> -----Original Message----- > From: Pavel Emelyanov [mailto:xemul@xxxxxxxxxxxxx] > Sent: Tuesday, June 17, 2014 8:13 PM > To: Chen, Hanxiao/陈 晗霄 > Cc: containers@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > Andrew Morton; Eric W. Biederman; Serge Hallyn; Daniel P. Berrange; Oleg Nesterov; > Al Viro; David Howells; Richard Weinberger; Vasiliy Kulikov; Gotou, Yasunori/ > 五? 康文 > Subject: Re: [PATCH] ns: introduce getnspid syscall > > On 06/17/2014 02:21 PM, Chen Hanxiao wrote: > > We need a direct method of getting the pid inside containers. > > If some issues occurred inside container guest, host user > > could not know which process is in trouble just by guest pid: > > the users of container guest only knew the pid inside containers. > > This will bring obstacle for trouble shooting. > > > > int getnspid(pid_t pid, int fd1, int fd2, int pidtype); > > > > pid: the pid number need to be translated. > > > > fd: a file descriptor referring to one of > > the namespace entries in a /proc/[pid]/ns/pid. > > fd1 for destination ns(ns1), where the pid came from. > > fd2 for reference ns(ns2), while fd2 = -2 means for current ns. > > > > pidtype: 0 PIDTYPE_PID; 1 PIDTYPE_PGID; 2 PIDTYPE_SID. > > > > return value: > > >0: translated pid in ns1(fd1) seen from ns2(fd2). > > <0: on failure. > > > > + } > > + > > + switch (pidtype) { > > There's no need in switch, the __task_pid_nr_ns() accepts > the type argument. > Yes, I think we still have that kind of functions, so I used them... > > + case PIDTYPE_PID: > > + ret = task_pid_nr_ns(task, ns2); > > But this is not correct. If task doesn't live in ns2, but ns2 > just has the ns->level small enough, then the wrong pid value > would be reported. > Right, we should check whether the task belonged to that namespace firstly. Thanks, - Chen > > + break; > > + case PIDTYPE_PGID: > > + ret = task_pgrp_nr_ns(task, ns2); > > + break; > > + case PIDTYPE_SID: > > + ret = task_session_nr_ns(task, ns2); > > + break; > > + default: > > + ret = -EINVAL; > > + } > > + ret = (ret == 0) ? -ESRCH : ret; > > + > > +out: > > + fput(file1); > > + if (file2) > > + fput(file2); > > + return ret; > > +} > > + > > int __init nsproxy_cache_init(void) > > { > > nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); > > >
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