[Tarantool-patches] [PATCH v8 2/4] module_cache: move module handling into own subsystem
Cyrill Gorcunov
gorcunov at gmail.com
Wed Oct 14 16:35:33 MSK 2020
The module handling should not be bound to particular
function implementation (we will have two users: already
existing functions for "_func" space, and a new upcoming
one which will be serving cbox submodule in next patch).
For this sake all module related code is moved to
module_cache file where we do symbol resolving,
calling and tracking of symbol usage.
Part-of #4642
Signed-off-by: Cyrill Gorcunov <gorcunov at gmail.com>
---
src/box/CMakeLists.txt | 1 +
src/box/box.cc | 2 +-
src/box/func.c | 453 +------------------------------------
src/box/func.h | 84 +------
src/box/module_cache.c | 503 +++++++++++++++++++++++++++++++++++++++++
src/box/module_cache.h | 156 +++++++++++++
6 files changed, 665 insertions(+), 534 deletions(-)
create mode 100644 src/box/module_cache.c
create mode 100644 src/box/module_cache.h
diff --git a/src/box/CMakeLists.txt b/src/box/CMakeLists.txt
index 8b2e704cf..91d85c6db 100644
--- a/src/box/CMakeLists.txt
+++ b/src/box/CMakeLists.txt
@@ -190,6 +190,7 @@ add_library(box STATIC
sql_stmt_cache.c
wal.c
call.c
+ module_cache.c
merger.c
${sql_sources}
${lua_sources}
diff --git a/src/box/box.cc b/src/box/box.cc
index 6ec813c12..2485b79f3 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -74,7 +74,7 @@
#include "sql.h"
#include "systemd.h"
#include "call.h"
-#include "func.h"
+#include "module_cache.h"
#include "sequence.h"
#include "sql_stmt_cache.h"
#include "msgpack.h"
diff --git a/src/box/func.c b/src/box/func.c
index 75d2abb5f..6119f182b 100644
--- a/src/box/func.c
+++ b/src/box/func.c
@@ -31,30 +31,12 @@
#include "func.h"
#include "fiber.h"
#include "trivia/config.h"
-#include "assoc.h"
#include "lua/utils.h"
#include "lua/call.h"
-#include "error.h"
-#include "errinj.h"
#include "diag.h"
#include "port.h"
#include "schema.h"
#include "session.h"
-#include "libeio/eio.h"
-#include <fcntl.h>
-#include <dlfcn.h>
-
-/**
- * Parsed symbol and package names.
- */
-struct func_name {
- /** Null-terminated symbol name, e.g. "func" for "mod.submod.func" */
- const char *sym;
- /** Package name, e.g. "mod.submod" for "mod.submod.func" */
- const char *package;
- /** A pointer to the last character in ->package + 1 */
- const char *package_end;
-};
struct func_c {
/** Function object base class. */
@@ -64,407 +46,6 @@ struct func_c {
struct module_sym mod_sym;
};
-/***
- * Split function name to symbol and package names.
- * For example, str = foo.bar.baz => sym = baz, package = foo.bar
- * @param str function name, e.g. "module.submodule.function".
- * @param[out] name parsed symbol and package names.
- */
-static void
-func_split_name(const char *str, struct func_name *name)
-{
- name->package = str;
- name->package_end = strrchr(str, '.');
- if (name->package_end != NULL) {
- /* module.submodule.function => module.submodule, function */
- name->sym = name->package_end + 1; /* skip '.' */
- } else {
- /* package == function => function, function */
- name->sym = name->package;
- name->package_end = str + strlen(str);
- }
-}
-
-/**
- * Arguments for luaT_module_find used by lua_cpcall()
- */
-struct module_find_ctx {
- const char *package;
- const char *package_end;
- char *path;
- size_t path_len;
-};
-
-/**
- * A cpcall() helper for module_find()
- */
-static int
-luaT_module_find(lua_State *L)
-{
- struct module_find_ctx *ctx = (struct module_find_ctx *)
- lua_topointer(L, 1);
-
- /*
- * Call package.searchpath(name, package.cpath) and use
- * the path to the function in dlopen().
