svn commit: r190673 - in head: lib/libc/gen libexec/rtld-elf

[Konstantin Belousov]

Author: kib
Date: Fri Apr  3 19:17:23 2009
New Revision: 190673
URL: http://svn.freebsd.org/changeset/base/190673

Log:
  Allow the NULL, RTLD_SELF and RTLD_NEXT handles to work with dlfunc(3).
  dlfunc() called dlsym() to do the work, and dlsym() determines the dso
  that originating the call by the return address. Due to this, dlfunc()
  operated as if the caller is always the libc.
  
  To fix this, move the dlfunc() to rtld, where it can call the internal
  implementation of dlsym, and still correctly fetch return address.
  Provide usual weak stub for the symbol from libc for static binaries.
  dlfunc is put to FBSD_1.0 symver namespace in the ld.so export to
  override dlfunc at FBSD_1.0 weak symbol, exported by libc.
  
  Reported, analyzed and tested by:	Tijl Coosemans <tijl ulyssis org>
  PR: standards/133339
  Reviewed by:	kan

Deleted:
  head/lib/libc/gen/dlfunc.c
Modified:
  head/lib/libc/gen/Makefile.inc
  head/lib/libc/gen/dlfcn.c
  head/libexec/rtld-elf/Symbol.map
  head/libexec/rtld-elf/rtld.c

Modified: head/lib/libc/gen/Makefile.inc
==============================================================================
--- head/lib/libc/gen/Makefile.inc	Fri Apr  3 18:00:19 2009	(r190672)
+++ head/lib/libc/gen/Makefile.inc	Fri Apr  3 19:17:23 2009	(r190673)
@@ -9,7 +9,7 @@ SRCS+=  __getosreldate.c __xuname.c \
 	alarm.c arc4random.c assert.c basename.c check_utility_compat.c \
 	clock.c closedir.c confstr.c \
 	crypt.c ctermid.c daemon.c devname.c dirname.c disklabel.c \
-	dlfcn.c dlfunc.c drand48.c erand48.c err.c errlst.c errno.c \
+	dlfcn.c drand48.c erand48.c err.c errlst.c errno.c \
 	exec.c fdevname.c feature_present.c fmtcheck.c fmtmsg.c fnmatch.c \
 	fpclassify.c frexp.c fstab.c ftok.c fts.c fts-compat.c ftw.c \
 	getbootfile.c getbsize.c \

Modified: head/lib/libc/gen/dlfcn.c
==============================================================================
--- head/lib/libc/gen/dlfcn.c	Fri Apr  3 18:00:19 2009	(r190672)
+++ head/lib/libc/gen/dlfcn.c	Fri Apr  3 19:17:23 2009	(r190673)
@@ -105,6 +105,14 @@ dlsym(void * __restrict handle, const ch
 	return NULL;
 }
 
+#pragma weak dlfunc
+dlfunc_t
+dlfunc(void * __restrict handle, const char * __restrict name)
+{
+	_rtld_error(sorry);
+	return NULL;
+}
+
 #pragma weak dlvsym
 void *
 dlvsym(void * __restrict handle, const char * __restrict name,

Modified: head/libexec/rtld-elf/Symbol.map
==============================================================================
--- head/libexec/rtld-elf/Symbol.map	Fri Apr  3 18:00:19 2009	(r190672)
+++ head/libexec/rtld-elf/Symbol.map	Fri Apr  3 19:17:23 2009	(r190673)
@@ -8,6 +8,7 @@ FBSD_1.0 {
     dlerror;
     dlopen;
     dlsym;
+    dlfunc;
     dlvsym;
     dladdr;
     dllockinit;

Modified: head/libexec/rtld-elf/rtld.c
==============================================================================
--- head/libexec/rtld-elf/rtld.c	Fri Apr  3 18:00:19 2009	(r190672)
+++ head/libexec/rtld-elf/rtld.c	Fri Apr  3 19:17:23 2009	(r190673)
@@ -200,6 +200,7 @@ static func_ptr_type exports[] = {
     (func_ptr_type) &dlerror,
     (func_ptr_type) &dlopen,
     (func_ptr_type) &dlsym,
+    (func_ptr_type) &dlfunc,
     (func_ptr_type) &dlvsym,
     (func_ptr_type) &dladdr,
     (func_ptr_type) &dllockinit,
@@ -2170,6 +2171,19 @@ dlsym(void *handle, const char *name)
 	    SYMLOOK_DLSYM);
 }
 
+dlfunc_t
+dlfunc(void *handle, const char *name)
+{
+	union {
+		void *d;
+		dlfunc_t f;
+	} rv;
+
+	rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL,
+	    SYMLOOK_DLSYM);
+	return (rv.f);
+}
+
 void *
 dlvsym(void *handle, const char *name, const char *version)
 {