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List: linux-kernel
Subject: Final(?) Patch : CLONE_PPID, CLONE_WAIT, CLONE_SUSPENDED
From: Tim Hockin <thockin () isunix ! it ! ilstu ! edu>
Date: 1999-07-31 20:41:48
[Download RAW message or body]
Here is the final patch with various fixes and suggested checks included.
Does anyone see anything else it is missing?
diff -ru clean-linux-2.2.10/fs/exec.c linux-2.2.10/fs/exec.c
--- clean-linux-2.2.10/fs/exec.c Sun Jun 13 10:50:04 1999
+++ linux-2.2.10/fs/exec.c Thu Jul 22 03:17:00 1999
@@ -846,9 +846,12 @@
if (retval >= 0)
retval = search_binary_handler(&bprm,regs);
- if (retval >= 0)
+ if (retval >= 0) {
+ /* clear any thread-special bits - JIC */
+ current->flags &= ~(PF_PPIDOK | PF_CLWAIT);
/* execve success */
return retval;
+ }
/* Something went wrong, return the inode and free the argument pages*/
if (bprm.dentry)
diff -ru clean-linux-2.2.10/include/linux/sched.h linux-2.2.10/include/linux/sched.h
--- clean-linux-2.2.10/include/linux/sched.h Tue May 11 10:35:45 1999
+++ linux-2.2.10/include/linux/sched.h Thu Jul 22 02:51:17 1999
@@ -34,6 +34,10 @@
#define CLONE_PID 0x00001000 /* set if pid shared */
#define CLONE_PTRACE 0x00002000 /* set if we want to let tracing continue on the child too */
#define CLONE_VFORK 0x00004000 /* set if the parent wants the child to wake it up on mm_release */
+#define CLONE_PPIDOK 0x00008000 /* set if the child should be able to create siblings */
+#define CLONE_PPID 0x00010000 /* set if we want to create a sibling, not a child */
+#define CLONE_WAIT 0x00020000 /* set if child is allowed to wait() for siblings */
+#define CLONE_SUSPENDED 0x00040000 /* create a process in the stopped state */
/*
* These are the constant used to fake the fixed-point load-average
@@ -332,6 +336,8 @@
#define PF_USEDFPU 0x00100000 /* task used FPU this quantum (SMP) */
#define PF_DTRACE 0x00200000 /* delayed trace (used on m68k, i386) */
+#define PF_PPIDOK 0x00400000 /* task is allowed to use CLONE_PPID */
+#define PF_CLWAIT 0x00800000 /* allowed to wait for siblings */
/*
* Limit the stack by to some sane default: root can always
diff -ru clean-linux-2.2.10/kernel/exit.c linux-2.2.10/kernel/exit.c
--- clean-linux-2.2.10/kernel/exit.c Fri Apr 30 08:13:37 1999
+++ linux-2.2.10/kernel/exit.c Thu Jul 29 10:09:11 1999
@@ -145,6 +145,7 @@
read_lock(&tasklist_lock);
for_each_task(p) {
if (p->p_opptr == father) {
+ p->flags &= ~(PF_PPIDOK | PF_CLWAIT);
p->exit_signal = SIGCHLD;
p->p_opptr = child_reaper; /* init */
if (p->pdeath_signal) send_sig(p->pdeath_signal, p, 0);
@@ -403,76 +404,90 @@
do_exit((error_code&0xff)<<8);
}
+/* to get around the ugly macro below */
+static inline void wait4_audit_ptree()
+{
+#ifdef DEBUG_PROC_TREE
+ audit_ptree();
+#endif
+}
+
+#define SYS_WAIT4_SEARCH(start_task) \
+ for (p = (start_task); p ; p = p->p_osptr) { \
+ if (pid>0) { \
+ if (p->pid != pid || current->pid == pid) \
+ continue; \
+ } else if (!pid) { \
+ if (p->pgrp != current->pgrp) \
+ continue; \
+ } else if (pid != -1) { \
+ if (p->pgrp != -pid) \
+ continue; \
+ } \
+ /* wait for cloned processes iff the __WCLONE flag is set */ \
+ if ((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0)) \
+ continue; \
+ flag = 1; \
+ switch (p->state) { \
+ case TASK_STOPPED: \
+ if (!p->exit_code) \
+ continue; \
+ if (!(options & WUNTRACED) && !(p->flags & PF_PTRACED)) \
+ continue; \
+ read_unlock(&tasklist_lock); \
+ retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; \
+ if (!retval && stat_addr) \
+ retval = put_user((p->exit_code << 8) | 0x7f, stat_addr); \
+ if (!retval) { \
+ p->exit_code = 0; \
+ retval = p->pid; \
+ } \
+ goto end_wait4; \
+ case TASK_ZOMBIE: \
+ current->times.tms_cutime += p->times.tms_utime + p->times.tms_cutime; \
+ current->times.tms_cstime += p->times.tms_stime + p->times.tms_cstime; \
+ read_unlock(&tasklist_lock); \
+ retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0; \
+ if (!retval && stat_addr) \
+ retval = put_user(p->exit_code, stat_addr); \
+ if (retval) \
