Add extensions for vtysh

vtysh/subdir.am

@@ -16,11 +16,13 @@ vtysh_vtysh_SOURCES = \
 	vtysh/vtysh.c \
 	vtysh/vtysh_user.c \
 	vtysh/vtysh_config.c \
+	vtysh/vtysh_extensions.c \
 	# end
 
 noinst_HEADERS += \
 	vtysh/vtysh.h \
 	vtysh/vtysh_user.h \
+	vtysh/vtysh_extensions.h \
 	# end
 
 vtysh_vtysh_LDADD = lib/libfrr.la $(LIBCAP) $(LIBREADLINE) $(LIBS) $(LIBPAM)

vtysh/vtysh.c

@@ -40,6 +40,7 @@
 #include "json.h"
 #include "ferr.h"
 #include "sockopt.h"
+#include "vtysh_extensions.h"
 
 DEFINE_MTYPE_STATIC(MVTYSH, VTYSH_CMD, "Vtysh cmd copy");
 
@@ -462,7 +463,7 @@ static int vtysh_client_execute(struct vtysh_client *head_client,
 }
 
 /* Execute by name */
-static int vtysh_client_execute_name(const char *name, const char *line)
+int vtysh_client_execute_name(const char *name, const char *line)
 {
 	int ret = CMD_SUCCESS;
 	int idx_client = -1;
@@ -3013,7 +3014,7 @@ static int show_per_daemon(struct vty *vty, struct cmd_token **argv, int argc,
 }
 #pragma GCC diagnostic pop
 
-static int show_one_daemon(struct vty *vty, struct cmd_token **argv, int argc,
+int show_one_daemon(struct vty *vty, struct cmd_token **argv, int argc,
 			   const char *name)
 {
 	int ret;
@@ -4623,6 +4624,18 @@ DEFUN_HIDDEN(show_cli_graph_vtysh,
 	return CMD_SUCCESS;
 }
 
+DEFUN (show_vtysh_extensions,
+        show_vtysh_extensions_cmd,
+        "show vtysh extensions",
+        SHOW_STR
+        "VTYSH\n"
+        "extension info\n")
+{
+    vtysh_show_extensions(vty);
+    return CMD_SUCCESS;
+}
+
+
 static void vtysh_install_default(enum node_type node)
 {
 	_install_element(node, &config_list_cmd);
@@ -5560,4 +5573,7 @@ void vtysh_init_vty(void)
 	install_element(CONFIG_NODE, &no_vtysh_password_cmd);
 	install_element(CONFIG_NODE, &vtysh_enable_password_cmd);
 	install_element(CONFIG_NODE, &no_vtysh_enable_password_cmd);
+
+	/* vtysh extensions */
+	install_element(VIEW_NODE, &show_vtysh_extensions_cmd);
 }

