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authorTheodore Ts'o <tytso@mit.edu>2008-09-12 10:15:26 -0400
committerTheodore Ts'o <tytso@mit.edu>2008-09-12 10:15:26 -0400
commitd7f45af802330a0e1450afa05185d3722e77a76c (patch)
tree4eb79fcc0ad80db68625e7412866c7d400e09402 /configure
parent3218dc9db8fc2affeae2fb563db0fc07a55a59de (diff)
downloade2fsprogs-d7f45af802330a0e1450afa05185d3722e77a76c.tar.gz
e2fsprogs-d7f45af802330a0e1450afa05185d3722e77a76c.tar.xz
e2fsprogs-d7f45af802330a0e1450afa05185d3722e77a76c.zip
libcom_err: Use sem_post/sem_init to prevent race conditions
SuSE has been carrying a patch for a long time to prevent a largely theoretical race condition if a multi-threaded application adds and removes error tables in multiple threads. Unfortunately SuSE's approach breaks compatibility by forcing applications to link and compile with the -pthread option; using pthread mutexes has historically been problematic. This commit fixes things in a more portable way by using sem_post/sem_wait instead, which is an older interface that doesn't require the pthreads library. Linux happens to implement sem_post/sem_init using futexes, and -lrt ends up pulling in -lpthread, but the advantage of using POSIX semaphores is that applications don't have to be built using -pthread, unlike the use of pthread mutexes. The add_error_table() and remove_error_table() interfaces are the preferred interfaces and locking protection have been added to only these interfaces. I have not added locking protection to the generated initialize_xxx_error_table and initialize_xxx_error_table_r interfaces, to avoid adding symbol dependencies that would cause a library to fail to work when linking against older com_err libraries that do not export et_list_lock() and et_list_unlock(). Threaded applications shouldn't be using these interfaces in any case. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'configure')
-rwxr-xr-xconfigure303
1 files changed, 301 insertions, 2 deletions
diff --git a/configure b/configure
index 0e3bdbed..a6b787b4 100755
--- a/configure
+++ b/configure
@@ -751,6 +751,7 @@ SIZEOF_LONG
SIZEOF_LONG_LONG
SOCKET_LIB
DLOPEN_LIB
+SEM_INIT_LIB
UNI_DIFF_OPTS
LINUX_CMT
CYGWIN_CMT
@@ -11646,7 +11647,8 @@ fi
-for ac_header in dirent.h errno.h getopt.h malloc.h mntent.h paths.h setjmp.h signal.h stdarg.h stdint.h stdlib.h termios.h termio.h unistd.h utime.h linux/fd.h linux/major.h net/if_dl.h netinet/in.h sys/disklabel.h sys/file.h sys/ioctl.h sys/mkdev.h sys/mman.h sys/prctl.h sys/queue.h sys/resource.h sys/select.h sys/socket.h sys/sockio.h sys/stat.h sys/syscall.h sys/sysmacros.h sys/time.h sys/types.h sys/un.h sys/wait.h
+
+for ac_header in dirent.h errno.h getopt.h malloc.h mntent.h paths.h semaphore.h setjmp.h signal.h stdarg.h stdint.h stdlib.h termios.h termio.h unistd.h utime.h linux/fd.h linux/major.h net/if_dl.h netinet/in.h sys/disklabel.h sys/file.h sys/ioctl.h sys/mkdev.h sys/mman.h sys/prctl.h sys/queue.h sys/resource.h sys/select.h sys/socket.h sys/sockio.h sys/stat.h sys/syscall.h sys/sysmacros.h sys/time.h sys/types.h sys/un.h sys/wait.h
do
as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
if { as_var=$as_ac_Header; eval "test \"\${$as_var+set}\" = set"; }; then
@@ -14972,6 +14974,302 @@ if test $ac_cv_have_optreset = yes; then
_ACEOF
fi
+SEM_INIT_LIB=''
+{ echo "$as_me:$LINENO: checking for sem_init" >&5
+echo $ECHO_N "checking for sem_init... $ECHO_C" >&6; }
+if test "${ac_cv_func_sem_init+set}" = set; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h. */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h. */
+/* Define sem_init to an innocuous variant, in case <limits.h> declares sem_init.
+ For example, HP-UX 11i <limits.h> declares gettimeofday. */
+#define sem_init innocuous_sem_init
+
+/* System header to define __stub macros and hopefully few prototypes,
+ which can conflict with char sem_init (); below.
+ Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+ <limits.h> exists even on freestanding compilers. */
+
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+
+#undef sem_init
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char sem_init ();
+/* The GNU C library defines this for functions which it implements
+ to always fail with ENOSYS. Some functions are actually named
+ something starting with __ and the normal name is an alias. */
+#if defined __stub_sem_init || defined __stub___sem_init
+choke me
+#endif
+
+int
+main ()
+{
+return sem_init ();
+ ;
+ return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+ *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+ *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+ (eval "$ac_link") 2>conftest.er1
+ ac_status=$?
+ grep -v '^ *+' conftest.er1 >conftest.err
+ rm -f conftest.er1
+ cat conftest.err >&5
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } && {
+ test -z "$ac_c_werror_flag" ||
+ test ! -s conftest.err
+ } && test -s conftest$ac_exeext &&
+ $as_test_x conftest$ac_exeext; then
+ ac_cv_func_sem_init=yes
+else
+ echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ ac_cv_func_sem_init=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+ conftest$ac_exeext conftest.$ac_ext
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_func_sem_init" >&5
+echo "${ECHO_T}$ac_cv_func_sem_init" >&6; }
+if test $ac_cv_func_sem_init = yes; then
+ :
+else
+ { echo "$as_me:$LINENO: checking for sem_init in -lpthread" >&5
+echo $ECHO_N "checking for sem_init in -lpthread... $ECHO_C" >&6; }
+if test "${ac_cv_lib_pthread_sem_init+set}" = set; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lpthread $LIBS"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h. */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char sem_init ();
+int
+main ()
+{
+return sem_init ();
+ ;
+ return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+ *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+ *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+ (eval "$ac_link") 2>conftest.er1
+ ac_status=$?
