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sshnet: fix fork race conditions

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sshreadproc() needs to be started after opening the sshfd file
descriptor.

fsnetproc() needs to run in the same filedescriptor group as
the fileserver.
This commit is contained in:
cinap_lenrek 2020-03-08 04:54:37 +01:00
parent 2c53dd32b5
commit 59fdb3a12c
1 changed files with 30 additions and 24 deletions
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54
sys/src/cmd/sshnet.c
View file

@ -33,7 +33,7 @@ enum
#define TYPE(path) ((int)(path) & 0xFF)
#define NUM(path) ((uint)(path)>>8)
Channel *ssherrchan; /* chan(char*) */
int sessionopen = 0;
Channel *sshmsgchan; /* chan(Msg*) */
Channel *fsreqchan; /* chan(Req*) */
Channel *fsreqwaitchan; /* chan(nil) */
@ -125,7 +125,7 @@ struct Msg
int nclient;
Client **client;
char *mtpt;
char *mtpt, *service;
int sshfd;
int
@ -1148,7 +1148,7 @@ handlemsg(Msg *m)
if(unpack(m, "_uuuu", &chan, &n, &win, &pkt) < 0)
break;
if(chan == SESSIONCHAN){
sendp(ssherrchan, nil);
sessionopen++;
break;
}
c = getclient(chan);
@ -1173,7 +1173,7 @@ handlemsg(Msg *m)
break;
s = smprint("%.*s", utfnlen(s, n), s);
if(chan == SESSIONCHAN){
sendp(ssherrchan, s);
sysfatal("ssh failed: %s", s);
break;
}
c = getclient(chan);
@ -1313,6 +1313,12 @@ fsdestroyfid(Fid *fid)
recvp(fsclunkwaitchan);
}
static void
startup(Srv*)
{
proccreate(fsnetproc, nil, 8*1024);
}
void
takedown(Srv*)
{
@ -1321,7 +1327,7 @@ takedown(Srv*)
Srv fs =
{
.attach= fssend,
.attach= fssend,
.destroyfid= fsdestroyfid,
.walk1= fswalk1,
.open= fssend,
@ -1329,6 +1335,7 @@ Srv fs =
.write= fssend,
.stat= fssend,
.flush= fssend,
.start= startup,
.end= takedown,
};
@ -1356,9 +1363,9 @@ startssh(void *)
void
ssh(int argc, char *argv[])
{
Alt a[3];
Alt a[4];
Waitmsg *w;
char *e;
Msg *m;
sshargc = argc + 2;
sshargv = emalloc9p(sizeof(char *) * (sshargc + 1));
@ -1366,11 +1373,14 @@ ssh(int argc, char *argv[])
sshargv[1] = "-X";
memcpy(sshargv + 2, argv, argc * sizeof(char *));
pipe(pfd);
if(pipe(pfd) < 0)
sysfatal("pipe: %r");
sshfd = pfd[0];
procrfork(startssh, nil, 8*1024, RFFDG|RFNOTEG|RFNAMEG);
procrfork(startssh, nil, 8*1024, RFFDG|RFNOTEG);
close(pfd[1]);
procrfork(sshreadproc, nil, 8*1024, RFFDG|RFNOTEG);
sendmsg(pack(nil, "bsuuu", MSG_CHANNEL_OPEN,
"session", 7,
SESSIONCHAN,
@ -1381,18 +1391,18 @@ ssh(int argc, char *argv[])
a[0].c = threadwaitchan();
a[0].v = &w;
a[1].op = CHANRCV;
a[1].c = ssherrchan;
a[1].v = &e;
a[1].c = sshmsgchan;
a[1].v = &m;
a[2].op = CHANEND;
switch(alt(a)){
case 0:
sysfatal("ssh failed: %s", w->msg);
case 1:
if(e != nil)
sysfatal("ssh failed: %s", e);
while(!sessionopen){
switch(alt(a)){
case 0:
sysfatal("ssh failed: %s", w->msg);
case 1:
handlemsg(m);
}
}
chanclose(ssherrchan);
}
void
@ -1405,8 +1415,6 @@ usage(void)
void
threadmain(int argc, char **argv)
{
char *service;
fmtinstall('H', encodefmt);
mtpt = "/net";
@ -1429,17 +1437,15 @@ threadmain(int argc, char **argv)
usage();
time0 = time(0);
ssherrchan = chancreate(sizeof(char*), 0);
sshmsgchan = chancreate(sizeof(Msg*), 16);
fsreqchan = chancreate(sizeof(Req*), 0);
fsreqwaitchan = chancreate(sizeof(void*), 0);
fsclunkchan = chancreate(sizeof(Fid*), 0);
fsclunkwaitchan = chancreate(sizeof(void*), 0);
procrfork(fsnetproc, nil, 8*1024, RFNAMEG|RFNOTEG);
procrfork(sshreadproc, nil, 8*1024, RFNAMEG|RFNOTEG);
ssh(argc, argv);
threadpostmountsrv(&fs, service, mtpt, MREPL);
exits(0);
threadexits(nil);
}