int main(int argc,char *argv[])
{
char *ptr[MAX_ALLOCS];
int freeStep,freeMin,freeMax,blockSize,numAllocs,j;
printf("\n");
if (argc < 3 || strcmp(argv[1],"--help") == 0)
{
usageErr("%s num-allocs block-size [step [min [max]]]\n",argv[0]);
}
numAllocs = getInt(argv[1],GN_GT_0,"num-allocs");
if (numAllocs > MAX_ALLOCS)
{
cmdLineErr("num-allocs > %d\n",MAX_ALLOCS);
}
blockSize = getInt(argv[2],GN_GT_0 | GN_ANY_BASE,"block-size");
freeStep = (argc > 3) ? getInt(argv[3],GN_GT_0,"step") : 1;
freeMin = (argc > 4) ? getInt(argv[4],GN_GT_0,"min") : 1;
freeMax = (argc > 5) ? getInt(argv[5],GN_GT_0,"max") : numAllocs;
if (freeMax > numAllocs)
{
cmdLineErr("free-max > num-allocs\n");
}
printf("Initial program break: %10p\n",sbrk(0));
printf("Allocating %d*%d bytes\n",numAllocs,blockSize);
for (j = 0; j < numAllocs; j++)
{
ptr[j] = malloc(blockSize);
if (ptr[j] == NULL)
{
errExit("malloc");
}
printf("Malloc[%d] program break: %10p\n ",j,sbrk(0));
}
printf("Program break is now: %10p\n",sbrk(0));
printf("Freeing blocks from %d to %d in steps of %d\n",freeMin,freeMax,freeStep);
for (j = freeMin - 1; j < freeMax; j += freeStep)
{
free(ptr[j]);
}
printf("After free(),program break is: %10p\n",sbrk(0));
exit(EXIT_SUCCESS);
}
int main (int argc, char *argv[]) {
if (argc != 2) {
usageErr("%s login-name\n", argv[0]);
}
errno = 0;
struct passwd *pw = my_getpwnam(argv[1]);
if (pw == NULL) {
if (errno != 0) {
errExit("my_getpwnam\n");
} else {
cmdLineErr("user %s doesn't exist\n", argv[1]);
}
}
printf("Login name: %s\n", pw->pw_name);
printf("Encrypted password: %s\n", pw->pw_passwd);
printf("User ID: %ld\n", (long) pw->pw_uid);
printf("Group ID: %ld\n", (long) pw->pw_gid);
printf("Comment: %s\n", pw->pw_gecos);
printf("Working directory: %s\n", pw->pw_dir);
printf("Login shell: %s\n", pw->pw_shell);
exit(EXIT_SUCCESS);
}
int main(int argc, char *argv[]) {
int fd;
char *addr;
fd = open(argv[1], O_RDWR);
if (fd == -1)
errExit("open");
addr = mmap(NULL, MEM_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (addr == MAP_FAILED)
errExit("mmap");
if (close(fd) == -1) /* No longer need 'fd' */
errExit("close");
printf("Current string=%.*s\n", MEM_SIZE, addr);
/* Secure practice: output at most MEM_SIZE bytes */
if (argc > 2) {
if (strlen(argv[2]) > MEM_SIZE)
cmdLineErr("'new-value' too large\n");
memset(addr, 0, MEM_SIZE);
strncpy(addr, argv[2], MEM_SIZE - 1);
if (msync(addr, MEM_SIZE, MS_SYNC) == -1)
errExit("msync");
printf("Copied \"%s\" to shared memory\n", argv[2]);
}
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
int level, options, opt;
options = 0;
level = LOG_INFO;
while ((opt = getopt(argc, argv, "l:pe")) != -1) {
switch (opt) {
case 'l':
switch (optarg[0]) {
case 'g': level = LOG_EMERG; break;
case 'a': level = LOG_ALERT; break;
case 'c': level = LOG_CRIT; break;
case 'e': level = LOG_ERR; break;
