Re: [PATCH v3 1/3] tools: Add initial code for btmon-logger

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Hi Szymon,

> This is intended for use for automated logging or unatrended systems.

unattended.

> It doesn't contain any packet decoding functionality which results
> in much smaller binary.
> ---
> .gitignore           |   1 +
> Makefile.tools       |   5 +
> tools/btmon-logger.c | 350 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 356 insertions(+)
> create mode 100644 tools/btmon-logger.c
> 
> diff --git a/.gitignore b/.gitignore
> index 47808059b..33ec66048 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -118,6 +118,7 @@ tools/btconfig
> tools/btmgmt
> tools/btsnoop
> tools/btpclient
> +tools/btmon-logger
> peripheral/btsensor
> monitor/btmon
> emulator/btvirt
> diff --git a/Makefile.tools b/Makefile.tools
> index 71d083e71..ba4b9b7d7 100644
> --- a/Makefile.tools
> +++ b/Makefile.tools
> @@ -62,6 +62,11 @@ monitor_btmon_SOURCES = monitor/main.c monitor/bt.h \
> 				monitor/tty.h
> monitor_btmon_LDADD = lib/libbluetooth-internal.la \
> 				src/libshared-mainloop.la @UDEV_LIBS@
> +
> +noinst_PROGRAMS += tools/btmon-logger
> +

We can keep it initially noinst here, but what is longer term plan. Give it its own configure switch or make it available when btmon is enabled. I think we need to treat this as a service and also provide a systemd unit file for it.

If we do it via systemd unit files, then we can give the right path as current dir and take all the privileges and other path access away since nothing else is needed. Actually too bad that systemd can not start us with the monitor socket opened, because then we could run without any extra privileges. Anyhow, we should drop CAP_NET_RAW once we open the monitor socket.

> +tools_btmon_logger_SOURCES = tools/btmon-logger.c lib/monitor.h
> +tools_btmon_logger_LDADD = src/libshared-mainloop.la
> endif
> 
> if TESTING
> diff --git a/tools/btmon-logger.c b/tools/btmon-logger.c
> new file mode 100644
> index 000000000..9787e6b03
> --- /dev/null
> +++ b/tools/btmon-logger.c
> @@ -0,0 +1,350 @@
> +/*
> + *
> + *  BlueZ - Bluetooth protocol stack for Linux
> + *
> + *  Copyright (C) 2017-2018  Codecoup
> + *  Copyright (C) 2011-2014  Intel Corporation
> + *  Copyright (C) 2002-2010  Marcel Holtmann <marcel@xxxxxxxxxxxx>
> + *
> + *
> + *  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 2 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, write to the Free Software
> + *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> + *
> + */
> +
> +#ifdef HAVE_CONFIG_H
> +#include <config.h>
> +#endif
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <limits.h>
> +#include <string.h>
> +#include <time.h>
> +#include <getopt.h>
> +#include <unistd.h>
> +#include <sys/socket.h>
> +
> +#include "lib/bluetooth.h"
> +#include "lib/hci.h"
> +
> +#include "src/shared/util.h"
> +#include "src/shared/mainloop.h"
> +#include "src/shared/btsnoop.h"
> +
> +#define MONITOR_INDEX_NONE 0xffff
> +
> +struct monitor_hdr {
> +	uint16_t opcode;
> +	uint16_t index;
> +	uint16_t len;
> +} __attribute__ ((packed));
> +
> +struct btsnoop_hdr {
> +	uint8_t		id[8];		/* Identification Pattern */
> +	uint32_t	version;	/* Version Number = 1 */
> +	uint32_t	type;		/* Datalink Type */
> +} __attribute__ ((packed));
> +#define BTSNOOP_HDR_SIZE (sizeof(struct btsnoop_hdr))
> +
> +struct btsnoop_pkt {
> +	uint32_t	size;		/* Original Length */
> +	uint32_t	len;		/* Included Length */
> +	uint32_t	flags;		/* Packet Flags */
> +	uint32_t	drops;		/* Cumulative Drops */
> +	uint64_t	ts;		/* Timestamp microseconds */
> +	uint8_t		data[0];	/* Packet Data */
> +} __attribute__ ((packed));
> +#define BTSNOOP_PKT_SIZE (sizeof(struct btsnoop_pkt))
> +
> +static const char *path = ".";
> +static const char *prefix = "hci";
> +static bool suffix_date = false;
> +static size_t write_limit = 0;
> +static size_t write_size = 0;
> +
> +static struct btsnoop *btsnoop_file = NULL;
> +
> +static bool create_btsnoop(void)
> +{
> +	static char real_path[FILENAME_MAX];
> +	struct timeval tv;
> +
> +	gettimeofday(&tv, NULL);
> +
> +	if (suffix_date) {
> +		struct tm tm;
> +
> +		localtime_r(&tv.tv_sec, &tm);
> +
> +		snprintf(real_path, FILENAME_MAX,
> +				"%s/%s_%04d-%02d-%02d_%02d:%02d:%02d.btsnoop",
> +				path, prefix, tm.tm_year + 1900, tm.tm_mon + 1,
> +				tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
> +	} else {
> +		static unsigned int cnt = 0;
> +
> +		snprintf(real_path, sizeof(real_path), "%s/%s_%u.btsnoop",
> +							path, prefix, cnt++);
> +	}
> +
> +	btsnoop_file = btsnoop_create(real_path, BTSNOOP_FORMAT_MONITOR);
> +	if(!btsnoop_file)

Missing space.

