From: adr <adr@SDF.ORG>
To: 9fans <9fans@9fans.net>
Subject: Re: [9fans] syscall silently kill processes
Date: Tue, 28 Jun 2022 18:19:53 +0000 (UTC) [thread overview]
Message-ID: <4cb721cd-616d-8f86-e499-ad9da41c40a2@SDF.ORG> (raw)
In-Reply-To: <87cff69b-4b82-8466-a34f-13c7eda24fc9@SDF.ORG>
On Tue, 28 Jun 2022, adr wrote:
>
> Andrey, if you want to use different note handlers per process (with a big
> number of processes) using libthread, this may be helpful.
>
> The idea is this:
>
> An array of handlers for all processes which can be changed by all processes.
> When a note is received by a process, this array takes priority.
>
> An array of pointers to structures of the type
>
> struct Onnote
> {
> int pid;
> int (*fn[NFN])(void*, char*);
> };
>
> initially of size PPCHUNK (I set it to 100, experiment with that),
> but it can grow if necessary (but not shrink, I think this would
> be overkilling).
>
> These structures are allocated the first time a process record a
> handler and freed when the process exits (or by calling
> threadcancelnotes(), note that this function can free other processes'
> function handlers, maybe should be better to make some restrictions)
>
> The use of "in" in threadnotify(int (*f)(void*, char*), int in) is:
>
> in > 0 : set the handler for the calling process.
> in == 0 : clear the handler for the calling process.
> in == -1 : clear the handler for all processes (except those who has
> registered it already for themselves).
> in < -1 : set the handler for all processes.
>
> There is no use of threadnotify with "in < 0" in /sys/src, so nothing is
> broken.
>
> As you are using 9front and they are serving their sources with
> 9p, here is a diff to their sources. I haven't compiled it in
> 9front, though. Note that if you want to compile the system with
> this changes, you have to eliminate the copy of note.c at
> /sys/src/cmd/execnet (it seems that note.c was added afterwards as
> I thought).
>
> I haven't test it too much, this has been more like a time-destroyer
> pastime.
This just evade going through the arrays twice. For the current
value of NFN it doesn't make too much a difference, note that this
structures are locked. It just was hurting my eyes.
--- /tmp/main.c
+++ /sys/src/libthread/main.c
@@ -28,6 +28,10 @@
_qlockinit(_threadrendezvous);
_sysfatal = _threadsysfatal;
__assert = _threadassert;
+ onnote = mallocz(PPCHUNK*sizeof(uintptr), 1);
+ if(!onnote)
+ sysfatal("Malloc of size %d failed: %r", PPCHUNK*sizeof(uintptr));
+ onnotesize = PPCHUNK;
notify(_threadnote);
if(mainstacksize == 0)
mainstacksize = 8*1024;
--- /tmp/note.c
+++ /sys/src/libthread/note.c
@@ -5,7 +5,6 @@
int _threadnopasser;
-#define NFN 33
#define ERRLEN 48
typedef struct Note Note;
struct Note
@@ -17,62 +16,161 @@
static Note notes[128];
static Note *enotes = notes+nelem(notes);
-static int (*onnote[NFN])(void*, char*);
-static int onnotepid[NFN];
+Onnote **onnote;
+int onnotesize;
+static int (*onnoteall[NFN])(void*, char*);
static Lock onnotelock;
int
threadnotify(int (*f)(void*, char*), int in)
{
- int i, topid;
- int (*from)(void*, char*), (*to)(void*, char*);
+ int i, j, n;
- if(in){
- from = nil;
- to = f;