case 'w': level = LOG_WARNING; break;
case 'n': level = LOG_NOTICE; break;
case 'i': level = LOG_INFO; break;
case 'd': level = LOG_DEBUG; break;
default: cmdLineErr("Bad level: %c\n", optarg[0]);
}
break;
case 'p':
options |= LOG_PID;
break;
#if ! defined(__hpux) && ! defined(__sun)
/* Not on HP-UX 11 or Solaris 8 */
case 'e':
options |= LOG_PERROR;
break;
#endif
default:
fprintf(stderr, "Bad option\n");
usageError(argv[0]);
}
}
if (argc != optind + 1)
usageError(argv[0]);
openlog(argv[0], options, LOG_USER);
syslog(LOG_USER | level, "%s", argv[optind]);
closelog();
exit(EXIT_SUCCESS);
}
static int
parseOps(char *arg, struct sembuf sops[])
{
char *comma, *sign, *remaining, *flags;
int numOps; /* Number of operations in 'arg' */
for (numOps = 0, remaining = arg; ; numOps++) {
if (numOps >= MAX_SEMOPS)
cmdLineErr("Too many operations (maximum=%d): \"%s\"\n",
MAX_SEMOPS, arg);
if (*remaining == '\0')
fatal("Trailing comma or empty argument: \"%s\"", arg);
if (!isdigit((unsigned char) *remaining))
cmdLineErr("Expected initial digit: \"%s\"\n", arg);
sops[numOps].sem_num = strtol(remaining, &sign, 10);
if (*sign == '\0' || strchr("+-=", *sign) == NULL)
cmdLineErr("Expected '+', '-', or '=' in \"%s\"\n", arg);
if (!isdigit((unsigned char) *(sign + 1)))
cmdLineErr("Expected digit after '%c' in \"%s\"\n", *sign, arg);
sops[numOps].sem_op = strtol(sign + 1, &flags, 10);
if (*sign == '-') /* Reverse sign of operation */
sops[numOps].sem_op = - sops[numOps].sem_op;
else if (*sign == '=') /* Should be '=0' */
if (sops[numOps].sem_op != 0)
cmdLineErr("Expected \"=0\" in \"%s\"\n", arg);
sops[numOps].sem_flg = 0;
for (;; flags++) {
if (*flags == 'n')
sops[numOps].sem_flg |= IPC_NOWAIT;
else if (*flags == 'u')
sops[numOps].sem_flg |= SEM_UNDO;
else
break;
}
if (*flags != ',' && *flags != '\0')
cmdLineErr("Bad trailing character (%c) in \"%s\"\n", *flags, arg);
comma = strchr(remaining, ',');
if (comma == NULL)
break; /* No comma --> no more ops */
else
remaining = comma + 1;
}
return numOps + 1;
}
int
main(int argc, char *argv[])
{
int msqid, flags, msgLen;
struct mbuf msg; /* Message buffer for msgsnd() */
int opt; /* Option character from getopt() */
/* Parse command-line options and arguments */
flags = 0;
while ((opt = getopt(argc, argv, "n")) != -1)
{
if (opt == 'n')
flags |= IPC_NOWAIT;
else
usageError(argv[0], NULL);
}
if (argc < optind + 2 || argc > optind + 3)
usageError(argv[0], "Wrong number of arguments\n");
msqid = getInt(argv[optind], 0, "msqid");
msg.mtype = getInt(argv[optind + 1], 0, "msg-type");
if (argc > optind + 2) /* 'msg-text' was supplied */
{
msgLen = strlen(argv[optind + 2]) + 1;
if (msgLen > MAX_MTEXT)
cmdLineErr("msg-text too long (max: %d characters)\n", MAX_MTEXT);
memcpy(msg.mtext, argv[optind + 2], msgLen);
}
else /* No 'msg-text' ==> zero-length msg */
{
msgLen = 0;
}
/* Send message */
