Re: [tarantool-patches] [PATCH v3 1/4] Configurable syslog destination

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Tue, Jul 24, 2018 at 08:11:49PM +0300, Olga Arkhangelskaia wrote:
> Added server option to syslog configuration.
> Server option is responsible for log destination. At the momemt
> there is two ways of usage:server=unix:/path/to/socket or
> server=ipv4:port. If port is not set default udp port 514 is used.
> If logging to syslog is set, however there is no sever options -
> default location is used: Linux /dev/log and Mac /var/run/syslog.
> 
> Closes #3487
> ---
>  src/say.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
>  src/say.h |  13 +++++++-
>  2 files changed, 113 insertions(+), 7 deletions(-)
> 
> diff --git a/src/say.c b/src/say.c
> index ac221dd19..b4836d9ee 100644
> --- a/src/say.c
> +++ b/src/say.c
> @@ -36,6 +36,7 @@
>  #include <stdarg.h>
>  #include <stdio.h>
>  #include <string.h>
> +#include <netdb.h>
>  #include <sys/types.h>
>  #include <unistd.h>
>  #include <fcntl.h>
> @@ -473,16 +474,86 @@ syslog_connect_unix(const char *path)
>  	return fd;
>  }
>  
> +/**
> + * Connect to remote syslogd using server:port.
> + * @param ip:port address string of remote host.

This function now takes a single argument, 'server_address'.
Please fix the comment.

> + * @retval not 0 Socket descriptor.
> + * @retval    -1 Socket error.
> + */
> +static int
> +syslog_connect_remote(const char *server_address)
> +{
> +	struct addrinfo *inf, hints, *ptr;
> +	const char *remote;
> +	char *portnum, *copy;
> +	int fd = -1;
> +
> +	copy = strdup(server_address);
> +	if (copy == NULL) {
> +		diag_set(OutOfMemory, strlen(server_address), "malloc",
> +			 "stslog server address");
> +		return fd;
> +	}
> +	portnum = copy;
> +	remote = strsep(&portnum, ":");
> +	if (remote == NULL) {
> +		remote = strdup("514");

The default port should be defined as a numeric constant and converted
to a string here with snprintf().

Also, shouldn't you use 'portnum' instead of 'remote' here?

Also, it looks like you leak 'remote' in this function. Why don't you
use a buffer on stack for storing port number?

> +		if (remote == NULL) {
> +			diag_set(OutOfMemory, strlen(remote), "strdup",
> +				 "port");
> +			free(copy);
> +			return fd;

Please use labels to free 'copy' (like 'goto out', 'out' points to the
'free(copy); return fd;' at the end of this function). That would look
neater IMHO.

> +		}
> +	}
> +	memset(&hints, 0, sizeof(hints));
> +	hints.ai_family = AF_INET;
> +	hints.ai_socktype = SOCK_DGRAM;
> +	hints.ai_protocol = IPPROTO_UDP;

> +	hints.ai_flags = 0;

Nit: this line is pointless as you zero the whole struct anyway.

> +
> +	if (getaddrinfo(remote, portnum, NULL, &inf) < 0) {

You should set diag here. Take a look at SystemError.

> +		free(copy);
> +		return -1;
> +	}
> +	for (ptr = inf; ptr; ptr = ptr->ai_next) {
> +		fd = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
> +		if (fd < 0) {

... and here

> +			continue;
> +		}
> +
> +		if (connect(fd, inf->ai_addr, inf->ai_addrlen) != 0) {

... and here, too

> +			close(fd);
> +			fd = -1;
> +			continue;
> +		}
> +		break;
> +	}
> +	freeaddrinfo(inf);
> +	free(copy);
> +	return fd;
> +}
> +
>  static inline int
>  log_syslog_connect(struct log *log)
>  {
> +

Nit: please don't add an empty line here.

>  	/*
> -	 * Try two locations: '/dev/log' for Linux and
> +	 * If server option is not set use '/dev/log' for Linux and
>  	 * '/var/run/syslog' for Mac.
>  	 */
> -	log->fd = syslog_connect_unix("/dev/log");
> -	if (log->fd < 0)
> -		log->fd = syslog_connect_unix("/var/run/syslog");
> +	switch (log->server_type) {
> +		case SAY_SYSLOG_UNIX:

Malformed indentation: 'switch' and 'case' should be at the same level.