vtysh/vtysh_extensions.c

@@ -0,0 +1,82 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+#include "memory.h"
+#include "vtysh_extensions.h"
+#include "lib/vty.h"
+#include "vtysh.h"
+
+DEFINE_MTYPE(MVTYSH, VTYSH_EXT, "Vtysh extension");
+DEFINE_MTYPE(MVTYSH, VTYSH_EXT_NAME, "Vtysh extension name");
+
+static struct vtysh_ext *extensions = NULL;
+
+static struct vtysh_ext *find_extension(char *name)
+{
+    for(struct vtysh_ext *e = extensions; e != NULL; e = e->next)
+        if (strcmp(e->name, name) == 0)
+            return e;
+    return NULL;
+}
+static int vtysh_load_extension(struct vtysh_ext *e)
+{
+    e->handle = dlopen(e->name, RTLD_GLOBAL | RTLD_NOW);
+    if (e->handle) {
+        int (*ext_load)(void);
+        *(void **)&ext_load = dlsym(e->handle, "vtysh_extension");
+        if (*ext_load) {
+            int r;
+            if ((r = (*ext_load)()) == 0)
+                e->loaded = true;
+            return r;
+        } else {
+            fprintf(stderr, " Failed to init vtysh extension '%s': %s\n", e->name, dlerror());
+            return -1;
+        }
+    } else {
+        fprintf(stderr, " Failed to load vtysh extension '%s': %s\n", e->name, dlerror());
+        return -1;
+    }
+}
+
+int vtysh_load_extensions(void)
+{
+    struct vtysh_ext *e;
+    for (e = extensions; e ; e = e->next) {
+        if (vtysh_load_extension(e) != 0)
+            return -1;
+    }
+    return 0;
+}
+void vtysh_unload_extensions(void)
+{
+    struct vtysh_ext *e;
+    for (e = extensions; e ; e = e->next) {
+        if (e->loaded)
+            dlclose(e->handle);
+        if (e->name)
+            XFREE(MTYPE_VTYSH_EXT_NAME, e->name);
+        XFREE(MTYPE_VTYSH_EXT, e);
+    }
+}
+void vtysh_register_extension(char *name)
+{
+    assert(name);
+    if (find_extension(name) != NULL) {
+        fprintf(stderr, "Omitting extension %s: it appears to be already registered", name);
+        return;
+    }
+    struct vtysh_ext *e = XCALLOC(MTYPE_VTYSH_EXT, sizeof(*e));
+    e->name = XSTRDUP(MTYPE_VTYSH_EXT_NAME, name);
+    e->next = extensions;
+    extensions = e;
+}
+
+void vtysh_show_extensions(struct vty *vty)
+{
+    struct vtysh_ext *e;
+    for (e = extensions; e ; e = e->next) {
+        vty_out(vty, " Extension: %s\n", e->name);
+        vty_out(vty, "    status: %s\n\n", e->loaded ? "loaded" : "not-loaded");
+    }
+}

vtysh/vtysh_extensions.h

@@ -0,0 +1,22 @@
+#ifndef _VTYSH_EXTENSIONS_H
+#define _VTYSH_EXTENSIONS_H
+
+#include <stdbool.h>
+#include "lib/vty.h"
+
+DECLARE_MTYPE(VTYSH_EXT);
+
+struct vtysh_ext {
+    char *name;
+    void *handle;
+    bool loaded;
+    struct vtysh_ext *next;
+};
+
+void vtysh_register_extension(char *name);
+int vtysh_load_extensions(void);
+void vtysh_unload_extensions(void);
+
+void vtysh_show_extensions(struct vty *vty);
+
+#endif /* _VTYSH_EXTENSIONS_H */

vtysh/vtysh_main.c

@@ -216,6 +216,7 @@ struct option longopts[] = {
 	{"user", no_argument, NULL, 'u'},
 	{"timestamp", no_argument, NULL, 't'},
 	{"no-fork", no_argument, NULL, OPTION_NOFORK},
+	{"extension", required_argument, NULL, 'X'},
 	{0}};
 
 bool vtysh_loop_exited;
@@ -322,6 +323,7 @@ void suid_off(void)
 	}
 }
 
+
 /* VTY shell main routine. */
 int main(int argc, char **argv, char **env)
 {
@@ -369,7 +371,7 @@ int main(int argc, char **argv, char **env)
 
 	/* Option handling. */
 	while (1) {
-		opt = getopt_long(argc, argv, "be:c:d:nf:H:mEhCwN:ut", longopts,
+		opt = getopt_long(argc, argv, "be:c:d:nf:H:mEhCwN:utX:", longopts,
 				  0);
 
 		if (opt == EOF)
@@ -446,6 +448,9 @@ int main(int argc, char **argv, char **env)
 		case 'H':
 			histfile = optarg;
 			break;
+		case 'X':
+		    vtysh_register_extension(optarg);
+		    break;
 		default:
 			usage(1);
 			break;
@@ -493,6 +498,7 @@ int main(int argc, char **argv, char **env)
 	vtysh_config_init();
 
 	vty_init_vtysh();
+	vtysh_load_extensions();
 
 	if (!user_mode) {
 		/* Read vtysh configuration file before connecting to daemons.
@@ -739,6 +745,7 @@ int main(int argc, char **argv, char **env)
 	vtysh_rl_run();
 
 	vtysh_uninit();
+	vtysh_unload_extensions();
 
 	history_truncate_file(history_file, 1000);
 	printf("\n");