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Implement RTLD_DEEPBIND.

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PR:	246462
Tested by:	Martin Birgmeier <d8zNeCFG@aon.at>
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D24841
This commit is contained in:
Konstantin Belousov 2020-05-15 11:58:01 +00:00
parent 8ffb1c8ce1
commit 1659238a0c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=361073
4 changed files with 11 additions and 1 deletions
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2
include/dlfcn.h
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@ -47,6 +47,8 @@
#define RTLD_TRACE 0x200 /* Trace loaded objects and exit. */ #define RTLD_TRACE 0x200 /* Trace loaded objects and exit. */
#define RTLD_NODELETE 0x01000 /* Do not remove members. */ #define RTLD_NODELETE 0x01000 /* Do not remove members. */
#define RTLD_NOLOAD 0x02000 /* Do not load if not already loaded. */ #define RTLD_NOLOAD 0x02000 /* Do not load if not already loaded. */
#define RTLD_DEEPBIND 0x04000 /* Put symbols from the dso ahead of
the global list */
/* /*
* Request arguments for dlinfo(). * Request arguments for dlinfo().

5
lib/libc/gen/dlopen.3
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@ -32,7 +32,7 @@
.\" @(#) dlopen.3 1.6 90/01/31 SMI .\" @(#) dlopen.3 1.6 90/01/31 SMI
.\" $FreeBSD$ .\" $FreeBSD$
.\" .\"
.Dd January 2, 2019 .Dd May 14, 2020
.Dt DLOPEN 3 .Dt DLOPEN 3
.Os .Os
.Sh NAME .Sh NAME
@ -162,6 +162,9 @@ the process address space, otherwise
is returned. is returned.
Other mode flags may be specified, which will be applied for promotion Other mode flags may be specified, which will be applied for promotion
for the found object. for the found object.
.It Dv RTLD_DEEPBIND
Symbols from the loaded library are put before global symbols when
resolving symbolic references originated from the library.
.El .El
.Pp .Pp
If If

4
libexec/rtld-elf/rtld.c
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@ -3366,6 +3366,8 @@ rtld_dlopen(const char *name, int fd, int mode)
lo_flags |= RTLD_LO_NODELETE; lo_flags |= RTLD_LO_NODELETE;
if (mode & RTLD_NOLOAD) if (mode & RTLD_NOLOAD)
lo_flags |= RTLD_LO_NOLOAD; lo_flags |= RTLD_LO_NOLOAD;
if (mode & RTLD_DEEPBIND)
lo_flags |= RTLD_LO_DEEPBIND;
if (ld_tracing != NULL) if (ld_tracing != NULL)
lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS;
@ -3417,6 +3419,8 @@ dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags,
if (globallist_next(old_obj_tail) != NULL) { if (globallist_next(old_obj_tail) != NULL) {
/* We loaded something new. */ /* We loaded something new. */
assert(globallist_next(old_obj_tail) == obj); assert(globallist_next(old_obj_tail) == obj);
if ((lo_flags & RTLD_LO_DEEPBIND) != 0)
obj->symbolic = true;
result = 0; result = 0;
if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 &&
obj->static_tls && !allocate_tls_offset(obj)) { obj->static_tls && !allocate_tls_offset(obj)) {

1
libexec/rtld-elf/rtld.h
View File

@ -309,6 +309,7 @@ TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry);
#define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the
initialization during the image start. */ initialization during the image start. */
#define RTLD_LO_IGNSTLS 0x40 /* Do not allocate static TLS */ #define RTLD_LO_IGNSTLS 0x40 /* Do not allocate static TLS */
#define RTLD_LO_DEEPBIND 0x80 /* Force symbolic for this object */
/* /*
* Symbol cache entry used during relocation to avoid multiple lookups * Symbol cache entry used during relocation to avoid multiple lookups