xref: /aosp_15_r20/external/ltp/testcases/kernel/controllers/libcontrollers/libcontrollers.c (revision 49cdfc7efb34551c7342be41a7384b9c40d7cab7)

/******************************************************************************/
/*                                                                            */
/* Copyright (c) International Business Machines  Corp., 2007                 */
/*                                                                            */
/* This program is free software;  you can redistribute it and/or modify      */
/* it under the terms of the GNU General Public License as published by       */
/* the Free Software Foundation; either version 2 of the License, or          */
/* (at your option) any later version.                                        */
/*                                                                            */
/* This program is distributed in the hope that it will be useful,            */
/* but WITHOUT ANY WARRANTY;  without even the implied warranty of            */
/* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See                  */
/* the GNU General Public License for more details.                           */
/*                                                                            */
/* You should have received a copy of the GNU General Public License          */
/* along with this program;  if not, write to the Free Software               */
/* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA    */
/*                                                                            */
/******************************************************************************/

/******************************************************************************/
/*                                                                            */
/* File:        libcontrollers.c                                              */
/*                                                                            */
/* Description: This file contains the definitions for the functions/apis     */
/*              for the controllers library. This library is used by the      */
/*              controllers testcases.                                        */
/*                                                                            */
/* Author:      Sudhir Kumar [email protected]                        */
/*                                                                            */
/* History:                                                                   */
/* Created-     15/02/2008 -Sudhir Kumar <[email protected]>          */
/*                                                                            */
/******************************************************************************/

#include "libcontrollers.h"

char fullpath[PATH_MAX];
int FLAG;
volatile int timer_expired = 0;
int retval;
unsigned int current_shares;
unsigned int total_shares;
unsigned int *shares_pointer;
struct dirent *dir_pointer;

/*
 * Function: scan_shares_file()
 * This function scans all the shares files under the mountpoint
 * of the controller and returns the total added shares of all
 * the groups (currently excludes default group) ??
 */
int scan_shares_files(unsigned int *shares_pointer)
{
	struct stat statbuffer;
	DIR *dp;
	char *path_pointer;

	/*
	 * Check if we can get stat of the file
	 */
	if (lstat(fullpath, &statbuffer) < 0) {
		error_function("Can not read stat for file ", fullpath);
		return -1;
	}

	if (S_ISDIR(statbuffer.st_mode) == 0) {	/* not a directory */
		/*
		 * We run all user tasks in the created groups and not default groups. So
		 * exclude the shares of default group. FLAG to ensure dir_pointer is non NULL
		 */
		if ((FLAG == 1)
		    && (strcmp(fullpath, "/dev/cpuctl/cpu.shares") != 0)
		    && (strcmp(dir_pointer->d_name, "cpu.shares") == 0)) {
			*shares_pointer += read_shares_file(fullpath);
		}
		return 0;
	}

	/*
	 * Now it's a directory. let the path_pointer point to the end
	 * of fullpath to append new files names
	 */

	path_pointer = fullpath + strlen(fullpath);
	*path_pointer++ = '/';
	*path_pointer = 0;

	if ((dp = opendir(fullpath)) == NULL) {	/* Error in opening directory */
		error_function("Can't open ", fullpath);
		return -1;
	}
	/*
	 * search all groups recursively and get total shares
	 */

	while ((dir_pointer = readdir(dp)) != NULL) {	/* Error in reading directory */
		if ((strcmp(dir_pointer->d_name, ".") == 0)
		    || (strcmp(dir_pointer->d_name, "..") == 0))
			continue;	/* ignore current and parent directory */

		FLAG = 1;
		strcpy(path_pointer, dir_pointer->d_name);	/* append name to fullpath */

		if ((retval = scan_shares_files(shares_pointer)) != 0)
			break;
	}

	/*
	 * This directory is searched fully. let us go back to parent directory again
	 */

	path_pointer[-1] = 0;

	if (closedir(dp) < 0) {
		error_function("Could not close dir ", fullpath);
		return -1;
	}
	return 0;
}

/*
 * Function: read_file ()
 * This function is written keeping in mind the support
 * to read other files also if required in future.
 * Each file under a group contains some diff parameter/s
 */

int read_file(char *filepath, int action, unsigned int *value)
{
	int num_line = 0;
	FILE *fp;
	int tmp;
	size_t len;
	char *target = NULL;

	switch (action) {
	case GET_SHARES:
		tmp = read_shares_file(filepath);
		if (tmp == -1)
			return -1;
		*value = (unsigned int)tmp;
		break;

	case GET_TASKS:
		fp = fopen(filepath, "r");
		if (fp == NULL) {
			error_function("Could not open file", filepath);
			return -1;
		}
		while (getline(&target, &len, fp) != -1)
			num_line++;
		free(target);
		*value = (unsigned int)num_line;
		if (fclose(fp)) {
			error_function("Could not close file", filepath);
			return -1;
		}
		break;

	default:
		error_function("Wrong action type passed to fun read_file for ",
			       filepath);
		return -1;
	}
	return 0;
}

/*
 * Function: error_function()
 * Prints error message and returns -1
 */

static inline void error_function(char *msg1, char *msg2)
{
	fprintf(stdout, "ERROR: %s ", msg1);
	fprintf(stdout, "%s\n", msg2);
}

/* Function: read_shares_file()
 * Reads shares value from a given shares file and writes them to
 * the given pointer location. Returns 0 if success
 */

int read_shares_file(char *filepath)
{
	FILE *fp;
	unsigned int shares;
	fp = fopen(filepath, "r");
	if (fp == NULL) {
		error_function("Could not open file", filepath);
		return -1;
	}
	fscanf(fp, "%u", &shares);
	if (fclose(fp)) {
		error_function("Could not close file", filepath);
		return -1;
	}
	return shares;
}

/* Function: write_to_file()
 * writes value to shares file or pid to tasks file
 */

int write_to_file(char *file, const char *mode, unsigned int value)
{
	FILE *fp;
	fp = fopen(file, mode);
	if (fp == NULL) {
		error_function("in opening file for writing:", file);
		return -1;
	}
	fprintf(fp, "%u\n", value);
	fclose(fp);
	return 0;
}

/* Function: signal_handler_alarm()
 * signal handler for the new action
 */

void signal_handler_alarm(int signal)
{
	timer_expired = 1;
}