[PATCH v2 6/6] linux: Use long time_t for wait4/getrusage
Alistair Francis
alistair23@gmail.com
Tue Feb 11 18:15:00 GMT 2020
On Tue, Feb 11, 2020 at 3:28 AM Lukasz Majewski <lukma@denx.de> wrote:
>
> Hi Alistair,
>
> > The Linux kernel expects rusage to use a 32-bit time_t, even on archs
> > with a 64-bit time_t (like RV32). To address this let's convert
> > rusage to/from 32-bit and 64-bit to ensure the kernel always gets
> > a 32-bit time_t.
> >
> > While we are converting these functions let's also convert them to be
> > the y2038 safe versions. This means there is a *64 function that is
> > called by a backwards compatible wrapper.
> > ---
> > include/sys/resource.h | 10 +++++
> > sysdeps/unix/sysv/linux/getrusage.c | 53
> > +++++++++++++++++++++++++++ sysdeps/unix/sysv/linux/tv32-compat.h |
> > 47 ++++++++++++++++++++++++ sysdeps/unix/sysv/linux/wait4.c |
> > 40 ++++++++++++++++++-- 4 files changed, 146 insertions(+), 4
> > deletions(-) create mode 100644 sysdeps/unix/sysv/linux/getrusage.c
> >
> > diff --git a/include/sys/resource.h b/include/sys/resource.h
> > index 9d604dfe3e..8e115b4df8 100644
> > --- a/include/sys/resource.h
> > +++ b/include/sys/resource.h
> > @@ -134,5 +134,15 @@ extern int __getrusage (enum __rusage_who __who,
> > struct rusage *__usage) extern int __setrlimit (enum
> > __rlimit_resource __resource, const struct rlimit *__rlimits);
> > libc_hidden_proto (__setrlimit);
> > +
> > +#if __TIMESIZE == 64
> > +# define __getrusage64 __getrusage
> > +# define __wait464 __wait4
> > +#else
> > +extern int __getrusage64 (enum __rusage_who who, struct __rusage64
> > *usage); +libc_hidden_proto (__getrusage64)
> > +pid_t __wait464 (pid_t pid, int *stat_loc, int options, struct
> > __rusage64 *usage); +libc_hidden_proto (__wait464)
> > +#endif
> > #endif
> > #endif
> > diff --git a/sysdeps/unix/sysv/linux/getrusage.c
> > b/sysdeps/unix/sysv/linux/getrusage.c new file mode 100644
> > index 0000000000..f8bcd3f9d0
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/getrusage.c
> > @@ -0,0 +1,53 @@
> > +/* getrusage -- get the rusage struct. Linux version.
> > + Copyright (C) 2020 Free Software Foundation, Inc.
> > + This file is part of the GNU C Library.
> > +
> > + The GNU C Library is free software; you can redistribute it and/or
> > + modify it under the terms of the GNU Lesser General Public
> > + License as published by the Free Software Foundation; either
> > + version 2.1 of the License, or (at your option) any later version.
> > +
> > + The GNU C Library is distributed in the hope that it will be
> > useful,
> > + but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + Lesser General Public License for more details.
> > +
> > + You should have received a copy of the GNU Lesser General Public
> > + License along with the GNU C Library; if not, see
> > + <http://www.gnu.org/licenses/>. */
> > +
> > +#include <sys/time.h>
> > +#include <sys/resource.h>
> > +#include <sysdep.h>
> > +#include <tv32-compat.h>
> > +
> > +int
> > +__getrusage64 (enum __rusage_who who, struct __rusage64 *usage)
> > +{
> > + struct __rusage32 usage32;
> > + if (INLINE_SYSCALL_CALL (getrusage, who, &usage32) == -1)
> > + return -1;
> > +
> > + rusage32_to_rusage64 (&usage32, usage);
> > + return 0;
> > +}
> > +
> > +#if __TIMESIZE != 64
> > +libc_hidden_def (__getrusage64)
> > +int
> > +__getrusage (enum __rusage_who who, struct rusage *usage)
> > +{
> > + int ret ;
> > + struct __rusage64 usage64;
> > +
> > + ret = __getrusage64 (who, &usage64);
> > +
> > + if (ret != 0)
> > + return ret;
> > +
> > + rusage64_to_rusage (&usage64, usage);
> > +
> > + return ret;
> > +}
> > +#endif
> > +weak_alias (__getrusage, getrusage)
> > diff --git a/sysdeps/unix/sysv/linux/tv32-compat.h
> > b/sysdeps/unix/sysv/linux/tv32-compat.h index 4eb6f216ea..c2231f042f
> > 100644 --- a/sysdeps/unix/sysv/linux/tv32-compat.h
> > +++ b/sysdeps/unix/sysv/linux/tv32-compat.h
> > @@ -24,6 +24,7 @@
> > #include <bits/types.h>
> > #include <bits/types/time_t.h>
> > #include <bits/types/struct_timeval.h>
> > +#include <sys/resource.h>
> >
> > /* Structures containing 'struct timeval' with 32-bit time_t. */
> > struct __itimerval32
> > @@ -32,4 +33,50 @@ struct __itimerval32
> > struct __timeval32 it_value;
> > };
> >
> > +struct __rusage32
> > +{
> > + struct __timeval32 ru_utime; /* user time used */
> > + struct __timeval32 ru_stime; /* system time used */