if (msgsnd(msqid, &msg, msgLen, flags) == -1)
errExit("msgsnd");
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
struct semid_ds ds;
union semun arg; /* Fourth argument for semctl() */
int j, semid;
if (argc < 3 || strcmp(argv[1], "--help") == 0)
usageErr("%s semid val...\n", argv[0]);
semid = getInt(argv[1], 0, "semid");
/* Obtain size of semaphore set */
arg.buf = &ds;
if (semctl(semid, 0, IPC_STAT, arg) == -1)
errExit("semctl");
/* The number of values supplied on the command line must match the
number of semaphores in the set */
if (ds.sem_nsems != argc - 2)
cmdLineErr("Set contains %ld semaphores, but %d values were supplied\n",
(long) ds.sem_nsems, argc - 2);
/* Set up array of values; perform semaphore initialization */
arg.array = calloc(ds.sem_nsems, sizeof(arg.array[0]));
if (arg.array == NULL)
errExit("calloc");
for (j = 2; j < argc; j++)
arg.array[j - 2] = getInt(argv[j], 0, "val");
if (semctl(semid, 0, SETALL, arg) == -1)
errExit("semctl-SETALL");
printf("Semaphore values changed (PID=%ld)\n", (long) getpid());
exit(EXIT_SUCCESS);
}
int main(int argc, char *argv[])
{
struct semid_ds ds;
union semun arg;
int semid;
if(argc<3 || !strcmp(argv[1], "--help"))
usageErr("%s semid val...\n", argv[0]);
semid = getInt(argv[1], 0, "semid");
/* Obtain size of semaphore set */
arg.buf = &ds;
if(semctl(semid, 0, IPC_STAT, arg) == -1)
errExit("semctl()");
if(ds.sem_nsems != (unsigned long) (argc-2))
cmdLineErr("Set contains %jd semaphores, but %d values were supplied\n",
(intmax_t) ds.sem_nsems, argc-2);
/* Set up array of values; perform semaphore initialization */
arg.array = calloc(ds.sem_nsems, sizeof(arg.array[0]));
if(arg.array == NULL)
errExit("calloc()");
for(int j=2; j<argc; ++j)
arg.array[j-2] = getInt(argv[j], 0, "val");
if(semctl(semid, 0, SETALL, arg) == -1)
errExit("semctl() - SETALL");
printf("Semaphore values changed (PID = %jd)\n", (intmax_t) getpid());
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
size_t len;
off_t offset;
int fd, ap, j;
char *buf;
ssize_t numRead, numWritten;
if (argc < 3 || strcmp(argv[1], "--help") == 0)
usageErr("%s file {r<length>|R<length>|w<string>|s<offset>}...\n",
argv[0]);
fd = open(argv[1], O_RDWR | O_CREAT,
S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP |
S_IROTH | S_IWOTH); /* rw-rw-rw- */
if (fd == -1)
errExit("open");
for (ap = 2; ap < argc; ap++) {
switch (argv[ap][0]) {
case 'r': /* Display bytes at current offset, as text */
case 'R': /* Display bytes at current offset, in hex */
len = getLong(&argv[ap][1], GN_ANY_BASE, argv[ap]);
buf = malloc(len);
if (buf == NULL)
errExit("malloc");
numRead = read(fd, buf, len);
if (numRead == -1)
errExit("read");
if (numRead == 0) {
printf("%s: end-of-file\n", argv[ap]);
} else {
printf("%s: ", argv[ap]);
for (j = 0; j < numRead; j++) {
if (argv[ap][0] == 'r')
printf("%c", isprint((unsigned char) buf[j]) ?