- */
- lua_getglobal(L, "package");
-
- lua_getfield(L, -1, "search");
-
- /* Argument of search: name */
- lua_pushlstring(L, ctx->package, ctx->package_end - ctx->package);
-
- lua_call(L, 1, 1);
- if (lua_isnil(L, -1))
- return luaL_error(L, "module not found");
- /* Convert path to absolute */
- char resolved[PATH_MAX];
- if (realpath(lua_tostring(L, -1), resolved) == NULL) {
- diag_set(SystemError, "realpath");
- return luaT_error(L);
- }
-
- snprintf(ctx->path, ctx->path_len, "%s", resolved);
- return 0;
-}
-
-/**
- * Find path to module using Lua's package.cpath
- * @param package package name
- * @param package_end a pointer to the last byte in @a package + 1
- * @param[out] path path to shared library
- * @param path_len size of @a path buffer
- * @retval 0 on success
- * @retval -1 on error, diag is set
- */
-static int
-module_find(const char *package, const char *package_end, char *path,
- size_t path_len)
-{
- struct module_find_ctx ctx = { package, package_end, path, path_len };
- lua_State *L = tarantool_L;
- int top = lua_gettop(L);
- if (luaT_cpcall(L, luaT_module_find, &ctx) != 0) {
- int package_len = (int) (package_end - package);
- diag_set(ClientError, ER_LOAD_MODULE, package_len, package,
- lua_tostring(L, -1));
- lua_settop(L, top);
- return -1;
- }
- assert(top == lua_gettop(L)); /* cpcall discard results */
- return 0;
-}
-
-static struct mh_strnptr_t *modules = NULL;
-
-static void
-module_gc(struct module *module);
-
-int
-module_init(void)
-{
- modules = mh_strnptr_new();
- if (modules == NULL) {
- diag_set(OutOfMemory, sizeof(*modules), "malloc",
- "modules hash table");
- return -1;
- }
- return 0;
-}
-
-void
-module_free(void)
-{
- while (mh_size(modules) > 0) {
- mh_int_t i = mh_first(modules);
- struct module *module =
- (struct module *) mh_strnptr_node(modules, i)->val;
- /* Can't delete modules if they have active calls */
- module_gc(module);
- }
- mh_strnptr_delete(modules);
-}
-
-/**
- * Look up a module in the modules cache.
- */
-static struct module *
-module_cache_find(const char *name, const char *name_end)
-{
- mh_int_t i = mh_strnptr_find_inp(modules, name, name_end - name);
- if (i == mh_end(modules))
- return NULL;
- return (struct module *)mh_strnptr_node(modules, i)->val;
-}
-
-/**
- * Save module to the module cache.
- */
-static inline int
-module_cache_put(struct module *module)
-{
- size_t package_len = strlen(module->package);
- uint32_t name_hash = mh_strn_hash(module->package, package_len);
- const struct mh_strnptr_node_t strnode = {
- module->package, package_len, name_hash, module};
-
- if (mh_strnptr_put(modules, &strnode, NULL, NULL) == mh_end(modules)) {
- diag_set(OutOfMemory, sizeof(strnode), "malloc", "modules");
- return -1;
- }
- return 0;
-}
-
-/**
- * Delete a module from the module cache
- */
-static void
-module_cache_del(const char *name, const char *name_end)
-{
- mh_int_t i = mh_strnptr_find_inp(modules, name, name_end - name);
- if (i == mh_end(modules))
- return;
- mh_strnptr_del(modules, i, NULL);
-}
-
-/*
- * Load a dso.
- * Create a new symlink based on temporary directory and try to
- * load via this symink to load a dso twice for cases of a function
- * reload.
- */
-static struct module *
-module_load(const char *package, const char *package_end)
-{
- char path[PATH_MAX];
- if (module_find(package, package_end, path, sizeof(path)) != 0)
- return NULL;
-
- int package_len = package_end - package;
- struct module *module = (struct module *)
- malloc(sizeof(*module) + package_len + 1);
- if (module == NULL) {
- diag_set(OutOfMemory, sizeof(struct module) + package_len + 1,
- "malloc", "struct module");
- return NULL;
- }
- memcpy(module->package, package, package_len);
- module->package[package_len] = 0;
- rlist_create(&module->funcs);
- module->calls = 0;
-
- const char *tmpdir = getenv("TMPDIR");
- if (tmpdir == NULL)
- tmpdir = "/tmp";
- char dir_name[PATH_MAX];
- int rc = snprintf(dir_name, sizeof(dir_name), "%s/tntXXXXXX", tmpdir);
- if (rc < 0 || (size_t) rc >= sizeof(dir_name)) {
- diag_set(SystemError, "failed to generate path to tmp dir");
- goto error;
- }
-
- if (mkdtemp(dir_name) == NULL) {
- diag_set(SystemError, "failed to create unique dir name: %s",
- dir_name);
- goto error;
- }
