d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add sysctlbyname system call

Browse Source 
Previously userspace would issue one syscall to resolve the sysctl and then
another one to actually use it. Do it all in one trip.

Fallback is provided in case newer libc happens to be running on an older
kernel.

Submitted by:	Pawel Biernacki
Reported by:	kib, brooks
Differential Revision:	https://reviews.freebsd.org/D17282
This commit is contained in:
mjg 2019-09-03 04:16:30 +00:00
parent 116c38c27d
commit 286ae5bd6b
20 changed files with 264 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

57
lib/libc/gen/sysctlbyname.c
View File

@ -1,28 +1,59 @@
/*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.org> wrote this file. As long as you retain this notice you
* can do whatever you want with this stuff. If we meet some day, and you think
* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
* ----------------------------------------------------------------------------
/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright 2019 Pawel Biernacki, Mysterious Code Ltd.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysctl.h>
#include <string.h>
#include "libc_private.h"
#define SYSCTLBYNAME_OSREL 1300045
extern int __sysctlbyname(const char *name, size_t namelen, void *oldp,
size_t *oldlenp, const void *newp, size_t newlen);
int
sysctlbyname(const char *name, void *oldp, size_t *oldlenp,
const void *newp, size_t newlen)
{
int real_oid[CTL_MAXNAME+2];
size_t oidlen;
int oid[CTL_MAXNAME];
size_t len;
oidlen = sizeof(real_oid) / sizeof(int);
if (sysctlnametomib(name, real_oid, &oidlen) < 0)
if (__getosreldate() >= SYSCTLBYNAME_OSREL) {
len = strlen(name);
return (__sysctlbyname(name, len, oldp, oldlenp, newp,
newlen));
}
len = nitems(oid);
if (sysctlnametomib(name, oid, &len) == -1)
return (-1);
return (sysctl(real_oid, oidlen, oldp, oldlenp, newp, newlen));
return (sysctl(oid, len, oldp, oldlenp, newp, newlen));
}

1
lib/libc/sys/Symbol.map
View File

@ -402,6 +402,7 @@ FBSD_1.5 {
};
FBSD_1.6 {
__sysctlbyname;
copy_file_range;
fhlink;
fhlinkat;

26
sys/compat/freebsd32/freebsd32_misc.c
View File

@ -2255,6 +2255,32 @@ freebsd32___sysctl(struct thread *td, struct freebsd32___sysctl_args *uap)
return (0);
}
int
freebsd32___sysctlbyname(struct thread *td,
struct freebsd32___sysctlbyname_args *uap)
{
size_t oldlen, rv;
int error;
uint32_t tmp;
if (uap->oldlenp != NULL) {
error = fueword32(uap->oldlenp, &tmp);
oldlen = tmp;
} else {
error = oldlen = 0;
}
if (error != 0)
return (EFAULT);
error = kern___sysctlbyname(td, uap->name, uap->namelen, uap->old,
&oldlen, uap->new, uap->newlen, &rv, SCTL_MASK32, 1);
if (error != 0)
return (error);
if (uap->oldlenp != NULL)
error = suword32(uap->oldlenp, rv);
return (error);
}
int
freebsd32_jail(struct thread *td, struct freebsd32_jail_args *uap)
{

10
sys/compat/freebsd32/freebsd32_proto.h
View File

@ -728,6 +728,14 @@ struct freebsd32_cpuset_setdomain_args {
char mask_l_[PADL_(domainset_t *)]; domainset_t * mask; char mask_r_[PADR_(domainset_t *)];
char policy_l_[PADL_(int)]; int policy; char policy_r_[PADR_(int)];
};
struct freebsd32___sysctlbyname_args {
char name_l_[PADL_(const char *)]; const char * name; char name_r_[PADR_(const char *)];
char namelen_l_[PADL_(size_t)]; size_t namelen; char namelen_r_[PADR_(size_t)];
char old_l_[PADL_(void *)]; void * old; char old_r_[PADR_(void *)];
char oldlenp_l_[PADL_(uint32_t *)]; uint32_t * oldlenp; char oldlenp_r_[PADR_(uint32_t *)];
char new_l_[PADL_(void *)]; void * new; char new_r_[PADR_(void *)];
char newlen_l_[PADL_(size_t)]; size_t newlen; char newlen_r_[PADR_(size_t)];
};
#if !defined(PAD64_REQUIRED) && !defined(__amd64__)
#define PAD64_REQUIRED
#endif
@ -865,6 +873,7 @@ int freebsd32_mknodat(struct thread *, struct freebsd32_mknodat_args *);
int freebsd32_kevent(struct thread *, struct freebsd32_kevent_args *);
int freebsd32_cpuset_getdomain(struct thread *, struct freebsd32_cpuset_getdomain_args *);
int freebsd32_cpuset_setdomain(struct thread *, struct freebsd32_cpuset_setdomain_args *);
int freebsd32___sysctlbyname(struct thread *, struct freebsd32___sysctlbyname_args *);
#ifdef COMPAT_43
@ -1419,6 +1428,7 @@ int freebsd11_freebsd32_fstatat(struct thread *, struct freebsd11_freebsd32_fsta
#define FREEBSD32_SYS_AUE_freebsd32_kevent AUE_KEVENT
#define FREEBSD32_SYS_AUE_freebsd32_cpuset_getdomain AUE_NULL
#define FREEBSD32_SYS_AUE_freebsd32_cpuset_setdomain AUE_NULL
#define FREEBSD32_SYS_AUE_freebsd32___sysctlbyname AUE_SYSCTL
#undef PAD_
#undef PADL_

