util-linux/ipcs.c - busybox - Git at Google

 /* vi: set sw=4 ts=4: */
 /*
  * ipcs.c -- provides information on allocated ipc resources.
  *
  * 01 Sept 2004 - Rodney Radford <rradford@mindspring.com>
  * Adapted for busybox from util-linux-2.12a.
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
 //config:config IPCS
 //config:	bool "ipcs (11 kb)"
 //config:	default y
 //config:	select PLATFORM_LINUX
 //config:	help
 //config:	The ipcs utility is used to provide information on the currently
 //config:	allocated System V interprocess (IPC) objects in the system.

 //applet:IF_IPCS(APPLET_NOEXEC(ipcs, ipcs, BB_DIR_USR_BIN, BB_SUID_DROP, ipcs))

 //kbuild:lib-$(CONFIG_IPCS) += ipcs.o

 /* X/OPEN tells us to use <sys/{types,ipc,sem}.h> for semctl() */
 /* X/OPEN tells us to use <sys/{types,ipc,msg}.h> for msgctl() */
 /* X/OPEN tells us to use <sys/{types,ipc,shm}.h> for shmctl() */
 #include <sys/types.h>
 #include <sys/ipc.h>
 #include <sys/sem.h>
 #include <sys/msg.h>
 #include <sys/shm.h>

 #include "libbb.h"

 /*-------------------------------------------------------------------*/
 /* SHM_DEST and SHM_LOCKED are defined in kernel headers,
    but inside #ifdef __KERNEL__ ... #endif */
 #ifndef SHM_DEST
 /* shm_mode upper byte flags */
 #define SHM_DEST        01000	/* segment will be destroyed on last detach */
 #define SHM_LOCKED      02000	/* segment will not be swapped */
 #endif

 /* For older kernels the same holds for the defines below */
 #ifndef MSG_STAT
 #define MSG_STAT	11
 #define MSG_INFO	12
 #endif

 #ifndef SHM_STAT
 #define SHM_STAT        13
 #define SHM_INFO        14
 struct shm_info {
 	int used_ids;
 	unsigned long shm_tot;		/* total allocated shm */
 	unsigned long shm_rss;		/* total resident shm */
 	unsigned long shm_swp;		/* total swapped shm */
 	unsigned long swap_attempts;
 	unsigned long swap_successes;
 };
 #endif

 #ifndef SEM_STAT
 #define SEM_STAT	18
 #define SEM_INFO	19
 #endif

 /* Some versions of libc only define IPC_INFO when __USE_GNU is defined. */
 #ifndef IPC_INFO
 #define IPC_INFO        3
 #endif
 /*-------------------------------------------------------------------*/

 /* The last arg of semctl is a union semun, but where is it defined?
    X/OPEN tells us to define it ourselves, but until recently
    Linux include files would also define it. */
 #if defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED)
 /* union semun is defined by including <sys/sem.h> */
 #else
 /* according to X/OPEN we have to define it ourselves */
 union semun {
 	int val;
 	struct semid_ds *buf;
 	unsigned short *array;
 	struct seminfo *__buf;
 };
 #endif

 /* X/OPEN (Jan 1987) does not define fields key, seq in struct ipc_perm;
    libc 4/5 does not mention struct ipc_term at all, but includes
    <linux/ipc.h>, which defines a struct ipc_perm with such fields.
    glibc-1.09 has no support for sysv ipc.
    glibc 2 uses __key, __seq */
 #if defined(__GNU_LIBRARY__) && __GNU_LIBRARY__ > 1
 #define KEY __key
 #else
 #define KEY key
 #endif

 #define LIMITS 1
 #define STATUS 2
 #define CREATOR 3
 #define TIME 4
 #define PID 5

 static void print_perms(int id, struct ipc_perm *ipcp)
 {
 	struct passwd *pw;
 	struct group *gr;

 	printf("%-10d %-10o", id, ipcp->mode & 0777);

 	pw = getpwuid(ipcp->cuid);
 	if (pw)	printf(" %-10s", pw->pw_name);
 	else	printf(" %-10d", ipcp->cuid);
 	gr = getgrgid(ipcp->cgid);
 	if (gr)	printf(" %-10s", gr->gr_name);
 	else	printf(" %-10d", ipcp->cgid);

 	pw = getpwuid(ipcp->uid);
 	if (pw)	printf(" %-10s", pw->pw_name);
 	else	printf(" %-10d", ipcp->uid);
 	gr = getgrgid(ipcp->gid);
 	if (gr)	printf(" %-10s\n", gr->gr_name);
 	else	printf(" %-10d\n", ipcp->gid);
 }

 static NOINLINE void do_shm(int format)
 {
 	int maxid, shmid, id;
 	struct shmid_ds shmseg;
 	struct shm_info shm_info;
 	struct shminfo shminfo;
 	struct ipc_perm *ipcp = &shmseg.shm_perm;
 	struct passwd *pw;

 	maxid = shmctl(0, SHM_INFO, (struct shmid_ds *) (void *) &shm_info);
 	if (maxid < 0) {
 		printf("kernel not configured for %s\n", "shared memory");
 		return;
 	}

 	switch (format) {
 	case LIMITS:
 		printf("------ Shared Memory %s --------\n", "Limits");
 		if ((shmctl(0, IPC_INFO, (struct shmid_ds *) (void *) &shminfo)) < 0)
 			return;
 		/* glibc 2.1.3 and all earlier libc's have ints as fields
 		 * of struct shminfo; glibc 2.1.91 has unsigned long; ach */
 		printf("max number of segments = %lu\n"
 				"max seg size (kbytes) = %lu\n"
 				"max total shared memory (pages) = %lu\n"
 				"min seg size (bytes) = %lu\n",
 				(unsigned long) shminfo.shmmni,
 				(unsigned long) (shminfo.shmmax >> 10),
 				(unsigned long) shminfo.shmall,
 				(unsigned long) shminfo.shmmin);
 		return;