- char load_name[PATH_MAX];
- rc = snprintf(load_name, sizeof(load_name), "%s/%.*s." TARANTOOL_LIBEXT,
- dir_name, package_len, package);
- if (rc < 0 || (size_t) rc >= sizeof(dir_name)) {
- diag_set(SystemError, "failed to generate path to DSO");
- goto error;
- }
-
- struct stat st;
- if (stat(path, &st) < 0) {
- diag_set(SystemError, "failed to stat() module %s", path);
- goto error;
- }
-
- int source_fd = open(path, O_RDONLY);
- if (source_fd < 0) {
- diag_set(SystemError, "failed to open module %s file for" \
- " reading", path);
- goto error;
- }
- int dest_fd = open(load_name, O_WRONLY|O_CREAT|O_TRUNC,
- st.st_mode & 0777);
- if (dest_fd < 0) {
- diag_set(SystemError, "failed to open file %s for writing ",
- load_name);
- close(source_fd);
- goto error;
- }
-
- off_t ret = eio_sendfile_sync(dest_fd, source_fd, 0, st.st_size);
- close(source_fd);
- close(dest_fd);
- if (ret != st.st_size) {
- diag_set(SystemError, "failed to copy DSO %s to %s",
- path, load_name);
- goto error;
- }
-
- module->handle = dlopen(load_name, RTLD_NOW | RTLD_LOCAL);
- if (unlink(load_name) != 0)
- say_warn("failed to unlink dso link %s", load_name);
- if (rmdir(dir_name) != 0)
- say_warn("failed to delete temporary dir %s", dir_name);
- if (module->handle == NULL) {
- diag_set(ClientError, ER_LOAD_MODULE, package_len,
- package, dlerror());
- goto error;
- }
- struct errinj *e = errinj(ERRINJ_DYN_MODULE_COUNT, ERRINJ_INT);
- if (e != NULL)
- ++e->iparam;
- return module;
-error:
- free(module);
- return NULL;
-}
-
-static void
-module_delete(struct module *module)
-{
- struct errinj *e = errinj(ERRINJ_DYN_MODULE_COUNT, ERRINJ_INT);
- if (e != NULL)
- --e->iparam;
- dlclose(module->handle);
- TRASH(module);
- free(module);
-}
-
-/*
- * Check if a dso is unused and can be closed.
- */
-static void
-module_gc(struct module *module)
-{
- if (rlist_empty(&module->funcs) && module->calls == 0)
- module_delete(module);
-}
-
-/*
- * Import a function from the module.
- */
-static box_function_f
-module_sym(struct module *module, const char *name)
-{
- box_function_f f = (box_function_f)dlsym(module->handle, name);
- if (f == NULL) {
- diag_set(ClientError, ER_LOAD_FUNCTION, name, dlerror());
- return NULL;
- }
- return f;
-}
-
-int
-module_sym_load(struct module_sym *mod_sym)
-{
- assert(mod_sym->addr == NULL);
-
- struct func_name name;
- func_split_name(mod_sym->name, &name);
-
- struct module *module = module_cache_find(name.package,
- name.package_end);
- if (module == NULL) {
- /* Try to find loaded module in the cache */
- module = module_load(name.package, name.package_end);
- if (module == NULL)
- return -1;
- if (module_cache_put(module)) {
- module_delete(module);
- return -1;
- }
- }
-
- mod_sym->addr = module_sym(module, name.sym);
- if (mod_sym->addr == NULL)
- return -1;
- mod_sym->module = module;
- rlist_add(&module->funcs, &mod_sym->item);
- return 0;
-}
-
-void
-module_sym_unload(struct module_sym *mod_sym)
-{
- if (mod_sym->module == NULL)
- return;
-
- rlist_del(&mod_sym->item);
- if (rlist_empty(&mod_sym->module->funcs)) {
- struct func_name name;
- func_split_name(mod_sym->name, &name);
- module_cache_del(name.package, name.package_end);
- }
- module_gc(mod_sym->module);
-
- mod_sym->module = NULL;
- mod_sym->addr = NULL;
-}
-
-int
-module_reload(const char *package, const char *package_end, struct module **module)
-{
- struct module *old_module = module_cache_find(package, package_end);
- if (old_module == NULL) {
- /* Module wasn't loaded - do nothing. */
- *module = NULL;
- return 0;
- }
-
- struct module *new_module = module_load(package, package_end);
- if (new_module == NULL)
- return -1;
-
- struct module_sym *mod_sym, *tmp;
- rlist_foreach_entry_safe(mod_sym, &old_module->funcs, item, tmp) {
- struct func_name name;
- func_split_name(mod_sym->name, &name);
- mod_sym->addr = module_sym(new_module, name.sym);
- if (mod_sym->addr == NULL)
- goto restore;
- mod_sym->module = new_module;
- rlist_move(&new_module->funcs, &mod_sym->item);
- }
- module_cache_del(package, package_end);
- if (module_cache_put(new_module) != 0)
- goto restore;
- module_gc(old_module);
- *module = new_module;
- return 0;
-restore:
- /*
- * Some old-dso func can't be load from new module, restore old
- * functions.
