[M] Change in libosmocore[master]: Add Emscripten build support and JS callback logging backend - gerrit-log

10 Jan 2026

Timur Davydov has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/41813?usp=email )
Change subject: Add Emscripten build support and JS callback logging backend
......................................................................
Add Emscripten build support and JS callback logging backend
Change-Id: Ia8d5f4bb6570b5e055826f3a051e5e5896866e31
---
M configure.ac
M include/osmocom/core/logging.h
M src/core/Makefile.am
A src/core/logging_web.c
M src/core/netdev.c
M src/core/osmo_io_internal.h
M src/core/serial.c
M src/core/socket.c
M src/core/stats_tcp.c
M src/core/tun.c
M src/vty/Makefile.am
A src/vty/telnet_interface_dummy.c
12 files changed, 230 insertions(+), 11 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/13/41813/1

diff --git a/configure.ac b/configure.ac
index 6a5f0c0..b678237 100644
--- a/configure.ac
+++ b/configure.ac
@@ -25,6 +25,18 @@
 AC_PROG_INSTALL
 LT_INIT([pic-only disable-static])
+dnl Detect emscripten compiler
+case "$CC" in
+*emcc*)
+	emscripten=yes
+	;;
+*)
+	emscripten=no
+	;;
+esac
+AM_CONDITIONAL(HAVE_EMSCRIPTEN, test "x$emscripten" = "xyes")
+AC_SUBST([HAVE_EMSCRIPTEN], [$emscripten])
+
 AC_CONFIG_MACRO_DIR([m4])
dnl patching ${archive_cmds} to affect generation of file "libtool" to fix linking with clang
diff --git a/include/osmocom/core/logging.h b/include/osmocom/core/logging.h
index 44263fb..5aa7f9b 100644
--- a/include/osmocom/core/logging.h
+++ b/include/osmocom/core/logging.h
@@ -282,6 +282,7 @@
    LOG_TGT_TYPE_STRRB,	/*!< osmo_strrb-backed logging */
    LOG_TGT_TYPE_GSMTAP,	/*!< GSMTAP network logging */
    LOG_TGT_TYPE_SYSTEMD,	/*!< systemd journal logging */
+	LOG_TGT_TYPE_WEB,       /*!< Web logging */
 };
/*! Whether/how to log the source filename (and line number). */
@@ -443,6 +444,7 @@
    				    bool ofd_wq_mode,
    				    bool add_sink);
 struct log_target *log_target_create_systemd(bool raw);
+struct log_target *log_target_create_web();
 void log_target_systemd_set_raw(struct log_target *target, bool raw);
 int log_target_file_reopen(struct log_target *tgt);
 int log_target_file_switch_to_stream(struct log_target *tgt);
diff --git a/src/core/Makefile.am b/src/core/Makefile.am
index 0b756da..338e6fa 100644
--- a/src/core/Makefile.am
+++ b/src/core/Makefile.am
@@ -46,6 +46,7 @@
    logging.c \
    logging_syslog.c \
    logging_gsmtap.c \
+	logging_web.c \
    loggingrb.c \
    macaddr.c \
    msgb.c \
diff --git a/src/core/logging_web.c b/src/core/logging_web.c
new file mode 100644
index 0000000..859cbe8
--- /dev/null
+++ b/src/core/logging_web.c
@@ -0,0 +1,98 @@
+/*! \file logging_web.c
+ *  Logging support code using a JS callback. This module sends log
+ *  messages to a JavaScript callback named `on_log`.
+ *  */
+/*
+ * (C) 2026 by Timur Davydov dtv.comp@gmail.com
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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.
