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Add sysctl kern.proc.sigfastblk for reporting sigfastblock word address.

Browse Source 
Tested by:	pho
Disscussed with:	cem, emaste, jilles
Sponsored by:	The FreeBSD Foundation
Differential revision:	https://reviews.freebsd.org/D12773
This commit is contained in:
Konstantin Belousov 2020-02-09 12:29:51 +00:00
parent fc908e5001
commit 48fcb46311
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=357700
2 changed files with 76 additions and 0 deletions
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75
sys/kern/kern_proc.c
View File

@ -2962,6 +2962,77 @@ sysctl_kern_proc_sigtramp(SYSCTL_HANDLER_ARGS)
return (error);
}
static int
sysctl_kern_proc_sigfastblk(SYSCTL_HANDLER_ARGS)
{
int *name = (int *)arg1;
u_int namelen = arg2;
pid_t pid;
struct proc *p;
struct thread *td1;
uintptr_t addr;
#ifdef COMPAT_FREEBSD32
uint32_t addr32;
#endif
int error;
if (namelen != 1 || req->newptr != NULL)
return (EINVAL);
pid = (pid_t)name[0];
error = pget(pid, PGET_HOLD | PGET_NOTWEXIT | PGET_CANDEBUG, &p);
if (error != 0)
return (error);
PROC_LOCK(p);
#ifdef COMPAT_FREEBSD32
if (SV_CURPROC_FLAG(SV_ILP32)) {
if (!SV_PROC_FLAG(p, SV_ILP32)) {
error = EINVAL;
goto errlocked;
}
}
#endif
if (pid <= PID_MAX) {
td1 = FIRST_THREAD_IN_PROC(p);
} else {
FOREACH_THREAD_IN_PROC(p, td1) {
if (td1->td_tid == pid)
break;
}
}
if (td1 == NULL) {
error = ESRCH;
goto errlocked;
}
/*
* The access to the private thread flags. It is fine as far
* as no out-of-thin-air values are read from td_pflags, and
* usermode read of the td_sigblock_ptr is racy inherently,
* since target process might have already changed it
* meantime.
*/
if ((td1->td_pflags & TDP_SIGFASTBLOCK) != 0)
addr = (uintptr_t)td1->td_sigblock_ptr;
else
error = ENOTTY;
errlocked:
_PRELE(p);
PROC_UNLOCK(p);
if (error != 0)
return (error);
#ifdef COMPAT_FREEBSD32
if (SV_CURPROC_FLAG(SV_ILP32)) {
addr32 = addr;
error = SYSCTL_OUT(req, &addr32, sizeof(addr32));
} else
#endif
error = SYSCTL_OUT(req, &addr, sizeof(addr));
return (error);
}
SYSCTL_NODE(_kern, KERN_PROC, proc, CTLFLAG_RD, 0, "Process table");
SYSCTL_PROC(_kern_proc, KERN_PROC_ALL, all, CTLFLAG_RD|CTLTYPE_STRUCT|
@ -3075,6 +3146,10 @@ static SYSCTL_NODE(_kern_proc, KERN_PROC_SIGTRAMP, sigtramp, CTLFLAG_RD |
CTLFLAG_MPSAFE, sysctl_kern_proc_sigtramp,
"Process signal trampoline location");
static SYSCTL_NODE(_kern_proc, KERN_PROC_SIGFASTBLK, sigfastblk, CTLFLAG_RD |
CTLFLAG_ANYBODY | CTLFLAG_MPSAFE, sysctl_kern_proc_sigfastblk,
"Thread sigfastblock address");
int allproc_gen;
/*

1
sys/sys/sysctl.h
View File

@ -1017,6 +1017,7 @@ TAILQ_HEAD(sysctl_ctx_list, sysctl_ctx_entry);
#define KERN_PROC_SIGTRAMP 41 /* signal trampoline location */
#define KERN_PROC_CWD 42 /* process current working directory */
#define KERN_PROC_NFDS 43 /* number of open file descriptors */
#define KERN_PROC_SIGFASTBLK 44 /* address of fastsigblk magic word */
/*
* KERN_IPC identifiers