> > + long ru_maxrss; /* maximum resident set size */
> > + long ru_ixrss; /* integral shared memory size */
> > + long ru_idrss; /* integral unshared data size */
> > + long ru_isrss; /* integral unshared stack size */
> > + long ru_minflt; /* page reclaims */
> > + long ru_majflt; /* page faults */
> > + long ru_nswap; /* swaps */
> > + long ru_inblock; /* block input operations */
> > + long ru_oublock; /* block output operations */
> > + long ru_msgsnd; /* messages sent */
> > + long ru_msgrcv; /* messages received */
> > + long ru_nsignals; /* signals received */
> > + long ru_nvcsw; /* voluntary context switches */
> > + long ru_nivcsw; /* involuntary " */
> > +};
> > +
> > +static inline void
> > +rusage32_to_rusage64 (const struct __rusage32 *restrict r32,
> > + struct __rusage64 *restrict r64)
> > +{
> > + /* Make sure the entire output structure is cleared, including
> > + padding and reserved fields. */
> > + memset (r64, 0, sizeof *r64);
> > +
> > + r64->ru_utime = valid_timeval32_to_timeval64 (r32->ru_utime);
> > + r64->ru_stime = valid_timeval32_to_timeval64 (r32->ru_stime);
> > + r64->ru_maxrss = r32->ru_maxrss;
> > + r64->ru_ixrss = r32->ru_ixrss;
> > + r64->ru_idrss = r32->ru_idrss;
> > + r64->ru_isrss = r32->ru_isrss;
> > + r64->ru_minflt = r32->ru_minflt;
> > + r64->ru_majflt = r32->ru_majflt;
> > + r64->ru_nswap = r32->ru_nswap;
> > + r64->ru_inblock = r32->ru_inblock;
> > + r64->ru_oublock = r32->ru_oublock;
> > + r64->ru_msgsnd = r32->ru_msgsnd;
> > + r64->ru_msgrcv = r32->ru_msgrcv;
> > + r64->ru_nsignals = r32->ru_nsignals;
> > + r64->ru_nvcsw = r32->ru_nvcsw;
> > + r64->ru_nivcsw = r32->ru_nivcsw;
> > +}
> > +
> > #endif /* tv32-compat.h */
> > diff --git a/sysdeps/unix/sysv/linux/wait4.c
> > b/sysdeps/unix/sysv/linux/wait4.c index 3a8bed1169..73f1c24269 100644
> > --- a/sysdeps/unix/sysv/linux/wait4.c
> > +++ b/sysdeps/unix/sysv/linux/wait4.c
> > @@ -19,12 +19,22 @@
> > #include <sys/wait.h>
> > #include <sys/resource.h>
> > #include <sysdep-cancel.h>
> > +#include <tv32-compat.h>
> >
> > pid_t
> > -__wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
> > +__wait464 (pid_t pid, int *stat_loc, int options, struct __rusage64
>
> Just some consideration regarding naming convention - maybe it would be
> more readable to have __wait4_time64 ? Frankly speaking - the __wait464
> seems a bit confusing for me.
Yep, good idea. Fixed in v3.
Alistair
>
> > *usage) {
> > + struct __rusage32 usage32;
> > #ifdef __NR_wait4
> > - return SYSCALL_CANCEL (wait4, pid, stat_loc, options, usage);
> > + pid_t ret = SYSCALL_CANCEL (wait4, pid, stat_loc, options,
> > &usage32); +
> > + if (ret != 0)
> > + return ret;
> > +
> > + if (usage != NULL)
> > + rusage32_to_rusage64 (&usage32, usage);
> > +
> > + return ret;
> > #elif defined (__ASSUME_WAITID_PID0_P_PGID)
> > idtype_t idtype = P_PID;
> >
> > @@ -41,7 +51,7 @@ __wait4 (pid_t pid, int *stat_loc, int options,
> > struct rusage *usage) options |= WEXITED;
> >
> > siginfo_t infop;
> > - if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, usage) <
> > 0)
> > + if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options,
> > &usage32) < 0) return -1;
> >
> > if (stat_loc)
> > @@ -70,8 +80,11 @@ __wait4 (pid_t pid, int *stat_loc, int options,
> > struct rusage *usage) }
> > }
> >
> > + if (usage != NULL)
> > + rusage32_to_rusage64 (&usage32, usage);
> > +
> > return infop.si_pid;
> > -# else
> > +#else
> > /* Linux waitid prior kernel 5.4 does not support waiting for the
> > current process. It is possible to emulate wait4 it by calling
> > getpgid for PID 0, however, it would require an additional syscall
> > and it is inherent @@ -81,5 +94,24 @@ __wait4 (pid_t pid, int
> > *stat_loc, int options, struct rusage *usage) # error "The kernel ABI
> > does not provide a way to implement wait4" #endif
> > }
> > +libc_hidden_def (__wait464)
> > +
> > +#if __TIMESIZE != 64
> > +pid_t
> > +__wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
> > +{
> > + pid_t ret ;
> > + struct __rusage64 usage64;
> > +
> > + ret = __wait464 (pid, stat_loc, options, &usage64);
> > +
> > + if (ret != 0)
> > + return ret;
> > +
> > + rusage64_to_rusage (&usage64, usage);
> > +
> > + return ret;
> > +}
> > libc_hidden_def (__wait4);
> > +#endif
> > weak_alias (__wait4, wait4)
>
>
>
>
> 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
More information about the Libc-alpha
mailing list