> +		      log->fd = syslog_connect_unix(log->path);
> +		      break;
> +		case SAY_SYSLOG_REMOTE:
> +		      log->fd = syslog_connect_remote(log->path);
> +		      break;
> +		default:
> +		      log->fd = syslog_connect_unix("/dev/log");
> +		      if (log->fd < 0)
> +			      log->fd = syslog_connect_unix("/var/run/syslog");
> +
> +	}
>  	return log->fd;
>  }
>  
> @@ -498,6 +569,17 @@ log_syslog_init(struct log *log, const char *init_str)
>  	if (say_parse_syslog_opts(init_str, &opts) < 0)
>  		return -1;
>  
> +	log->server_type = opts.syslog_server;
> +	if (log->server_type == SAY_SYSLOG_DEFAULT)
> +		log->path = NULL;

Nit: no need to set 'log->path' to NULL - it's already been done by
'log_create'.

> +	else {
> +		log->path = strdup(opts.server);
> +			if (log->path == NULL) {

Malformed indentation.

> +				diag_set(OutOfMemory, strlen(opts.server),
> +				         "malloc", "server address");
> +				return -1;
> +		}
> +	}
>  	if (opts.identity == NULL)
>  		log->syslog_ident = strdup("tarantool");
>  	else
> @@ -1031,6 +1113,8 @@ say_syslog_facility_by_name(const char *facility)
>  int
>  say_parse_syslog_opts(const char *init_str, struct say_syslog_opts *opts)
>  {
> +	opts->server = NULL;
> +	opts->syslog_server = SAY_SYSLOG_DEFAULT;

Hmm, 'server', 'syslog_server', this looks weird...

May be, 'server_path' and 'server_type' or simply 'path' and 'type'?

>  	opts->identity = NULL;
>  	opts->facility = syslog_facility_MAX;
>  	opts->copy = strdup(init_str);
> @@ -1038,7 +1122,7 @@ say_parse_syslog_opts(const char *init_str, struct say_syslog_opts *opts)
>  		diag_set(OutOfMemory, strlen(init_str), "malloc", "opts->copy");
>  		return -1;
>  	}
> -	char *ptr = opts->copy;
> +	char *ptr = opts->copy; 

What's this doing? Adding a space at the end of the line?
Please remove.

>  	const char *option, *value;
>  
>  	/* strsep() overwrites the separator with '\0' */
> @@ -1047,7 +1131,18 @@ say_parse_syslog_opts(const char *init_str, struct say_syslog_opts *opts)
>  			break;
>  
>  		value = option;
> -		if (say_parse_prefix(&value, "identity=")) {
> +		if (say_parse_prefix(&value, "server=")) {
> +			if (opts->server != NULL ||
> +			    opts->syslog_server != SAY_SYSLOG_DEFAULT)
> +				goto duplicate;
> +			if (say_parse_prefix(&value, "unix:")) {
> +				opts->syslog_server = SAY_SYSLOG_UNIX;
> +				opts->server = value;
> +			} else {
> +				opts->syslog_server = SAY_SYSLOG_REMOTE;
> +				opts->server = value;
> +			}
> +		} else if (say_parse_prefix(&value, "identity=")) {
>  			if (opts->identity != NULL)
>  				goto duplicate;
>  			opts->identity = value;
> diff --git a/src/say.h b/src/say.h
> index 2c2395fe0..6681aae98 100644
> --- a/src/say.h
> +++ b/src/say.h
> @@ -79,6 +79,12 @@ say_log_level_is_enabled(int level)
>  
>  extern enum say_format log_format;
>  
> +enum say_logger_syslog_server {

This sounds awkward. May be, say_syslog_server or say_syslog_server_type
or simply say_syslog_type? Whatever name you choose, please be
consistent throughout the code. That is, if you choose to call the enum
say_syslog_type, then other names should be log->syslog_type and
say_syslog_opts->type.

> +	SAY_SYSLOG_DEFAULT,
> +	SAY_SYSLOG_UNIX,
> +	SAY_SYSLOG_REMOTE
> +};
> +
>  enum say_logger_type {
>  	/**
>  	 * Before the app server core is initialized, we do not
> @@ -141,7 +147,10 @@ struct log {
>  	/** The current log level. */
>  	int level;
>  	enum say_logger_type type;
> -	/** path to file if logging to file. */
> +	enum say_logger_syslog_server server_type;

Let's prefix this with syslog_, like other syslog-related options
(syslog_identity, syslog_facility).

> +	/** Path to file if logging to file, socket
> +	 *  or server address in case of syslog.
> +	 */

Malformed comment style.

>  	char *path;
>  	bool nonblock;
>  	log_format_func_t format_func;
> @@ -384,6 +393,8 @@ say_parse_logger_type(const char **str, enum say_logger_type *type);
>  
>  /** Syslog logger initialization params */
>  struct say_syslog_opts {
> +	enum say_logger_syslog_server syslog_server;

Here you don't need syslog_ prefix, because the struct is already named
after syslog.

> +	const char *server;
>  	const char *identity;
>  	enum syslog_facility facility;
>  	/* Input copy (content unspecified). */