3
sys/compat/freebsd32/freebsd32_syscall.h
View File

@ -496,4 +496,5 @@
#define FREEBSD32_SYS_fhreadlink 567
#define FREEBSD32_SYS_funlinkat 568
#define FREEBSD32_SYS_copy_file_range 569
#define FREEBSD32_SYS_MAXSYSCALL 570
#define FREEBSD32_SYS_freebsd32___sysctlbyname 570
#define FREEBSD32_SYS_MAXSYSCALL 571

1
sys/compat/freebsd32/freebsd32_syscalls.c
View File

@ -606,4 +606,5 @@ const char *freebsd32_syscallnames[] = {
"fhreadlink", /* 567 = fhreadlink */
"funlinkat", /* 568 = funlinkat */
"copy_file_range", /* 569 = copy_file_range */
"freebsd32___sysctlbyname", /* 570 = freebsd32___sysctlbyname */
};

1
sys/compat/freebsd32/freebsd32_sysent.c
View File

@ -653,4 +653,5 @@ struct sysent freebsd32_sysent[] = {
{ AS(fhreadlink_args), (sy_call_t *)sys_fhreadlink, AUE_NULL, NULL, 0, 0, 0, SY_THR_STATIC }, /* 567 = fhreadlink */
{ AS(funlinkat_args), (sy_call_t *)sys_funlinkat, AUE_UNLINKAT, NULL, 0, 0, SYF_CAPENABLED, SY_THR_STATIC }, /* 568 = funlinkat */
{ AS(copy_file_range_args), (sy_call_t *)sys_copy_file_range, AUE_NULL, NULL, 0, 0, SYF_CAPENABLED, SY_THR_STATIC }, /* 569 = copy_file_range */
{ AS(freebsd32___sysctlbyname_args), (sy_call_t *)freebsd32___sysctlbyname, AUE_SYSCTL, NULL, 0, 0, SYF_CAPENABLED, SY_THR_STATIC }, /* 570 = freebsd32___sysctlbyname */
};

42
sys/compat/freebsd32/freebsd32_systrace_args.c
View File

@ -3332,6 +3332,18 @@ systrace_args(int sysnum, void *params, uint64_t *uarg, int *n_args)
*n_args = 6;
break;
}
/* freebsd32___sysctlbyname */
case 570: {
struct freebsd32___sysctlbyname_args *p = params;
uarg[0] = (intptr_t) p->name; /* const char * */
uarg[1] = p->namelen; /* size_t */
uarg[2] = (intptr_t) p->old; /* void * */
uarg[3] = (intptr_t) p->oldlenp; /* uint32_t * */
uarg[4] = (intptr_t) p->new; /* void * */
uarg[5] = p->newlen; /* size_t */
*n_args = 6;
break;
}
default:
*n_args = 0;
break;
@ -8971,6 +8983,31 @@ systrace_entry_setargdesc(int sysnum, int ndx, char *desc, size_t descsz)
break;
};
break;
/* freebsd32___sysctlbyname */
case 570:
switch(ndx) {
case 0:
p = "userland const char *";
break;
case 1:
p = "size_t";
break;
case 2:
p = "userland void *";
break;
case 3:
p = "userland uint32_t *";
break;
case 4:
p = "userland void *";
break;
case 5:
p = "size_t";
break;
default:
break;
};
break;
default:
break;
};
@ -10850,6 +10887,11 @@ systrace_return_setargdesc(int sysnum, int ndx, char *desc, size_t descsz)
if (ndx == 0 || ndx == 1)
p = "ssize_t";
break;
/* freebsd32___sysctlbyname */
case 570:
if (ndx == 0 || ndx == 1)
p = "int";
break;
default:
break;
};

3
sys/compat/freebsd32/syscalls.master
View File

@ -1150,5 +1150,8 @@
569 AUE_NULL NOPROTO { ssize_t copy_file_range(int infd, \
off_t *inoffp, int outfd, off_t *outoffp, \
size_t len, unsigned int flags); }
570 AUE_SYSCTL STD { int freebsd32___sysctlbyname(const char *name, \
size_t namelen, void *old, uint32_t *oldlenp, \
void *new, size_t newlen); }
; vim: syntax=off

1
sys/kern/capabilities.conf
View File

@ -58,6 +58,7 @@ __mac_set_proc
## proxying daemon in userspace.
##
__sysctl
__sysctlbyname
##
## Allow umtx operations as these are scoped by address space.

