[Asterisk-code-review] loader: support for permanent dlopen() (...asterisk[16])
Friendly Automation
asteriskteam at digium.com
Fri Apr 19 08:32:13 CDT 2019
Friendly Automation has submitted this change and it was merged. ( https://gerrit.asterisk.org/c/asterisk/+/11228 )
Change subject: loader: support for permanent dlopen()
......................................................................
loader: support for permanent dlopen()
Asterisk assumes that dlopen() will always run the constructor of a
shared library and every dlclose() will run its destructor. But dlopen()
may be permanent, meaning the constructor will only be run once, as is
the case with musl libc.
With a permanent dlopen() the Asterisk module loader does not work
correctly, because it's expectations regarding when the constructors and
destructors are run are not met. In fact a segmentation fault will occur
when the first module is "re-opened" that has AST_MODFLAG_GLOBAL_SYMBOLS
set (the dlopen() does not call the constructor, resource_being_loaded
is not set to NULL, then strlen is called with NULL instead of a string,
see issue ASTERISK-28319).
This commit adds code to the loader that will manually run the
constructors/destructors of the (non-builtin) modules where needed. To
achieve this a new ao2 container (linked list) is started and filled
with objects that contain the names of the modules and the pointers to
their respective info structs.
This behavior can be activated when configuring Asterisk
(--enable-permanent-dlopen). By default this is disabled, of course.
ASTERISK-28319 #close
Signed-off-by: Sebastian Kemper <sebastian_ml at gmx.net>
Change-Id: I86693a0ecf25d5ba81c73773a03df4abc3426875
---
M configure
M configure.ac
M include/asterisk/autoconfig.h.in
M main/loader.c
4 files changed, 194 insertions(+), 20 deletions(-)
Approvals:
Corey Farrell: Looks good to me, but someone else must approve
Joshua Colp: Looks good to me, but someone else must approve
George Joseph: Looks good to me, approved
Friendly Automation: Approved for Submit
diff --git a/configure b/configure
index d8e1cbf..bb3244d 100755
--- a/configure
+++ b/configure
@@ -702,6 +702,7 @@
POW_LIB
PBX_WORKING_FORK
LIBOBJS
+PERMANENT_DLOPEN
DISABLE_XMLDOC
CONFIG_LIBXML2
JANSSON_LIBS
@@ -1337,7 +1338,6 @@
docdir
oldincludedir
includedir
-runstatedir
localstatedir
sharedstatedir
sysconfdir
@@ -1446,6 +1446,7 @@
with_x11
with_z
enable_xmldoc
+enable_permanent_dlopen
enable_largefile
enable_internal_poll
enable_asteriskssl
@@ -1525,7 +1526,6 @@
sysconfdir='${prefix}/etc'
sharedstatedir='${prefix}/com'
localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
includedir='${prefix}/include'
oldincludedir='/usr/include'
docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1778,15 +1778,6 @@
| -silent | --silent | --silen | --sile | --sil)
silent=yes ;;
- -runstatedir | --runstatedir | --runstatedi | --runstated \
- | --runstate | --runstat | --runsta | --runst | --runs \
- | --run | --ru | --r)
- ac_prev=runstatedir ;;
- -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
- | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
- | --run=* | --ru=* | --r=*)
- runstatedir=$ac_optarg ;;
-
-sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
ac_prev=sbindir ;;
-sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1924,7 +1915,7 @@
for ac_var in exec_prefix prefix bindir sbindir libexecdir datarootdir \
datadir sysconfdir sharedstatedir localstatedir includedir \
oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
- libdir localedir mandir runstatedir
+ libdir localedir mandir
do
eval ac_val=\$$ac_var
# Remove trailing slashes.
@@ -2077,7 +2068,6 @@
--sysconfdir=DIR read-only single-machine data [PREFIX/etc]
--sharedstatedir=DIR modifiable architecture-independent data [PREFIX/com]
--localstatedir=DIR modifiable single-machine data [PREFIX/var]
- --runstatedir=DIR modifiable per-process data [LOCALSTATEDIR/run]
--libdir=DIR object code libraries [EPREFIX/lib]
--includedir=DIR C header files [PREFIX/include]
--oldincludedir=DIR C header files for non-gcc [/usr/include]
@@ -2116,6 +2106,9 @@
--enable-dev-mode Turn on developer mode
--enable-coverage Turn on code coverage tracking (for gcov)
--disable-xmldoc Explicitly disable XML documentation
+ --enable-permanent-dlopen
+ Enable when your libc has a permanent dlopen like
+ musl
--disable-largefile omit support for large files
--enable-internal-poll Use Asterisk's poll implementation
--disable-asteriskssl Disable Asterisk's SSL wrapper library
@@ -14816,6 +14809,25 @@
fi
+# Check whether --enable-permanent-dlopen was given.
