From patchwork Mon Apr 29 10:46:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukasz Majewski X-Patchwork-Id: 32452 Received: (qmail 98481 invoked by alias); 29 Apr 2019 10:46:51 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 98390 invoked by uid 89); 29 Apr 2019 10:46:50 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-20.4 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 spammy=req X-HELO: mail-out.m-online.net From: Lukasz Majewski To: libc-alpha@sourceware.org Cc: Stepan Golosunov , Arnd Bergmann , Paul Eggert , Joseph Myers , Lukasz Majewski Subject: [PATCH v2 7/7] y2038: linux: Provide __clock_nanosleep64 implementation Date: Mon, 29 Apr 2019 12:46:13 +0200 Message-Id: <20190429104613.16209-8-lukma@denx.de> In-Reply-To: <20190429104613.16209-1-lukma@denx.de> References: <20190414220841.20243-1-lukma@denx.de> <20190429104613.16209-1-lukma@denx.de> This patch provides new __clock_nanosleep64 explicit 64 bit function for sleeping specified time on specified clock ID. Moreover, a 32 bit version - __clock_nanosleep has been refactored to internally use __clock_nanosleep64. The __clock_nanosleep is now supposed to be used on 32 bit systems - hence the necessary checks and conversions to 64 bit type. After this change it is intrinsically Y2038 safe. The new 64 bit syscall (clock_nanosleep_time64) available from Linux 5.1+ has been used when applicable on 32 bit systems. The __ASSUME_64BIT_TIME flag indicates if the Linux kernel provides 64 bit version of clock_nanosleep (i.e. clock_nanosleep_time64). If defined - return value is returned unconditionally. If not - the 32 bit version of this syscall is executed instead. When working on 32 bit systems without Y2038 time support the clock_nanosleep returns error when received tv_sec is wrong (i.e. overflowed). Moreover, the correctness of tv_nsec is checked. The data passed to it is checked as well. The execution path on 64 bit systems has not been changed or affected in any way. Tests: - The code has been tested with x86_64/x86 (native compilation): make PARALLELMFLAGS="-j8" && make xcheck PARALLELMFLAGS="-j8" - Run specific tests on ARM/x86 32bit systems (qemu): https://github.com/lmajewski/meta-y2038 and run tests: https://github.com/lmajewski/y2038-tests/commits/master on kernels with and without 64 bit time support. No regressions were observed. * include/time.h (__clock_nanosleep64): Add __clock_nanosleep alias according to __TIMESIZE define * sysdeps/unix/sysv/linux/clock_nanosleep.c (__clock_nanosleep): Refactor this function to be used only on 32 bit machines as a wrapper on __clock_nanosleep64. * sysdeps/unix/sysv/linux/clock_nanosleep.c (__clock_nanosleep64): Add * sysdeps/unix/sysv/linux/clock_nanosleep.c (__clock_nanosleep64): Use clock_nanosleep_time64 kernel syscall (available from 5.1-rc1+ Linux) by 32 bit Y2038 safe systems --- Changes for v2: - Add support for __ASSUME_64BIT_TIME flag when Linux kernel provides syscalls supporting 64 bit time on 32 bit systems - Provide fallback to 32 bit version of clock_nanosleep when clock_nanosleep_time64 is not available - Do not copy *req to timespec - this seems like an overkill as in clock_nanosleep() the 32 bit struct timespec is copied to internal 64 bit struct __timespec64 --- include/time.h | 9 ++++ sysdeps/unix/sysv/linux/clock_nanosleep.c | 71 +++++++++++++++++++++++++++++-- 2 files changed, 76 insertions(+), 4 deletions(-) diff --git a/include/time.h b/include/time.h index 73d8f1a0cc..e37e623bf4 100644 --- a/include/time.h +++ b/include/time.h @@ -156,6 +156,15 @@ extern int __clock_getres64 (clockid_t clock_id, libc_hidden_proto (__clock_getres64); #endif +#if __TIMESIZE == 64 +# define __clock_nanosleep64 __clock_nanosleep +#else +extern int __clock_nanosleep64 (clockid_t clock_id, int flags, + const struct __timespec64 *req, + struct __timespec64 *rem); +libc_hidden_proto (__clock_nanosleep64); +#endif + /* Compute the `struct tm' representation of T, offset OFFSET seconds east of UTC, and store year, yday, mon, mday, wday, hour, min, sec into *TP. diff --git a/sysdeps/unix/sysv/linux/clock_nanosleep.c b/sysdeps/unix/sysv/linux/clock_nanosleep.c index 0cb6614dc9..a2b3896950 100644 --- a/sysdeps/unix/sysv/linux/clock_nanosleep.c +++ b/sysdeps/unix/sysv/linux/clock_nanosleep.c @@ -25,8 +25,8 @@ /* We can simply use the syscall. The CPU clocks are not supported with this function. */ int -__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req, - struct timespec *rem) +__clock_nanosleep64 (clockid_t clock_id, int flags, + const struct __timespec64 *req, struct __timespec64 *rem) { if (clock_id == CLOCK_THREAD_CPUTIME_ID) return EINVAL; @@ -36,9 +36,72 @@ __clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req, /* If the call is interrupted by a signal handler or encounters an error, it returns a positive value similar to errno. */ INTERNAL_SYSCALL_DECL (err); +#if defined (__TIMESIZE) && __TIMESIZE != 64 + int r; +# ifdef __NR_clock_nanosleep_time64 + /* For 32 bit systems with no Y2038 support the *req may have tv_pad + with some random values as *req from __clock_nanosleep is converted + to automatically allocated struct __timespec64 (req64). + + For 32 bit systems being Y2038 safe the tv_pad may be not zero, + as glibc exported struct timespec has 64 bit tv_sec, 32 bit + tv_nsec (to be still POSIX compliant -> long tv_nsec ) and 32 + bits of unnamed padding. + If user program allocates the struct timespec automatically, the + padding may have random value and as being directly passed to + *req needs to be cleared. */ + timespec64_clear_padding (req); + r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id, + flags, req, rem); + int ret = (INTERNAL_SYSCALL_ERROR_P (r, err) + ? INTERNAL_SYSCALL_ERRNO (r, err) : 0); +# ifdef __ASSUME_64BIT_TIME + return ret; +# else + if (r == 0 || errno != ENOSYS) + /* Preserve non-error/non-ENOSYS return values. */ + return ret; +# endif +# endif + struct timespec req32, rem32; + valid_timespec64_to_timespec(req, &req32); + r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep, err, clock_id, flags, + &req32, &rem32); + + if (! INTERNAL_SYSCALL_ERROR_P (r, err)) + valid_timespec_to_timespec64(&rem32, rem); +#else int r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep, err, clock_id, flags, - req, rem); + req, rem); +#endif return (INTERNAL_SYSCALL_ERROR_P (r, err) - ? INTERNAL_SYSCALL_ERRNO (r, err) : 0); + ? INTERNAL_SYSCALL_ERRNO (r, err) : 0); } weak_alias (__clock_nanosleep, clock_nanosleep) + +#if __TIMESIZE != 64 +int +__clock_nanosleep (clockid_t clock_id, int flags, const struct timespec *req, + struct timespec *rem) +{ + struct __timespec64 req64, rem64; + int retval; + + if (! in_time_t_range (req->tv_sec)) + { + __set_errno (EOVERFLOW); + return -1; + } + + valid_timespec_to_timespec64 (req, &req64); + retval = __clock_nanosleep64 (clock_id, flags, &req64, &rem64); + + if (! retval && rem && ! timespec64_to_timespec (&rem64, rem)) + { + __set_errno (EOVERFLOW); + return -1; + } + + return retval; +} +#endif