- topid = _threadgetproc()->pid;
- }else{
- from = f;
- to = nil;
- topid = 0;
- }
lock(&onnotelock);
- for(i=0; i<NFN; i++)
- if(onnote[i]==from){
- onnote[i] = to;
- onnotepid[i] = topid;
+
+ /* add note for all processes */
+ if(in < -1){
+ n = -1;
+ for(i=0; i<NFN; i++){
+ if(onnoteall[i] == f){
+ unlock(&onnotelock);
+ return 1;
+ }
+ if(onnoteall[i]==nil && n==-1)
+ n = i;
+ }
+ if(n > -1)
+ onnoteall[n] = f;
+ unlock(&onnotelock);
+ return n>-1;
+ }
+
+ /* remove note for all processes */
+ if(in == -1){
+ for(i=0; i<NFN; i++)
+ if(onnoteall[i] == f){
+ onnoteall[i] = nil;
+ break;
+ }
+ unlock(&onnotelock);
+ return i<NFN;
+ }
+
+ /* remove note for current process */
+ if(!in){
+ for(i=0; i<onnotesize; i++){
+ if(onnote[i]!=nil && onnote[i]->pid==_threadgetproc()->pid){
+ for(j=0; j<NFN; j++){
+ if(onnote[i]->fn[j] == f){
+ onnote[i]->fn[j] = 0;
+ break;
+ }
+ }
+ unlock(&onnotelock);
+ return j<NFN;
+ }
+ }
+ unlock(&onnotelock);
+ return 0;
+ }
+
+ /* add note for current process */
+ for(i=0; i<onnotesize; i++)
+ if(onnote[i] && onnote[i]->pid==_threadgetproc()->pid)
+ break;
+
+ /* process has already a slot */
+ if(i < onnotesize){
+ n = -1;
+ for(j=0; j<NFN; j++){
+ if(onnote[i]->fn[j] == f){
+ unlock(&onnotelock);
+ return 1;
+ }
+ if(onnote[i]->fn[j] == nil)
+ n = j;
+ }
+ if(n > -1)
+ onnote[i]->fn[n] = f;
+ unlock(&onnotelock);
+ return n>-1;
+
+ }
+
+ for(i=0; i<onnotesize; i++)
+ if(!onnote[i])
+ break;
+
+ /* there is no free slot */
+ if(i == onnotesize){
+ onnotesize += PPCHUNK;
+ onnote = realloc(onnote, onnotesize*sizeof(uintptr));
+ if(!onnote){
+ unlock(&onnotelock);
+ sysfatal("Malloc of size %d failed: %r", onnotesize*sizeof(uintptr));
+ }
+ memset(onnote+i+1, 0, PPCHUNK-1);
+ }
+
+ onnote[i]=mallocz(sizeof(Onnote), 1);
+ if(!onnote[i]){
+ unlock(&onnotelock);
+ sysfatal("Malloc of size %d failed: %r", sizeof(Onnote));
+ }
+ onnote[i]->pid = _threadgetproc()->pid;
+ onnote[i]->fn[0] = f;
+ unlock(&onnotelock);
+ return 1;
+}
+
+void
+threadcancelnotes(int pid)
+{
+ int i;
+
+ lock(&onnotelock);
+ for(i=0; i<onnotesize; i++)
+ if(onnote[i] && onnote[i]->pid==pid){
+ free(onnote[i]);
+ onnote[i] = nil;
break;
}
unlock(&onnotelock);
- return i<NFN;
+ return;
}
static void
delayednotes(Proc *p, void *v)
{
- int i;
+ int i, j, all;
Note *n;
- char s[ERRMAX];
- int (*fn)(void*, char*);
+ int (*f)(void*, char*);
if(!p->pending)
return;
p->pending = 0;
+ all = j = 0;
for(n=notes; n<enotes; n++){
if(n->proc == p){
- strcpy(s, n->s);
- n->proc = nil;
- unlock(&n->inuse);
-
- for(i=0; i<NFN; i++){
- if(onnotepid[i]!=p->pid || (fn = onnote[i])==nil)
- continue;
- if((*fn)(v, s))
- break;
+ for(i=0; i<NFN; i++)
+ if(f=onnoteall[i])
+ if((*f)(v, n->s)){
+ all = 1;
+ break;
+ }
+ if(!all){
+ for(i=0; i<onnotesize; i++)
+ if(onnote[i] && onnote[i]->pid==p->pid){
+ for(j=0; j<NFN; j++)
+ if(f=onnote[i]->fn[j])
+ if((*f)(v, n->s))
+ break;
+ break;
+ }
}
- if(i==NFN){
- _threaddebug(DBGNOTE, "Unhandled note %s, proc %p", n->s, p);
+ if(!all && (i==onnotesize || j==NFN)){
+ _threaddebug(DBGNOTE, "Unhandled note %s, proc %p\n", n->s, p);
if(v != nil)
noted(NDFLT);
else if(strncmp(n->s, "sys:", 4)==0)
@@ -79,6 +177,8 @@
abort();