- */
- do {
- struct func_name name;
- func_split_name(mod_sym->name, &name);
- mod_sym->addr = module_sym(old_module, name.sym);
- if (mod_sym->addr == NULL) {
- /*
- * Something strange was happen, an early loaden
- * function was not found in an old dso.
- */
- panic("Can't restore module function, "
- "server state is inconsistent");
- }
- mod_sym->module = old_module;
- rlist_move(&old_module->funcs, &mod_sym->item);
- } while (mod_sym != rlist_first_entry(&old_module->funcs,
- struct module_sym,
- item));
- assert(rlist_empty(&new_module->funcs));
- module_delete(new_module);
- return -1;
-}
-
static struct func *
func_c_new(struct func_def *def);
@@ -544,39 +125,9 @@ func_c_call(struct func *base, struct port *args, struct port *ret)
{
assert(base->vtab == &func_c_vtab);
assert(base != NULL && base->def->language == FUNC_LANGUAGE_C);
- struct func_c *func = (struct func_c *) base;
- if (func->mod_sym.addr == NULL) {
- if (module_sym_load(&func->mod_sym) != 0)
- return -1;
- }
-
- struct region *region = &fiber()->gc;
- size_t region_svp = region_used(region);
- uint32_t data_sz;
- const char *data = port_get_msgpack(args, &data_sz);
- if (data == NULL)
- return -1;
- port_c_create(ret);
- box_function_ctx_t ctx = { ret };
-
- /* Module can be changed after function reload. */
- struct module *module = func->mod_sym.module;
- assert(module != NULL);
- ++module->calls;
- int rc = func->mod_sym.addr(&ctx, data, data + data_sz);
- --module->calls;
- module_gc(module);
- region_truncate(region, region_svp);
- if (rc != 0) {
- if (diag_last_error(&fiber()->diag) == NULL) {
- /* Stored procedure forget to set diag */
- diag_set(ClientError, ER_PROC_C, "unknown error");
- }
- port_destroy(ret);
- return -1;
- }
- return rc;
+ struct func_c *func = (struct func_c *) base;
+ return module_sym_call(&func->mod_sym, args, ret);
}
static struct func_vtab func_c_vtab = {
diff --git a/src/box/func.h b/src/box/func.h
index acf2df9a9..11a466b28 100644
--- a/src/box/func.h
+++ b/src/box/func.h
@@ -34,7 +34,8 @@
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
-#include "small/rlist.h"
+
+#include "module_cache.h"
#include "func_def.h"
#include "user_def.h"
@@ -44,43 +45,6 @@ extern "C" {
struct func;
-/**
- * Dynamic shared module.
- */
-struct module {
- /** Module dlhandle. */
- void *handle;
- /** List of imported functions. */
- struct rlist funcs;
- /** Count of active calls. */
- size_t calls;
- /** Module's package name. */
- char package[0];
-};
-
-/**
- * Callable symbol bound to a module.
- */
-struct module_sym {
- /**
- * Anchor for module membership.
- */
- struct rlist item;
- /**
- * For C functions, address of the function.
- */
- box_function_f addr;
- /**
- * Each stored function keeps a handle to the
- * dynamic library for the C callback.
- */
- struct module *module;
- /**
- * Function name definition.
- */
- char *name;
-};
-
/** Virtual method table for func object. */
struct func_vtab {
/** Call function with given arguments. */
@@ -107,18 +71,6 @@ struct func {
struct access access[BOX_USER_MAX];
};
-/**
- * Initialize modules subsystem.
- */
-int
-module_init(void);
-
-/**
- * Cleanup modules subsystem.
- */
-void
-module_free(void);
-
struct func *
func_new(struct func_def *def);
@@ -131,38 +83,6 @@ func_delete(struct func *func);
int
func_call(struct func *func, struct port *args, struct port *ret);
-/**
- * Resolve C entry (find the respective DLL and fetch the
- * symbol from it).
- *
- * @param mod_sym module symbol pointer.
- * @retval -1 on error.
- * @retval 0 on success.
- */
-int
-module_sym_load(struct module_sym *mod_sym);
-
-/**
- * Unload module symbol and drop it from the package
- * cache if there is no users left.
- *
- * @param mod_sym module symbol pointer.
- */
-void
-module_sym_unload(struct module_sym *mod_sym);
-
-/**
- * Reload dynamically loadable module.
- *
- * @param package name begin pointer.
- * @param package_end package_end name end pointer.
- * @param[out] module a pointer to store module object on success.
- * @retval -1 on error.
- * @retval 0 on success.