 	case STATUS:
 		printf("------ Shared Memory %s --------\n", "Status");
 		printf("segments allocated %d\n"
 				"pages allocated %lu\n"
 				"pages resident  %lu\n"
 				"pages swapped   %lu\n"
 				"Swap performance: %lu attempts\t%lu successes\n",
 				shm_info.used_ids,
 				shm_info.shm_tot,
 				shm_info.shm_rss,
 				shm_info.shm_swp,
 				shm_info.swap_attempts, shm_info.swap_successes);
 		return;

 	case CREATOR:
 		printf("------ Shared Memory %s --------\n", "Segment Creators/Owners");
 		printf("%-10s %-10s %-10s %-10s %-10s %-10s\n",
 				"shmid", "perms", "cuid", "cgid", "uid", "gid");
 		break;

 	case TIME:
 		printf("------ Shared Memory %s --------\n", "Attach/Detach/Change Times");
 		printf("%-10s %-10s %-20s %-20s %-20s\n",
 				"shmid", "owner", "attached", "detached", "changed");
 		break;

 	case PID:
 		printf("------ Shared Memory %s --------\n", "Creator/Last-op");
 		printf("%-10s %-10s %-10s %-10s\n",
 				"shmid", "owner", "cpid", "lpid");
 		break;

 	default:
 		printf("------ Shared Memory %s --------\n", "Segments");
 		printf("%-10s %-10s %-10s %-10s %-10s %-10s %-12s\n",
 				"key", "shmid", "owner", "perms", "bytes", "nattch",
 				"status");
 		break;
 	}

 	for (id = 0; id <= maxid; id++) {
 		shmid = shmctl(id, SHM_STAT, &shmseg);
 		if (shmid < 0)
 			continue;
 		if (format == CREATOR) {
 			print_perms(shmid, ipcp);
 			continue;
 		}
 		pw = getpwuid(ipcp->uid);
 		switch (format) {
 		case TIME:
 			if (pw)
 				printf("%-10d %-10.10s", shmid, pw->pw_name);
 			else
 				printf("%-10d %-10d", shmid, ipcp->uid);
 			/* ctime uses static buffer: use separate calls */
 			printf(" %-20.16s", shmseg.shm_atime
 					? ctime(&shmseg.shm_atime) + 4 : "Not set");
 			printf(" %-20.16s", shmseg.shm_dtime
 					? ctime(&shmseg.shm_dtime) + 4 : "Not set");
 			printf(" %-20.16s\n", shmseg.shm_ctime
 					? ctime(&shmseg.shm_ctime) + 4 : "Not set");
 			break;
 		case PID:
 			if (pw)
 				printf("%-10d %-10.10s", shmid, pw->pw_name);
 			else
 				printf("%-10d %-10d", shmid, ipcp->uid);
 			printf(" %-10d %-10d\n", shmseg.shm_cpid, shmseg.shm_lpid);
 			break;

 		default:
 			printf("0x%08x ", ipcp->KEY);
 			if (pw)
 				printf("%-10d %-10.10s", shmid, pw->pw_name);
 			else
 				printf("%-10d %-10d", shmid, ipcp->uid);
 			printf(" %-10o %-10lu %-10ld %-6s %-6s\n", ipcp->mode & 0777,
 					/*
 					 * earlier: int, Austin has size_t
 					 */
 					(unsigned long) shmseg.shm_segsz,
 					/*
 					 * glibc-2.1.3 and earlier has unsigned short;
 					 * Austin has shmatt_t
 					 */
 					(long) shmseg.shm_nattch,
 					ipcp->mode & SHM_DEST ? "dest" : " ",
 					ipcp->mode & SHM_LOCKED ? "locked" : " ");
 			break;
 		}
 	}
 }

 static NOINLINE void do_sem(int format)
 {
 	int maxid, semid, id;
 	struct semid_ds semary;
 	struct seminfo seminfo;
 	struct ipc_perm *ipcp = &semary.sem_perm;
 	struct passwd *pw;
 	union semun arg;

 	arg.array = (unsigned short *) (void *) &seminfo;
 	maxid = semctl(0, 0, SEM_INFO, arg);
 	if (maxid < 0) {
 		printf("kernel not configured for %s\n", "semaphores");
 		return;
 	}

 	switch (format) {
 	case LIMITS:
 		printf("------ Semaphore %s --------\n", "Limits");
 		arg.array = (unsigned short *) (void *) &seminfo;	/* damn union */
 		if ((semctl(0, 0, IPC_INFO, arg)) < 0)
 			return;
 		printf("max number of arrays = %d\n"
 				"max semaphores per array = %d\n"
 				"max semaphores system wide = %d\n"
 				"max ops per semop call = %d\n"
 				"semaphore max value = %d\n",
 				seminfo.semmni,
 				seminfo.semmsl,
 				seminfo.semmns, seminfo.semopm, seminfo.semvmx);
 		return;

 	case STATUS:
 		printf("------ Semaphore %s --------\n", "Status");
 		printf("used arrays = %d\n"
 				"allocated semaphores = %d\n",
 				seminfo.semusz, seminfo.semaem);
 		return;

 	case CREATOR:
 		printf("------ Semaphore %s --------\n", "Arrays Creators/Owners");
 		printf("%-10s %-10s %-10s %-10s %-10s %-10s\n",
 				"semid", "perms", "cuid", "cgid", "uid", "gid");
 		break;

 	case TIME:
 		printf("------ Shared Memory %s --------\n", "Operation/Change Times");
 		printf("%-8s %-10s %-26.24s %-26.24s\n",
 				"shmid", "owner", "last-op", "last-changed");
 		break;

 	case PID:
 		break;

 	default:
 		printf("------ Semaphore %s --------\n", "Arrays");
 		printf("%-10s %-10s %-10s %-10s %-10s\n",
 				"key", "semid", "owner", "perms", "nsems");
 		break;
 	}