+ goto end_wait4; \
+ retval = p->pid; \
+ if (p->p_opptr != p->p_pptr) { \
+ write_lock_irq(&tasklist_lock); \
+ REMOVE_LINKS(p); \
+ p->p_pptr = p->p_opptr; \
+ SET_LINKS(p); \
+ write_unlock_irq(&tasklist_lock); \
+ notify_parent(p, SIGCHLD); \
+ } else \
+ release(p); \
+ wait4_audit_ptree(); \
+ goto end_wait4; \
+ default: \
+ continue; \
+ } \
+ } \
+
asmlinkage int sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru)
{
int flag, retval;
struct wait_queue wait = { current, NULL };
+ struct wait_queue wait_sib = { current, NULL };
struct task_struct *p;
if (options & ~(WNOHANG|WUNTRACED|__WCLONE))
return -EINVAL;
add_wait_queue(¤t->wait_chldexit,&wait);
+ if (current->flags & PF_CLWAIT)
+ add_wait_queue(¤t->p_pptr->wait_chldexit,&wait_sib);
repeat:
flag = 0;
read_lock(&tasklist_lock);
- for (p = current->p_cptr ; p ; p = p->p_osptr) {
- if (pid>0) {
- if (p->pid != pid)
- continue;
- } else if (!pid) {
- if (p->pgrp != current->pgrp)
- continue;
- } else if (pid != -1) {
- if (p->pgrp != -pid)
- continue;
- }
- /* wait for cloned processes iff the __WCLONE flag is set */
- if ((p->exit_signal != SIGCHLD) ^ ((options & __WCLONE) != 0))
- continue;
- flag = 1;
- switch (p->state) {
- case TASK_STOPPED:
- if (!p->exit_code)
- continue;
- if (!(options & WUNTRACED) && !(p->flags & PF_PTRACED))
- continue;
- read_unlock(&tasklist_lock);
- retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
- if (!retval && stat_addr)
- retval = put_user((p->exit_code << 8) | 0x7f, stat_addr);
- if (!retval) {
- p->exit_code = 0;
- retval = p->pid;
- }
- goto end_wait4;
- case TASK_ZOMBIE:
- current->times.tms_cutime += p->times.tms_utime + p->times.tms_cutime;
- current->times.tms_cstime += p->times.tms_stime + p->times.tms_cstime;
- read_unlock(&tasklist_lock);
- retval = ru ? getrusage(p, RUSAGE_BOTH, ru) : 0;
- if (!retval && stat_addr)
- retval = put_user(p->exit_code, stat_addr);
- if (retval)
- goto end_wait4;
- retval = p->pid;
- if (p->p_opptr != p->p_pptr) {
- write_lock_irq(&tasklist_lock);
- REMOVE_LINKS(p);
- p->p_pptr = p->p_opptr;
- SET_LINKS(p);
- write_unlock_irq(&tasklist_lock);
- notify_parent(p, SIGCHLD);
- } else
- release(p);
-#ifdef DEBUG_PROC_TREE
- audit_ptree();
-#endif
- goto end_wait4;
- default:
- continue;
- }
- }
+ SYS_WAIT4_SEARCH(current->p_cptr);
+ if (!flag && (current->flags & PF_CLWAIT))
+ SYS_WAIT4_SEARCH(current->p_pptr->p_cptr);
read_unlock(&tasklist_lock);
if (flag) {
retval = 0;
@@ -488,6 +503,8 @@
retval = -ECHILD;
end_wait4:
remove_wait_queue(¤t->wait_chldexit,&wait);
+ if (current->flags & PF_CLWAIT)
+ remove_wait_queue(¤t->p_pptr->wait_chldexit,&wait_sib);
return retval;
}
diff -ru clean-linux-2.2.10/kernel/fork.c linux-2.2.10/kernel/fork.c
--- clean-linux-2.2.10/kernel/fork.c Mon Apr 12 12:44:26 1999
+++ linux-2.2.10/kernel/fork.c Thu Jul 29 10:08:13 1999
@@ -517,12 +517,18 @@
{
unsigned long new_flags = p->flags;
- new_flags &= ~(PF_SUPERPRIV | PF_USEDFPU | PF_VFORK);
+ new_flags &= ~(PF_SUPERPRIV | PF_USEDFPU | PF_VFORK
+ | PF_PPIDOK | PF_CLWAIT);
new_flags |= PF_FORKNOEXEC;
if (!(clone_flags & CLONE_PTRACE))
new_flags &= ~(PF_PTRACED|PF_TRACESYS);
if (clone_flags & CLONE_VFORK)
new_flags |= PF_VFORK;
+ if (clone_flags & CLONE_PPIDOK)
+ new_flags |= PF_PPIDOK;
+ if (clone_flags & CLONE_WAIT)
+ new_flags |= PF_CLWAIT;
+
p->flags = new_flags;
}
@@ -587,7 +593,14 @@
p->next_run = p;
p->prev_run = p;
- p->p_pptr = p->p_opptr = current;
+ if (!(clone_flags & CLONE_PPID)) {
+ p->p_pptr = p->p_opptr = current;
+ } else if (current->flags & PF_PPIDOK) {
+ p->p_pptr = p->p_opptr = current->p_opptr;
+ } else {
+ retval = -EPERM;
+ goto bad_fork_cleanup;
+ }
p->p_cptr = NULL;
init_waitqueue(&p->wait_chldexit);
p->vfork_sem = NULL;
@@ -668,7 +681,10 @@
p->next_run = NULL;
p->prev_run = NULL;
- wake_up_process(p); /* do this last */
+ if (!(clone_flags & CLONE_SUSPENDED))
+ wake_up_process(p); /* do this last */
+ else
+ p->state = TASK_STOPPED;
}
++total_forks;
bad_fork:
-
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