elf: Rework exception handling in the dynamic loader [BZ #25486]

The old exception handling implementation used function interposition
to replace the dynamic loader implementation (no TLS support) with the
libc implementation (TLS support).  This results in problems if the
link order between the dynamic loader and libc is reversed (bug 25486).

The new implementation moves the entire implementation of the
exception handling functions back into the dynamic loader, using
THREAD_GETMEM and THREAD_SETMEM for thread-local data support.
These depends on Hurd support for these macros, added in commit
b65a82e4e757c1e6cb7073916 ("hurd: Add THREAD_GET/SETMEM/_NC").

One small obstacle is that the exception handling facilities are used
before the TCB has been set up, so a check is needed if the TCB is
available.  If not, a regular global variable is used to store the
exception handling information.

Also rename dl-error.c to dl-catch.c, to avoid confusion with the
dlerror function.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

22 files changed, 0 insertions, 110 deletions

diff --git a/sysdeps/unix/sysv/linux/aarch64/localplt.data b/sysdeps/unix/sysv/linux/aarch64/localplt.data
index 348b3f3793..5d217cc50d 100644
--- a/sysdeps/unix/sysv/linux/aarch64/localplt.data
+++ b/sysdeps/unix/sysv/linux/aarch64/localplt.data
@@ -11,8 +11,3 @@ libm.so: matherr
 libc.so: __getauxval ?
 # The dynamic loader needs __tls_get_addr for TLS.
 ld.so: __tls_get_addr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/alpha/localplt.data b/sysdeps/unix/sysv/linux/alpha/localplt.data
index 44bf36f4f1..8548e0294b 100644
--- a/sysdeps/unix/sysv/linux/alpha/localplt.data
+++ b/sysdeps/unix/sysv/linux/alpha/localplt.data
@@ -25,8 +25,3 @@ libm.so: matherr + RELA R_ALPHA_GLOB_DAT
 libm.so: __atan2
 # The dynamic loader needs __tls_get_addr for TLS.
 ld.so: __tls_get_addr ?
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error + RELA R_ALPHA_GLOB_DAT
-ld.so: _dl_catch_error + RELA R_ALPHA_GLOB_DAT
-ld.so: _dl_signal_exception + RELA R_ALPHA_GLOB_DAT
-ld.so: _dl_catch_exception + RELA R_ALPHA_GLOB_DAT
diff --git a/sysdeps/unix/sysv/linux/arc/localplt.data b/sysdeps/unix/sysv/linux/arc/localplt.data
index ac5332caf7..8a13efc7d0 100644
--- a/sysdeps/unix/sysv/linux/arc/localplt.data
+++ b/sysdeps/unix/sysv/linux/arc/localplt.data
@@ -4,8 +4,3 @@ libc.so: calloc
 libc.so: free
 # At -Os, a struct assignment in libgcc-static pulls this in
 libc.so: memcpy ?
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/arm/localplt.data b/sysdeps/unix/sysv/linux/arm/localplt.data
index 78896444c6..162c664a01 100644
--- a/sysdeps/unix/sysv/linux/arm/localplt.data
+++ b/sysdeps/unix/sysv/linux/arm/localplt.data
@@ -6,8 +6,3 @@ libc.so: realloc
 libm.so: matherr
 # The dynamic loader needs __tls_get_addr for TLS.
 ld.so: __tls_get_addr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/csky/localplt.data b/sysdeps/unix/sysv/linux/csky/localplt.data
index 817ab2659a..547b1c1b7f 100644
--- a/sysdeps/unix/sysv/linux/csky/localplt.data
+++ b/sysdeps/unix/sysv/linux/csky/localplt.data
@@ -5,8 +5,3 @@ libc.so: calloc
 libc.so: free
 libc.so: malloc
 libc.so: realloc
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/hppa/localplt.data b/sysdeps/unix/sysv/linux/hppa/localplt.data
index baf857a750..f8582c08d2 100644
--- a/sysdeps/unix/sysv/linux/hppa/localplt.data
+++ b/sysdeps/unix/sysv/linux/hppa/localplt.data
@@ -9,8 +9,3 @@ libc.so: __sigsetjmp
 libc.so: _IO_funlockfile
 libc.so: __errno_location
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/i386/localplt.data b/sysdeps/unix/sysv/linux/i386/localplt.data
index f9bf7fb410..a998772f04 100644
--- a/sysdeps/unix/sysv/linux/i386/localplt.data
+++ b/sysdeps/unix/sysv/linux/i386/localplt.data
@@ -6,8 +6,3 @@ libc.so: free + REL R_386_GLOB_DAT
 libc.so: malloc + REL R_386_GLOB_DAT
 libc.so: realloc + REL R_386_GLOB_DAT
 libm.so: matherr + REL R_386_GLOB_DAT
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error + REL R_386_GLOB_DAT
-ld.so: _dl_catch_error + REL R_386_GLOB_DAT
-ld.so: _dl_signal_exception + REL R_386_GLOB_DAT
-ld.so: _dl_catch_exception + REL R_386_GLOB_DAT
diff --git a/sysdeps/unix/sysv/linux/ia64/localplt.data b/sysdeps/unix/sysv/linux/ia64/localplt.data
index 174fb88128..9673d4b20e 100644
--- a/sysdeps/unix/sysv/linux/ia64/localplt.data
+++ b/sysdeps/unix/sysv/linux/ia64/localplt.data
@@ -5,8 +5,3 @@ libc.so: realloc
 libm.so: matherr
 libm.so: matherrf
 libm.so: matherrl
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/loongarch/localplt.data b/sysdeps/unix/sysv/linux/loongarch/localplt.data
index 817ab2659a..547b1c1b7f 100644
--- a/sysdeps/unix/sysv/linux/loongarch/localplt.data
+++ b/sysdeps/unix/sysv/linux/loongarch/localplt.data
@@ -5,8 +5,3 @@ libc.so: calloc
