From 0e75c4a4634f44ad24a65fda01f571781ac79d5f Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Wed, 17 Jul 2024 14:06:25 +0200
Subject: [PATCH] hurd: Fix pthread_self() without libpthread

5476f8cd2e68 ("htl: move pthread_self info libc.") moved the htl
pthread_self() function from libpthread to libc, replacing the previous libc
stub that just returns 0. And 53da64d1cf36 ("htl: Initialize ___pthread_self
early") added initialization code which is needed before being able to
call pthread_self. It is currently in libpthread, and thus never called
before programs can call pthread_self from libc, which then segfaults
when accessing _pthread_self()->thread.

This moves the initialization to libc itself, as initialized variables, so
pthread_self can always be called fine.
---
 htl/Versions                            |  1 +
 sysdeps/mach/hurd/htl/pt-pthread_self.c |  9 ++++++++-
 sysdeps/mach/hurd/htl/pt-sysdep.c       | 12 ++----------
 sysdeps/mach/hurd/htl/pt-sysdep.h       |  2 ++
 4 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/htl/Versions b/htl/Versions
index e1524117a0..69b79b4f1b 100644
--- a/htl/Versions
+++ b/htl/Versions
@@ -38,6 +38,7 @@ libc {
     __pthread_cleanup_stack;
     __pthread_total;
     ___pthread_self;
+    __pthread_init_thread;
   }
 }
 
diff --git a/sysdeps/mach/hurd/htl/pt-pthread_self.c b/sysdeps/mach/hurd/htl/pt-pthread_self.c
index 04fa283aab..08ef2e4956 100644
--- a/sysdeps/mach/hurd/htl/pt-pthread_self.c
+++ b/sysdeps/mach/hurd/htl/pt-pthread_self.c
@@ -17,6 +17,13 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <pt-sysdep.h>
+#include <pt-internal.h>
 
-__thread struct __pthread *___pthread_self;
+/* Initial thread structure used before libpthread is initialized, so various
+ * functions can already work at least basically.  */
+struct __pthread __pthread_init_thread = {
+	.thread = 1,
+};
+
+__thread struct __pthread *___pthread_self = &__pthread_init_thread;
 libc_hidden_tls_def (___pthread_self)
diff --git a/sysdeps/mach/hurd/htl/pt-sysdep.c b/sysdeps/mach/hurd/htl/pt-sysdep.c
index 5372cbf77f..f5c1c246eb 100644
--- a/sysdeps/mach/hurd/htl/pt-sysdep.c
+++ b/sysdeps/mach/hurd/htl/pt-sysdep.c
@@ -26,10 +26,6 @@
 #include <pt-internal.h>
 #include <pthreadP.h>
 
-/* Initial thread structure used temporarily during initialization, so various
- * functions can already work at least basically.  */
-static struct __pthread init_thread;
-
 static void
 reset_pthread_total (void)
 {
@@ -51,10 +47,6 @@ _init_routine (void *stack)
     /* Already initialized */
     return;
 
-  /* Initialize early thread structure.  */
-  init_thread.thread = 1;
-  ___pthread_self = &init_thread;
-
   /* Initialize the library.  */
   ___pthread_init ();
 
@@ -116,9 +108,9 @@ _init_routine (void *stack)
 #endif
 
   /* Copy over the thread-specific state */
-  assert (!init_thread.thread_specifics);
+  assert (!__pthread_init_thread.thread_specifics);
   memcpy (&thread->static_thread_specifics,
-          &init_thread.static_thread_specifics,
+          &__pthread_init_thread.static_thread_specifics,
           sizeof (thread->static_thread_specifics));
 
   ___pthread_self = thread;
diff --git a/sysdeps/mach/hurd/htl/pt-sysdep.h b/sysdeps/mach/hurd/htl/pt-sysdep.h
index 09d9547a8e..ef7f509611 100644
--- a/sysdeps/mach/hurd/htl/pt-sysdep.h
+++ b/sysdeps/mach/hurd/htl/pt-sysdep.h
@@ -34,6 +34,8 @@
 
 extern __thread struct __pthread *___pthread_self;
 libc_hidden_tls_proto (___pthread_self)
+extern struct __pthread ___pthread_init_thread;
+libc_hidden_proto (___pthread_init_thread)
 
 #ifdef DEBUG
 #define _pthread_self()                                            \