sortix-mirror/kernel/ptable.cpp
Jonas 'Sortie' Termansen 2b72262b4f Relicense Sortix to the ISC license.
I hereby relicense all my work on Sortix under the ISC license as below.

All Sortix contributions by other people are already under this license,
are not substantial enough to be copyrightable, or have been removed.

All imported code from other projects is compatible with this license.

All GPL licensed code from other projects had previously been removed.

Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors.

Permission to use, copy, modify, and distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.

THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
2016-03-05 22:21:50 +01:00

127 lines
3.2 KiB
C++

/*
* Copyright (c) 2014 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* ptable.cpp
* Process table.
*/
#include <sys/types.h>
#include <assert.h>
#include <errno.h>
#include <string.h>
#include <sortix/kernel/kthread.h>
#include <sortix/kernel/process.h>
#include <sortix/kernel/ptable.h>
#include <sortix/kernel/refcount.h>
// TODO: Process memory ownership needs to be reference counted.
// TODO: This implementation is rather run-time inefficient.
// TODO: The Free method potentially leaks memory as the ptable is never shrunk.
// TODO: The next_pid counter could potentially overflow.
namespace Sortix {
ProcessTable::ProcessTable()
{
ptablelock = KTHREAD_MUTEX_INITIALIZER;
next_pid = 0;
entries = NULL;
entries_used = 0;
entries_length = 0;
}
ProcessTable::~ProcessTable()
{
delete[] entries;
}
Process* ProcessTable::Get(pid_t pid)
{
ScopedLock lock(&ptablelock);
for ( size_t i = 0; i < entries_used; i++ )
if ( entries[i].pid == pid )
return entries[i].process;
return errno = ESRCH, (Process*) NULL;
}
pid_t ProcessTable::Allocate(Process* process)
{
ScopedLock lock(&ptablelock);
if ( entries_used == entries_length )
{
size_t new_length = entries_length ? 2 * entries_length : 64;
struct ptable_entry* new_entries = new struct ptable_entry[new_length];
if ( !new_entries )
return -1;
if ( entries )
{
size_t old_size = sizeof(struct ptable_entry) * entries_length;
memcpy(new_entries, entries, old_size);
delete[] entries;
}
entries = new_entries;
entries_length = new_length;
}
struct ptable_entry* entry = &entries[entries_used++];
entry->process = process;
return entry->pid = next_pid++;
}
void ProcessTable::Free(pid_t pid)
{
ScopedLock lock(&ptablelock);
for ( size_t i = 0; i < entries_used; i++ )
{
if ( entries[i].pid != pid )
continue;
entries[i] = entries[--entries_used];
return;
}
assert(false);
}
pid_t ProcessTable::Prev(pid_t pid)
{
ScopedLock lock(&ptablelock);
pid_t result = -1;
for ( size_t i = 0; i < entries_used; i++ )
{
if ( pid <= entries[i].process->pid )
continue;
if ( result == -1 || result < entries[i].process->pid )
result = entries[i].process->pid;
}
return result;
}
pid_t ProcessTable::Next(pid_t pid)
{
ScopedLock lock(&ptablelock);
pid_t result = -1;
for ( size_t i = 0; i < entries_used; i++ )
{
if ( entries[i].process->pid <= pid )
continue;
if ( result == -1 || entries[i].process->pid < result )
result = entries[i].process->pid;
}
return result;
}
} // namespace Sortix