+ *
+ */
+
+/*! \addtogroup logging
+ *  @{
+ * \file logging_web.c */
+
+#include "config.h"
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdbool.h>
+#include <unistd.h>
+
+#ifdef HAVE_STRINGS_H
+#include <strings.h>
+#endif
+
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/utils.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/byteswap.h>
+
+#if defined(__EMSCRIPTEN__)
+
+#include <emscripten.h>
+
+EM_JS(void, on_log_wrapper, (const char *subsys, int level, const char *msg), {
+	return on_log(subsys, level, msg);
+});
+#else
+void on_log_wrapper(const char *subsys, int level, const char *msg)
+{
+}
+#endif
+
+static void _web_raw_output(struct log_target *target, int subsys,
+			       unsigned int level, const char *file,
+			       int line, int cont, const char *format,
+			       va_list ap)
+{
+	const int msgLen = 4096;
+	char msg[msgLen + 1];
+	const char *subsys_name = log_category_name(subsys);
+	char subsys_buf[16];
+	int rc;
+
+	if (subsys_name)
+		OSMO_STRLCPY_ARRAY(subsys_buf, subsys_name + 1);
+	else
+		subsys_buf[0] = '\0';
+
+	rc = vsnprintf(msg, msgLen, format, ap);
+	if (rc > 0) {
+		if (msg[rc - 1] == '\n') msg[rc - 1] = '\0';
+		on_log_wrapper(subsys_buf, level, msg);
+	}
+}
+
+/*! Create a new logging target for JS callback logging (uses `on_log`)
+ *  \returns Log target in case of success, NULL in case of error
+ */
+struct log_target *log_target_create_web()
+{
+	struct log_target *target;
+
+	target = log_target_create();
+	if (!target)
+		return NULL;
+
+	target->type = LOG_TGT_TYPE_WEB;
+	target->raw_output = _web_raw_output;
+
+	return target;
+}
+
+/* @} */
diff --git a/src/core/netdev.c b/src/core/netdev.c
index 1e886f9..4abc30a 100644
--- a/src/core/netdev.c
+++ b/src/core/netdev.c
@@ -64,7 +64,7 @@
  *	osmo_netdev_free(netdev);
  */
-#if (!EMBEDDED)
+#if (!EMBEDDED) && !defined(__EMSCRIPTEN__)
#include <stdio.h>
 #include <stdlib.h>
@@ -1018,6 +1018,6 @@
    return rc;
 }
-#endif /* (!EMBEDDED) */
+#endif /* (!EMBEDDED) && !defined(__EMSCRIPTEN__) */
/*! @} */
diff --git a/src/core/osmo_io_internal.h b/src/core/osmo_io_internal.h
index f425da2..03ec70a 100644
--- a/src/core/osmo_io_internal.h
+++ b/src/core/osmo_io_internal.h
@@ -4,7 +4,9 @@
#include <unistd.h>
 #include <stdbool.h>
+#ifdef HAVE_LIBSCTP
 #include <netinet/sctp.h>
+#endif
#include <osmocom/core/osmo_io.h>
 #include <osmocom/core/linuxlist.h>
diff --git a/src/core/serial.c b/src/core/serial.c
index 117c049..5ed1b34 100644
--- a/src/core/serial.c
+++ b/src/core/serial.c
@@ -24,6 +24,8 @@
  *
  * \file serial.c */
+#if !defined(__EMSCRIPTEN__)
+
 #include <errno.h>
 #include <fcntl.h>
 #include <stdio.h>
@@ -277,3 +279,5 @@
 }
/*! @} */
+
+#endif /* if !defined(__EMSCRIPTEN__) */
diff --git a/src/core/socket.c b/src/core/socket.c
index bb32185..1379bb6 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -1695,7 +1695,7 @@
static unsigned int in6_addr_netmask_to_prefixlen(const struct in6_addr *netmask)
 {
-	#if defined(__linux__)
+	#if defined(__linux__) || defined(__EMSCRIPTEN__)
    	#define ADDRFIELD(i) s6_addr32[i]
    #else
    	#define ADDRFIELD(i) __u6_addr.__u6_addr32[i]
@@ -1895,7 +1895,6 @@
    return 0;
 }
-#ifdef HAVE_LIBSCTP
 /*! Get multiple IP addresses and/or port number on socket in separate string buffers
  *  \param[in] fd file descriptor of socket.
  *  \param[out] ip_proto IPPROTO of the socket, eg: IPPROTO_SCTP.