buf[j] : '?');
else
printf("%02x ", (unsigned int) buf[j]);
}
printf("\n");
}
free(buf);
break;
case 'w': /* Write string at current offset */
numWritten = write(fd, &argv[ap][1], strlen(&argv[ap][1]));
if (numWritten == -1)
errExit("write");
printf("%s: wrote %ld bytes\n", argv[ap], (long) numWritten);
break;
case 's': /* Change file offset */
offset = getLong(&argv[ap][1], GN_ANY_BASE, argv[ap]);
if (lseek(fd, offset, SEEK_SET) == -1)
errExit("lseek");
printf("%s: seek succeeded\n", argv[ap]);
break;
default:
cmdLineErr("Argument must start with [rRws]: %s\n", argv[ap]);
}
}
if (close(fd) == -1)
errExit("close");
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
fd_set readfds;
int ready, nfds, flags;
struct timeval timeout;
struct timeval *pto;
struct sigaction sa;
char ch;
int fd, j;
if (argc < 2 || strcmp(argv[1], "--help") == 0)
usageErr("%s {timeout|-} fd...\n"
"\t\t('-' means infinite timeout)\n", argv[0]);
/* Initialize 'timeout', 'readfds', and 'nfds' for select() */
if (strcmp(argv[1], "-") == 0) {
pto = NULL; /* Infinite timeout */
} else {
pto = &timeout;
timeout.tv_sec = getLong(argv[1], 0, "timeout");
timeout.tv_usec = 0; /* No microseconds */
}
nfds = 0;
/* Build the 'readfds' from the fd numbers given in command line */
FD_ZERO(&readfds);
for (j = 2; j < argc; j++) {
fd = getInt(argv[j], 0, "fd");
if (fd >= FD_SETSIZE)
cmdLineErr("file descriptor exceeds limit (%d)\n", FD_SETSIZE);
if (fd >= nfds)
nfds = fd + 1; /* Record maximum fd + 1 */
FD_SET(fd, &readfds);
}
/* Create pipe before establishing signal handler to prevent race */
if (pipe(pfd) == -1)
errExit("pipe");
FD_SET(pfd[0], &readfds); /* Add read end of pipe to 'readfds' */
nfds = max(nfds, pfd[0] + 1); /* And adjust 'nfds' if required */
/* Make read and write ends of pipe nonblocking */
flags = fcntl(pfd[0], F_GETFL);
if (flags == -1)
errExit("fcntl-F_GETFL");
flags |= O_NONBLOCK; /* Make read end nonblocking */
if (fcntl(pfd[0], F_SETFL, flags) == -1)
errExit("fcntl-F_SETFL");
flags = fcntl(pfd[1], F_GETFL);
if (flags == -1)
errExit("fcntl-F_GETFL");
flags |= O_NONBLOCK; /* Make write end nonblocking */
if (fcntl(pfd[1], F_SETFL, flags) == -1)
errExit("fcntl-F_SETFL");
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_RESTART; /* Restart interrupted reads()s */
sa.sa_handler = handler;
if (sigaction(SIGINT, &sa, NULL) == -1)
errExit("sigaction");
while ((ready = select(nfds, &readfds, NULL, NULL, pto)) == -1 &&
errno == EINTR)
continue; /* Restart if interrupted by signal */
if (ready == -1) /* Unexpected error */
errExit("select");
if (FD_ISSET(pfd[0], &readfds)) { /* Handler was called */
printf("A signal was caught\n");
for (;;) { /* Consume bytes from pipe */
if (read(pfd[0], &ch, 1) == -1) {
if (errno == EAGAIN)
break; /* No more bytes */
else
errExit("read"); /* Some other error */
}
/* Perform any actions that should be taken in response to signal */
}
}
/* Examine file descriptor sets returned by select() to see
which other file descriptors are ready */
printf("ready = %d\n", ready);
for (j = 2; j < argc; j++) {
fd = getInt(argv[j], 0, "fd");
printf("%d: %s\n", fd, FD_ISSET(fd, &readfds) ? "r" : "");
}
/* And check if read end of pipe is ready */
printf("%d: %s (read end of pipe)\n", pfd[0],
FD_ISSET(pfd[0], &readfds) ? "r" : "");
if (pto != NULL)
printf("timeout after select(): %ld.%03ld\n",
(long) timeout.tv_sec, (long) timeout.tv_usec / 1000);
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
DIR *dirp;
struct dirent *dp;
char path[PATH_MAX];
char line[MAX_LINE], cmd[MAX_LINE];
FILE *fp;
