Not a perfect solution for overriding syscall(), but at least it makes the testsuite to pass in a modified nsswitch.conf (one that has a module which calls syscall() to get the thread id). --- testsuite/init_module.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/testsuite/init_module.c b/testsuite/init_module.c index 199186b..130dd32 100644 --- a/testsuite/init_module.c +++ b/testsuite/init_module.c @@ -355,6 +355,22 @@ TS_EXPORT long int syscall(long int __sysno, ...) return ret; } + if (__sysno == __NR_gettid) { + static void *nextlib = NULL; + static long (*nextlib_syscall)(long number, ...); + + if (nextlib == NULL) { +#ifdef RTLD_NEXT + nextlib = RTLD_NEXT; +#else + nextlib = dlopen("libc.so.6", RTLD_LAZY); +#endif + nextlib_syscall = dlsym(nextlib, "syscall"); + } + + return nextlib_syscall(__NR_gettid); + } + /* * FIXME: no way to call the libc function due since this is a * variadic argument function and we don't have a vsyscall() variant -- 2.14.3
Not a perfect solution for overriding syscall(), but at least it makes the testsuite to pass in a modified nsswitch.conf (one that has a module which calls syscall() to get the thread id). --- v2: - Check nextlib_syscall rather than nextlib to avoid races in multithreaded programs - Add error message in case we fail to get symbol testsuite/init_module.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/testsuite/init_module.c b/testsuite/init_module.c index 199186b..c70147e 100644 --- a/testsuite/init_module.c +++ b/testsuite/init_module.c @@ -355,6 +355,26 @@ TS_EXPORT long int syscall(long int __sysno, ...) return ret; } + if (__sysno == __NR_gettid) { + static void *nextlib = NULL; + static long (*nextlib_syscall)(long number, ...); + + if (nextlib_syscall == NULL) { +#ifdef RTLD_NEXT + nextlib = RTLD_NEXT; +#else + nextlib = dlopen("libc.so.6", RTLD_LAZY); +#endif + nextlib_syscall = dlsym(nextlib, "syscall"); + if (nextlib_syscall == NULL) { + fprintf(stderr, "FIXME FIXME FIXME: libc is missing syscall symbol\n"); + abort(); + } + } + + return nextlib_syscall(__NR_gettid); + } + /* * FIXME: no way to call the libc function due since this is a * variadic argument function and we don't have a vsyscall() variant -- 2.14.3
+1
On Mon, Jan 08, 2018 at 01:28:29PM -0800, Lucas De Marchi wrote:
> Not a perfect solution for overriding syscall(), but at least
> it makes the testsuite to pass in a modified nsswitch.conf (one that has
> a module which calls syscall() to get the thread id).
> ---
>
> v2:
> - Check nextlib_syscall rather than nextlib to avoid races in
> multithreaded programs
> - Add error message in case we fail to get symbol
>
> testsuite/init_module.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/testsuite/init_module.c b/testsuite/init_module.c
> index 199186b..c70147e 100644
> --- a/testsuite/init_module.c
> +++ b/testsuite/init_module.c
> @@ -355,6 +355,26 @@ TS_EXPORT long int syscall(long int __sysno, ...)
> return ret;
> }
>
> + if (__sysno == __NR_gettid) {
> + static void *nextlib = NULL;
> + static long (*nextlib_syscall)(long number, ...);
> +
> + if (nextlib_syscall == NULL) {
> +#ifdef RTLD_NEXT
> + nextlib = RTLD_NEXT;
> +#else
> + nextlib = dlopen("libc.so.6", RTLD_LAZY);
> +#endif
> + nextlib_syscall = dlsym(nextlib, "syscall");
> + if (nextlib_syscall == NULL) {
> + fprintf(stderr, "FIXME FIXME FIXME: libc is missing syscall symbol\n");
> + abort();
> + }
> + }
> +
> + return nextlib_syscall(__NR_gettid);
> + }
> +
> /*
> * FIXME: no way to call the libc function due since this is a
> * variadic argument function and we don't have a vsyscall() variant
> --
> 2.14.3
>
On Mon, Jan 8, 2018 at 1:31 PM, Caio Marcelo de Oliveira Filho
<caio.oliveira@intel.com> wrote:
> +1
>
> On Mon, Jan 08, 2018 at 01:28:29PM -0800, Lucas De Marchi wrote:
>> Not a perfect solution for overriding syscall(), but at least
>> it makes the testsuite to pass in a modified nsswitch.conf (one that has
>> a module which calls syscall() to get the thread id).
>> ---
>>
>> v2:
>> - Check nextlib_syscall rather than nextlib to avoid races in
>> multithreaded programs
>> - Add error message in case we fail to get symbol
>>
>> testsuite/init_module.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/testsuite/init_module.c b/testsuite/init_module.c
>> index 199186b..c70147e 100644
>> --- a/testsuite/init_module.c
>> +++ b/testsuite/init_module.c
>> @@ -355,6 +355,26 @@ TS_EXPORT long int syscall(long int __sysno, ...)
>> return ret;
>> }
>>
>> + if (__sysno == __NR_gettid) {
>> + static void *nextlib = NULL;
>> + static long (*nextlib_syscall)(long number, ...);
>> +
>> + if (nextlib_syscall == NULL) {
>> +#ifdef RTLD_NEXT
>> + nextlib = RTLD_NEXT;
>> +#else
>> + nextlib = dlopen("libc.so.6", RTLD_LAZY);
>> +#endif
>> + nextlib_syscall = dlsym(nextlib, "syscall");
>> + if (nextlib_syscall == NULL) {
>> + fprintf(stderr, "FIXME FIXME FIXME: libc is missing syscall symbol\n");
I added a call to dlerror() here and applied.
thanks for reviewing.
Lucas De Marchi