ping?
On Sun, Feb 12, 2017 at 07:58:27PM +0200, Ossi Herrala wrote:
> On Sun, Feb 12, 2017 at 01:34:14AM +0200, Ossi Herrala wrote:
>
> > After couple of private mails with guenther@ we came up with the
> > following patch.
> >
> > Introduce new flag FORK_PID1 for fork1(9).
> >
> > This flag is special and only for forking init(8) which wants to be
> > PID 1.
> >
> > With this flag in place, it's possible to remove global randompid
> > variable which was used to control if allocpid() returns random PIDs
> > or PID 1 for init(8). Now allocpid() can also be simplified.
> >
>
> New patch which works with latest changes to fork1(9).
>
> This version also documents FORK_PID1 flag in fork1(9) man page.
>
>
> ---
> share/man/man9/fork1.9 | 3 +++
> sys/kern/init_main.c | 5 ++---
> sys/kern/kern_fork.c | 24 ++++++++++--------------
> sys/sys/proc.h | 2 +-
> 4 files changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/share/man/man9/fork1.9 b/share/man/man9/fork1.9
> index c22c9800aa4..21175416ed4 100644
> --- a/share/man/man9/fork1.9
> +++ b/share/man/man9/fork1.9
> @@ -109,6 +109,9 @@ must also be set.
> .It Dv FORK_PTRACE
> The child will start with tracing enabled, as if
> ptrace(PT_TRACE_ME, 0, 0, 0) had been invoked in the child.
> +.It Dv FORK_PID1
> +Special flag to assign PID 1 for
> +.Xr init 8 process.
> .El
> .Pp
> If
> diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
> index faa74aa4244..f1975a6aa89 100644
> --- a/sys/kern/init_main.c
> +++ b/sys/kern/init_main.c
> @@ -437,13 +437,12 @@ main(void *framep)
> {
> struct proc *initproc;
>
> - if (fork1(p, FORK_FORK, start_init, NULL, NULL, &initproc))
> + if (fork1(p, FORK_FORK|FORK_PID1, start_init, NULL, NULL,
> + &initproc))
> panic("fork init");
> initprocess = initproc->p_p;
> }
>
> - randompid = 1;
> -
> /*
> * Create any kernel threads whose creation was deferred because
> * initprocess had not yet been created.
> diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
> index 38c1be4a981..b5f99d3c4dc 100644
> --- a/sys/kern/kern_fork.c
> +++ b/sys/kern/kern_fork.c
> @@ -71,7 +71,6 @@
>
> int nprocesses = 1; /* process 0 */
> int nthreads = 1; /* proc 0 */
> -int randompid; /* when set to 1, pid's go random */
> struct forkstat forkstat;
>
> void fork_return(void *);
> @@ -220,7 +219,11 @@ process_new(struct proc *p, struct process *parent, int
> flags)
> (caddr_t)&pr->ps_endcopy - (caddr_t)&pr->ps_startcopy);
>
> process_initialize(pr, p);
> - pr->ps_pid = allocpid();
> +
> + if (flags & FORK_PID1)
> + pr->ps_pid = 1;
> + else
> + pr->ps_pid = allocpid();
>
> /* post-copy fixups */
> pr->ps_pptr = parent;
> @@ -332,7 +335,7 @@ fork1(struct proc *curp, int flags, void (*func)(void *),
> void *arg,
>
> KASSERT((flags & ~(FORK_FORK | FORK_VFORK | FORK_PPWAIT | FORK_PTRACE
> | FORK_IDLE | FORK_SHAREVM | FORK_SHAREFILES | FORK_NOZOMBIE
> - | FORK_SYSTEM | FORK_SIGHAND)) == 0);
> + | FORK_SYSTEM | FORK_SIGHAND | FORK_PID1)) == 0);
> KASSERT((flags & FORK_SIGHAND) == 0 || (flags & FORK_SHAREVM));
> KASSERT(func != NULL);
>
> @@ -631,19 +634,12 @@ ispidtaken(pid_t pid)
> pid_t
> allocpid(void)
> {
> - static pid_t lastpid;
> pid_t pid;
>
> - if (!randompid) {
> - /* only used early on for system processes */
> - pid = ++lastpid;
> - } else {
> - /* Find an unused pid satisfying lastpid < pid <= PID_MAX */
> - do {
> - pid = arc4random_uniform(PID_MAX - lastpid) + 1 +
> - lastpid;
> - } while (ispidtaken(pid));
> - }
> + /* Find an unused pid satisfying 1 < pid <= PID_MAX */
> + do {
> + pid = 2 + arc4random_uniform(PID_MAX - 1);
> + } while (ispidtaken(pid));
>
> return pid;
> }
> diff --git a/sys/sys/proc.h b/sys/sys/proc.h
> index 4f015f2eeb0..b3b3ac4bb0d 100644
> --- a/sys/sys/proc.h
> +++ b/sys/sys/proc.h
> @@ -449,6 +449,7 @@ struct uidinfo *uid_find(uid_t);
> #define FORK_SHAREVM 0x00000080
> #define FORK_SIGHAND 0x00000200
> #define FORK_PTRACE 0x00000400
> +#define FORK_PID1 0x00000800
>
> #define EXIT_NORMAL 0x00000001
> #define EXIT_THREAD 0x00000002
> @@ -470,7 +471,6 @@ extern struct proc proc0; /* Process slot for
> swapper. */
> extern struct process process0; /* Process slot for kernel
> threads. */
> extern int nprocesses, maxprocess; /* Cur and max number of processes. */
> extern int nthreads, maxthread; /* Cur and max number of
> threads. */
> -extern int randompid; /* fork() should create random
> pid's */
>
> LIST_HEAD(proclist, proc);
> LIST_HEAD(processlist, process);
> --
> 2.11.1
>
>
>
> --
> Ossi Herrala
>
--
Ossi Herrala