> +		return false;
> +
> +	write_size = BTSNOOP_HDR_SIZE;
> +
> +	return true;
> +}

And I have the feeling that it would be best to put that code all in src/shared/btsnoop.c so that we have a more generic rotate function and don’t have to play tricks with the struct btsnoop pointer.

> +
> +static void rotate_btsnoop(uint16_t pktlen)
> +{
> +	write_size += BTSNOOP_PKT_SIZE + pktlen;
> +
> +	if (write_size <= write_limit)
> +		return;
> +
> +	btsnoop_unref(btsnoop_file);
> +
> +	if (!create_btsnoop()) {
> +		fprintf(stderr, "Failed to create btsnoop file, exiting.\n");
> +		mainloop_quit();
> +		return;
> +	}
> +
> +	write_size += BTSNOOP_PKT_SIZE + pktlen;
> +}
> +
> +static void data_callback(int fd, uint32_t events, void *user_data)
> +{
> +	uint8_t buf[BTSNOOP_MAX_PACKET_SIZE];
> +	unsigned char control[64];
> +	struct monitor_hdr hdr;
> +	struct msghdr msg;
> +	struct iovec iov[2];
> +
> +	if (events & (EPOLLERR | EPOLLHUP)) {
> +		mainloop_remove_fd(fd);
> +		return;
> +	}
> +
> +	iov[0].iov_base = &hdr;
> +	iov[0].iov_len = sizeof(hdr);
> +	iov[1].iov_base = buf;
> +	iov[1].iov_len = sizeof(buf);
> +
> +	memset(&msg, 0, sizeof(msg));
> +	msg.msg_iov = iov;
> +	msg.msg_iovlen = 2;
> +	msg.msg_control = control;
> +	msg.msg_controllen = sizeof(control);
> +
> +	while (1) {
> +		struct cmsghdr *cmsg;
> +		struct timeval *tv = NULL;
> +		struct timeval ctv;
> +		uint16_t opcode, index, pktlen;
> +		ssize_t len;
> +
> +		len = recvmsg(fd, &msg, MSG_DONTWAIT);
> +		if (len < 0)
> +			break;
> +
> +		if (len < (ssize_t) sizeof(hdr))
> +			break;
> +
> +		for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
> +					cmsg = CMSG_NXTHDR(&msg, cmsg)) {
> +			if (cmsg->cmsg_level != SOL_SOCKET)
> +				continue;
> +
> +			if (cmsg->cmsg_type == SCM_TIMESTAMP) {
> +				memcpy(&ctv, CMSG_DATA(cmsg), sizeof(ctv));
> +				tv = &ctv;
> +			}
> +		}
> +
> +		opcode = le16_to_cpu(hdr.opcode);
> +		index  = le16_to_cpu(hdr.index);
> +		pktlen = le16_to_cpu(hdr.len);
> +
> +		if (write_limit)
> +			rotate_btsnoop(pktlen);

Sounds rather pointless to do a check here for write_limit and then check everything else in the function. Which is still wrongly named since it is a maybe_rotate_btsnoop what is actually happening. Fold it all into one place and name it accordingly.

> +
> +		btsnoop_write_hci(btsnoop_file, tv, index, opcode, 0, buf,
> +									pktlen);
> +	}
> +}
> +
> +static bool open_monitor_channel(void)
> +{
> +	struct sockaddr_hci addr;
> +	int fd, opt = 1;
> +
> +	fd = socket(AF_BLUETOOTH, SOCK_RAW | SOCK_CLOEXEC, BTPROTO_HCI);
> +	if (fd < 0) {
> +		perror("Failed to open monitor channel");
> +		return false;
> +	}
> +
> +	memset(&addr, 0, sizeof(addr));
> +	addr.hci_family = AF_BLUETOOTH;
> +	addr.hci_dev = HCI_DEV_NONE;
> +	addr.hci_channel = HCI_CHANNEL_MONITOR;
> +
> +	if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
> +		perror("Failed to bind monitor channel");
> +		close(fd);
> +		return false;
> +	}
> +
> +	if (setsockopt(fd, SOL_SOCKET, SO_TIMESTAMP, &opt, sizeof(opt)) < 0) {
> +		perror("Failed to enable timestamps");
> +		close(fd);
> +		return false;
> +	}
> +
> +	if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &opt, sizeof(opt)) < 0) {
> +		perror("Failed to enable credentials");
> +		close(fd);
> +		return false;
> +	}
> +
> +	mainloop_add_fd(fd, EPOLLIN, data_callback, NULL, NULL);
> +
> +	return true;
> +}
> +
> +static void signal_callback(int signum, void *user_data)
> +{
> +	switch (signum) {
> +	case SIGINT:
> +	case SIGTERM:
> +		mainloop_quit();
> +		break;
> +	}
> +}
> +
> +static void usage(void)
> +{
> +	printf("btmon-logger - Bluetooth monitor\n"
> +		"Usage:\n");
> +	printf("\tbtmon-logger [options]\n");
> +	printf("options:\n"
> +		"\t-p, --path <path>      Save traces in specified path\n”