+if test "${enable_permanent_dlopen+set}" = set; then :
+ enableval=$enable_permanent_dlopen; case "${enableval}" in
+ y|ye|yes) PERMANENT_DLOPEN=yes ;;
+ n|no) PERMANENT_DLOPEN=no ;;
+ *) as_fn_error $? "bad value ${enableval} for --enable-permanent-dlopen" "$LINENO" 5 ;;
+ esac
+else
+ PERMANENT_DLOPEN=no
+fi
+
+
+
+if test "${PERMANENT_DLOPEN}" == "yes"; then
+
+$as_echo "#define HAVE_PERMANENT_DLOPEN 1" >>confdefs.h
+
+fi
+
# some embedded systems omit internationalization (locale) support
for ac_header in xlocale.h
do :
@@ -14880,7 +14892,7 @@
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -14926,7 +14938,7 @@
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -14950,7 +14962,7 @@
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -14995,7 +15007,7 @@
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -15019,7 +15031,7 @@
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
-#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
+#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -16319,8 +16331,6 @@
if (*(data + i) != *(data3 + i))
return 14;
close (fd);
- free (data);
- free (data3);
return 0;
}
_ACEOF
diff --git a/configure.ac b/configure.ac
index 7acfcbc..3c64307 100644
--- a/configure.ac
+++ b/configure.ac
@@ -727,6 +727,20 @@
fi
+AC_ARG_ENABLE([permanent-dlopen],
+ [AS_HELP_STRING([--enable-permanent-dlopen],
+ [Enable when your libc has a permanent dlopen like musl])],
+ [case "${enableval}" in
+ y|ye|yes) PERMANENT_DLOPEN=yes ;;
+ n|no) PERMANENT_DLOPEN=no ;;
+ *) AC_MSG_ERROR(bad value ${enableval} for --enable-permanent-dlopen) ;;
+ esac], [PERMANENT_DLOPEN=no])
+
+AC_SUBST([PERMANENT_DLOPEN])
+if test "${PERMANENT_DLOPEN}" == "yes"; then
+ AC_DEFINE([HAVE_PERMANENT_DLOPEN], 1, [Define to support libc with permanent dlopen.])
+fi
+
# some embedded systems omit internationalization (locale) support
AC_CHECK_HEADERS([xlocale.h])
diff --git a/include/asterisk/autoconfig.h.in b/include/asterisk/autoconfig.h.in
index 72f6ee0..9de15e5 100644
--- a/include/asterisk/autoconfig.h.in
+++ b/include/asterisk/autoconfig.h.in
@@ -603,6 +603,9 @@
/* Define to 1 if your system defines the file flag O_SYMLINK in fcntl.h */
#undef HAVE_O_SYMLINK
+/* Define to support libc with permanent dlopen. */
+#undef HAVE_PERMANENT_DLOPEN
+
/* Define to indicate the PostgreSQL library */
#undef HAVE_PGSQL
diff --git a/main/loader.c b/main/loader.c
index 3749c95..b46f745 100644
--- a/main/loader.c
+++ b/main/loader.c
@@ -153,6 +153,117 @@
static struct ast_vector_string startup_errors;
static struct ast_str *startup_error_builder;
+#if defined(HAVE_PERMANENT_DLOPEN)
+#define FIRST_DLOPEN 999
+
+struct ao2_container *info_list = NULL;
+
+struct info_list_obj {
+ const struct ast_module_info *info;
+ int dlopened;
+ char name[0];
+};
+
+static struct info_list_obj *info_list_obj_alloc(const char *name,
+ const struct ast_module_info *info)
+{
+ struct info_list_obj *new_entry;
+
+ new_entry = ao2_alloc(sizeof(*new_entry) + strlen(name) + 1, NULL);
+
+ if (!new_entry) {
+ return NULL;
+ }
+
+ strcpy(new_entry->name, name); /* SAFE */
+ new_entry->info = info;
+ new_entry->dlopened = FIRST_DLOPEN;
+
+ return new_entry;
+}
+
+AO2_STRING_FIELD_CMP_FN(info_list_obj, name)
+
+static char *get_name_from_resource(const char *resource)
+{
+ int len;
+ const char *last_three;
+ char *mod_name;
+
+ if (!resource) {
+ return NULL;
+ }
+
+ len = strlen(resource);
+ if (len > 3) {
+ last_three = &resource[len-3];
+ if (!strcasecmp(last_three, ".so")) {
+ mod_name = ast_calloc(1, len - 2);
+ if (mod_name) {
+ ast_copy_string(mod_name, resource, len - 2);
+ return mod_name;
+ } else {
+ /* Unable to allocate memory. */
+ return NULL;
+ }
+ }
+ }
+