 	for (id = 0; id <= maxid; id++) {
 		arg.buf = (struct semid_ds *) &semary;
 		semid = semctl(id, 0, SEM_STAT, arg);
 		if (semid < 0)
 			continue;
 		if (format == CREATOR) {
 			print_perms(semid, ipcp);
 			continue;
 		}
 		pw = getpwuid(ipcp->uid);
 		switch (format) {
 		case TIME:
 			if (pw)
 				printf("%-8d %-10.10s", semid, pw->pw_name);
 			else
 				printf("%-8d %-10d", semid, ipcp->uid);
 			/* ctime uses static buffer: use separate calls */
 			printf("  %-26.24s", semary.sem_otime
 					? ctime(&semary.sem_otime) : "Not set");
 			printf(" %-26.24s\n", semary.sem_ctime
 					? ctime(&semary.sem_ctime) : "Not set");
 			break;
 		case PID:
 			break;

 		default:
 			printf("0x%08x ", ipcp->KEY);
 			if (pw)
 				printf("%-10d %-10.9s", semid, pw->pw_name);
 			else
 				printf("%-10d %-9d", semid, ipcp->uid);
 			printf(" %-10o %-10ld\n", ipcp->mode & 0777,
 					/*
 					 * glibc-2.1.3 and earlier has unsigned short;
 					 * glibc-2.1.91 has variation between
 					 * unsigned short and unsigned long
 					 * Austin prescribes unsigned short.
 					 */
 					(long) semary.sem_nsems);
 			break;
 		}
 	}
 }

 static NOINLINE void do_msg(int format)
 {
 	int maxid, msqid, id;
 	struct msqid_ds msgque;
 	struct msginfo msginfo;
 	struct ipc_perm *ipcp = &msgque.msg_perm;
 	struct passwd *pw;

 	maxid = msgctl(0, MSG_INFO, (struct msqid_ds *) (void *) &msginfo);
 	if (maxid < 0) {
 		printf("kernel not configured for %s\n", "message queues");
 		return;
 	}

 	switch (format) {
 	case LIMITS:
 		if ((msgctl(0, IPC_INFO, (struct msqid_ds *) (void *) &msginfo)) < 0)
 			return;
 		printf("------ Message%s --------\n", "s: Limits");
 		printf("max queues system wide = %d\n"
 				"max size of message (bytes) = %d\n"
 				"default max size of queue (bytes) = %d\n",
 				msginfo.msgmni, msginfo.msgmax, msginfo.msgmnb);
 		return;

 	case STATUS:
 		printf("------ Message%s --------\n", "s: Status");
 		printf("allocated queues = %d\n"
 				"used headers = %d\n"
 				"used space = %d bytes\n",
 				msginfo.msgpool, msginfo.msgmap, msginfo.msgtql);
 		return;

 	case CREATOR:
 		printf("------ Message%s --------\n", " Queues: Creators/Owners");
 		printf("%-10s %-10s %-10s %-10s %-10s %-10s\n",
 				"msqid", "perms", "cuid", "cgid", "uid", "gid");
 		break;

 	case TIME:
 		printf("------ Message%s --------\n", " Queues Send/Recv/Change Times");
 		printf("%-8s %-10s %-20s %-20s %-20s\n",
 				"msqid", "owner", "send", "recv", "change");
 		break;

 	case PID:
 		printf("------ Message%s --------\n", " Queues PIDs");
 		printf("%-10s %-10s %-10s %-10s\n",
 				"msqid", "owner", "lspid", "lrpid");
 		break;

 	default:
 		printf("------ Message%s --------\n", " Queues");
 		printf("%-10s %-10s %-10s %-10s %-12s %-12s\n",
 				"key", "msqid", "owner", "perms", "used-bytes", "messages");
 		break;
 	}

 	for (id = 0; id <= maxid; id++) {
 		msqid = msgctl(id, MSG_STAT, &msgque);
 		if (msqid < 0)
 			continue;
 		if (format == CREATOR) {
 			print_perms(msqid, ipcp);
 			continue;
 		}
 		pw = getpwuid(ipcp->uid);
 		switch (format) {
 		case TIME:
 			if (pw)
 				printf("%-8d %-10.10s", msqid, pw->pw_name);
 			else
 				printf("%-8d %-10d", msqid, ipcp->uid);
 			printf(" %-20.16s", msgque.msg_stime
 					? ctime(&msgque.msg_stime) + 4 : "Not set");
 			printf(" %-20.16s", msgque.msg_rtime
 					? ctime(&msgque.msg_rtime) + 4 : "Not set");
 			printf(" %-20.16s\n", msgque.msg_ctime
 					? ctime(&msgque.msg_ctime) + 4 : "Not set");
 			break;
 		case PID:
 			if (pw)
 				printf("%-8d %-10.10s", msqid, pw->pw_name);
 			else
 				printf("%-8d %-10d", msqid, ipcp->uid);
 			printf("  %5d     %5d\n", msgque.msg_lspid, msgque.msg_lrpid);
 			break;

 		default:
 			printf("0x%08x ", ipcp->KEY);
 			if (pw)
 				printf("%-10d %-10.10s", msqid, pw->pw_name);
 			else
 				printf("%-10d %-10d", msqid, ipcp->uid);
 			printf(" %-10o %-12ld %-12ld\n", ipcp->mode & 0777,
 					/*
 					 * glibc-2.1.3 and earlier has unsigned short;
 					 * glibc-2.1.91 has variation between
 					 * unsigned short, unsigned long
 					 * Austin has msgqnum_t
 					 */
 					(long) msgque.msg_cbytes, (long) msgque.msg_qnum);
 			break;
 		}
 	}
 }

 static void print_shm(int shmid)
 {
 	struct shmid_ds shmds;
 	struct ipc_perm *ipcp = &shmds.shm_perm;

 	if (shmctl(shmid, IPC_STAT, &shmds) == -1) {
 		bb_perror_msg("shmctl");
 		return;
 	}