- */
-int
-module_reload(const char *package, const char *package_end, struct module **module);
-
#if defined(__cplusplus)
} /* extern "C" */
#endif /* defined(__cplusplus) */
diff --git a/src/box/module_cache.c b/src/box/module_cache.c
new file mode 100644
index 000000000..a44f3d110
--- /dev/null
+++ b/src/box/module_cache.c
@@ -0,0 +1,503 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright 2010-2020, Tarantool AUTHORS, please see AUTHORS file.
+ */
+
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "assoc.h"
+#include "diag.h"
+#include "error.h"
+#include "errinj.h"
+#include "fiber.h"
+#include "port.h"
+
+#include "box/error.h"
+#include "lua/utils.h"
+#include "libeio/eio.h"
+
+#include "module_cache.h"
+
+/** Modules name to descriptor hash. */
+static struct mh_strnptr_t *mod_hash = NULL;
+
+/**
+ * Parse function descriptor from a string.
+ */
+void
+parse_func_name(const char *str, struct func_name_desc *d)
+{
+ d->package = str;
+ d->package_end = strrchr(str, '.');
+ if (d->package_end != NULL) {
+ /* module.submodule.function => module.submodule, function */
+ d->sym = d->package_end + 1; /* skip '.' */
+ } else {
+ /* package == function => function, function */
+ d->sym = d->package;
+ d->package_end = str + strlen(str);
+ }
+}
+
+/**
+ * Look up a module in the modules cache.
+ */
+static struct module *
+module_cache_find(const char *name, const char *name_end)
+{
+ mh_int_t e = mh_strnptr_find_inp(mod_hash, name, name_end - name);
+ if (e == mh_end(mod_hash))
+ return NULL;
+ return mh_strnptr_node(mod_hash, e)->val;
+}
+
+/**
+ * Save a module to the modules cache.
+ */
+static int
+module_cache_add(struct module *module)
+{
+ size_t package_len = strlen(module->package);
+ const struct mh_strnptr_node_t nd = {
+ .str = module->package,
+ .len = package_len,
+ .hash = mh_strn_hash(module->package, package_len),
+ .val = module,
+ };
+
+ if (mh_strnptr_put(mod_hash, &nd, NULL, NULL) == mh_end(mod_hash)) {
+ diag_set(OutOfMemory, sizeof(nd), "malloc",
+ "module cache node");
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * Delete a module from the modules cache.
+ */
+static void
+module_cache_del(const char *name, const char *name_end)
+{
+ mh_int_t e = mh_strnptr_find_inp(mod_hash, name, name_end - name);
+ if (e != mh_end(mod_hash))
+ mh_strnptr_del(mod_hash, e, NULL);
+}
+
+/**
+ * Arguments for luaT_module_find used by lua_cpcall().
+ */
+struct module_find_ctx {
+ const char *package;
+ const char *package_end;
+ char *path;
+ size_t path_len;
+};
+
+/**
+ * A cpcall() helper for module_find().
+ */
+static int
+luaT_module_find(lua_State *L)
+{
+ struct module_find_ctx *ctx = (void *)lua_topointer(L, 1);
+
+ /*
+ * Call package.searchpath(name, package.cpath) and use
+ * the path to the function in dlopen().
+ */
+ lua_getglobal(L, "package");
+ lua_getfield(L, -1, "search");
+
+ /* Argument of search: name */
+ lua_pushlstring(L, ctx->package, ctx->package_end - ctx->package);
+
+ lua_call(L, 1, 1);
+ if (lua_isnil(L, -1))
+ return luaL_error(L, "module not found");
+
+ /* Convert path to absolute */
+ char resolved[PATH_MAX];
+ if (realpath(lua_tostring(L, -1), resolved) == NULL) {
+ diag_set(SystemError, "realpath");
+ return luaT_error(L);
+ }
+
+ snprintf(ctx->path, ctx->path_len, "%s", resolved);
+ return 0;
+}
+
+/**
+ * Find a path to a module using Lua's package.cpath.
+ *
+ * @param ctx module find context
+ * @param[out] ctx->path path to shared library.
+ * @param[out] ctx->path_len size of @a ctx->path buffer.
+ *
+ * @return 0 on succes, -1 otherwise, diag is set.
+ */
+static int
+module_find(struct module_find_ctx *ctx)
+{
+ lua_State *L = tarantool_L;
+ int top = lua_gettop(L);
+ if (luaT_cpcall(L, luaT_module_find, ctx) != 0) {
+ diag_set(ClientError, ER_LOAD_MODULE,
+ (int)(ctx->package_end - ctx->package),
+ ctx->package, lua_tostring(L, -1));
+ lua_settop(L, top);
+ return -1;
+ }
+ assert(top == lua_gettop(L)); /* cpcall discard results */
+ return 0;
+}
+
+/**
+ * Load dynamic shared object, ie module library.