+ /* Resource is the name - happens when manually unloading a module. */
+ mod_name = ast_calloc(1, len + 1);
+ if (mod_name) {
+ ast_copy_string(mod_name, resource, len + 1);
+ return mod_name;
+ }
+
+ /* Unable to allocate memory. */
+ return NULL;
+}
+
+static void manual_mod_reg(const void *lib, const char *resource)
+{
+ struct info_list_obj *obj_tmp;
+ char *mod_name;
+
+ if (lib) {
+ mod_name = get_name_from_resource(resource);
+ if (mod_name) {
+ obj_tmp = ao2_find(info_list, mod_name, OBJ_SEARCH_KEY);
+ if (obj_tmp) {
+ if (obj_tmp->dlopened == FIRST_DLOPEN) {
+ obj_tmp->dlopened = 1;
+ } else {
+ ast_module_register(obj_tmp->info);
+ }
+ ao2_ref(obj_tmp, -1);
+ }
+ ast_free(mod_name);
+ }
+ }
+}
+
+static void manual_mod_unreg(const char *resource)
+{
+ struct info_list_obj *obj_tmp;
+ char *mod_name;
+
+ /* When Asterisk shuts down the destructor is called automatically. */
+ if (ast_shutdown_final()) {
+ return;
+ }
+
+ mod_name = get_name_from_resource(resource);
+ if (mod_name) {
+ obj_tmp = ao2_find(info_list, mod_name, OBJ_SEARCH_KEY);
+ if (obj_tmp) {
+ ast_module_unregister(obj_tmp->info);
+ ao2_ref(obj_tmp, -1);
+ }
+ ast_free(mod_name);
+ }
+}
+#endif
+
static __attribute__((format(printf, 1, 2))) void module_load_error(const char *fmt, ...)
{
char *copy = NULL;
@@ -597,6 +708,23 @@
/* give the module a copy of its own handle, for later use in registrations and the like */
*((struct ast_module **) &(info->self)) = mod;
+
+#if defined(HAVE_PERMANENT_DLOPEN)
+ if (mod->flags.builtin != 1) {
+ struct info_list_obj *obj_tmp = ao2_find(info_list, info->name,
+ OBJ_SEARCH_KEY);
+
+ if (!obj_tmp) {
+ obj_tmp = info_list_obj_alloc(info->name, info);
+ if (obj_tmp) {
+ ao2_link(info_list, obj_tmp);
+ ao2_ref(obj_tmp, -1);
+ }
+ } else {
+ ao2_ref(obj_tmp, -1);
+ }
+ }
+#endif
}
static int module_post_register(struct ast_module *mod)
@@ -843,6 +971,10 @@
error = dlerror();
ast_log(AST_LOG_ERROR, "Failure in dlclose for module '%s': %s\n",
S_OR(name, "unknown"), S_OR(error, "Unknown error"));
+#if defined(HAVE_PERMANENT_DLOPEN)
+ } else {
+ manual_mod_unreg(name);
+#endif
}
}
@@ -949,6 +1081,9 @@
resource_being_loaded = mod;
mod->lib = dlopen(filename, flags);
+#if defined(HAVE_PERMANENT_DLOPEN)
+ manual_mod_reg(mod->lib, mod->resource);
+#endif
if (resource_being_loaded) {
struct ast_str *list;
int c = 0;
@@ -968,6 +1103,9 @@
resource_being_loaded = mod;
mod->lib = dlopen(filename, RTLD_LAZY | RTLD_LOCAL);
+#if defined(HAVE_PERMANENT_DLOPEN)
+ manual_mod_reg(mod->lib, mod->resource);
+#endif
if (resource_being_loaded) {
resource_being_loaded = NULL;
@@ -2206,6 +2344,15 @@
ast_verb(1, "Asterisk Dynamic Loader Starting:\n");
+#if defined(HAVE_PERMANENT_DLOPEN)
+ info_list = ao2_container_alloc_list(AO2_ALLOC_OPT_LOCK_NOLOCK, 0, NULL,
+ info_list_obj_cmp_fn); /* must not be cleaned at shutdown */
+ if (!info_list) {
+ fprintf(stderr, "Module info list allocation failure.\n");
+ return 1;
+ }
+#endif
+
AST_LIST_HEAD_INIT_NOLOCK(&load_order);
AST_DLLIST_LOCK(&module_list);
--
To view, visit https://gerrit.asterisk.org/c/asterisk/+/11228
To unsubscribe, or for help writing mail filters, visit https://gerrit.asterisk.org/settings
Gerrit-Project: asterisk
Gerrit-Branch: 16
Gerrit-Change-Id: I86693a0ecf25d5ba81c73773a03df4abc3426875
Gerrit-Change-Number: 11228
Gerrit-PatchSet: 1
Gerrit-Owner: Corey Farrell <git at cfware.com>
Gerrit-Reviewer: Corey Farrell <git at cfware.com>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>
Gerrit-Reviewer: Sebastian Kemper <sebastian_ml at gmx.net>
Gerrit-MessageType: merged
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-code-review/attachments/20190419/684dbf2f/attachment-0001.html>
More information about the asterisk-code-review
mailing list