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/*
* Copyright (c) 2018 Samsung Electronics Co., Ltd.
*
* Licensed under the Flora License, Version 1.1 (the License);
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://floralicense.org/license/
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdlib.h>
#include "proc-scanner.h"
#include "procfs.h"
#include "process.h"
#include "err-check.h"
#include "clock.h"
#define SWAP(a, b, type) do { type tmp = (a); (a) = (b); (b) = tmp; } while(0);
#define PROCTAB_INITIAL_LEN 64
struct proctab {
struct process *processes;
int size;
int max;
};
struct proc_scanner {
struct proctab current;
struct proctab history;
int last_history_index;
};
void proctab_free(struct proctab *tab)
{
if (!tab) return;
for (int i = 0; i < tab->size; i++)
process_shutdown(&tab->processes[i]);
free(tab->processes);
}
void proctab_resize(struct proctab *tab, int new_max)
{
tab->processes = realloc(tab->processes, new_max * sizeof(struct process));
if (!tab->processes) abort();
tab->max = new_max;
}
void proctab_move_back(struct proctab *tab, struct process *proc)
{
if (tab->size >= tab->max)
proctab_resize(tab, tab->max *= 2);
process_move(&tab->processes[tab->size++],proc);
}
void proctab_reset(struct proctab *tab)
{
for (int i = 0; i < tab->size; i++)
process_shutdown(&tab->processes[i]);
tab->size = 0;
}
proc_scanner_t *proc_scanner_new()
{
proc_scanner_t *ret = calloc(1, sizeof(proc_scanner_t));
if (!ret) {
return NULL;
}
proctab_resize(&ret->current, PROCTAB_INITIAL_LEN);
proctab_resize(&ret->history, PROCTAB_INITIAL_LEN);
return ret;
}
void proc_scanner_free(proc_scanner_t *scanner)
{
if (!scanner) return;
proctab_free(&scanner->current);
proctab_free(&scanner->history);
free(scanner);
}
static int _sort_processes_by_pid(const void *a, const void *b)
{
const struct process *proc1 = a;
const struct process *proc2 = b;
return process_get_pid(proc1) - process_get_pid(proc2);
}
static int _search_for_pid_key(const void *a, const void *b)
{
const int *key = a;
const struct process *proc = b;
return *key - proc->pid;
}
static int _sort_pids(const void *a, const void *b)
{
const int *pid1 = a;
const int *pid2 = a;
return pid1 - pid2;
}
// Search for process entry in history
static struct process *_proc_scanner_find_process_in_history(proc_scanner_t *scanner, int pid)
{
if (scanner->history.size == 0)
return NULL;
// the scanner->history_last_history_index helps for quickly find
// history entry matching given pid. We assume that history is sorted ascending by pid
// and searching for pid is done in same order.
// the speedup gain is about ~15% compared to bsearch only.
while (scanner->last_history_index < scanner->history.size)
{
if (scanner->history.processes[scanner->last_history_index].pid < pid)
{
scanner->last_history_index++;
continue;
}
if (scanner->history.processes[scanner->last_history_index].pid == pid) {
return &scanner->history.processes[scanner->last_history_index++];
}
break;
}
return bsearch(&pid, scanner->history.processes, scanner->history.size, sizeof(struct process), _search_for_pid_key);
}
static bool _proc_scanner_read_pid(int pid, void *user_data)
{
proc_scanner_t *scanner = user_data;
struct process proc_new = {0,};
struct process *proc = _proc_scanner_find_process_in_history(scanner, pid);
if (!proc) {
process_init_process(pid, &proc_new);
proc = &proc_new;
}
if (process_update(proc) != 0) {
process_shutdown(proc);
return true;
}
proctab_move_back(&scanner->current, proc);
return true;
}
static int _proc_scanner_iterate_array(int *pids, int n_pids, procfs_pid_iterator_cb cb, void *user_data)
{
qsort(pids, n_pids, sizeof(int), _sort_pids);
for (int i = 0; i < n_pids; ++i) {
if (!cb(pids[i], user_data))
break;
}
return 0;
}
static int _proc_scanner_scan_internal(proc_scanner_t *scanner, int *pids, int n_pids)
{
ON_NULL_RETURN_VAL(scanner, -1);
// swap processes and history
SWAP(scanner->current, scanner->history, struct proctab);
// reset current tab, so we can start adding results of current scan
proctab_reset(&scanner->current);
// prepare history
scanner->last_history_index = 0;
qsort(scanner->history.processes, scanner->history.size, sizeof(struct process), _sort_processes_by_pid);
if (pids)
return _proc_scanner_iterate_array(pids, n_pids, _proc_scanner_read_pid, scanner);
else
return procfs_iterate_pids(_proc_scanner_read_pid, scanner);
}
int proc_scanner_scan(proc_scanner_t *scanner)
{
return _proc_scanner_scan_internal(scanner, NULL, -1);
}
int proc_scanner_scan_pids(proc_scanner_t *scanner, int *pids, int n_pids)
{
return _proc_scanner_scan_internal(scanner, pids, n_pids);
}
int proc_scanner_foreach_process(proc_scanner_t *scanner, foreach_t cb, void *data)
{
ON_NULL_RETURN_VAL(scanner, -1);
ON_NULL_RETURN_VAL(cb, -1);
for (int i = 0; i < scanner->current.size; ++i) {
if (!cb(&scanner->current.processes[i], data))
break;
}
return 0;
}
int proc_scanner_sort_processes(proc_scanner_t *scanner, sort_t cb)
{
ON_NULL_RETURN_VAL(scanner, -1);
ON_NULL_RETURN_VAL(cb, -1);
qsort(scanner->current.processes, scanner->current.size, sizeof(struct process), (__compar_fn_t)cb);
return 0;
}
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