[PATCH v5 7/8] linux: Use long time_t for wait4/getrusage
Alistair Francis
alistair23@gmail.com
Fri Mar 27 18:42:10 GMT 2020
On Fri, Mar 27, 2020 at 11:32 AM Adhemerval Zanella via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
>
>
> On 03/03/2020 14:53, Alistair Francis wrote:
> > 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.
> >
> > Reviewed-by: Lukasz Majewski <lukma@denx.de>
> > ---
> > include/sys/resource.h | 11 +++++
> > sysdeps/unix/syscalls.list | 1 -
> > sysdeps/unix/sysv/linux/getrusage.c | 58 +++++++++++++++++++++++++++
> > sysdeps/unix/sysv/linux/tv32-compat.h | 47 ++++++++++++++++++++++
> > sysdeps/unix/sysv/linux/wait4.c | 50 ++++++++++++++++++++++-
> > 5 files changed, 164 insertions(+), 3 deletions(-)
> > create mode 100644 sysdeps/unix/sysv/linux/getrusage.c
> >
> > diff --git a/include/sys/resource.h b/include/sys/resource.h
> > index 9d604dfe3e..64925f257c 100644
> > --- a/include/sys/resource.h
> > +++ b/include/sys/resource.h
> > @@ -134,5 +134,16 @@ 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 __wait4_time64 __wait4
> > +#else
> > +extern int __getrusage64 (enum __rusage_who who, struct __rusage64 *usage);
> > +libc_hidden_proto (__getrusage64)
> > +extern pid_t __wait4_time64 (pid_t pid, int *stat_loc, int options,
> > + struct __rusage64 *usage);
> > +libc_hidden_proto (__wait4_time64)
> > +#endif
> > #endif
> > #endif
>
> Ok.
>
> > diff --git a/sysdeps/unix/syscalls.list b/sysdeps/unix/syscalls.list
> > index d249049d6e..01c4a0e6b1 100644
> > --- a/sysdeps/unix/syscalls.list
> > +++ b/sysdeps/unix/syscalls.list
> > @@ -29,7 +29,6 @@ getpeername - getpeername i:ibN __getpeername getpeername
> > getpid - getpid Ei: __getpid getpid
> > getpriority - getpriority i:ii __getpriority getpriority
> > getrlimit - getrlimit i:ip __getrlimit getrlimit
> > -getrusage - getrusage i:ip __getrusage getrusage
> > getsockname - getsockname i:ibN __getsockname getsockname
> > getsockopt - getsockopt i:iiiBN getsockopt
> > getuid - getuid Ei: __getuid getuid
>
> Ok.
>
> > diff --git a/sysdeps/unix/sysv/linux/getrusage.c b/sysdeps/unix/sysv/linux/getrusage.c
> > new file mode 100644
> > index 0000000000..a4e382ed53
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/getrusage.c
> > @@ -0,0 +1,58 @@
> > +/* 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 <sys/types.h>
> > +#include <sysdep.h>
> > +#include <tv32-compat.h>
> > +
> > +int
> > +__getrusage64 (enum __rusage_who who, struct __rusage64 *usage)
> > +{
> > +#if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
> > + return INLINE_SYSCALL_CALL (getrusage, who, usage);
> > +#else
> > + struct __rusage32 usage32;
> > + if (INLINE_SYSCALL_CALL (getrusage, who, &usage32) == -1)
> > + return -1;
> > +
> > + rusage32_to_rusage64 (&usage32, usage);
> > + return 0;
> > +#endif
> > +}
> > +
>
> Ok.
>
> > +#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)
>
> Ok.