@@ -1943,6 +1942,7 @@
    	return osmo_sock_get_ip_and_port(fd, ip, ip_len, port, port_len, local);
    }
+#ifdef HAVE_LIBSCTP
    rc = local ? sctp_getladdrs(fd, 0, &addrs) : sctp_getpaddrs(fd, 0, &addrs);
    if (rc < 0)
    	return rc;
@@ -1983,8 +1983,10 @@
 free_addrs_ret:
    local ? sctp_freeladdrs(addrs) : sctp_freepaddrs(addrs);
    return rc;
-}
+#else
+	return -ENOTSUP;
 #endif
+}
/*! Get local IP address on socket
  *  \param[in] fd file descriptor of socket
@@ -2047,7 +2049,6 @@
    return talloc_asprintf(ctx, "(%s)", str);
 }
-#ifdef HAVE_LIBSCTP
 /*! Format multiple IP addresses and/or port number into a combined string buffer
  *  \param[out] str  Destination string buffer.
  *  \param[in] str_len  sizeof(str), usually OSMO_SOCK_MULTIADDR_PEER_STR_MAXLEN.
@@ -2153,7 +2154,6 @@
return sb.chars_needed;
 }
-#endif
/*! Get address/port information on socket in provided string buffer, like "r=1.2.3.4:5<->l=6.7.8.9:10".
  * This does not include braces like osmo_sock_get_name().
diff --git a/src/core/stats_tcp.c b/src/core/stats_tcp.c
index c6459fe..8341979 100644
--- a/src/core/stats_tcp.c
+++ b/src/core/stats_tcp.c
@@ -24,6 +24,7 @@
 #include "config.h"
 #if !defined(EMBEDDED)
+#if !defined(__EMSCRIPTEN__)
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
@@ -186,6 +187,7 @@
return false;
 }
+#endif /* !defined(__EMSCRIPTEN__) */
/*! Register an osmo_fd for TCP stats monitoring.
  *  \param[in] fd osmocom file descriptor to be registered.
@@ -193,6 +195,7 @@
  *  \returns 0 on success; negative in case of error. */
 int osmo_stats_tcp_osmo_fd_register(const struct osmo_fd *fd, const char *name)
 {
+#if !defined(__EMSCRIPTEN__)
    struct stats_tcp_entry *stats_tcp_entry;
/* Only TCP sockets can be registered for monitoring, anything else will fall through. */
@@ -212,10 +215,12 @@
    pthread_mutex_lock(&stats_tcp_lock);
    llist_add_tail(&stats_tcp_entry->entry, &stats_tcp);
    pthread_mutex_unlock(&stats_tcp_lock);
+#endif /* !defined(__EMSCRIPTEN__) */
return 0;
 }
+#if !defined(__EMSCRIPTEN__)
 static void next_stats_tcp_entry(void)
 {
    struct stats_tcp_entry *last;
@@ -235,12 +240,14 @@
    	    (struct stats_tcp_entry *)llist_entry(stats_tcp_entry_cur->entry.next, struct stats_tcp_entry,
    						  entry);
 }
+#endif /* !defined(__EMSCRIPTEN__) */
/*! Register an osmo_fd for TCP stats monitoring.
  *  \param[in] fd osmocom file descriptor to be unregistered.
  *  \returns 0 on success; negative in case of error. */
 int osmo_stats_tcp_osmo_fd_unregister(const struct osmo_fd *fd)
 {
+#if !defined(__EMSCRIPTEN__)
    struct stats_tcp_entry *stats_tcp_entry;
    int rc = -EINVAL;
@@ -269,8 +276,12 @@
    pthread_mutex_unlock(&stats_tcp_lock);
return rc;
+#else
+	return 0;
+#endif /* !defined(__EMSCRIPTEN__) */
 }
+#if !defined(__EMSCRIPTEN__)
 static void stats_tcp_poll_timer_cb(void *data)
 {
    int i;
@@ -298,18 +309,22 @@
    if (osmo_tcp_stats_config->interval > 0)
    	osmo_timer_schedule(&stats_tcp_poll_timer, osmo_tcp_stats_config->interval, 0);
 }
+#endif /* !defined(__EMSCRIPTEN__) */
/*! Set the polling interval (common for all sockets)
  *  \param[in] interval Poll interval in seconds
  *  \returns 0 on success; negative on error */
 int osmo_stats_tcp_set_interval(int interval)
 {
+#if !defined(__EMSCRIPTEN__)
