xref: /openbmc/obmc-console/log-handler.c (revision 533f9702)
1 /**
2  * Copyright © 2016 IBM Corporation
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 
17 #include <endian.h>
18 #include <err.h>
19 #include <fcntl.h>
20 #include <stdbool.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <unistd.h>
25 
26 #include <sys/mman.h>
27 
28 #include <linux/types.h>
29 
30 #include "console-server.h"
31 
32 struct log_handler {
33 	struct handler handler;
34 	struct console *console;
35 	struct ringbuffer_consumer *rbc;
36 	int fd;
37 	size_t size;
38 	size_t maxsize;
39 	size_t pagesize;
40 	char *log_filename;
41 	char *rotate_filename;
42 };
43 
44 static const char *default_filename = LOCALSTATEDIR "/log/obmc-console.log";
45 static const size_t default_logsize = 16ul * 1024ul;
46 
47 static struct log_handler *to_log_handler(struct handler *handler)
48 {
49 	return container_of(handler, struct log_handler, handler);
50 }
51 
52 static int log_trim(struct log_handler *lh)
53 {
54 	int rc;
55 
56 	/* Move the log buffer file to the rotate file */
57 	close(lh->fd);
58 	rc = rename(lh->log_filename, lh->rotate_filename);
59 	if (rc) {
60 		warn("Failed to rename %s to %s", lh->log_filename,
61 		     lh->rotate_filename);
62 		/* don't return, as we need to re-open the logfile */
63 	}
64 
65 	lh->fd = open(lh->log_filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
66 	if (lh->fd < 0) {
67 		warn("Can't open log buffer file %s", lh->log_filename);
68 		return -1;
69 	}
70 
71 	lh->size = 0;
72 
73 	return 0;
74 }
75 
76 static int log_data(struct log_handler *lh, uint8_t *buf, size_t len)
77 {
78 	int rc;
79 
80 	if (len > lh->maxsize) {
81 		buf += len - lh->maxsize;
82 		len = lh->maxsize;
83 	}
84 
85 	if (lh->size + len > lh->maxsize) {
86 		rc = log_trim(lh);
87 		if (rc) {
88 			return rc;
89 		}
90 	}
91 
92 	rc = write_buf_to_fd(lh->fd, buf, len);
93 	if (rc) {
94 		return rc;
95 	}
96 
97 	lh->size += len;
98 
99 	return 0;
100 }
101 
102 static enum ringbuffer_poll_ret log_ringbuffer_poll(void *arg, size_t force_len
103 						    __attribute__((unused)))
104 {
105 	struct log_handler *lh = arg;
106 	uint8_t *buf;
107 	size_t len;
108 	int rc;
109 
110 	/* we log synchronously, so just dequeue everything we can, and
111 	 * commit straight away. */
112 	for (;;) {
113 		len = ringbuffer_dequeue_peek(lh->rbc, 0, &buf);
114 		if (!len) {
115 			break;
116 		}
117 
118 		rc = log_data(lh, buf, len);
119 		if (rc) {
120 			return RINGBUFFER_POLL_REMOVE;
121 		}
122 
123 		ringbuffer_dequeue_commit(lh->rbc, len);
124 	}
125 
126 	return RINGBUFFER_POLL_OK;
127 }
128 
129 static int log_init(struct handler *handler, struct console *console,
130 		    struct config *config)
131 {
132 	struct log_handler *lh = to_log_handler(handler);
133 	const char *filename;
134 	const char *logsize_str;
135 	size_t logsize = default_logsize;
136 	int rc;
137 
138 	lh->console = console;
139 	lh->pagesize = 4096;
140 	lh->size = 0;
141 	lh->log_filename = NULL;
142 	lh->rotate_filename = NULL;
143 
144 	logsize_str = config_get_value(config, "logsize");
145 	rc = config_parse_logsize(logsize_str, &logsize);
146 	if (logsize_str != NULL && rc) {
147 		logsize = default_logsize;
148 		warn("Invalid logsize. Default to %ukB",
149 		     (unsigned int)(logsize >> 10));
150 	}
151 	lh->maxsize = logsize <= lh->pagesize ? lh->pagesize + 1 : logsize;
152 
153 	filename = config_get_value(config, "logfile");
154 	if (!filename) {
155 		filename = default_filename;
156 	}
157 
158 	lh->fd = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
159 	if (lh->fd < 0) {
160 		warn("Can't open log buffer file %s", filename);
161 		return -1;
162 	}
163 
164 	lh->log_filename = strdup(filename);
165 
166 	rc = asprintf(&lh->rotate_filename, "%s.1", filename);
167 	if (rc < 0) {
168 		warn("Failed to construct rotate filename");
169 		return -1;
170 	}
171 
172 	lh->rbc = console_ringbuffer_consumer_register(console,
173 						       log_ringbuffer_poll, lh);
174 
175 	return 0;
176 }
177 
178 static void log_fini(struct handler *handler)
179 {
180 	struct log_handler *lh = to_log_handler(handler);
181 	ringbuffer_consumer_unregister(lh->rbc);
182 	close(lh->fd);
183 	free(lh->log_filename);
184 	free(lh->rotate_filename);
185 }
186 
187 static struct log_handler log_handler = {
188 	.handler = {
189 		.name		= "log",
190 		.init		= log_init,
191 		.fini		= log_fini,
192 	},
193 };
194 
195 console_handler_register(&log_handler.handler);
196