>
> > diff --git a/sysdeps/unix/sysv/linux/tv32-compat.h b/sysdeps/unix/sysv/linux/tv32-compat.h
> > index b8791b1db8..1ada1f729c 100644
> > --- a/sysdeps/unix/sysv/linux/tv32-compat.h
> > +++ b/sysdeps/unix/sysv/linux/tv32-compat.h
> > @@ -20,6 +20,7 @@
> > #define _TV32_COMPAT_H 1
> >
> > #include <bits/types/time_t.h>
> > +#include <sys/resource.h>
> >
> > /* Structures containing 'struct timeval' with 32-bit time_t. */
> > struct __itimerval32
> > @@ -28,4 +29,50 @@ 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 */
>
> Ok.
>
> > diff --git a/sysdeps/unix/sysv/linux/wait4.c b/sysdeps/unix/sysv/linux/wait4.c
> > index 3a8bed1169..da591da4d4 100644
> > --- a/sysdeps/unix/sysv/linux/wait4.c
> > +++ b/sysdeps/unix/sysv/linux/wait4.c
> > @@ -18,14 +18,30 @@
> >
> > #include <sys/wait.h>
> > #include <sys/resource.h>
> > +#include <sys/types.h>
> > #include <sysdep-cancel.h>
> > +#include <tv32-compat.h>
> >
> > pid_t
> > -__wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
> > +__wait4_time64 (pid_t pid, int *stat_loc, int options, struct __rusage64 *usage)
> > {
> > #ifdef __NR_wait4
> > +# if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
> > return SYSCALL_CANCEL (wait4, pid, stat_loc, options, usage);
> > +# else
> > + struct __rusage32 usage32;
> > + pid_t ret = SYSCALL_CANCEL (wait4, pid, stat_loc, options, &usage32);
> > +
> > + if (ret != 0)
> > + return ret;
> > +
> > + if (usage != NULL)
> > + rusage32_to_rusage64 (&usage32, usage);
>
> Indentation seems wrong.
Fixed.
>
> > +
> > + return ret;
> > +# endif
> > #elif defined (__ASSUME_WAITID_PID0_P_PGID)
> > + struct __rusage32 usage32;
> > idtype_t idtype = P_PID;
> >
> > if (pid < -1)
> > @@ -41,7 +57,12 @@ __wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
> > options |= WEXITED;
> >
> > siginfo_t infop;
> > +
> > +# if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
> > if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, usage) < 0)
> > +# else
> > + if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, &usage32) < 0)
> > +# endif
> > return -1;
> >
> > if (stat_loc)
> > @@ -70,8 +91,13 @@ __wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
> > }
> > }
> >
> > +# if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64 == 0
> > + if (usage != NULL)
> > + rusage32_to_rusage64 (&usage32, usage);
> > +# endif
>
> I think compiler will start to emit an unused variable warning if this
> code is being used with an 64 bit architecture that only supports
> waitid (which seems to be idea for new generic on Linux).
>
> So I think it should be:
>
> # if __KERNEL_OLD_TIMEVAL_MATCHES_TIMEVAL64
> if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, usage) < 0)
> return -1;
> # else
> {
> struct __rusage32 usage32;
> if (SYSCALL_CANCEL (waitid, idtype, pid, &infop, options, &usage32) < 0)
> return -1;
> if (usage != NULL)
> rusage32_to_rusage64 (&usage32, usage);
> }
> # endif
Good point, I have fixed this.
Alistair
>
> > +
> > 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 +107,25 @@ __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
> > }
> > +
> > +#if __TIMESIZE != 64
> > +libc_hidden_def (__wait4_time64)
> > +
> > +pid_t
> > +__wait4 (pid_t pid, int *stat_loc, int options, struct rusage *usage)
> > +{
> > + pid_t ret ;
> > + struct __rusage64 usage64;
> > +
> > + ret = __wait4_time64 (pid, stat_loc, options, &usage64);
> > +
> > + if (ret != 0)
> > + return ret;
> > +
> > + rusage64_to_rusage (&usage64, usage);
> > +
> > + return ret;
> > +}
> > +#endif
> > libc_hidden_def (__wait4);
> > weak_alias (__wait4, wait4)
> >
>
> Ok.
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