1
sys/kern/init_sysent.c
View File

@ -619,4 +619,5 @@ struct sysent sysent[] = {
{ AS(fhreadlink_args), (sy_call_t *)sys_fhreadlink, AUE_NULL, NULL, 0, 0, 0, SY_THR_STATIC }, /* 567 = fhreadlink */
{ AS(funlinkat_args), (sy_call_t *)sys_funlinkat, AUE_UNLINKAT, NULL, 0, 0, SYF_CAPENABLED, SY_THR_STATIC }, /* 568 = funlinkat */
{ AS(copy_file_range_args), (sy_call_t *)sys_copy_file_range, AUE_NULL, NULL, 0, 0, SYF_CAPENABLED, SY_THR_STATIC }, /* 569 = copy_file_range */
{ AS(__sysctlbyname_args), (sy_call_t *)sys___sysctlbyname, AUE_SYSCTL, NULL, 0, 0, SYF_CAPENABLED, SY_THR_STATIC }, /* 570 = __sysctlbyname */
};

62
sys/kern/kern_sysctl.c
View File

@ -2145,6 +2145,68 @@ sys___sysctl(struct thread *td, struct sysctl_args *uap)
return (error);
}
int
kern___sysctlbyname(struct thread *td, const char *oname, size_t namelen,
void *old, size_t *oldlenp, void *new, size_t newlen, size_t *retval,
int flags, bool inkernel)
{
int oid[CTL_MAXNAME];
char namebuf[16];
char *name;
size_t oidlen;
int error;
if (namelen > MAXPATHLEN || namelen == 0)
return (EINVAL);
name = namebuf;
if (namelen > sizeof(namebuf))
name = malloc(namelen, M_SYSCTL, M_WAITOK);
error = copyin(oname, name, namelen);
if (error != 0)
goto out;
oid[0] = 0;
oid[1] = 3;
oidlen = sizeof(oid);
error = kernel_sysctl(td, oid, 2, oid, &oidlen, (void *)name, namelen,
retval, flags);
if (error != 0)
goto out;
error = userland_sysctl(td, oid, *retval / sizeof(int), old, oldlenp,
inkernel, new, newlen, retval, flags);
out:
if (namelen > sizeof(namebuf))
free(name, M_SYSCTL);
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct __sysctlbyname_args {
const char *name;
size_t namelen;
void *old;
size_t *oldlenp;
void *new;
size_t newlen;
};
#endif
int
sys___sysctlbyname(struct thread *td, struct __sysctlbyname_args *uap)
{
size_t rv;
int error;
error = kern___sysctlbyname(td, uap->name, uap->namelen, uap->old,
uap->oldlenp, uap->new, uap->newlen, &rv, 0, 0);
if (error != 0)
return (error);
if (uap->oldlenp != NULL)
error = copyout(&rv, uap->oldlenp, sizeof(rv));
return (error);
}
/*
* This is used from various compatibility syscalls too. That's why name
* must be in kernel space.

1
sys/kern/syscalls.c
View File

@ -576,4 +576,5 @@ const char *syscallnames[] = {
"fhreadlink", /* 567 = fhreadlink */
"funlinkat", /* 568 = funlinkat */
"copy_file_range", /* 569 = copy_file_range */
"__sysctlbyname", /* 570 = __sysctlbyname */
};

9
sys/kern/syscalls.master
View File

@ -3185,6 +3185,15 @@
unsigned int flags
);
}
570 AUE_SYSCTL STD {
int __sysctlbyname(
_In_reads_(namelen) const char *name,
size_t namelen,
_Out_writes_bytes_opt_(*oldlenp) void *old,
_Inout_opt_ size_t *oldlenp,
_In_reads_bytes_opt_(newlen) void *new,
size_t newlen);
}
; Please copy any additions and changes to the following compatability tables:
; sys/compat/freebsd32/syscalls.master