Should be current path if nothing is provided.

> +		"\t-P, --prefix <name>    Prefix filenames (defaults: \"hci\"\n”

that part is generally called basename. And default basename should be hci.log actually.

> +		"\t-d, --date             Suffix filenames with date\n”

As discussed, I do not like the idea of a data suffix at all. That seems all pointless to be for no gain. You are trying to make something human readable which is clearly not. If people want to extra ranges from a set of log traces, then btmon (or btsnoop utility) can gain that functionality. However here, I prefer that we do a simple path/basename.1 style.

Also path/basename will be the current file and all other numeration will be increased and thus files moved along. Same as what logrotate and others are actually doing. I kind dislike breaking with known way how others are handled.

> +		"\t-l, --limit <limit>    Limit btsnoop file size (rotate)\n”

We also need a directory size limit after which the oldest files will be deleted. This can be as simple as n * limit.

> +		"\t-v, --version          Show version\n"
> +		"\t-h, --help             Show help options\n");
> +}
> +
> +static const struct option main_options[] = {
> +	{ "path",	required_argument,	NULL, 'p' },
> +	{ "prefix",	required_argument,	NULL, 'P' },
> +	{ "date",	no_argument,		NULL, 'd' },
> +	{ "limit",	required_argument,	NULL, 'l' },
> +	{ "version",	no_argument,		NULL, 'v' },
> +	{ "help",	no_argument,		NULL, 'h' },
> +	{ }
> +};
> +
> +int main(int argc, char *argv[])
> +{
> +	sigset_t mask;
> +	char *endptr;
> +	int ret;

I am using exit_status for these kind of main() return values.

> +
> +	mainloop_init();
> +
> +	while (true) {
> +		int opt;
> +
> +		opt = getopt_long(argc, argv, "p:P:dl:Lvh", main_options,
> +									NULL);
> +		if (opt < 0)
> +			break;
> +
> +		switch (opt) {
> +		case 'p':
> +			path = optarg;
> +			if (strlen(path) > PATH_MAX) {
> +				fprintf(stderr, "Too long path\n");
> +				return EXIT_FAILURE;
> +			}
> +			break;
> +		case 'P':
> +			prefix = optarg;
> +			break;
> +		case 'd':
> +			suffix_date = true;
> +			break;
> +		case 'l':
> +			write_limit = strtoul(optarg, &endptr, 10);
> +
> +			if (write_limit == ULONG_MAX) {
> +				fprintf(stderr, "Invalid limit\n");
> +				return EXIT_FAILURE;
> +			}
> +
> +			if (*endptr != '\0') {
> +				if (*endptr == 'K' || *endptr == 'k') {
> +					write_limit *= 1024;
> +				} else if (*endptr == 'M' || *endptr == 'm') {
> +					write_limit *= 1024 * 1024;
> +				} else {
> +					fprintf(stderr, "Invalid limit\n");
> +					return EXIT_FAILURE;
> +				}
> +			}
> +
> +			/* limit this to reasonable size */
> +			if (write_limit < 4096) {
> +				fprintf(stderr, "Too small limit value\n");
> +				return EXIT_FAILURE;
> +			}
> +			break;
> +		case 'v':
> +			printf("%s\n", VERSION);
> +			return EXIT_SUCCESS;
> +		case 'h':
> +			usage();
> +			return EXIT_SUCCESS;
> +		default:
> +			return EXIT_FAILURE;
> +		}
> +	}
> +
> +	if (argc - optind > 0) {
> +		fprintf(stderr, "Invalid command line parameters\n");
> +		return EXIT_FAILURE;
> +	}
> +
> +	if (!open_monitor_channel() || !create_btsnoop())
> +		return EXIT_FAILURE;

Can we please clean up properly.

> +
> +	sigemptyset(&mask);
> +	sigaddset(&mask, SIGINT);
> +	sigaddset(&mask, SIGTERM);
> +
> +	mainloop_set_signal(&mask, signal_callback, NULL, NULL);
> +
> +	printf("Bluetooth monitor ver %s\n", VERSION);
> +
> +	ret = mainloop_run();
> +
> +	btsnoop_unref(btsnoop_file);
> +
> +	return ret;
> +}

Regards

Marcel

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