+ *
+ * Create a new symlink based on temporary directory
+ * and try to load via this symink to load a dso twice
+ * for cases of a function reload.
+ */
+static struct module *
+module_load(const char *package, const char *package_end)
+{
+ char path[PATH_MAX];
+ struct module_find_ctx ctx = {
+ .package = package,
+ .package_end = package_end,
+ .path = path,
+ .path_len = sizeof(path),
+ };
+ if (module_find(&ctx) != 0)
+ return NULL;
+
+ int package_len = package_end - package;
+ struct module *module = malloc(sizeof(*module) + package_len + 1);
+ if (module == NULL) {
+ diag_set(OutOfMemory, sizeof(*module) + package_len + 1,
+ "malloc", "struct module");
+ return NULL;
+ }
+ memcpy(module->package, package, package_len);
+ module->package[package_len] = 0;
+ rlist_create(&module->mod_sym_head);
+ module->calls = 0;
+
+ const char *tmpdir = getenv("TMPDIR");
+ if (tmpdir == NULL)
+ tmpdir = "/tmp";
+
+ char dir_name[PATH_MAX];
+ int rc = snprintf(dir_name, sizeof(dir_name), "%s/tntXXXXXX", tmpdir);
+ if (rc < 0 || (size_t)rc >= sizeof(dir_name)) {
+ diag_set(SystemError, "failed to generate path to tmp dir");
+ goto error;
+ }
+
+ if (mkdtemp(dir_name) == NULL) {
+ diag_set(SystemError, "failed to create unique dir name: %s",
+ dir_name);
+ goto error;
+ }
+
+ char load_name[PATH_MAX];
+ rc = snprintf(load_name, sizeof(load_name), "%s/%.*s." TARANTOOL_LIBEXT,
+ dir_name, package_len, package);
+ if (rc < 0 || (size_t)rc >= sizeof(dir_name)) {
+ diag_set(SystemError, "failed to generate path to DSO");
+ goto error;
+ }
+
+ struct stat st;
+ if (stat(path, &st) < 0) {
+ diag_set(SystemError, "failed to stat() module %s", path);
+ goto error;
+ }
+
+ int source_fd = open(path, O_RDONLY);
+ if (source_fd < 0) {
+ diag_set(SystemError, "failed to open module %s", path);
+ goto error;
+ }
+
+ int dest_fd = open(load_name, O_WRONLY | O_CREAT | O_TRUNC,
+ st.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO));
+ if (dest_fd < 0) {
+ diag_set(SystemError, "failed to open file %s for writing ",
+ load_name);
+ close(source_fd);
+ goto error;
+ }
+
+ off_t ret = eio_sendfile_sync(dest_fd, source_fd, 0, st.st_size);
+ close(source_fd);
+ close(dest_fd);
+ if (ret != st.st_size) {
+ diag_set(SystemError, "failed to copy DSO %s to %s",
+ path, load_name);
+ goto error;
+ }
+
+ module->handle = dlopen(load_name, RTLD_NOW | RTLD_LOCAL);
+ if (unlink(load_name) != 0)
+ say_warn("failed to unlink dso link %s", load_name);
+ if (rmdir(dir_name) != 0)
+ say_warn("failed to delete temporary dir %s", dir_name);
+ if (module->handle == NULL) {
+ diag_set(ClientError, ER_LOAD_MODULE, package_len,
+ package, dlerror());
+ goto error;
+ }
+
+ struct errinj *e = errinj(ERRINJ_DYN_MODULE_COUNT, ERRINJ_INT);
+ if (e != NULL)
+ ++e->iparam;
+ return module;
+
+error:
+ free(module);
+ return NULL;
+}
+
+/**
+ * Delete a module.
+ */
+static void
+module_delete(struct module *module)
+{
+ struct errinj *e = errinj(ERRINJ_DYN_MODULE_COUNT, ERRINJ_INT);
+ if (e != NULL)
+ --e->iparam;
+ dlclose(module->handle);
+ TRASH(module);
+ free(module);
+}
+
+/**
+ * Check if a module is unused and delete it then.
+ */
+static void
+module_gc(struct module *module)
+{
+ if (rlist_empty(&module->mod_sym_head) && module->calls == 0)
+ module_delete(module);
+}
+
+/**
+ * Import a function from a module.
+ */
+static box_function_f
+module_sym(struct module *module, const char *name)
+{
+ box_function_f f = dlsym(module->handle, name);
+ if (f == NULL) {
+ diag_set(ClientError, ER_LOAD_FUNCTION, name, dlerror());
+ return NULL;
+ }
+ return f;
+}
+
+/**
+ * Load a new module symbol.