char *p;
uid_t uid, checkedUid;
Boolean gotName, gotUid;
if (argc < 2 || strcmp(argv[1], "--help") == 0)
usageErr("%s username\n", argv[0]);
checkedUid = userIdFromName(argv[1]);
if (checkedUid == -1)
cmdLineErr("Bad username: %s\n", argv[1]);
dirp = opendir("/proc");
if (dirp == NULL)
errExit("opendir");
for (;;) {
errno = 0; /* To distinguish error from end-of-directory */
dp = readdir(dirp);
if (dp == NULL) {
if (errno != 0)
errExit("readdir");
else
break;
}
if (dp->d_type != DT_DIR || !isdigit((unsigned char) dp->d_name[0]))
continue;
snprintf(path, PATH_MAX, "/proc/%s/status", dp->d_name);
fp = fopen(path, "r");
if (fp == NULL)
continue; /* Ignore errors: fopen() might fail if
process has just terminated */
gotName = FALSE;
gotUid = FALSE;
while (!gotName || !gotUid) {
if (fgets(line, MAX_LINE, fp) == NULL)
break;
/* The "Name:" line contains the name of the command that
this process is running */
if (strncmp(line, "Name:", 5) == 0) {
for (p = line + 5; *p != '\0' && isspace((unsigned char) *p); )
p++;
strncpy(cmd, p, MAX_LINE - 1);
cmd[MAX_LINE -1] = '\0'; /* Ensure null-terminated */
gotName = TRUE;
}
/* The "Uid:" line contains the real, effective, saved set-,
and file-system user IDs */
if (strncmp(line, "Uid:", 4) == 0) {
uid = strtol(line + 4, NULL, 10);
gotUid = TRUE;
}
}
fclose(fp);
/* If we found a username and a UID, and the UID matches,
then display the PID and command name */
if (gotName && gotUid && uid == checkedUid)
printf("%5s %s", dp->d_name, cmd);
}
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
int numKeyFlags; /* Counts -f, -k, and -p options */
int flags, shmid, segSize;
unsigned int perms;
long lkey;
key_t key;
int opt; /* Option character from getopt() */
/* Parse command-line options and arguments */
numKeyFlags = 0;
flags = 0;
while ((opt = getopt(argc, argv, "cf:k:px")) != -1) {
switch (opt) {
case 'c':
flags |= IPC_CREAT;
break;
case 'f': /* -f pathname */
key = ftok(optarg, 1);
if (key == -1)
errExit("ftok");
numKeyFlags++;
break;
case 'k': /* -k key (octal, decimal or hexadecimal) */
if (sscanf(optarg, "%li", &lkey) != 1)
cmdLineErr("-k option requires a numeric argument\n");
key = lkey;
numKeyFlags++;
break;
case 'p':
key = IPC_PRIVATE;
numKeyFlags++;
break;
case 'x':
flags |= IPC_EXCL;
break;
default:
usageError(argv[0], NULL);
}
}
if (numKeyFlags != 1)
usageError(argv[0], "Exactly one of the options -f, -k, "
"or -p must be supplied\n");
if (optind >= argc)
usageError(argv[0], "Size of segment must be specified\n");
segSize = getLong(argv[optind], GN_ANY_BASE, "seg-size");
perms = (argc <= optind + 1) ? (S_IRUSR | S_IWUSR) :
getInt(argv[optind + 1], GN_BASE_8, "octal-perms");
shmid = shmget(key, segSize, flags | perms);
if (shmid == -1)
errExit("shmget");
printf("%d\n", shmid); /* On success, display shared mem. id */
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
struct requestMsg req;
struct responseMsg resp;
int serverId, numMsgs;
ssize_t msgLen, totBytes;
if (argc != 2 || strcmp(argv[1], "--help") == 0)
usageErr("%s pathname\n", argv[0]);
if (strlen(argv[1]) > sizeof(req.pathname) - 1)
cmdLineErr("pathname too long (max: %ld bytes)\n",
(long) sizeof(req.pathname) - 1);
/* Get server's queue identifier; create queue for response */
serverId = msgget(SERVER_KEY, S_IWUSR);
if (serverId == -1)
errExit("msgget - server message queue");
clientId = msgget(IPC_PRIVATE, S_IRUSR | S_IWUSR | S_IWGRP);
if (clientId == -1)
errExit("msgget - client message queue");
if (atexit(removeQueue) != 0)
errExit("atexit");
/* Send message asking for file named in argv[1] */
