1 files changed, 347 insertions, 0 deletions

diff --git a/src/util/msg_logger.c b/src/util/msg_logger.c
new file mode 100644
index 0000000..7c8f34d
--- /dev/null
+++ b/src/util/msg_logger.c
@@ -0,0 +1,347 @@
+/*++
+/* NAME
+/*	msg_logger 3
+/* SUMMARY
+/*	direct diagnostics to logger service
+/* SYNOPSIS
+/*	#include <msg_logger.h>
+/*
+/*	void	msg_logger_init(
+/*	const char *progname,
+/*	const char *hostname,
+/*	const char *unix_path,
+/*	void	(*fallback)(const char *))
+/*
+/*	void	msg_logger_control(
+/*	int	key,...)
+/* DESCRIPTION
+/*	This module implements support to report msg(3) diagnostics
+/*	through a logger daemon, with an optional fallback mechanism.
+/*	The log record format is like traditional syslog:
+/*
+/* .nf
+/*	    Mmm dd host progname[pid]: text...
+/* .fi
+/*
+/*	msg_logger_init() arranges that subsequent msg(3) calls
+/*	will write to an internal logging service. This function
+/*	may also be used to update msg_logger settings.
+/*
+/*	Arguments:
+/* .IP progname
+/*	The program name that is prepended to a log record.
+/* .IP hostname
+/*	The host name that is prepended to a log record. Only the
+/*	first hostname label will be used.
+/* .IP unix_path
+/*	Pathname of a unix-domain datagram service endpoint. A
+/*	typical use case is the pathname of the postlog socket.
+/* .IP fallback
+/*	Null pointer, or pointer to function that will be called
+/*	with a formatted message when the logger service is not
+/*	(yet) available. A typical use case is to pass the record
+/*	to the logwriter(3) module.
+/* .PP
+/*	msg_logger_control() makes adjustments to the msg_logger
+/*	client. These adjustments remain in effect until the next
+/*	msg_logger_init() or msg_logger_control() call. The arguments
+/*	are a list of macros with zero or more arguments, terminated
+/*	with CA_MSG_LOGGER_CTL_END which has none. The following
+/*	lists the names and the types of the corresponding value
+/*	arguments.
+/*
+/*	Arguments:
+/* .IP CA_MSG_LOGGER_CTL_FALLBACK_ONLY
+/*	Disable the logging socket, and use the fallback function
+/*	only. This remains in effect until the next msg_logger_init()
+/*	call.
+/* .IP CA_MSG_LOGGER_CTL_FALLBACK(void (*)(const char *))
+/*	Override the fallback setting (see above) with the specified
+/*	function pointer. This remains in effect until the next
+/*	msg_logger_init() or msg_logger_control() call.
+/* .IP CA_MSG_LOGGER_CTL_DISABLE
+/*	Disable the msg_logger. This remains in effect until the
+/*	next msg_logger_init() call.
+/* SEE ALSO
+/*	msg(3)  diagnostics module
+/* BUGS
+/*	Output records are truncated to ~2000 characters, because
+/*	unlimited logging is a liability.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+ /*
+  * System libraries.
+  */
+#include <sys_defs.h>
+#include <sys/socket.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+ /*
+  * Application-specific.
+  */
+#include <connect.h>
+#include <logwriter.h>
+#include <msg.h>
+#include <msg_logger.h>
+#include <msg_output.h>
+#include <mymalloc.h>
+#include <safe.h>
+#include <vstream.h>
+#include <vstring.h>
+
+ /*
+  * Saved state from msg_logger_init().
+  */
+static char *msg_logger_progname;
+static char *msg_logger_hostname;
+static char *msg_logger_unix_path;
+static void (*msg_logger_fallback_fn) (const char *);
+static int msg_logger_fallback_only_override = 0;
+static int msg_logger_enable = 0;
+
+ /*
+  * Other state.
+  */
+#define MSG_LOGGER_SOCK_NONE	(-1)
+
+static VSTRING *msg_logger_buf;
+static int msg_logger_sock = MSG_LOGGER_SOCK_NONE;
+
+ /*
+  * Safety limit.
