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authorVineet Gupta <vgupta@synopsys.com>2014-04-16 15:27:52 +0530
committerBernhard Reutner-Fischer <rep.dot.nop@gmail.com>2014-04-23 13:21:03 +0200
commit8f550715c2b211036fc273add3cb5219397ed312 (patch)
treeb879f37f1ce879c1785c975b5dbdb38db603e71b
parent5799194b75b238491501cbb122f5d7025edd3aa2 (diff)
LT.old: Make __errno_location/__h_errno_location thread safe
WHY: errno in uClibc is not thread safe HOW: __errno_location and it's sibling __h_errno_location need to be called via PLT - even from within libc. That way when linked with pthread, intra-uClibc callers will also use the thread safe version. This is achieved by removing the GI alias for these functions, ensuring that they get called normally (via PLT) Verified with ARC LT.old and ARM cubieboard2 buildroot (LT.old) NPTL is unaffected by this bug. ------------ History behind this patch --------------------- This is a long standing bug (https://bugs.busybox.net/show_bug.cgi?id=2089) Others have tried to fix it in past (alteast Peter Korsgaard's patch in 2010), but somehow failed to be merged (or were backed out afterwards). http://lists.uclibc.org/pipermail/uclibc/2010-July/044176.html One of the causes could be side effect of atleast one more bug related to pthreads and static link which has now been fixed. http://lists.uclibc.org/pipermail/uclibc/2013-October/047958.html I have solved this w/o looking at other pacthes but would like to give credit to Peter and others for confirming that it makes sense. Cc: Christian Ruppert <christian.ruppert@abilis.com> CC: Francois Bedard <Francois.Bedard@synopsys.com> Cc: Joern Rennecke <joern.rennecke@embecosm.com> Cc: Jeremy Bennett <jeremy.bennett@embecosm.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Peter Korsgaard <peter@korsgaard.com> Cc: Khem Raj <raj.khem@gmail.com> Cc: buildroot@busybox.net Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
-rw-r--r--include/netdb.h3
-rw-r--r--libc/misc/internals/__errno_location.c1
-rw-r--r--libc/misc/internals/__h_errno_location.c1
-rw-r--r--libc/sysdeps/linux/common/bits/errno.h3
4 files changed, 0 insertions, 8 deletions
diff --git a/include/netdb.h b/include/netdb.h
index 8fdfa0fcc..0f361bb6f 100644
--- a/include/netdb.h
+++ b/include/netdb.h
@@ -59,11 +59,8 @@ __BEGIN_DECLS
/* Function to get address of global `h_errno' variable. */
extern int *__h_errno_location (void) __THROW __attribute__ ((__const__));
#ifdef _LIBC
-# if !defined(__UCLIBC_HAS_TLS__) && !defined(__UCLIBC_HAS_THREADS__)
extern int weak_const_function *__h_errno_location(void);
-# endif
#endif
-libc_hidden_proto(__h_errno_location)
/* Macros for accessing h_errno from inside libc. */
#ifdef _LIBC
diff --git a/libc/misc/internals/__errno_location.c b/libc/misc/internals/__errno_location.c
index be7a9093e..9bbc2d779 100644
--- a/libc/misc/internals/__errno_location.c
+++ b/libc/misc/internals/__errno_location.c
@@ -16,4 +16,3 @@ int *__errno_location(void)
{
return &errno;
}
-libc_hidden_weak(__errno_location)
diff --git a/libc/misc/internals/__h_errno_location.c b/libc/misc/internals/__h_errno_location.c
index 6653681cb..b30859e81 100644
--- a/libc/misc/internals/__h_errno_location.c
+++ b/libc/misc/internals/__h_errno_location.c
@@ -16,4 +16,3 @@ int *__h_errno_location(void)
{
return &h_errno;
}
-libc_hidden_weak(__h_errno_location)
diff --git a/libc/sysdeps/linux/common/bits/errno.h b/libc/sysdeps/linux/common/bits/errno.h
index 777338fb1..611b83590 100644
--- a/libc/sysdeps/linux/common/bits/errno.h
+++ b/libc/sysdeps/linux/common/bits/errno.h
@@ -43,11 +43,8 @@
/* Function to get address of global `errno' variable. */
extern int *__errno_location (void) __THROW __attribute__ ((__const__));
# ifdef _LIBC
-# if !defined(__UCLIBC_HAS_TLS__) && !defined(__UCLIBC_HAS_THREADS__)
extern int weak_const_function *__errno_location(void);
-# endif
# endif
-libc_hidden_proto(__errno_location)
# ifdef __UCLIBC_HAS_THREADS__
/* When using threads, errno is a per-thread value. */