+ */
+int
+module_sym_load(struct module_sym *mod_sym)
+{
+ assert(mod_sym->addr == NULL);
+
+ struct func_name_desc d;
+ parse_func_name(mod_sym->name, &d);
+
+ struct module *module = module_cache_find(d.package, d.package_end);
+ if (module == NULL) {
+ module = module_load(d.package, d.package_end);
+ if (module == NULL)
+ return -1;
+ if (module_cache_add(module)) {
+ module_delete(module);
+ return -1;
+ }
+ }
+
+ mod_sym->addr = module_sym(module, d.sym);
+ if (mod_sym->addr == NULL)
+ return -1;
+
+ mod_sym->module = module;
+ rlist_add(&module->mod_sym_head, &mod_sym->list);
+ return 0;
+}
+
+/**
+ * Unload a module's symbol.
+ */
+void
+module_sym_unload(struct module_sym *mod_sym)
+{
+ if (mod_sym->module == NULL)
+ return;
+
+ rlist_del(&mod_sym->list);
+ if (rlist_empty(&mod_sym->module->mod_sym_head)) {
+ struct func_name_desc d;
+ parse_func_name(mod_sym->name, &d);
+ module_cache_del(d.package, d.package_end);
+ }
+ module_gc(mod_sym->module);
+
+ mod_sym->module = NULL;
+ mod_sym->addr = NULL;
+}
+
+/**
+ * Execute module symbol (run a function).
+ */
+int
+module_sym_call(struct module_sym *mod_sym, struct port *args,
+ struct port *ret)
+{
+ if (mod_sym->addr == NULL) {
+ if (module_sym_load(mod_sym) != 0)
+ return -1;
+ }
+
+ struct region *region = &fiber()->gc;
+ size_t region_svp = region_used(region);
+
+ uint32_t data_sz;
+ const char *data = port_get_msgpack(args, &data_sz);
+ if (data == NULL)
+ return -1;
+
+ port_c_create(ret);
+ box_function_ctx_t ctx = {
+ .port = ret,
+ };
+
+ /*
+ * Module can be changed after function reload. Also
+ * keep in mind that stored C procedure may yield inside.
+ */
+ struct module *module = mod_sym->module;
+ assert(module != NULL);
+ ++module->calls;
+ int rc = mod_sym->addr(&ctx, data, data + data_sz);
+ --module->calls;
+ module_gc(module);
+ region_truncate(region, region_svp);
+
+ if (rc != 0) {
+ if (diag_last_error(&fiber()->diag) == NULL) {
+ /* Stored procedure forget to set diag */
+ diag_set(ClientError, ER_PROC_C, "unknown error");
+ }
+ port_destroy(ret);
+ return -1;
+ }
+
+ return rc;
+}
+
+/**
+ * Reload a module and all associated symbols.
+ */
+int
+module_reload(const char *package, const char *package_end,
+ struct module **module)
+{
+ struct module *old = module_cache_find(package, package_end);
+ if (old == NULL) {
+ /* Module wasn't loaded - do nothing. */
+ *module = NULL;
+ return 0;
+ }
+
+ struct module *new = module_load(package, package_end);
+ if (new == NULL)
+ return -1;
+
+ struct module_sym *mod_sym, *tmp;
+ rlist_foreach_entry_safe(mod_sym, &old->mod_sym_head, list, tmp) {
+ struct func_name_desc d;
+ parse_func_name(mod_sym->name, &d);
+
+ mod_sym->addr = module_sym(new, d.sym);
+ if (mod_sym->addr == NULL) {
+ say_error("module: reload %s, symbol %s not found",
+ package, d.sym);
+ goto restore;
+ }
+
+ mod_sym->module = new;
+ rlist_move(&new->mod_sym_head, &mod_sym->list);
+ }
+
+ module_cache_del(package, package_end);
+ if (module_cache_add(new) != 0)
+ goto restore;
+
+ module_gc(old);
+ *module = new;
+ return 0;
+
+restore:
+ /*
+ * Some old-dso func can't be load from new module,
+ * restore old functions.
+ */
+ do {
+ struct func_name_desc d;
+ parse_func_name(mod_sym->name, &d);
+ mod_sym->addr = module_sym(old, d.sym);
+ if (mod_sym->addr == NULL) {
+ /*
+ * Something strange was happen, an early loaden
+ * function was not found in an old dso.