+  */
+#define MSG_LOGGER_RECLEN	2000
+
+ /*
+  * SLMs.
+  */
+#define STR(x)	vstring_str(x)
+#define LEN(x)	VSTRING_LEN(x)
+
+
+/* msg_logger_print - log info to service or file */
+
+static void msg_logger_print(int level, const char *text)
+{
+    time_t  now;
+    struct tm *lt;
+    ssize_t len;
+
+    /*
+     * This test is simple enough that we don't bother with unregistering the
+     * msg_logger_print() function.
+     */
+    if (msg_logger_enable == 0)
+	return;
+
+    /*
+     * TODO: this should be a reusable NAME_CODE table plus lookup function.
+     */
+    static int log_level[] = {
+	MSG_INFO, MSG_WARN, MSG_ERROR, MSG_FATAL, MSG_PANIC,
+    };
+    static char *severity_name[] = {
+	"info", "warning", "error", "fatal", "panic",
+    };
+
+    /*
+     * Note: there is code in postlogd(8) that attempts to strip off
+     * information that is prepended here. If the formatting below is
+     * changed, then postlogd needs to be updated as well.
+     */
+
+    /*
+     * Format the time stamp.
+     */
+    if (time(&now) < 0)
+	msg_fatal("no time: %m");
+    lt = localtime(&now);
+    VSTRING_RESET(msg_logger_buf);
+    if ((len = strftime(vstring_str(msg_logger_buf),
+			vstring_avail(msg_logger_buf),
+			"%b %d %H:%M:%S ", lt)) == 0)
+	msg_fatal("strftime: %m");
+    vstring_set_payload_size(msg_logger_buf, len);
+
+    /*
+     * Format the host name (first name label only).
+     */
+    vstring_sprintf_append(msg_logger_buf, "%.*s ",
+			   (int) strcspn(msg_logger_hostname, "."),
+			   msg_logger_hostname);
+
+    /*
+     * Format the message.
+     */
+    if (level < 0 || level >= (int) (sizeof(log_level) / sizeof(log_level[0])))
+	msg_panic("msg_logger_print: invalid severity level: %d", level);
+
+    if (level == MSG_INFO) {
+	vstring_sprintf_append(msg_logger_buf, "%s[%ld]: %.*s",
+			       msg_logger_progname, (long) getpid(),
+			       (int) MSG_LOGGER_RECLEN, text);
+    } else {
+	vstring_sprintf_append(msg_logger_buf, "%s[%ld]: %s: %.*s",
+			       msg_logger_progname, (long) getpid(),
+		       severity_name[level], (int) MSG_LOGGER_RECLEN, text);
+    }
+
+    /*
+     * Connect to logging service, or fall back to direct log. Many systems
+     * will report ENOENT if the endpoint does not exist, ECONNREFUSED if no
+     * server has opened the endpoint.
+     */
+    if (msg_logger_fallback_only_override == 0
+	&& msg_logger_sock == MSG_LOGGER_SOCK_NONE) {
+	msg_logger_sock = unix_dgram_connect(msg_logger_unix_path, BLOCKING);
+	if (msg_logger_sock >= 0)
+	    close_on_exec(msg_logger_sock, CLOSE_ON_EXEC);
+    }
+    if (msg_logger_sock != MSG_LOGGER_SOCK_NONE) {
+	send(msg_logger_sock, STR(msg_logger_buf), LEN(msg_logger_buf), 0);
+    } else if (msg_logger_fallback_fn) {
+	msg_logger_fallback_fn(STR(msg_logger_buf));
+    }
+}
+
+/* msg_logger_init - initialize */
+
+void    msg_logger_init(const char *progname, const char *hostname,
+	             const char *unix_path, void (*fallback) (const char *))
+{
+    static int first_call = 1;
+    extern char **environ;
+
+    /*
+     * XXX If this program is set-gid, then TZ must not be trusted. This
+     * scrubbing code is in the wrong place.
