg; | |
89 | size_t send_len; | |
90 | ||
91 | if (this_->fd < 0) { | |
92 | /* Failed to open socket for logging. */ | |
93 | return; | |
94 | } | |
95 | ||
96 | if (!(pri & FACILITY_MASK)) { | |
97 | pri |= this_->facility; | |
98 | } | |
99 | ds_put_format(&ds, "<%u>%s", pri, msg); | |
100 | wire_msg = ds_cstr(&ds); | |
ea53e3a8 | 101 | send_len = MIN(strlen(wire_msg), max_len); |
fe089c0d AA |
102 | while (send(this_->fd, wire_msg, send_len, 0) < 0 && errno == EMSGSIZE) { |
103 | /* If message was too large for send() function then try to discover | |
104 | * max_len supported for this particular socket and retry sending a | |
105 | * truncated version of the same message. */ | |
106 | send_len -= send_len / 20; | |
107 | max_len = send_len; | |
108 | } | |
109 | ds_destroy(&ds); | |
110 | } |