 	printf("\nShared memory Segment shmid=%d\n"
 			"uid=%d\tgid=%d\tcuid=%d\tcgid=%d\n"
 			"mode=%#o\taccess_perms=%#o\n"
 			"bytes=%ld\tlpid=%d\tcpid=%d\tnattch=%ld\n",
 			shmid,
 			ipcp->uid, ipcp->gid, ipcp->cuid, ipcp->cgid,
 			ipcp->mode, ipcp->mode & 0777,
 			(long) shmds.shm_segsz, shmds.shm_lpid, shmds.shm_cpid,
 			(long) shmds.shm_nattch);
 	printf("att_time=%-26.24s\n",
 			shmds.shm_atime ? ctime(&shmds.shm_atime) : "Not set");
 	printf("det_time=%-26.24s\n",
 			shmds.shm_dtime ? ctime(&shmds.shm_dtime) : "Not set");
 	printf("change_time=%-26.24s\n\n", ctime(&shmds.shm_ctime));
 }

 static void print_msg(int msqid)
 {
 	struct msqid_ds buf;
 	struct ipc_perm *ipcp = &buf.msg_perm;

 	if (msgctl(msqid, IPC_STAT, &buf) == -1) {
 		bb_perror_msg("msgctl");
 		return;
 	}

 	printf("\nMessage Queue msqid=%d\n"
 			"uid=%d\tgid=%d\tcuid=%d\tcgid=%d\tmode=%#o\n"
 			"cbytes=%ld\tqbytes=%ld\tqnum=%ld\tlspid=%d\tlrpid=%d\n",
 			msqid, ipcp->uid, ipcp->gid, ipcp->cuid, ipcp->cgid, ipcp->mode,
 			/*
 			 * glibc-2.1.3 and earlier has unsigned short;
 			 * glibc-2.1.91 has variation between
 			 * unsigned short, unsigned long
 			 * Austin has msgqnum_t (for msg_qbytes)
 			 */
 			(long) buf.msg_cbytes, (long) buf.msg_qbytes,
 			(long) buf.msg_qnum, buf.msg_lspid, buf.msg_lrpid);

 	printf("send_time=%-26.24s\n",
 			buf.msg_stime ? ctime(&buf.msg_stime) : "Not set");
 	printf("rcv_time=%-26.24s\n",
 			buf.msg_rtime ? ctime(&buf.msg_rtime) : "Not set");
 	printf("change_time=%-26.24s\n\n",
 			buf.msg_ctime ? ctime(&buf.msg_ctime) : "Not set");
 }

 static void print_sem(int semid)
 {
 	struct semid_ds semds;
 	struct ipc_perm *ipcp = &semds.sem_perm;
 	union semun arg;
 	unsigned int i;

 	arg.buf = &semds;
 	if (semctl(semid, 0, IPC_STAT, arg)) {
 		bb_perror_msg("semctl");
 		return;
 	}

 	printf("\nSemaphore Array semid=%d\n"
 			"uid=%d\t gid=%d\t cuid=%d\t cgid=%d\n"
 			"mode=%#o, access_perms=%#o\n"
 			"nsems = %ld\n"
 			"otime = %-26.24s\n",
 			semid,
 			ipcp->uid, ipcp->gid, ipcp->cuid, ipcp->cgid,
 			ipcp->mode, ipcp->mode & 0777,
 			(long) semds.sem_nsems,
 			semds.sem_otime ? ctime(&semds.sem_otime) : "Not set");
 	printf("ctime = %-26.24s\n"
 			"%-10s %-10s %-10s %-10s %-10s\n",
 			ctime(&semds.sem_ctime),
 			"semnum", "value", "ncount", "zcount", "pid");

 	arg.val = 0;
 	for (i = 0; i < semds.sem_nsems; i++) {
 		int val, ncnt, zcnt, pid;

 		val = semctl(semid, i, GETVAL, arg);
 		ncnt = semctl(semid, i, GETNCNT, arg);
 		zcnt = semctl(semid, i, GETZCNT, arg);
 		pid = semctl(semid, i, GETPID, arg);
 		if (val < 0 || ncnt < 0 || zcnt < 0 || pid < 0) {
 			bb_perror_msg_and_die("semctl");
 		}
 		printf("%-10u %-10d %-10d %-10d %-10d\n", i, val, ncnt, zcnt, pid);
 	}
 	bb_putchar('\n');
 }

 //usage:#define ipcs_trivial_usage
 //usage:       "[[-smq] -i SHMID] | [[-asmq] [-tcplu]]"
 //usage:#define ipcs_full_usage "\n\n"
 //usage:       "	-i ID	Show specific resource"
 //usage:     "\nResource specification:"
 //usage:     "\n	-m	Shared memory segments"
 //usage:     "\n	-q	Message queues"
 //usage:     "\n	-s	Semaphore arrays"
 //usage:     "\n	-a	All (default)"
 //usage:     "\nOutput format:"
 //usage:     "\n	-t	Time"
 //usage:     "\n	-c	Creator"
 //usage:     "\n	-p	Pid"
 //usage:     "\n	-l	Limits"
 //usage:     "\n	-u	Summary"

 int ipcs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int ipcs_main(int argc UNUSED_PARAM, char **argv)
 {
 	int format = 0;
 	unsigned opt;
 	char *opt_i;

 	opt = getopt32(argv, "i:aqsmtcplu", &opt_i);
 #define flag_msg (1<<2)
 #define flag_sem (1<<3)
 #define flag_shm (1<<4)
 	if (opt & (1<<5)) format = TIME; // -t
 	if (opt & (1<<6)) format = CREATOR; // -c
 	if (opt & (1<<7)) format = PID; // -p
 	if (opt & (1<<8)) format = LIMITS; // -l
 	if (opt & (1<<9)) format = STATUS; // -u

 	if (opt & (1<<0)) { // -i
 		int id;

 		id = xatoi(opt_i);
 		if (opt & flag_shm) {
 			print_shm(id);
 			fflush_stdout_and_exit(EXIT_SUCCESS);
 		}
 		if (opt & flag_sem) {
 			print_sem(id);
 			fflush_stdout_and_exit(EXIT_SUCCESS);
 		}
 		if (opt & flag_msg) {
 			print_msg(id);
 			fflush_stdout_and_exit(EXIT_SUCCESS);
 		}
 		bb_show_usage();
 	}