req.mtype = 1; /* Any type will do */
req.clientId = clientId;
strncpy(req.pathname, argv[1], sizeof(req.pathname) - 1);
req.pathname[sizeof(req.pathname) - 1] = '\0';
/* Ensure string is terminated */
if (msgsnd(serverId, &req, REQ_MSG_SIZE, 0) == -1)
errExit("msgsnd");
/* Get first response, which may be failure notification */
msgLen = msgrcv(clientId, &resp, RESP_MSG_SIZE, 0, 0);
if (msgLen == -1)
errExit("msgrcv");
if (resp.mtype == RESP_MT_FAILURE) {
printf("%s\n", resp.data); /* Display msg from server */
exit(EXIT_FAILURE);
}
/* File was opened successfully by server; process messages
(including the one already received) containing file data */
totBytes = msgLen; /* Count first message */
for (numMsgs = 1; resp.mtype == RESP_MT_DATA; numMsgs++) {
msgLen = msgrcv(clientId, &resp, RESP_MSG_SIZE, 0, 0);
if (msgLen == -1)
errExit("msgrcv");
totBytes += msgLen;
}
printf("Received %ld bytes (%d messages)\n", (long) totBytes, numMsgs);
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
fd_set readfds, writefds;
int ready, nfds, fd, numRead, j;
struct timeval timeout;
struct timeval *pto;
char buf[10]; /* Large enough to hold "rw\0" */
if (argc < 2 || strcmp(argv[1], "--help") == 0)
usageError(argv[0]);
/* Timeout for select() is specified in argv[1] */
if (strcmp(argv[1], "-") == 0) {
pto = NULL; /* Infinite timeout */
} else {
pto = &timeout;
timeout.tv_sec = getLong(argv[1], 0, "timeout");
timeout.tv_usec = 0; /* No microseconds */
}
/* Process remaining arguments to build file descriptor sets */
nfds = 0;
FD_ZERO(&readfds);
FD_ZERO(&writefds);
for (j = 2; j < argc; j++) {
numRead = sscanf(argv[j], "%d%2[rw]", &fd, buf);
if (numRead != 2)
usageError(argv[0]);
if (fd >= FD_SETSIZE)
cmdLineErr("file descriptor exceeds limit (%d)\n", FD_SETSIZE);
if (fd >= nfds)
nfds = fd + 1; /* Record maximum fd + 1 */
if (strchr(buf, 'r') != NULL)
FD_SET(fd, &readfds);
if (strchr(buf, 'w') != NULL)
FD_SET(fd, &writefds);
}
/* We've built all of the arguments; now call select() */
ready = select(nfds, &readfds, &writefds, NULL, pto);
/* Ignore exceptional events */
if (ready == -1)
errExit("select");
/* Display results of select() */
printf("ready = %d\n", ready);
for (fd = 0; fd < nfds; fd++)
printf("%d: %s%s\n", fd, FD_ISSET(fd, &readfds) ? "r" : "",
FD_ISSET(fd, &writefds) ? "w" : "");
if (pto != NULL)
printf("timeout after select(): %ld.%03ld\n",
(long) timeout.tv_sec, (long) timeout.tv_usec / 10000);
exit(EXIT_SUCCESS);
}
int
main(int argc, char *argv[])
{
int numKeyFlags; /* Counts -f, -k, and -p options */
int flags, msqid, opt;
unsigned int perms;
long lkey;
key_t key;
/* Parse command-line options and arguments */
numKeyFlags = 0;
flags = 0;
while ((opt = getopt(argc, argv, "cf:k:px")) != -1) {
switch (opt) {
case 'c':
flags |= IPC_CREAT;
break;
case 'f': /* -f pathname */
key = ftok(optarg, 1);
if (key == -1)
errExit("ftok");
numKeyFlags++;
break;
case 'k': /* -k key (octal, decimal or hexadecimal) */
if (sscanf(optarg, "%li", &lkey) != 1)
cmdLineErr("-k option requires a numeric argument\n");
key = lkey;
numKeyFlags++;
break;
case 'p':
key = IPC_PRIVATE;
numKeyFlags++;
break;
case 'x':
flags |= IPC_EXCL;
break;
default:
usageError(argv[0], "Bad option\n");
}
}
if (numKeyFlags != 1)
usageError(argv[0], "Exactly one of the options -f, -k, "
"or -p must be supplied\n");
perms = (optind == argc) ? (S_IRUSR | S_IWUSR) :
getInt(argv[optind], GN_BASE_8, "octal-perms");
msqid = msgget(key, flags | perms);
if (msqid == -1)
errExit("msgget");
printf("%d\n", msqid);
exit(EXIT_SUCCESS);
}