+     */
+    if (first_call) {
+	if (unsafe())
+	    while (getenv("TZ"))		/* There may be multiple. */
+		if (unsetenv("TZ") < 0) {	/* Desperate measures. */
+		    environ[0] = 0;
+		    msg_fatal("unsetenv: %m");
+		}
+	tzset();
+    }
+
+    /*
+     * Save the request info. Use free-after-update because this data will be
+     * accessed when mystrdup() runs out of memory.
+     */
+#define UPDATE_AND_FREE(dst, src) do { \
+	if ((dst) == 0 || strcmp((dst), (src)) != 0) { \
+	    char *_bak = (dst); \
+	    (dst) = mystrdup(src); \
+	    if ((_bak)) myfree(_bak); \
+	} \
+    } while (0)
+
+    UPDATE_AND_FREE(msg_logger_progname, progname);
+    UPDATE_AND_FREE(msg_logger_hostname, hostname);
+    UPDATE_AND_FREE(msg_logger_unix_path, unix_path);
+    msg_logger_fallback_fn = fallback;
+
+    /*
+     * One-time activity: register the output handler, and allocate a buffer.
+     */
+    if (first_call) {
+	first_call = 0;
+	msg_output(msg_logger_print);
+	msg_logger_buf = vstring_alloc(2048);
+    }
+
+    /*
+     * Always.
+     */
+    msg_logger_enable = 1;
+    msg_logger_fallback_only_override = 0;
+}
+
+/* msg_logger_control - tweak the client */
+
+void    msg_logger_control(int name,...)
+{
+    const char *myname = "msg_logger_control";
+    va_list ap;
+
+    /*
+     * Overrides remain in effect until the next msg_logger_init() or
+     * msg_logger_control() call,
+     */
+    for (va_start(ap, name); name != MSG_LOGGER_CTL_END; name = va_arg(ap, int)) {
+	switch (name) {
+	case MSG_LOGGER_CTL_FALLBACK_ONLY:
+	    msg_logger_fallback_only_override = 1;
+	    if (msg_logger_sock != MSG_LOGGER_SOCK_NONE) {
+		(void) close(msg_logger_sock);
+		msg_logger_sock = MSG_LOGGER_SOCK_NONE;
+	    }
+	    break;
+	case MSG_LOGGER_CTL_FALLBACK_FN:
+	    msg_logger_fallback_fn = va_arg(ap, MSG_LOGGER_FALLBACK_FN);
+	    break;
+	case MSG_LOGGER_CTL_DISABLE:
+	    msg_logger_enable = 0;
+	    break;
+	default:
+	    msg_panic("%s: bad name %d", myname, name);
+	}
+    }
+    va_end(ap);
+}
+
+#ifdef TEST
+
+ /*
+  * Proof-of-concept program to test the msg_logger module.
+  * 
+  * Usage: msg_logger hostname unix_path fallback_path text...
+  */
+static char *fallback_path;
+
+static void fallback(const char *msg)
+{
+    if (logwriter_one_shot(fallback_path, msg) != 0)
+	msg_fatal("unable to fall back to directly write %s: %m",
+		  fallback_path);
+}
+
+int     main(int argc, char **argv)
+{
+    VSTRING *vp = vstring_alloc(256);
+
+    if (argc < 4)
+	msg_fatal("usage: %s host port path text to log", argv[0]);
+    msg_logger_init(argv[0], argv[1], argv[2], fallback);
+    fallback_path = argv[3];
+    argc -= 3;
+    argv += 3;
+    while (--argc && *++argv) {
+	vstring_strcat(vp, *argv);
+	if (argv[1])
+	    vstring_strcat(vp, " ");
+    }
+    msg_warn("static text");
+    msg_warn("dynamic text: >%s<", vstring_str(vp));
+    msg_warn("dynamic numeric: >%d<", 42);
+    msg_warn("error text: >%m<");
+    msg_warn("dynamic: >%s<: error: >%m<", vstring_str(vp));
+    vstring_free(vp);
+    return (0);
+}
+
+#endif