u-boot/common/log_syslog.c
Heinrich Schuchardt e5b35f706d log: mute messages generated by log drivers
When a message is written by a log driver (e.g. via the network stack) this
may result in the generation of further messages. We cannot allow these
additional messages to be emitted as this might result in an infinite
recursion.

Up to now only the syslog driver was safeguarded. We should safeguard all
log drivers instead.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-09-22 12:54:13 -06:00

110 lines
2.5 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Log to syslog.
*
* Copyright (c) 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
*/
#include <common.h>
#include <log.h>
#include <net.h>
DECLARE_GLOBAL_DATA_PTR;
#define BUFFER_SIZE 480
static void append(char **buf, char *buf_end, const char *fmt, ...)
{
va_list args;
size_t size = buf_end - *buf;
va_start(args, fmt);
vsnprintf(*buf, size, fmt, args);
va_end(args);
*buf += strlen(*buf);
}
static int log_syslog_emit(struct log_device *ldev, struct log_rec *rec)
{
int ret;
int fmt = gd->log_fmt;
char msg[BUFFER_SIZE];
char *msg_end = msg + BUFFER_SIZE;
char *ptr = msg;
char *iphdr;
char *log_msg;
int eth_hdr_size;
struct in_addr bcast_ip;
unsigned int log_level;
char *log_hostname;
/* Setup packet buffers */
net_init();
/* Disable hardware and put it into the reset state */
eth_halt();
/* Set current device according to environment variables */
eth_set_current();
/* Get hardware ready for send and receive operations */
ret = eth_init();
if (ret < 0) {
eth_halt();
goto out;
}
memset(msg, 0, BUFFER_SIZE);
/* Set ethernet header */
eth_hdr_size = net_set_ether((uchar *)ptr, net_bcast_ethaddr, PROT_IP);
ptr += eth_hdr_size;
iphdr = ptr;
ptr += IP_UDP_HDR_SIZE;
log_msg = ptr;
/*
* The syslog log levels defined in RFC 5424 match the U-Boot ones up to
* level 7 (debug).
*/
log_level = rec->level;
if (log_level > 7)
log_level = 7;
/* Leave high bits as 0 to write a 'kernel message' */
/* Write log message to buffer */
append(&ptr, msg_end, "<%u>", log_level);
log_hostname = env_get("log_hostname");
if (log_hostname)
append(&ptr, msg_end, "%s ", log_hostname);
append(&ptr, msg_end, "uboot: ");
if (fmt & BIT(LOGF_LEVEL))
append(&ptr, msg_end, "%s.",
log_get_level_name(rec->level));
if (fmt & BIT(LOGF_CAT))
append(&ptr, msg_end, "%s,",
log_get_cat_name(rec->cat));
if (fmt & BIT(LOGF_FILE))
append(&ptr, msg_end, "%s:", rec->file);
if (fmt & BIT(LOGF_LINE))
append(&ptr, msg_end, "%d-", rec->line);
if (fmt & BIT(LOGF_FUNC))
append(&ptr, msg_end, "%s()", rec->func);
if (fmt & BIT(LOGF_MSG))
append(&ptr, msg_end, "%s%s",
fmt != BIT(LOGF_MSG) ? " " : "", rec->msg);
/* Consider trailing 0x00 */
ptr++;
debug("log message: '%s'\n", log_msg);
/* Broadcast message */
bcast_ip.s_addr = 0xFFFFFFFFL;
net_set_udp_header((uchar *)iphdr, bcast_ip, 514, 514, ptr - log_msg);
net_send_packet((uchar *)msg, ptr - msg);
out:
return ret;
}
LOG_DRIVER(syslog) = {
.name = "syslog",
.emit = log_syslog_emit,
};