others
/* $Id$ */
							/* Copyright (c) 2006-2014 Pierre Pronchery <khorben@defora.org> */
							/* This file is part of DeforaOS Unix others */
							/* 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, version 3 of the License.
							 *
							 * 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, see <http://www.gnu.org/licenses/>. */
							#include <sys/types.h>
							#include <sys/stat.h>
							#include <sys/time.h>
							#include <unistd.h>
							#include <time.h>
							#include <stdio.h>
							#ifndef PROGNAME
							# define PROGNAME "w"
							#endif
							#include "utmpx.c"
							/* w */
							/* private */
							/* prototypes */
							static int _w(void);
							static int _w_error(char * message, int ret);
							static int _w_usage(void);
							/* functions */
							/* w */
							static int _print_idle(struct timeval * tv, char * device);
							static int _print_what(pid_t pid);
							static int _w(void)
							{
								struct utmpx * u;
								struct timeval tv;
								if(gettimeofday(&tv, NULL) != 0)
									return _w_error("gettimeofday", 2);
								printf("%-8s %-8s %-16s %-5s %5s %s\n", "USER", "TTY", "FROM",
										"LOGIN@", "IDLE", "WHAT");
							#ifdef USER_PROCESS
								while((u = getutxent()) != NULL)
								{
									if(u->ut_type != USER_PROCESS)
										continue;
									printf("%-8s %-8s %-16s  %2ld:%02ld ", u->ut_user, u->ut_line,
											u->ut_host,
											(u->ut_tv.tv_sec - u->ut_tv.tv_sec % 3600) % 24,
											(u->ut_tv.tv_sec - u->ut_tv.tv_sec % 60) / 60
											% 60);
									_print_idle(&tv, u->ut_line);
									_print_what(u->ut_pid);
								}
							#else
							# warning Unsupported platform: USER_PROCESS is not supported
							#endif
								return 0;
							}
							static int _print_idle(struct timeval * tv, char * device)
							{
								char dev[16];
								struct stat st;
								unsigned long idle;
								if(snprintf(dev, sizeof(dev), "%s%s", "/dev/", device)
										> (int)sizeof(dev))
									return printf("%5s ", "?");
								if(lstat(dev, &st) != 0)
									return printf("%5s ", "?");
								idle = tv->tv_sec - st.st_atime;
								if(idle / 3600 >= 24)
									return printf("%4lud ", idle / 3600 / 24);
								else if(idle / 60 >= 60)
									return printf("%02lu:%02lu ", idle / 3600, idle % 3600 / 60);
								return printf("%02lum%02lu ", idle / 60, idle % 60);
							}
							static int _print_what(pid_t pid)
							{
								char proc[33];
								FILE * fp;
								int len;
								if(pid < 0)
									return putchar('\n');
								if(snprintf(proc, sizeof(proc), "%s%d%s", "/proc/", pid, "/cmdline")
										> (int)sizeof(proc))
									return printf(" %d\n", pid);
								if((fp = fopen(proc, "r")) == NULL)
								{
									printf(" %d\n", pid);
									return _w_error(proc, 0);
								}
								if((len = fread(proc, sizeof(char), sizeof(proc) - 1, fp)) < 0)
								{
									fclose(fp);
									printf(" %d\n", pid);
									return _w_error(proc, 0);
								}
								proc[len] = '\0';
								printf("%s\n", proc);
								return fclose(fp);
							}
							/* w_error */
							static int _w_error(char * message, int ret)
							{
								fputs(PROGNAME ": ", stderr);
								perror(message);
								return ret;
							}
							/* w_usage */
							static int _w_usage(void)
							{
								fputs("Usage: " PROGNAME "\n", stderr);
								return 1;
							}
							/* public */
							/* functions */
							/* main */
							int main(int argc, char * argv[])
							{
								int o;
								while((o = getopt(argc, argv, "")) != -1)
									return _w_usage();
								if(optind != argc)
									return _w_usage();
								return (_w() == 0) ? 0 : 2;
							}
							