    osmo_tcp_stats_config->interval = interval;
    if (osmo_tcp_stats_config->interval > 0)
    	osmo_timer_schedule(&stats_tcp_poll_timer, osmo_tcp_stats_config->interval, 0);
+#endif /* !defined(__EMSCRIPTEN__) */
    return 0;
 }
+#if !defined(__EMSCRIPTEN__)
 static __attribute__((constructor))
 void on_dso_load_stats_tcp(void)
 {
@@ -321,7 +336,8 @@
osmo_timer_setup(&stats_tcp_poll_timer, stats_tcp_poll_timer_cb, NULL);
 }
+#endif /* !defined(__EMSCRIPTEN__) */
-#endif /* !EMBEDDED */
+#endif /* !defined(EMBEDDED) */
/* @} */
diff --git a/src/core/tun.c b/src/core/tun.c
index 09a3f81..97475ad 100644
--- a/src/core/tun.c
+++ b/src/core/tun.c
@@ -67,7 +67,7 @@
  *	osmo_tundev_free(tundev);
  */
-#if (!EMBEDDED)
+#if (!EMBEDDED) && !defined(__EMSCRIPTEN__)
#include <stdio.h>
 #include <stdlib.h>
@@ -584,6 +584,6 @@
 }
-#endif /* (!EMBEDDED) */
+#endif /* (!EMBEDDED) && !defined(__EMSCRIPTEN__) */
/*! @} */
diff --git a/src/vty/Makefile.am b/src/vty/Makefile.am
index ecdd050..25735da 100644
--- a/src/vty/Makefile.am
+++ b/src/vty/Makefile.am
@@ -27,12 +27,17 @@
    stats_vty.c \
    talloc_ctx_vty.c \
    tdef_vty.c \
-	telnet_interface.c \
    utils.c \
    vector.c \
    vty.c \
    $(NULL)
+if HAVE_EMSCRIPTEN
+libosmovty_la_SOURCES += telnet_interface_dummy.c
+else
+libosmovty_la_SOURCES += telnet_interface.c
+endif
+
 libosmovty_la_LDFLAGS = -version-info $(LIBVERSION) -no-undefined
 libosmovty_la_LIBADD = \
    $(top_builddir)/src/core/libosmocore.la \
diff --git a/src/vty/telnet_interface_dummy.c b/src/vty/telnet_interface_dummy.c
new file mode 100644
index 0000000..714cc30
--- /dev/null
+++ b/src/vty/telnet_interface_dummy.c
@@ -0,0 +1,79 @@
+/* (C) 2026 by Timur Davydov dtv.comp@gmail.com
+ * All Rights Reserved
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ *
+ * 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.
+ *
+ */
+
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/socket.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/logging.h>
+#include <osmocom/core/signal.h>
+
+#include <osmocom/vty/telnet_interface.h>
+#include <osmocom/vty/buffer.h>
+#include <osmocom/vty/command.h>
+
+/*! \file telnet_interface_dummy.c
+ *  Telnet interface towards Osmocom VTY
+ *
+ *  This module contains the dummy code implementing a telnet server for VTY
+ *  access.
+ */
+
+int telnet_init(void *tall_ctx, void *priv, int port)
+{
+	return 0;
+}
+
+int telnet_init_dynif(void *tall_ctx, void *priv, const char *ip, int port)
+{
+	return 0;
+}
+
+int telnet_init_default(void *tall_ctx, void *priv, int default_port)
+{
+	return 0;
+}
+
+
+/*! close a telnet connection */
+int telnet_close_client(struct osmo_fd *fd)
+{
+	return 0;
+}
+
+bool vty_is_active(struct vty *vty)
+{
+	return false;
+}
+
+/*! callback from core VTY code about VTY related events */
+void vty_event(enum event event, int sock, struct vty *vty)
+{
+	return;
+}
+
+/*! Close all telnet connections and release the telnet socket */
+void telnet_exit(void)
+{
+}
-- 
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Gerrit-MessageType: newchange
Gerrit-Project: libosmocore
Gerrit-Branch: master
Gerrit-Change-Id: Ia8d5f4bb6570b5e055826f3a051e5e5896866e31
Gerrit-Change-Number: 41813
Gerrit-PatchSet: 1
Gerrit-Owner: Timur Davydov dtv.comp@gmail.com



    