 	if ((opt & (1<<1)) // -a
 	 || !(opt & (flag_msg | flag_sem | flag_shm)) // none of -q,-s,-m == all
 	) {
 		opt |= flag_msg | flag_sem | flag_shm;
 	}

 	bb_putchar('\n');

 	if (opt & flag_msg) {
 		do_msg(format);
 		bb_putchar('\n');
 	}
 	if (opt & flag_shm) {
 		do_shm(format);
 		bb_putchar('\n');
 	}
 	if (opt & flag_sem) {
 		do_sem(format);
 		bb_putchar('\n');
 	}
 	fflush_stdout_and_exit(EXIT_SUCCESS);
 }
	/* vi: set sw=4 ts=4: */
	/*
	* ipcs.c -- provides information on allocated ipc resources.
	*
	* 01 Sept 2004 - Rodney Radford <rradford@mindspring.com>
	* Adapted for busybox from util-linux-2.12a.
	*
	* Licensed under GPLv2 or later, see file LICENSE in this source tree.
	*/
	//config:config IPCS
	//config: bool "ipcs (11 kb)"
	//config: default y
	//config: select PLATFORM_LINUX
	//config: help
	//config: The ipcs utility is used to provide information on the currently
	//config: allocated System V interprocess (IPC) objects in the system.

	//applet:IF_IPCS(APPLET_NOEXEC(ipcs, ipcs, BB_DIR_USR_BIN, BB_SUID_DROP, ipcs))

	//kbuild:lib-$(CONFIG_IPCS) += ipcs.o

	/* X/OPEN tells us to use <sys/{types,ipc,sem}.h> for semctl() */
	/* X/OPEN tells us to use <sys/{types,ipc,msg}.h> for msgctl() */
	/* X/OPEN tells us to use <sys/{types,ipc,shm}.h> for shmctl() */
	#include <sys/types.h>
	#include <sys/ipc.h>
	#include <sys/sem.h>
	#include <sys/msg.h>
	#include <sys/shm.h>

	#include "libbb.h"

	/-------------------------------------------------------------------/
	/* SHM_DEST and SHM_LOCKED are defined in kernel headers,
	but inside #ifdef __KERNEL__ ... #endif */
	#ifndef SHM_DEST
	/* shm_mode upper byte flags */
	#define SHM_DEST 01000 /* segment will be destroyed on last detach */
	#define SHM_LOCKED 02000 /* segment will not be swapped */
	#endif

	/* For older kernels the same holds for the defines below */
	#ifndef MSG_STAT
	#define MSG_STAT 11
	#define MSG_INFO 12
	#endif

	#ifndef SHM_STAT
	#define SHM_STAT 13
	#define SHM_INFO 14
	struct shm_info {
	int used_ids;
	unsigned long shm_tot; /* total allocated shm */
	unsigned long shm_rss; /* total resident shm */
	unsigned long shm_swp; /* total swapped shm */
	unsigned long swap_attempts;
	unsigned long swap_successes;
	};
	#endif

	#ifndef SEM_STAT
	#define SEM_STAT 18
	#define SEM_INFO 19
	#endif

	/* Some versions of libc only define IPC_INFO when __USE_GNU is defined. */
	#ifndef IPC_INFO
	#define IPC_INFO 3
	#endif
	/-------------------------------------------------------------------/

	/* The last arg of semctl is a union semun, but where is it defined?
	X/OPEN tells us to define it ourselves, but until recently
	Linux include files would also define it. */
	#if defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED)
	/* union semun is defined by including <sys/sem.h> */
	#else
	/* according to X/OPEN we have to define it ourselves */
	union semun {
	int val;
	struct semid_ds *buf;
	unsigned short *array;
	struct seminfo *__buf;
	};
	#endif

	/* X/OPEN (Jan 1987) does not define fields key, seq in struct ipc_perm;
	libc 4/5 does not mention struct ipc_term at all, but includes
	<linux/ipc.h>, which defines a struct ipc_perm with such fields.
	glibc-1.09 has no support for sysv ipc.
	glibc 2 uses __key, __seq */
	#if defined(__GNU_LIBRARY__) && __GNU_LIBRARY__ > 1
	#define KEY __key
	#else
	#define KEY key
	#endif

	#define LIMITS 1
	#define STATUS 2
	#define CREATOR 3
	#define TIME 4
	#define PID 5

	static void print_perms(int id, struct ipc_perm *ipcp)
	{
	struct passwd *pw;
	struct group *gr;

	printf("%-10d %-10o", id, ipcp->mode & 0777);

	pw = getpwuid(ipcp->cuid);
	if (pw) printf(" %-10s", pw->pw_name);
	else printf(" %-10d", ipcp->cuid);
	gr = getgrgid(ipcp->cgid);
	if (gr) printf(" %-10s", gr->gr_name);
	else printf(" %-10d", ipcp->cgid);

	pw = getpwuid(ipcp->uid);
	if (pw) printf(" %-10s", pw->pw_name);
	else printf(" %-10d", ipcp->uid);
	gr = getgrgid(ipcp->gid);
	if (gr) printf(" %-10s\n", gr->gr_name);
	else printf(" %-10d\n", ipcp->gid);
	}

	static NOINLINE void do_shm(int format)
	{
	int maxid, shmid, id;
	struct shmid_ds shmseg;
	struct shm_info shm_info;
	struct shminfo shminfo;
	struct ipc_perm *ipcp = &shmseg.shm_perm;
	struct passwd *pw;

	maxid = shmctl(0, SHM_INFO, (struct shmid_ds ) (void ) &shm_info);
	if (maxid < 0) {
	printf("kernel not configured for %s\n", "shared memory");
	return;
	}

	switch (format) {
	case LIMITS:
	printf("------ Shared Memory %s --------\n", "Limits");
	if ((shmctl(0, IPC_INFO, (struct shmid_ds ) (void ) &shminfo)) < 0)
	return;
	/* glibc 2.1.3 and all earlier libc's have ints as fields
	* of struct shminfo; glibc 2.1.91 has unsigned long; ach */
	printf("max number of segments = %lu\n"
	"max seg size (kbytes) = %lu\n"
	"max total shared memory (pages) = %lu\n"
	"min seg size (bytes) = %lu\n",
	(unsigned long) shminfo.shmmni,
	(unsigned long) (shminfo.shmmax >> 10),
	(unsigned long) shminfo.shmall,
	(unsigned long) shminfo.shmmin);
	return;

