diff mbox series

[RFC,11/34] mach, hurd: Drop __libc_lock_self0

Message ID 20230319151017.531737-12-bugaevc@gmail.com (mailing list archive)
State Committed, archived
Headers
Series The rest of the x86_64-gnu port |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Sergey Bugaev March 19, 2023, 3:09 p.m. UTC 
  This was used for the value of libc-lock's owner when TLS is not yet set
up, so THREAD_SELF can not be used. Since the value need not be anything
specific -- it just has to be non-NULL -- we can just use a plain
constant, such as (void *) 1, for this. This avoids accessing the symbol
through GOT, and exporting it from libc.so in the first place.

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
 sysdeps/mach/hurd/Versions   | 4 ++--
 sysdeps/mach/hurd/cthreads.c | 4 ----
 sysdeps/mach/libc-lock.h     | 3 +--
 3 files changed, 3 insertions(+), 8 deletions(-)

Comments

Samuel Thibault April 2, 2023, 11:02 p.m. UTC | #1 
Applied, thanks!

Sergey Bugaev, le dim. 19 mars 2023 18:09:54 +0300, a ecrit:
> This was used for the value of libc-lock's owner when TLS is not yet set
> up, so THREAD_SELF can not be used. Since the value need not be anything
> specific -- it just has to be non-NULL -- we can just use a plain
> constant, such as (void *) 1, for this. This avoids accessing the symbol
> through GOT, and exporting it from libc.so in the first place.
> 
> Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
> ---
>  sysdeps/mach/hurd/Versions   | 4 ++--
>  sysdeps/mach/hurd/cthreads.c | 4 ----
>  sysdeps/mach/libc-lock.h     | 3 +--
>  3 files changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/sysdeps/mach/hurd/Versions b/sysdeps/mach/hurd/Versions
> index bf2e870a..20ac0067 100644
> --- a/sysdeps/mach/hurd/Versions
> +++ b/sysdeps/mach/hurd/Versions
> @@ -20,7 +20,7 @@ libc {
>      __open_nocancel;
>      __read_nocancel; __pread64_nocancel;
>      __write_nocancel;
> -    __libc_lock_self0; __getcwd;
> +    __getcwd;
>      __stat64;
>  
>      _dl_init_first;
> @@ -61,7 +61,7 @@ ld {
>      __open_nocancel;
>      __read_nocancel; __pread64_nocancel;
>      __write_nocancel;
> -    __libc_lock_self0; __getcwd;
> +    __getcwd;
>      __stat64; __fstat64;
>    }
>  }
> diff --git a/sysdeps/mach/hurd/cthreads.c b/sysdeps/mach/hurd/cthreads.c
> index 9f17cfe4..87b6c06b 100644
> --- a/sysdeps/mach/hurd/cthreads.c
> +++ b/sysdeps/mach/hurd/cthreads.c
> @@ -20,10 +20,6 @@
>  #include <stdlib.h>
>  #include <pthreadP.h>
>  
> -/* This serves as stub "self" pointer for libc locks when TLS is not initialized
> -   yet.  */
> -char __libc_lock_self0[0];
> -
>  /* Placeholder for key creation routine from Hurd cthreads library.  */
>  int
>  weak_function
> diff --git a/sysdeps/mach/libc-lock.h b/sysdeps/mach/libc-lock.h
> index 14248a05..c5c2553c 100644
> --- a/sysdeps/mach/libc-lock.h
> +++ b/sysdeps/mach/libc-lock.h
> @@ -34,9 +34,8 @@ typedef struct
>  
>  typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
>  
> -extern char __libc_lock_self0[0];
>  #define __libc_lock_owner_self()   \
> -  (__LIBC_NO_TLS () ? (void *)&__libc_lock_self0 : THREAD_SELF)
> +  (__LIBC_NO_TLS () ? (void *) 1 : THREAD_SELF)
>  
>  #else
>  typedef struct __libc_lock_opaque__ __libc_lock_t;
> -- 
> 2.39.2
>
diff mbox series

Patch

diff --git a/sysdeps/mach/hurd/Versions b/sysdeps/mach/hurd/Versions
index bf2e870a..20ac0067 100644
--- a/sysdeps/mach/hurd/Versions
+++ b/sysdeps/mach/hurd/Versions
@@ -20,7 +20,7 @@  libc {
     __open_nocancel;
     __read_nocancel; __pread64_nocancel;
     __write_nocancel;
-    __libc_lock_self0; __getcwd;
+    __getcwd;
     __stat64;
 
     _dl_init_first;
@@ -61,7 +61,7 @@  ld {
     __open_nocancel;
     __read_nocancel; __pread64_nocancel;
     __write_nocancel;
-    __libc_lock_self0; __getcwd;
+    __getcwd;
     __stat64; __fstat64;
   }
 }
diff --git a/sysdeps/mach/hurd/cthreads.c b/sysdeps/mach/hurd/cthreads.c
index 9f17cfe4..87b6c06b 100644
--- a/sysdeps/mach/hurd/cthreads.c
+++ b/sysdeps/mach/hurd/cthreads.c
@@ -20,10 +20,6 @@ 
 #include <stdlib.h>
 #include <pthreadP.h>
 
-/* This serves as stub "self" pointer for libc locks when TLS is not initialized
-   yet.  */
-char __libc_lock_self0[0];
-
 /* Placeholder for key creation routine from Hurd cthreads library.  */
 int
 weak_function
diff --git a/sysdeps/mach/libc-lock.h b/sysdeps/mach/libc-lock.h
index 14248a05..c5c2553c 100644
--- a/sysdeps/mach/libc-lock.h
+++ b/sysdeps/mach/libc-lock.h
@@ -34,9 +34,8 @@  typedef struct
 
 typedef __libc_lock_recursive_t __rtld_lock_recursive_t;
 
-extern char __libc_lock_self0[0];
 #define __libc_lock_owner_self()   \
-  (__LIBC_NO_TLS () ? (void *)&__libc_lock_self0 : THREAD_SELF)
+  (__LIBC_NO_TLS () ? (void *) 1 : THREAD_SELF)
 
 #else
 typedef struct __libc_lock_opaque__ __libc_lock_t;