WIP: migrate gsmtap logging over to osmo_iolaforge/log_io_gsmtap

This is working in principle;  The problem is just that osmo_io itself
contains LOGP calls from within osmo_iofd_write_msgb() and downstream
code, so we might easily get up in an infinite recursion bug.

This needs further study; possibly we need a "safe" logging function
which will never use osmo_io.  Or something like a per-thread global
boolean variable which the code can check to know if it's re-entering?

Change-Id: I69d7eca7d50666b4fcfe73a1dc03f8e8491b32fc

4 files changed, 24 insertions, 5 deletions

diff --git a/include/osmocom/core/gsmtap_util.h b/include/osmocom/core/gsmtap_util.h
index d24ee95f..e7559311 100644
--- a/include/osmocom/core/gsmtap_util.h
+++ b/include/osmocom/core/gsmtap_util.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <stdbool.h>
 #include <stdint.h>
 #include <osmocom/core/write_queue.h>
 #include <osmocom/core/select.h>
@@ -31,6 +32,8 @@ int gsmtap_inst_fd(struct gsmtap_inst *gti)
 
 int gsmtap_inst_fd2(const struct gsmtap_inst *gti);
 
+bool gsmtap_inst_get_osmo_io_mode(const struct gsmtap_inst *gti);
+
 int gsmtap_source_init_fd(const char *host, uint16_t port);
 int gsmtap_source_init_fd2(const char *local_host, uint16_t local_port, const char *rem_host, uint16_t rem_port);
 
diff --git a/src/core/gsmtap_util.c b/src/core/gsmtap_util.c
index b64c7b05..6c36b28f 100644
--- a/src/core/gsmtap_util.c
+++ b/src/core/gsmtap_util.c
@@ -38,6 +38,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <stdint.h>
+#include <stdbool.h>
 #include <string.h>
 #include <errno.h>
 
@@ -85,6 +86,12 @@ int gsmtap_inst_fd2(const struct gsmtap_inst *gti)
 	return gti->wq.bfd.fd;
 }
 
+/*! determine whether the gsmtap_inst is in osmo_io mode or not. */
+bool gsmtap_inst_get_osmo_io_mode(const struct gsmtap_inst *gti)
+{
+	return gti->osmo_io_mode;
+}
+
 /*! convert RSL channel number to GSMTAP channel type
  *  \param[in] rsl_chantype RSL channel type
  *  \param[in] link_id RSL link identifier
diff --git a/src/core/libosmocore.map b/src/core/libosmocore.map
index 072efee3..bdbfe075 100644
--- a/src/core/libosmocore.map
+++ b/src/core/libosmocore.map
@@ -41,6 +41,7 @@ get_value_string_or_null;
 gsmtap_gsm_channel_names;
 gsmtap_inst_fd;
 gsmtap_inst_fd2;
+gsmtap_inst_get_osmo_io_mode;
 gsmtap_makemsg;
 gsmtap_makemsg_ex;
 gsmtap_send;
diff --git a/src/vty/logging_vty.c b/src/vty/logging_vty.c
index 2a074222..bfe73bb1 100644
--- a/src/vty/logging_vty.c
+++ b/src/vty/logging_vty.c
@@ -29,6 +29,7 @@
 #include <osmocom/core/strrb.h>
 #include <osmocom/core/loggingrb.h>
 #include <osmocom/core/gsmtap.h>
+#include <osmocom/core/gsmtap_util.h>
 #include <osmocom/core/application.h>
 
 #include <osmocom/vty/command.h>
@@ -803,18 +804,24 @@ DEFUN(cfg_no_log_systemd_journal, cfg_no_log_systemd_journal_cmd,
 }
 
 DEFUN(cfg_log_gsmtap, cfg_log_gsmtap_cmd,
-	"log gsmtap [HOSTNAME]",
+	"log gsmtap [HOSTNAME] [sync-io]",
 	LOG_STR "Logging via GSMTAP\n"
 	"Host name to send the GSMTAP logging to (UDP port 4729)\n")
 {
-	const char *hostname = argc ? argv[0] : "127.0.0.1";
+	const char *hostname = "127.0.0.1";
+	bool async_io = true;
 	struct log_target *tgt;
 
+	if (argc >= 1)
+		hostname = argv[0];
+	if (argc >= 2 && !strcmp(argv[1], "sync-io"))
+		async_io = false;
+
 	log_tgt_mutex_lock();
 	tgt = log_target_find(LOG_TGT_TYPE_GSMTAP, hostname);
 	if (!tgt) {
 		tgt = log_target_create_gsmtap(hostname, GSMTAP_UDP_PORT,
-					       host.app_info->name, false,
+					       host.app_info->name, async_io,
 					       true);
 		if (!tgt) {
 			vty_out(vty, "%% Unable to create GSMTAP log for %s%s",
@@ -1032,8 +1039,9 @@ static int config_write_log_single(struct vty *vty, struct log_target *tgt)
 			log_target_rb_avail_size(tgt), VTY_NEWLINE);
 		break;
 	case LOG_TGT_TYPE_GSMTAP:
-		vty_out(vty, "log gsmtap %s%s",
-			tgt->tgt_gsmtap.hostname, VTY_NEWLINE);
+		vty_out(vty, "log gsmtap %s%s%s", tgt->tgt_gsmtap.hostname,
+			gsmtap_inst_get_osmo_io_mode(tgt->tgt_gsmtap.gsmtap_inst) ? "" : " sync-io",
+			VTY_NEWLINE);
 		break;
 	case LOG_TGT_TYPE_SYSTEMD:
 		vty_out(vty, "log systemd-journal%s%s",