+ */
+ panic("Can't restore module function, "
+ "server state is inconsistent");
+ }
+ mod_sym->module = old;
+ rlist_move(&old->mod_sym_head, &mod_sym->list);
+ } while (mod_sym != rlist_first_entry(&old->mod_sym_head,
+ struct module_sym,
+ list));
+ assert(rlist_empty(&new->mod_sym_head));
+ module_delete(new);
+ return -1;
+}
+
+/**
+ * Initialize modules subsystem.
+ */
+int
+module_init(void)
+{
+ mod_hash = mh_strnptr_new();
+ if (mod_hash == NULL) {
+ diag_set(OutOfMemory, sizeof(*mod_hash),
+ "malloc", "modules hash table");
+ return -1;
+ }
+ return 0;
+}
+
+/**
+ * Free modules subsystem.
+ */
+void
+module_free(void)
+{
+ while (mh_size(mod_hash) > 0) {
+ mh_int_t i = mh_first(mod_hash);
+ struct module *m = mh_strnptr_node(mod_hash, i)->val;
+ module_gc(m);
+ }
+ mh_strnptr_delete(mod_hash);
+ mod_hash = NULL;
+}
diff --git a/src/box/module_cache.h b/src/box/module_cache.h
new file mode 100644
index 000000000..3f275024a
--- /dev/null
+++ b/src/box/module_cache.h
@@ -0,0 +1,156 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright 2010-2020, Tarantool AUTHORS, please see AUTHORS file.
+ */
+
+#pragma once
+
+#include <small/rlist.h>
+
+#include "func_def.h"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif /* defined(__cplusplus) */
+
+/**
+ * Function name descriptor: a symbol and a package.
+ */
+struct func_name_desc {
+ /**
+ * Null-terminated symbol name, e.g.
+ * "func" for "mod.submod.func".
+ */
+ const char *sym;
+ /**
+ * Package name, e.g. "mod.submod" for
+ * "mod.submod.func".
+ */
+ const char *package;
+ /**
+ * A pointer to the last character in ->package + 1.
+ */
+ const char *package_end;
+};
+
+/***
+ * Parse function name into a name descriptor.
+ *
+ * For example, str = foo.bar.baz => sym = baz, package = foo.bar
+ *
+ * @param str function name, e.g. "module.submodule.function".
+ * @param[out] d parsed symbol and a package name.
+ */
+void
+parse_func_name(const char *str, struct func_name_desc *d);
+
+/**
+ * Dynamic shared module.
+ */
+struct module {
+ /**
+ * Module dlhandle.
+ */
+ void *handle;
+ /**
+ * List of associated symbols (functions).
+ */
+ struct rlist mod_sym_head;
+ /**
+ * Count of active calls.
+ */
+ size_t calls;
+ /**
+ * Module's package name.
+ */
+ char package[0];
+};
+
+/**
+ * Callable symbol bound to a module.
+ */
+struct module_sym {
+ /**
+ * Anchor for module membership.
+ */
+ struct rlist list;
+ /**
+ * For C functions, address of the function.
+ */
+ box_function_f addr;
+ /**
+ * Each stored function keeps a handle to the
+ * dynamic library for the C callback.
+ */
+ struct module *module;
+ /**
+ * Symbol (function) name definition.
+ */
+ char *name;
+};
+
+/**
+ * Load a new module symbol.
+ *
+ * @param mod_sym symbol to load.
+ *
+ * @returns 0 on succse, -1 otherwise, diag is set.
+ */
+int
+module_sym_load(struct module_sym *mod_sym);
+
+/**
+ * Unload a module's symbol.
+ *
+ * @param mod_sym symbol to unload.
+ */
+void
+module_sym_unload(struct module_sym *mod_sym);
+
+/**
+ * Execute a module symbol (run a function).
+ *
+ * The function packs function arguments into a message pack
+ * and send it as a function argument. Function may return
+ * results via @a ret stream.
+ *
+ * @param mod_sym module symbol to run.
+ * @param args function arguments
+ * @param[out] execution results
+ *
+ * @returns 0 on success, -1 otherwise, diag is set.
+ */
+int
+module_sym_call(struct module_sym *mod_sym, struct port *args,
+ struct port *ret);
+
+/**
+ * Reload a module and all associated symbols.
+ *
+ * @param str function name, e.g. "module.submodule.function".
+ * @param[out] d parsed symbol and a package name.
+ *
+ * @return 0 on succes, -1 otherwise, diag is set.
+ */
+int
+module_reload(const char *package, const char *package_end,
+ struct module **module);
+
+/**
+ * Initialize modules subsystem.
+ *
+ * @return 0 on succes, -1 otherwise, diag is set.
+ */
+int
+module_init(void);
+
+/**
+ * Free modules subsystem.
+ */
+void
+module_free(void);
+
+#if defined(__cplusplus)
+}
+#endif /* defined(__plusplus) */
--
2.26.2
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