	case STATUS:
	printf("------ Shared Memory %s --------\n", "Status");
	printf("segments allocated %d\n"
	"pages allocated %lu\n"
	"pages resident %lu\n"
	"pages swapped %lu\n"
	"Swap performance: %lu attempts\t%lu successes\n",
	shm_info.used_ids,
	shm_info.shm_tot,
	shm_info.shm_rss,
	shm_info.shm_swp,
	shm_info.swap_attempts, shm_info.swap_successes);
	return;

	case CREATOR:
	printf("------ Shared Memory %s --------\n", "Segment Creators/Owners");
	printf("%-10s %-10s %-10s %-10s %-10s %-10s\n",
	"shmid", "perms", "cuid", "cgid", "uid", "gid");
	break;

	case TIME:
	printf("------ Shared Memory %s --------\n", "Attach/Detach/Change Times");
	printf("%-10s %-10s %-20s %-20s %-20s\n",
	"shmid", "owner", "attached", "detached", "changed");
	break;

	case PID:
	printf("------ Shared Memory %s --------\n", "Creator/Last-op");
	printf("%-10s %-10s %-10s %-10s\n",
	"shmid", "owner", "cpid", "lpid");
	break;

	default:
	printf("------ Shared Memory %s --------\n", "Segments");
	printf("%-10s %-10s %-10s %-10s %-10s %-10s %-12s\n",
	"key", "shmid", "owner", "perms", "bytes", "nattch",
	"status");
	break;
	}

	for (id = 0; id <= maxid; id++) {
	shmid = shmctl(id, SHM_STAT, &shmseg);
	if (shmid < 0)
	continue;
	if (format == CREATOR) {
	print_perms(shmid, ipcp);
	continue;
	}
	pw = getpwuid(ipcp->uid);
	switch (format) {
	case TIME:
	if (pw)
	printf("%-10d %-10.10s", shmid, pw->pw_name);
	else
	printf("%-10d %-10d", shmid, ipcp->uid);
	/* ctime uses static buffer: use separate calls */
	printf(" %-20.16s", shmseg.shm_atime
	? ctime(&shmseg.shm_atime) + 4 : "Not set");
	printf(" %-20.16s", shmseg.shm_dtime
	? ctime(&shmseg.shm_dtime) + 4 : "Not set");
	printf(" %-20.16s\n", shmseg.shm_ctime
	? ctime(&shmseg.shm_ctime) + 4 : "Not set");
	break;
	case PID:
	if (pw)
	printf("%-10d %-10.10s", shmid, pw->pw_name);
	else
	printf("%-10d %-10d", shmid, ipcp->uid);
	printf(" %-10d %-10d\n", shmseg.shm_cpid, shmseg.shm_lpid);
	break;

	default:
	printf("0x%08x ", ipcp->KEY);
	if (pw)
	printf("%-10d %-10.10s", shmid, pw->pw_name);
	else
	printf("%-10d %-10d", shmid, ipcp->uid);
	printf(" %-10o %-10lu %-10ld %-6s %-6s\n", ipcp->mode & 0777,
	/*
	* earlier: int, Austin has size_t
	*/
	(unsigned long) shmseg.shm_segsz,
	/*
	* glibc-2.1.3 and earlier has unsigned short;
	* Austin has shmatt_t
	*/
	(long) shmseg.shm_nattch,
	ipcp->mode & SHM_DEST ? "dest" : " ",
	ipcp->mode & SHM_LOCKED ? "locked" : " ");
	break;
	}
	}
	}

	static NOINLINE void do_sem(int format)
	{
	int maxid, semid, id;
	struct semid_ds semary;
	struct seminfo seminfo;
	struct ipc_perm *ipcp = &semary.sem_perm;
	struct passwd *pw;
	union semun arg;

	arg.array = (unsigned short ) (void ) &seminfo;
	maxid = semctl(0, 0, SEM_INFO, arg);
	if (maxid < 0) {
	printf("kernel not configured for %s\n", "semaphores");
	return;
	}

	switch (format) {
	case LIMITS:
	printf("------ Semaphore %s --------\n", "Limits");
	arg.array = (unsigned short ) (void ) &seminfo; /* damn union */
	if ((semctl(0, 0, IPC_INFO, arg)) < 0)
	return;
	printf("max number of arrays = %d\n"
	"max semaphores per array = %d\n"
	"max semaphores system wide = %d\n"
	"max ops per semop call = %d\n"
	"semaphore max value = %d\n",
	seminfo.semmni,
	seminfo.semmsl,
	seminfo.semmns, seminfo.semopm, seminfo.semvmx);
	return;

	case STATUS:
	printf("------ Semaphore %s --------\n", "Status");
	printf("used arrays = %d\n"
	"allocated semaphores = %d\n",
	seminfo.semusz, seminfo.semaem);
	return;

	case CREATOR:
	printf("------ Semaphore %s --------\n", "Arrays Creators/Owners");
	printf("%-10s %-10s %-10s %-10s %-10s %-10s\n",
	"semid", "perms", "cuid", "cgid", "uid", "gid");
	break;

	case TIME:
	printf("------ Shared Memory %s --------\n", "Operation/Change Times");
	printf("%-8s %-10s %-26.24s %-26.24s\n",
	"shmid", "owner", "last-op", "last-changed");
	break;

	case PID:
	break;

	default:
	printf("------ Semaphore %s --------\n", "Arrays");
	printf("%-10s %-10s %-10s %-10s %-10s\n",
	"key", "semid", "owner", "perms", "nsems");
	break;
	}

