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@gmx.net>
Change-Id: I86693a0ecf25d5ba81c73773a03df4abc3426875
This commit is contained in:
Sebastian Kemper
2019-04-02 22:49:52 +02:00
committed by Corey Farrell
parent 012706c6c5
commit ccac55b894
4 changed files with 194 additions and 20 deletions

50
configure vendored
View File

@@ -702,6 +702,7 @@ PBX_DYNAMIC_LIST
POW_LIB
PBX_WORKING_FORK
LIBOBJS
PERMANENT_DLOPEN
DISABLE_XMLDOC
CONFIG_LIBXML2
JANSSON_LIBS
@@ -1345,7 +1346,6 @@ infodir
docdir
oldincludedir
includedir
runstatedir
localstatedir
sharedstatedir
sysconfdir
@@ -1454,6 +1454,7 @@ with_vpb
with_x11
with_z
enable_xmldoc
enable_permanent_dlopen
enable_largefile
enable_internal_poll
enable_asteriskssl
@@ -1533,7 +1534,6 @@ datadir='${datarootdir}'
sysconfdir='${prefix}/etc'
sharedstatedir='${prefix}/com'
localstatedir='${prefix}/var'
runstatedir='${localstatedir}/run'
includedir='${prefix}/include'
oldincludedir='/usr/include'
docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
@@ -1786,15 +1786,6 @@ do
| -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=$ac_optarg ;;
-sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
ac_prev=sbindir ;;
-sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1932,7 +1923,7 @@ fi
for ac_var in exec_prefix prefix bindir sbindir libexecdir datarootdir \
datadir sysconfdir sharedstatedir localstatedir includedir \
oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
libdir localedir mandir runstatedir
libdir localedir mandir
do
eval ac_val=\$$ac_var
# Remove trailing slashes.
@@ -2085,7 +2076,6 @@ Fine tuning of the installation directories:
--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]
@@ -2124,6 +2114,9 @@ Optional Features:
--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
@@ -14852,6 +14845,25 @@ fi
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
$as_echo "#define HAVE_PERMANENT_DLOPEN 1" >>confdefs.h
fi
# some embedded systems omit internationalization (locale) support
@@ -14918,7 +14930,7 @@ else
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -14964,7 +14976,7 @@ else
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -14988,7 +15000,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -15033,7 +15045,7 @@ else
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@@ -15057,7 +15069,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
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];
@@ -16357,8 +16369,6 @@ main ()
if (*(data + i) != *(data3 + i))
return 14;
close (fd);
free (data);
free (data3);
return 0;
}
_ACEOF