42
sys/kern/systrace_args.c
View File

@ -3324,6 +3324,18 @@ systrace_args(int sysnum, void *params, uint64_t *uarg, int *n_args)
*n_args = 6;
break;
}
/* __sysctlbyname */
case 570: {
struct __sysctlbyname_args *p = params;
uarg[0] = (intptr_t) p->name; /* const char * */
uarg[1] = p->namelen; /* size_t */
uarg[2] = (intptr_t) p->old; /* void * */
uarg[3] = (intptr_t) p->oldlenp; /* size_t * */
uarg[4] = (intptr_t) p->new; /* void * */
uarg[5] = p->newlen; /* size_t */
*n_args = 6;
break;
}
default:
*n_args = 0;
break;
@ -8876,6 +8888,31 @@ systrace_entry_setargdesc(int sysnum, int ndx, char *desc, size_t descsz)
break;
};
break;
/* __sysctlbyname */
case 570:
switch(ndx) {
case 0:
p = "userland const char *";
break;
case 1:
p = "size_t";
break;
case 2:
p = "userland void *";
break;
case 3:
p = "userland size_t *";
break;
case 4:
p = "userland void *";
break;
case 5:
p = "size_t";
break;
default:
break;
};
break;
default:
break;
};
@ -10782,6 +10819,11 @@ systrace_return_setargdesc(int sysnum, int ndx, char *desc, size_t descsz)
if (ndx == 0 || ndx == 1)
p = "ssize_t";
break;
/* __sysctlbyname */
case 570:
if (ndx == 0 || ndx == 1)
p = "int";
break;
default:
break;
};

2
sys/sys/param.h
View File

@ -60,7 +60,7 @@
* in the range 5 to 9.
*/
#undef __FreeBSD_version
#define __FreeBSD_version 1300044 /* Master, propagated to newvers */
#define __FreeBSD_version 1300045 /* Master, propagated to newvers */
/*
* __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,

3
sys/sys/syscall.h
View File

@ -505,4 +505,5 @@
#define SYS_fhreadlink 567
#define SYS_funlinkat 568
#define SYS_copy_file_range 569
#define SYS_MAXSYSCALL 570
#define SYS___sysctlbyname 570
#define SYS_MAXSYSCALL 571

3
sys/sys/syscall.mk
View File

@ -410,4 +410,5 @@ MIASM = \
fhlinkat.o \
fhreadlink.o \
funlinkat.o \
copy_file_range.o
copy_file_range.o \
__sysctlbyname.o

3
sys/sys/sysctl.h
View File

@ -1128,6 +1128,9 @@ int sysctl_find_oid(int *name, u_int namelen, struct sysctl_oid **noid,
void sysctl_wlock(void);
void sysctl_wunlock(void);
int sysctl_wire_old_buffer(struct sysctl_req *req, size_t len);
int kern___sysctlbyname(struct thread *td, const char *name,
size_t namelen, void *old, size_t *oldlenp, void *new,
size_t newlen, size_t *retval, int flags, bool inkernel);
struct sbuf;
struct sbuf *sbuf_new_for_sysctl(struct sbuf *, char *, int,

10
sys/sys/sysproto.h
View File

@ -1804,6 +1804,14 @@ struct copy_file_range_args {
char len_l_[PADL_(size_t)]; size_t len; char len_r_[PADR_(size_t)];
char flags_l_[PADL_(unsigned int)]; unsigned int flags; char flags_r_[PADR_(unsigned int)];
};
struct __sysctlbyname_args {
char name_l_[PADL_(const char *)]; const char * name; char name_r_[PADR_(const char *)];
char namelen_l_[PADL_(size_t)]; size_t namelen; char namelen_r_[PADR_(size_t)];
char old_l_[PADL_(void *)]; void * old; char old_r_[PADR_(void *)];
char oldlenp_l_[PADL_(size_t *)]; size_t * oldlenp; char oldlenp_r_[PADR_(size_t *)];
char new_l_[PADL_(void *)]; void * new; char new_r_[PADR_(void *)];
char newlen_l_[PADL_(size_t)]; size_t newlen; char newlen_r_[PADR_(size_t)];
};
int nosys(struct thread *, struct nosys_args *);
void sys_sys_exit(struct thread *, struct sys_exit_args *);
int sys_fork(struct thread *, struct fork_args *);
@ -2190,6 +2198,7 @@ int sys_fhlinkat(struct thread *, struct fhlinkat_args *);
int sys_fhreadlink(struct thread *, struct fhreadlink_args *);
int sys_funlinkat(struct thread *, struct funlinkat_args *);
int sys_copy_file_range(struct thread *, struct copy_file_range_args *);
int sys___sysctlbyname(struct thread *, struct __sysctlbyname_args *);
#ifdef COMPAT_43
@ -3098,6 +3107,7 @@ int freebsd11_mknodat(struct thread *, struct freebsd11_mknodat_args *);
#define SYS_AUE_fhreadlink AUE_NULL
#define SYS_AUE_funlinkat AUE_UNLINKAT
#define SYS_AUE_copy_file_range AUE_NULL
#define SYS_AUE___sysctlbyname AUE_SYSCTL
#undef PAD_
#undef PADL_