 libc.so: free
 libc.so: malloc
 libc.so: realloc
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/localplt.data b/sysdeps/unix/sysv/linux/m68k/coldfire/localplt.data
index 42fa90508c..ea770469b6 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/localplt.data
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/localplt.data
@@ -4,8 +4,3 @@ libc.so: free
 libc.so: malloc
 libc.so: realloc
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/localplt.data b/sysdeps/unix/sysv/linux/m68k/m680x0/localplt.data
index 34bd4c1aca..8ffdf3bfb9 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/localplt.data
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/localplt.data
@@ -5,8 +5,3 @@ libc.so: free
 libc.so: malloc
 libc.so: realloc
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/microblaze/localplt.data b/sysdeps/unix/sysv/linux/microblaze/localplt.data
index c3801314c9..7cd3653372 100644
--- a/sysdeps/unix/sysv/linux/microblaze/localplt.data
+++ b/sysdeps/unix/sysv/linux/microblaze/localplt.data
@@ -6,8 +6,3 @@ libc.so: realloc
 libm.so: matherr
 # The dynamic loader needs __tls_get_addr for TLS.
 ld.so: __tls_get_addr ?
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/nios2/localplt.data b/sysdeps/unix/sysv/linux/nios2/localplt.data
index c9802cc8eb..f502a3f0f6 100644
--- a/sysdeps/unix/sysv/linux/nios2/localplt.data
+++ b/sysdeps/unix/sysv/linux/nios2/localplt.data
@@ -28,8 +28,3 @@ libc.so: __extendsfdf2
 libc.so: __floatundidf ?
 libc.so: __floatunsidf ?
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/or1k/localplt.data b/sysdeps/unix/sysv/linux/or1k/localplt.data
index 04eb9fc8dc..e7704955f1 100644
--- a/sysdeps/unix/sysv/linux/or1k/localplt.data
+++ b/sysdeps/unix/sysv/linux/or1k/localplt.data
@@ -7,8 +7,3 @@ libc.so: malloc
 libc.so: realloc
 # Generated by the compiler because there is no trap insn pattern.
 libc.so: abort ?
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/localplt.data b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/localplt.data
index c0af84eef7..6c1efff68f 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/localplt.data
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/localplt.data
@@ -4,8 +4,3 @@ libc.so: free
 libc.so: malloc
 libc.so: realloc
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/localplt.data b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/localplt.data
index 581e54b95c..eca59e1ed6 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/localplt.data
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/localplt.data
@@ -35,8 +35,3 @@ libc.so: realloc
 libm.so: copysignl ?
 libm.so: fabsl
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/localplt.data b/sysdeps/unix/sysv/linux/powerpc/powerpc64/localplt.data
index d69b7ae646..240d998f57 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/localplt.data
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/localplt.data
@@ -3,8 +3,3 @@ libc.so: free
 libc.so: malloc
 libc.so: realloc
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/riscv/localplt.data b/sysdeps/unix/sysv/linux/riscv/localplt.data
index e6d5330d5b..ea887042e0 100644
--- a/sysdeps/unix/sysv/linux/riscv/localplt.data
+++ b/sysdeps/unix/sysv/linux/riscv/localplt.data
@@ -6,8 +6,3 @@ libc.so: free
 libc.so: malloc
 libc.so: memset ?
 libc.so: realloc
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/s390/localplt.data b/sysdeps/unix/sysv/linux/s390/localplt.data
index c0af84eef7..6c1efff68f 100644
--- a/sysdeps/unix/sysv/linux/s390/localplt.data
+++ b/sysdeps/unix/sysv/linux/s390/localplt.data
@@ -4,8 +4,3 @@ libc.so: free
 libc.so: malloc
 libc.so: realloc
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/sh/localplt.data b/sysdeps/unix/sysv/linux/sh/localplt.data
index 6491b9e37b..3d2e4c1c28 100644
--- a/sysdeps/unix/sysv/linux/sh/localplt.data
+++ b/sysdeps/unix/sysv/linux/sh/localplt.data
@@ -11,8 +11,3 @@ libc.so: __errno_location
 libm.so: matherr
 # Generated by the compiler because there is no trap insn pattern.
 libc.so: abort ?
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data b/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data
index 38309a1393..b5fc6d9c3a 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/localplt.data
@@ -18,8 +18,3 @@ libc.so: free
 libc.so: malloc
 libc.so: realloc
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data b/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data
index 6a216f3a5a..12520b1586 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/localplt.data
@@ -17,8 +17,3 @@ libc.so: free
 libc.so: malloc
 libc.so: realloc
 libm.so: matherr
-# The TLS-enabled version of these functions is interposed from libc.so.
-ld.so: _dl_signal_error
-ld.so: _dl_catch_error
-ld.so: _dl_signal_exception
-ld.so: _dl_catch_exception