Hi Alistair, Please find my comments regarding checking of NULL pointers. > The clock_nanosleep syscall is not supported on newer 32-bit > platforms (such as RV32). To fix this issue let's use > clock_nanosleep_time64 if it is avaliable. > --- > This was patch was runtime tested with RV32 and RV64 > It was build tested using the ./scripts/build-many-glibcs.py script. > > I also ran: > $ make ; make install ; make check > tests on native ARM (32-bit) with the following three confiugrations: > - 4.19 Kernel and 4.19 Headers > - 5.2 Kernel and 4.19 Headers > - 5.2 Kernel and 5.2 Headers > and didn't see any regressions > > v5: > - Fix clock_nanosleep syscall > - Rebase on master > > v4: > - Rebase on master > - Use __clock_nanosleep to avoid duplicate implementations > - Fix the error handling when a syscall fails > v2: > - Explicitly include `#include ` > > include/time.h | 20 +++++++ > sysdeps/unix/sysv/linux/clock_nanosleep.c | 66 > +++++++++++++++++++++-- 2 files changed, 81 insertions(+), 5 > deletions(-) > > diff --git a/include/time.h b/include/time.h > index b3e635395db..03389bda290 100644 > --- a/include/time.h > +++ b/include/time.h > @@ -209,6 +209,26 @@ libc_hidden_proto (__difftime64) > > extern double __difftime (time_t time1, time_t time0); > > +#if __TIMESIZE == 64 > +# define __thrd_sleep_time64 thrd_sleep > +# define __clock_nanosleep_time64 __clock_nanosleep > +# define __nanosleep_time64 __nanosleep > +# define __nanosleep_nocancel_time64 __nanosleep_nocancel > +#else > +extern int __thrd_sleep_time64 (const struct __timespec64* > time_point, > + struct __timespec64* remaining); > +libc_hidden_proto (__thrd_sleep_time64) > +extern int __clock_nanosleep_time64 (clockid_t clock_id, > + int flags, const struct > __timespec64 *req, > + struct __timespec64 *rem); > +libc_hidden_proto (__clock_nanosleep_time64) > +extern int __nanosleep_time64 (const struct __timespec64 > *requested_time, > + struct __timespec64 *remaining); > +libc_hidden_proto (__nanosleep_time64) > +extern int __nanosleep_nocancel_time64 (const struct __timespec64 > *requested_time, > + struct __timespec64 > *remaining); +libc_hidden_proto (__nanosleep_nocancel_time64) > +#endif > > /* Use in the clock_* functions. Size of the field representing the > actual clock ID. */ > diff --git a/sysdeps/unix/sysv/linux/clock_nanosleep.c > b/sysdeps/unix/sysv/linux/clock_nanosleep.c index > f3c6fd2d5f7..7212dcf9c6d 100644 --- > a/sysdeps/unix/sysv/linux/clock_nanosleep.c +++ > b/sysdeps/unix/sysv/linux/clock_nanosleep.c @@ -16,6 +16,7 @@ > . */ > > #include > +#include > #include > > #include > @@ -26,9 +27,11 @@ > /* 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_nanosleep_time64 (clockid_t clock_id, int flags, const > struct __timespec64 *req, > + struct __timespec64 *rem) > { > + int r; > + > if (clock_id == CLOCK_THREAD_CPUTIME_ID) > return EINVAL; > if (clock_id == CLOCK_PROCESS_CPUTIME_ID) > @@ -37,11 +40,64 @@ __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); > - int r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep, err, clock_id, > flags, > - req, rem); > + > +#ifdef __ASSUME_TIME64_SYSCALLS > +# ifndef __NR_clock_nanosleep_time64 > +# define __NR_clock_nanosleep_time64 __NR_clock_nanosleep > +# endif > + r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id, > + flags, req, rem); > +#else > +# ifdef __NR_clock_nanosleep_time64 > + r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep_time64, err, clock_id, > + flags, req, rem); > + > + if (r == 0 || errno != ENOSYS) > + { > + return (INTERNAL_SYSCALL_ERROR_P (r, err) > + ? INTERNAL_SYSCALL_ERRNO (r, err) : 0); > + } > +# endif /* __NR_clock_nanosleep_time64 */ > + struct timespec ts32, tr32; > + > + if (! in_time_t_range (req->tv_sec)) > + { > + __set_errno (EOVERFLOW); > + return -1; > + } > + > + ts32 = valid_timespec64_to_timespec (*req); Here we don't need to check req == NULL, as we will go into this piece of code only for 32 bit systems (and kernel < 5.1) with glibc's local copy of struct __timespec64. > + r = INTERNAL_SYSCALL_CANCEL (clock_nanosleep, err, clock_id, > flags, > + &ts32, &tr32); > + > + if ((r == 0 || errno != ENOSYS) && rem) > + *rem = valid_timespec_to_timespec64 (tr32); > +#endif /* __ASSUME_TIME64_SYSCALLS */ > + > return (INTERNAL_SYSCALL_ERROR_P (r, err) > - ? INTERNAL_SYSCALL_ERRNO (r, err) : 0); > + ? INTERNAL_SYSCALL_ERRNO (r, err) : 0); > } > + > +#if __TIMESIZE != 64 > +int > +__clock_nanosleep (clockid_t clock_id, int flags, const struct > timespec *req, > + struct timespec *rem) > +{ > + int r; > + struct __timespec64 treq64, trem64; > + ^^^^^^^^^^^^ - [*] > + treq64 = valid_timespec_to_timespec64 (*req); The above line would cause regression. Please find below explanation: The check on *rqtp (in Linux kernel's clock_nanosleep syscall handling): https://elixir.bootlin.com/linux/v5.4-rc5/source/kernel/time/posix-timers.c#L1220 When compiling test program with clock_nanosleep() passing *request [1] as NULL [3] - the clock_nanosleep returns 14, which corresponds to #define EFAULT 14 [2] (which matches [1]). Hence we should have following code in [*]: if (req == NULL) { __set_errno(EFAULT) returm 1; } Otherwise we will break in glibc before we enter the clock_nanosleep syscall (which would then return with proper error code). Links: [1] - http://man7.org/linux/man-pages/man2/clock_nanosleep.2.html [2] - cpp -dM /usr/include/errno.h | grep 'define E' | sort -n -k 3 [3] - test program: int main(int argc, char **argv) { int result; result = clock_nanosleep(CLOCK_REALTIME, 0 /* relative */, NULL, NULL); if (result) printf("clock_nanosleep: %d\n", result); return 0; } > + r = __clock_nanosleep_time64 (clock_id, flags, &treq64, &trem64); > + > + if (r == 0 || errno != ENOSYS) > + { > + if (rem) > + *rem = valid_timespec64_to_timespec (trem64); > + } > + > + return r; > +} > +#endif > libc_hidden_def (__clock_nanosleep) > versioned_symbol (libc, __clock_nanosleep, clock_nanosleep, > GLIBC_2_17); /* clock_nanosleep moved to libc in version 2.17; Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de