threadexitsall(n->s);
}
+ n->proc = nil;
+ unlock(&n->inuse);
}
}
}
@@ -94,7 +194,7 @@
noted(NDFLT);
if(_threadexitsallstatus){
- _threaddebug(DBGNOTE, "Threadexitsallstatus = '%s'", _threadexitsallstatus);
+ _threaddebug(DBGNOTE, "Threadexitsallstatus = '%s'\n", _threadexitsallstatus);
_exits(_threadexitsallstatus);
}
--- /tmp/sched.c
+++ /sys/src/libthread/sched.c
@@ -157,6 +157,7 @@
t = runthread(p);
if(t == nil){
_threaddebug(DBGSCHED, "all threads gone; exiting");
+ threadcancelnotes(p->pid);
unlinkproc(p);
_schedexit(p); /* frees proc */
}
--- /tmp/thread.h
+++ /sys/include/thread.h
@@ -97,6 +97,7 @@
void threadkillgrp(int); /* kill threads in group */
void threadmain(int argc, char *argv[]);
int threadnotify(int (*f)(void*, char*), int in);
+void threadcancelnotes(int pid);
int threadid(void);
int threadpid(int);
int threadsetgrp(int); /* set thread group, return old */
--- /tmp/threadimpl.h
+++ /sys/src/libthread/threadimpl.h
@@ -192,3 +192,15 @@
#define _threaddebug(flag, ...) if((_threaddebuglevel&(flag))==0){}else _threadprint(__VA_ARGS__)
#define ioproc_arg(io, type) (va_arg((io)->arg, type))
+
+#define PPCHUNK 100
+#define NFN 33
+typedef struct Onnote Onnote;
+struct Onnote
+{
+ int pid;
+ int (*fn[NFN])(void*, char*);
+};
+extern Onnote **onnote;
+extern int onnotesize;
+void _threadnote(void*, char*);
------------------------------------------
9fans: 9fans
Permalink: https://9fans.topicbox.com/groups/9fans/Tfa6823048ad90a21-Mfa798aacff90ff14ee10e8cf
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next prev parent reply other threads:[~2022-06-28 18:20 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-17 9:37 andrey100100100
2022-06-17 13:46 ` Thaddeus Woskowiak
2022-06-17 14:11 ` Jacob Moody
2022-06-17 14:39 ` Thaddeus Woskowiak
2022-06-17 15:06 ` andrey100100100
2022-06-17 16:08 ` Skip Tavakkolian
2022-06-17 16:11 ` Skip Tavakkolian
2022-06-17 16:16 ` Skip Tavakkolian
2022-06-17 17:42 ` adr
2022-06-17 16:11 ` Jacob Moody
2022-06-17 18:48 ` andrey100100100
2022-06-17 19:28 ` Jacob Moody
2022-06-17 21:15 ` adr
2022-06-18 6:40 ` andrey100100100
2022-06-18 8:37 ` adr
2022-06-18 9:22 ` adr
2022-06-18 12:53 ` Jacob Moody
2022-06-18 22:03 ` andrey100100100
2022-06-19 5:54 ` adr
2022-06-19 6:13 ` Jacob Moody
2022-06-18 22:22 ` andrey100100100
2022-06-18 16:57 ` andrey100100100
2022-06-19 2:40 ` adr
2022-06-19 5:01 ` adr
2022-06-19 8:52 ` andrey100100100
2022-06-19 10:32 ` adr
2022-06-19 11:40 ` andrey100100100
2022-06-19 12:01 ` andrey100100100
2022-06-19 15:10 ` andrey100100100
2022-06-19 16:41 ` adr
2022-06-19 21:22 ` andrey100100100
2022-06-19 21:26 ` andrey100100100
2022-06-20 4:41 ` adr
2022-06-20 5:39 ` andrey100100100
2022-06-20 5:59 ` adr
2022-06-20 15:56 ` andrey100100100
2022-06-20 22:29 ` Skip Tavakkolian
2022-06-21 7:07 ` andrey100100100
2022-06-21 11:26 ` adr
2022-06-21 13:03 ` andrey100100100
2022-06-21 13:22 ` adr
2022-06-28 15:28 ` adr
2022-06-28 16:43 ` ori
2022-06-28 18:19 ` adr [this message]
2022-06-28 18:28 ` adr
2022-06-28 19:09 ` andrey100100100
2022-06-28 19:42 ` adr
2022-06-29 13:14 ` adr
2022-06-21 13:47 ` andrey100100100
2022-06-21 7:22 ` adr
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