+ grep -v '^ *+' conftest.er1 >conftest.err
+ rm -f conftest.er1
+ cat conftest.err >&5
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } && {
+ test -z "$ac_c_werror_flag" ||
+ test ! -s conftest.err
+ } && test -s conftest$ac_exeext &&
+ $as_test_x conftest$ac_exeext; then
+ ac_cv_lib_pthread_sem_init=yes
+else
+ echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ ac_cv_lib_pthread_sem_init=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_lib_pthread_sem_init" >&5
+echo "${ECHO_T}$ac_cv_lib_pthread_sem_init" >&6; }
+if test $ac_cv_lib_pthread_sem_init = yes; then
+ cat >>confdefs.h <<\_ACEOF
+#define HAVE_SEM_INIT 1
+_ACEOF
+
+ SEM_INIT_LIB=-lpthread
+else
+ { echo "$as_me:$LINENO: checking for sem_init in -lrt" >&5
+echo $ECHO_N "checking for sem_init in -lrt... $ECHO_C" >&6; }
+if test "${ac_cv_lib_rt_sem_init+set}" = set; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lrt $LIBS"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h. */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char sem_init ();
+int
+main ()
+{
+return sem_init ();
+ ;
+ return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+ *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+ *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+ (eval "$ac_link") 2>conftest.er1
+ ac_status=$?
+ grep -v '^ *+' conftest.er1 >conftest.err
+ rm -f conftest.er1
+ cat conftest.err >&5
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } && {
+ test -z "$ac_c_werror_flag" ||
+ test ! -s conftest.err
+ } && test -s conftest$ac_exeext &&
+ $as_test_x conftest$ac_exeext; then
+ ac_cv_lib_rt_sem_init=yes
+else
+ echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ ac_cv_lib_rt_sem_init=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_lib_rt_sem_init" >&5
+echo "${ECHO_T}$ac_cv_lib_rt_sem_init" >&6; }
+if test $ac_cv_lib_rt_sem_init = yes; then
+ cat >>confdefs.h <<\_ACEOF
+#define HAVE_SEM_INIT 1
+_ACEOF
+
+ SEM_INIT_LIB=-lrt
+else
+ { echo "$as_me:$LINENO: checking for sem_init in -lposix4" >&5
+echo $ECHO_N "checking for sem_init in -lposix4... $ECHO_C" >&6; }
+if test "${ac_cv_lib_posix4_sem_init+set}" = set; then
+ echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+ ac_check_lib_save_LIBS=$LIBS
+LIBS="-lposix4 $LIBS"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h. */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h. */
+
+/* Override any GCC internal prototype to avoid an error.
+ Use char because int might match the return type of a GCC
+ builtin and then its argument prototype would still apply. */
+#ifdef __cplusplus
+extern "C"
+#endif
+char sem_init ();
+int
+main ()
+{
+return sem_init ();
+ ;
+ return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+ *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+ *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+ (eval "$ac_link") 2>conftest.er1
+ ac_status=$?
+ grep -v '^ *+' conftest.er1 >conftest.err
+ rm -f conftest.er1
+ cat conftest.err >&5
+ echo "$as_me:$LINENO: \$? = $ac_status" >&5
+ (exit $ac_status); } && {
+ test -z "$ac_c_werror_flag" ||
+ test ! -s conftest.err
+ } && test -s conftest$ac_exeext &&
+ $as_test_x conftest$ac_exeext; then
+ ac_cv_lib_posix4_sem_init=yes
+else
+ echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+ ac_cv_lib_posix4_sem_init=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+ conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_lib_posix4_sem_init" >&5
+echo "${ECHO_T}$ac_cv_lib_posix4_sem_init" >&6; }
+if test $ac_cv_lib_posix4_sem_init = yes; then
+ cat >>confdefs.h <<\_ACEOF
+#define HAVE_SEM_INIT 1
+_ACEOF
+
+ SEM_INIT_LIB=-lposix4
+fi
+
+fi
+
+fi
+
+fi
+
{ echo "$as_me:$LINENO: checking for unified diff option" >&5
echo $ECHO_N "checking for unified diff option... $ECHO_C" >&6; }
if diff -u $0 $0 > /dev/null 2>&1 ; then
@@ -16050,6 +16348,7 @@ SIZEOF_LONG!$SIZEOF_LONG$ac_delim
SIZEOF_LONG_LONG!$SIZEOF_LONG_LONG$ac_delim
SOCKET_LIB!$SOCKET_LIB$ac_delim
DLOPEN_LIB!$DLOPEN_LIB$ac_delim
+SEM_INIT_LIB!$SEM_INIT_LIB$ac_delim
UNI_DIFF_OPTS!$UNI_DIFF_OPTS$ac_delim
LINUX_CMT!$LINUX_CMT$ac_delim
CYGWIN_CMT!$CYGWIN_CMT$ac_delim
@@ -16070,7 +16369,7 @@ LIBOBJS!$LIBOBJS$ac_delim
LTLIBOBJS!$LTLIBOBJS$ac_delim
_ACEOF
- if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 83; then
+ if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 84; then
break
elif $ac_last_try; then
{ { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5