	for (id = 0; id <= maxid; id++) {
	arg.buf = (struct semid_ds *) &semary;
	semid = semctl(id, 0, SEM_STAT, arg);
	if (semid < 0)
	continue;
	if (format == CREATOR) {
	print_perms(semid, ipcp);
	continue;
	}
	pw = getpwuid(ipcp->uid);
	switch (format) {
	case TIME:
	if (pw)
	printf("%-8d %-10.10s", semid, pw->pw_name);
	else
	printf("%-8d %-10d", semid, ipcp->uid);
	/* ctime uses static buffer: use separate calls */
	printf(" %-26.24s", semary.sem_otime
	? ctime(&semary.sem_otime) : "Not set");
	printf(" %-26.24s\n", semary.sem_ctime
	? ctime(&semary.sem_ctime) : "Not set");
	break;
	case PID:
	break;

	default:
	printf("0x%08x ", ipcp->KEY);
	if (pw)
	printf("%-10d %-10.9s", semid, pw->pw_name);
	else
	printf("%-10d %-9d", semid, ipcp->uid);
	printf(" %-10o %-10ld\n", ipcp->mode & 0777,
	/*
	* glibc-2.1.3 and earlier has unsigned short;
	* glibc-2.1.91 has variation between
	* unsigned short and unsigned long
	* Austin prescribes unsigned short.
	*/
	(long) semary.sem_nsems);
	break;
	}
	}
	}

	static NOINLINE void do_msg(int format)
	{
	int maxid, msqid, id;
	struct msqid_ds msgque;
	struct msginfo msginfo;
	struct ipc_perm *ipcp = &msgque.msg_perm;
	struct passwd *pw;

	maxid = msgctl(0, MSG_INFO, (struct msqid_ds ) (void ) &msginfo);
	if (maxid < 0) {
	printf("kernel not configured for %s\n", "message queues");
	return;
	}

	switch (format) {
	case LIMITS:
	if ((msgctl(0, IPC_INFO, (struct msqid_ds ) (void ) &msginfo)) < 0)
	return;
	printf("------ Message%s --------\n", "s: Limits");
	printf("max queues system wide = %d\n"
	"max size of message (bytes) = %d\n"
	"default max size of queue (bytes) = %d\n",
	msginfo.msgmni, msginfo.msgmax, msginfo.msgmnb);
	return;

	case STATUS:
	printf("------ Message%s --------\n", "s: Status");
	printf("allocated queues = %d\n"
	"used headers = %d\n"
	"used space = %d bytes\n",
	msginfo.msgpool, msginfo.msgmap, msginfo.msgtql);
	return;

	case CREATOR:
	printf("------ Message%s --------\n", " Queues: Creators/Owners");
	printf("%-10s %-10s %-10s %-10s %-10s %-10s\n",
	"msqid", "perms", "cuid", "cgid", "uid", "gid");
	break;

	case TIME:
	printf("------ Message%s --------\n", " Queues Send/Recv/Change Times");
	printf("%-8s %-10s %-20s %-20s %-20s\n",
	"msqid", "owner", "send", "recv", "change");
	break;

	case PID:
	printf("------ Message%s --------\n", " Queues PIDs");
	printf("%-10s %-10s %-10s %-10s\n",
	"msqid", "owner", "lspid", "lrpid");
	break;

	default:
	printf("------ Message%s --------\n", " Queues");
	printf("%-10s %-10s %-10s %-10s %-12s %-12s\n",
	"key", "msqid", "owner", "perms", "used-bytes", "messages");
	break;
	}

	for (id = 0; id <= maxid; id++) {
	msqid = msgctl(id, MSG_STAT, &msgque);
	if (msqid < 0)
	continue;
	if (format == CREATOR) {
	print_perms(msqid, ipcp);
	continue;
	}
	pw = getpwuid(ipcp->uid);
	switch (format) {
	case TIME:
	if (pw)
	printf("%-8d %-10.10s", msqid, pw->pw_name);
	else
	printf("%-8d %-10d", msqid, ipcp->uid);
	printf(" %-20.16s", msgque.msg_stime
	? ctime(&msgque.msg_stime) + 4 : "Not set");
	printf(" %-20.16s", msgque.msg_rtime
	? ctime(&msgque.msg_rtime) + 4 : "Not set");
	printf(" %-20.16s\n", msgque.msg_ctime
	? ctime(&msgque.msg_ctime) + 4 : "Not set");
	break;
	case PID:
	if (pw)
	printf("%-8d %-10.10s", msqid, pw->pw_name);
	else
	printf("%-8d %-10d", msqid, ipcp->uid);
	printf(" %5d %5d\n", msgque.msg_lspid, msgque.msg_lrpid);
	break;

	default:
	printf("0x%08x ", ipcp->KEY);
	if (pw)
	printf("%-10d %-10.10s", msqid, pw->pw_name);
	else
	printf("%-10d %-10d", msqid, ipcp->uid);
	printf(" %-10o %-12ld %-12ld\n", ipcp->mode & 0777,
	/*
	* glibc-2.1.3 and earlier has unsigned short;
	* glibc-2.1.91 has variation between
	* unsigned short, unsigned long
	* Austin has msgqnum_t
	*/
	(long) msgque.msg_cbytes, (long) msgque.msg_qnum);
	break;
	}
	}
	}

	static void print_shm(int shmid)
	{
	struct shmid_ds shmds;
	struct ipc_perm *ipcp = &shmds.shm_perm;

	if (shmctl(shmid, IPC_STAT, &shmds) == -1) {
	bb_perror_msg("shmctl");
	return;
	}

	printf("\nShared memory Segment shmid=%d\n"
	"uid=%d\tgid=%d\tcuid=%d\tcgid=%d\n"
	"mode=%#o\taccess_perms=%#o\n"
	"bytes=%ld\tlpid=%d\tcpid=%d\tnattch=%ld\n",
	shmid,
	ipcp->uid, ipcp->gid, ipcp->cuid, ipcp->cgid,
	ipcp->mode, ipcp->mode & 0777,
	(long) shmds.shm_segsz, shmds.shm_lpid, shmds.shm_cpid,
	(long) shmds.shm_nattch);
	printf("att_time=%-26.24s\n",
	shmds.shm_atime ? ctime(&shmds.shm_atime) : "Not set");
	printf("det_time=%-26.24s\n",
	shmds.shm_dtime ? ctime(&shmds.shm_dtime) : "Not set");
	printf("change_time=%-26.24s\n\n", ctime(&shmds.shm_ctime));
	}

