This patch changes forking procedure. Basically it adds a function
do_fork_pid() that alows forking task with predefined virtual pid.
Also it adds required vpid manipulations on fork().
Simple and straightforward.
--- ./kernel/fork.c.vpid_fork 2006-02-02 14:33:58.811003152 +0300
+++ ./kernel/fork.c 2006-02-02 14:41:40.806769120 +0300
@@ -871,7 +871,7 @@ static task_t *copy_process(unsigned lon
unsigned long stack_size,
int __user *parent_tidptr,
int __user *child_tidptr,
- int pid)
+ int pid, int vpid)
{
int retval;
struct task_struct *p = NULL;
@@ -932,9 +932,11 @@ static task_t *copy_process(unsigned lon
p->did_exec = 0;
copy_flags(clone_flags, p);
p->pid = pid;
+ if (set_virt_pid(p, alloc_vpid(p->pid, vpid ? : -1)) < 0)
+ goto bad_fork_cleanup_module;
retval = -EFAULT;
if (clone_flags & CLONE_PARENT_SETTID)
- if (put_user(p->pid, parent_tidptr))
+ if (put_user(virt_pid(p), parent_tidptr))
goto bad_fork_cleanup;
p->proc_dentry = NULL;
@@ -985,8 +987,13 @@ static task_t *copy_process(unsigned lon
#endif
p->tgid = p->pid;
- if (clone_flags & CLONE_THREAD)
+ set_virt_tgid(p, virt_pid(p));
+ set_virt_pgid(p, virt_pgid(current));
+ set_virt_sid(p, virt_sid(current));
+ if (clone_flags & CLONE_THREAD) {
p->tgid = current->tgid;
+ set_virt_tgid(p, virt_tgid(current));
+ }
if ((retval = security_task_alloc(p)))
goto bad_fork_cleanup_policy;
@@ -1181,6 +1188,9 @@ bad_fork_cleanup_cpuset:
#endif
cpuset_exit(p);
bad_fork_cleanup:
+ if (virt_pid(p) != p->pid && virt_pid(p) > 0)
+ free_vpid(virt_pid(p));
+bad_fork_cleanup_module:
if (p->binfmt)
module_put(p->binfmt->module);
bad_fork_cleanup_put_domain:
@@ -1206,7 +1216,7 @@ task_t * __devinit fork_idle(int cpu)
task_t *task;
struct pt_regs regs;
- task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0);
+ task = copy_process(CLONE_VM, 0, idle_regs(®s), 0, NULL, NULL, 0, 0);
if (!task)
return ERR_PTR(-ENOMEM);
init_idle(task, cpu);
@@ -1236,12 +1246,12 @@ static inline int fork_traceflag (unsign
* It copies the process, and if successful kick-starts
* it and waits for it to finish using the VM if required.
*/
-long do_fork(unsigned long clone_flags,
+static long do_fork_pid(unsigned long clone_flags,
unsigned long stack_start,
struct pt_regs *regs,
unsigned long stack_size,
int __user *parent_tidptr,
- int __user *child_tidptr)
+ int __user *child_tidptr, int vpid)
{
struct task_struct *p;
int trace = 0;
@@ -1255,7 +1265,8 @@ long do_fork(unsigned long clone_flags,
clone_flags |= CLONE_PTRACE;
}
- p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr, pid);
+ p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr,
+ child_tidptr, pid, vpid);
/*
* Do this prior waking up the new thread - the thread pointer
* might get invalid after that point, if the thread exits quickly.
@@ -1298,6 +1309,17 @@ long do_fork(unsigned long clone_flags,
return pid;
}
+long do_fork(unsigned long clone_flags,
+ unsigned long stack_start,
+ struct pt_regs *regs,
+ unsigned long stack_size,
+ int __user *parent_tidptr,
+ int __user *child_tidptr)
+{
+ return do_fork_pid(clone_flags, stack_start, regs, stack_size,
+ parent_tidptr, child_tidptr, 0);
+}
+
#ifndef ARCH_MIN_MMSTRUCT_ALIGN
#define ARCH_MIN_MMSTRUCT_ALIGN 0
#endif
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