mirror of
https://gitlab.com/sortix/sortix.git
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131 lines
3.3 KiB
C++
131 lines
3.3 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2014.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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ptable.cpp
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Process table.
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*******************************************************************************/
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <string.h>
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#include <sortix/kernel/kthread.h>
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#include <sortix/kernel/process.h>
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#include <sortix/kernel/ptable.h>
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#include <sortix/kernel/refcount.h>
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// TODO: Process memory ownership needs to be reference counted.
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// TODO: This implementation is rather run-time inefficient.
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// TODO: The Free method potentially leaks memory as the ptable is never shrunk.
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// TODO: The next_pid counter could potentially overflow.
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namespace Sortix {
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ProcessTable::ProcessTable()
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{
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ptablelock = KTHREAD_MUTEX_INITIALIZER;
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next_pid = 0;
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entries = NULL;
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entries_used = 0;
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entries_length = 0;
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}
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ProcessTable::~ProcessTable()
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{
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delete[] entries;
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}
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Process* ProcessTable::Get(pid_t pid)
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{
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ScopedLock lock(&ptablelock);
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for ( size_t i = 0; i < entries_used; i++ )
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if ( entries[i].pid == pid )
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return entries[i].process;
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return errno = ESRCH, (Process*) NULL;
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}
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pid_t ProcessTable::Allocate(Process* process)
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{
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ScopedLock lock(&ptablelock);
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if ( entries_used == entries_length )
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{
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size_t new_length = entries_length ? 2 * entries_length : 64;
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struct ptable_entry* new_entries = new struct ptable_entry[new_length];
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if ( !new_entries )
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return -1;
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if ( entries )
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{
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size_t old_size = sizeof(struct ptable_entry) * entries_length;
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memcpy(new_entries, entries, old_size);
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delete[] entries;
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}
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entries = new_entries;
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entries_length = new_length;
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}
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struct ptable_entry* entry = &entries[entries_used++];
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entry->process = process;
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return entry->pid = next_pid++;
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}
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void ProcessTable::Free(pid_t pid)
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{
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ScopedLock lock(&ptablelock);
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for ( size_t i = 0; i < entries_used; i++ )
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{
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if ( entries[i].pid != pid )
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continue;
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entries[i] = entries[--entries_used];
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return;
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}
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assert(false);
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}
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pid_t ProcessTable::Prev(pid_t pid)
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{
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ScopedLock lock(&ptablelock);
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pid_t result = -1;
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for ( size_t i = 0; i < entries_used; i++ )
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{
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if ( pid <= entries[i].process->pid )
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continue;
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if ( result == -1 || result < entries[i].process->pid )
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result = entries[i].process->pid;
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}
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return result;
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}
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pid_t ProcessTable::Next(pid_t pid)
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{
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ScopedLock lock(&ptablelock);
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pid_t result = -1;
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for ( size_t i = 0; i < entries_used; i++ )
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{
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if ( entries[i].process->pid <= pid )
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continue;
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if ( result == -1 || entries[i].process->pid < result )
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result = entries[i].process->pid;
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}
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return result;
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}
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} // namespace Sortix
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