	static void print_msg(int msqid)
	{
	struct msqid_ds buf;
	struct ipc_perm *ipcp = &buf.msg_perm;

	if (msgctl(msqid, IPC_STAT, &buf) == -1) {
	bb_perror_msg("msgctl");
	return;
	}

	printf("\nMessage Queue msqid=%d\n"
	"uid=%d\tgid=%d\tcuid=%d\tcgid=%d\tmode=%#o\n"
	"cbytes=%ld\tqbytes=%ld\tqnum=%ld\tlspid=%d\tlrpid=%d\n",
	msqid, ipcp->uid, ipcp->gid, ipcp->cuid, ipcp->cgid, ipcp->mode,
	/*
	* glibc-2.1.3 and earlier has unsigned short;
	* glibc-2.1.91 has variation between
	* unsigned short, unsigned long
	* Austin has msgqnum_t (for msg_qbytes)
	*/
	(long) buf.msg_cbytes, (long) buf.msg_qbytes,
	(long) buf.msg_qnum, buf.msg_lspid, buf.msg_lrpid);

	printf("send_time=%-26.24s\n",
	buf.msg_stime ? ctime(&buf.msg_stime) : "Not set");
	printf("rcv_time=%-26.24s\n",
	buf.msg_rtime ? ctime(&buf.msg_rtime) : "Not set");
	printf("change_time=%-26.24s\n\n",
	buf.msg_ctime ? ctime(&buf.msg_ctime) : "Not set");
	}

	static void print_sem(int semid)
	{
	struct semid_ds semds;
	struct ipc_perm *ipcp = &semds.sem_perm;
	union semun arg;
	unsigned int i;

	arg.buf = &semds;
	if (semctl(semid, 0, IPC_STAT, arg)) {
	bb_perror_msg("semctl");
	return;
	}

	printf("\nSemaphore Array semid=%d\n"
	"uid=%d\t gid=%d\t cuid=%d\t cgid=%d\n"
	"mode=%#o, access_perms=%#o\n"
	"nsems = %ld\n"
	"otime = %-26.24s\n",
	semid,
	ipcp->uid, ipcp->gid, ipcp->cuid, ipcp->cgid,
	ipcp->mode, ipcp->mode & 0777,
	(long) semds.sem_nsems,
	semds.sem_otime ? ctime(&semds.sem_otime) : "Not set");
	printf("ctime = %-26.24s\n"
	"%-10s %-10s %-10s %-10s %-10s\n",
	ctime(&semds.sem_ctime),
	"semnum", "value", "ncount", "zcount", "pid");

	arg.val = 0;
	for (i = 0; i < semds.sem_nsems; i++) {
	int val, ncnt, zcnt, pid;

	val = semctl(semid, i, GETVAL, arg);
	ncnt = semctl(semid, i, GETNCNT, arg);
	zcnt = semctl(semid, i, GETZCNT, arg);
	pid = semctl(semid, i, GETPID, arg);
	if (val < 0 \|\| ncnt < 0 \|\| zcnt < 0 \|\| pid < 0) {
	bb_perror_msg_and_die("semctl");
	}
	printf("%-10u %-10d %-10d %-10d %-10d\n", i, val, ncnt, zcnt, pid);
	}
	bb_putchar('\n');
	}

	//usage:#define ipcs_trivial_usage
	//usage: "[[-smq] -i SHMID] \| [[-asmq] [-tcplu]]"
	//usage:#define ipcs_full_usage "\n\n"
	//usage: " -i ID Show specific resource"
	//usage: "\nResource specification:"
	//usage: "\n -m Shared memory segments"
	//usage: "\n -q Message queues"
	//usage: "\n -s Semaphore arrays"
	//usage: "\n -a All (default)"
	//usage: "\nOutput format:"
	//usage: "\n -t Time"
	//usage: "\n -c Creator"
	//usage: "\n -p Pid"
	//usage: "\n -l Limits"
	//usage: "\n -u Summary"

	int ipcs_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
	int ipcs_main(int argc UNUSED_PARAM, char **argv)
	{
	int format = 0;
	unsigned opt;
	char *opt_i;

	opt = getopt32(argv, "i:aqsmtcplu", &opt_i);
	#define flag_msg (1<<2)
	#define flag_sem (1<<3)
	#define flag_shm (1<<4)
	if (opt & (1<<5)) format = TIME; // -t
	if (opt & (1<<6)) format = CREATOR; // -c
	if (opt & (1<<7)) format = PID; // -p
	if (opt & (1<<8)) format = LIMITS; // -l
	if (opt & (1<<9)) format = STATUS; // -u

	if (opt & (1<<0)) { // -i
	int id;

	id = xatoi(opt_i);
	if (opt & flag_shm) {
	print_shm(id);
	fflush_stdout_and_exit(EXIT_SUCCESS);
	}
	if (opt & flag_sem) {
	print_sem(id);
	fflush_stdout_and_exit(EXIT_SUCCESS);
	}
	if (opt & flag_msg) {
	print_msg(id);
	fflush_stdout_and_exit(EXIT_SUCCESS);
	}
	bb_show_usage();
	}

	if ((opt & (1<<1)) // -a
	\|\| !(opt & (flag_msg \| flag_sem \| flag_shm)) // none of -q,-s,-m == all
	) {
	opt \|= flag_msg \| flag_sem \| flag_shm;
	}

	bb_putchar('\n');

	if (opt & flag_msg) {
	do_msg(format);
	bb_putchar('\n');
	}
	if (opt & flag_shm) {
	do_shm(format);
	bb_putchar('\n');
	}
	if (opt & flag_sem) {
	do_sem(format);
	bb_putchar('\n');
	}
	fflush_stdout_and_exit(EXIT_SUCCESS);
	}