io.c

早期freebsd实现

	int flag = 0;
	struct stat buf;
	extern double strtod();

	flag = str2mode(mode);

	if (do_unix)
		goto strictopen;

#ifdef VMS
	if ((openfd = vms_devopen(name, flag)) >= 0)
		return openfd;
#endif /* VMS */

	if (STREQ(name, "-"))
		openfd = fileno(stdin);
	else if (STREQN(name, "/dev/", 5) && stat(name, &buf) == -1) {
		cp = name + 5;
		
		if (STREQ(cp, "stdin") && (flag & O_RDONLY) == O_RDONLY)
			openfd = fileno(stdin);
		else if (STREQ(cp, "stdout") && (flag & O_WRONLY) == O_WRONLY)
			openfd = fileno(stdout);
		else if (STREQ(cp, "stderr") && (flag & O_WRONLY) == O_WRONLY)
			openfd = fileno(stderr);
		else if (STREQN(cp, "fd/", 3)) {
			cp += 3;
			openfd = (int)strtod(cp, &ptr);
			if (openfd <= INVALID_HANDLE || ptr == cp)
				openfd = INVALID_HANDLE;
		}
	}

strictopen:
	if (openfd == INVALID_HANDLE)
		openfd = open(name, flag, 0666);
	if (openfd != INVALID_HANDLE && fstat(openfd, &buf) > 0) 
		if (S_ISDIR(buf.st_mode))
			fatal("file `%s' is a directory", name);
	return openfd;
}


/* spec_setup --- setup an IOBUF for a special internal file */

void
spec_setup(iop, len, allocate)
IOBUF *iop;
int len;
int allocate;
{
	char *cp;

	if (allocate) {
		emalloc(cp, char *, len+2, "spec_setup");
		iop->buf = cp;
	} else {
		len = strlen(iop->buf);
		iop->buf[len++] = '\n';	/* get_a_record clobbered it */
		iop->buf[len] = '\0';	/* just in case */
	}
	iop->off = iop->buf;
	iop->cnt = 0;
	iop->secsiz = 0;
	iop->size = len;
	iop->end = iop->buf + len;
	iop->fd = -1;
	iop->flag = IOP_IS_INTERNAL;
}

/* specfdopen --- open a fd special file */

int
specfdopen(iop, name, mode)
IOBUF *iop;
char *name, *mode;
{
	int fd;
	IOBUF *tp;

	fd = devopen(name, mode);
	if (fd == INVALID_HANDLE)
		return INVALID_HANDLE;
	tp = iop_alloc(fd);
	if (tp == NULL)
		return INVALID_HANDLE;
	*iop = *tp;
	iop->flag |= IOP_NO_FREE;
	free(tp);
	return 0;
}

/* pidopen --- "open" /dev/pid, /dev/ppid, and /dev/pgrpid */

int
pidopen(iop, name, mode)
IOBUF *iop;
char *name, *mode;
{
	char tbuf[BUFSIZ];
	int i;

	if (name[6] == 'g')
/* following #if will improve in 2.16 */
#if defined(__svr4__) || defined(i860) || defined(_AIX) || defined(BSD4_4)
		sprintf(tbuf, "%d\n", getpgrp());
#else
		sprintf(tbuf, "%d\n", getpgrp(getpid()));
#endif
	else if (name[6] == 'i')
		sprintf(tbuf, "%d\n", getpid());
	else
		sprintf(tbuf, "%d\n", getppid());
	i = strlen(tbuf);
	spec_setup(iop, i, 1);
	strcpy(iop->buf, tbuf);
	return 0;
}

/* useropen --- "open" /dev/user */

/*
 * /dev/user creates a record as follows:
 *	$1 = getuid()
 *	$2 = geteuid()
 *	$3 = getgid()
 *	$4 = getegid()
 * If multiple groups are supported, the $5 through $NF are the
 * supplementary group set.
 */

int
useropen(iop, name, mode)
IOBUF *iop;
char *name, *mode;
{
	char tbuf[BUFSIZ], *cp;
	int i;
#if defined(NGROUPS_MAX) && NGROUPS_MAX > 0
	int groupset[NGROUPS_MAX];
	int ngroups;
#endif

	sprintf(tbuf, "%d %d %d %d", getuid(), geteuid(), getgid(), getegid());

	cp = tbuf + strlen(tbuf);
#if defined(NGROUPS_MAX) && NGROUPS_MAX > 0
	ngroups = getgroups(NGROUPS_MAX, groupset);
	if (ngroups == -1)
		fatal("could not find groups: %s", strerror(errno));

	for (i = 0; i < ngroups; i++) {
		*cp++ = ' ';
		sprintf(cp, "%d", groupset[i]);
		cp += strlen(cp);
	}
#endif
	*cp++ = '\n';
	*cp++ = '\0';


	i = strlen(tbuf);
	spec_setup(iop, i, 1);
	strcpy(iop->buf, tbuf);
	return 0;
}

/* iop_open --- handle special and regular files for input */

static IOBUF *
iop_open(name, mode)
char *name, *mode;
{
	int openfd = INVALID_HANDLE;
	char *cp, *ptr;
	int flag = 0;
	int i;
	struct stat buf;
	IOBUF *iop;
	static struct internal {
		char *name;
		int compare;
		int (*fp)();
		IOBUF iob;
	} table[] = {
		{ "/dev/fd/",		8,	specfdopen },
		{ "/dev/stdin",		10,	specfdopen },
		{ "/dev/stdout",	11,	specfdopen },
		{ "/dev/stderr",	11,	specfdopen },
		{ "/dev/pid",		8,	pidopen },
		{ "/dev/ppid",		9,	pidopen },
		{ "/dev/pgrpid",	11,	pidopen },
		{ "/dev/user",		9,	useropen },
	};
	int devcount = sizeof(table) / sizeof(table[0]);

	flag = str2mode(mode);

	if (do_unix)
		goto strictopen;

	if (STREQ(name, "-"))
		openfd = fileno(stdin);
	else if (STREQN(name, "/dev/", 5) && stat(name, &buf) == -1) {
		int i;

		for (i = 0; i < devcount; i++) {
			if (STREQN(name, table[i].name, table[i].compare)) {
				IOBUF *iop = & table[i].iob;

				if (iop->buf != NULL) {
					spec_setup(iop, 0, 0);
					return iop;
				} else if ((*table[i].fp)(iop, name, mode) == 0)
					return iop;
				else {
					warning("could not open %s, mode `%s'",
						name, mode);
					return NULL;
				}
			}
		}
	}

strictopen:
	if (openfd == INVALID_HANDLE)
		openfd = open(name, flag, 0666);
	if (openfd != INVALID_HANDLE && fstat(openfd, &buf) > 0) 
		if ((buf.st_mode & S_IFMT) == S_IFDIR)
			fatal("file `%s' is a directory", name);
	iop = iop_alloc(openfd);
	return iop;
}

#ifndef PIPES_SIMULATED
	/* real pipes */
static int
wait_any(interesting)
int interesting;	/* pid of interest, if any */
{
	SIGTYPE (*hstat)(), (*istat)(), (*qstat)();
	int pid;
	int status = 0;
	struct redirect *redp;
	extern int errno;

	hstat = signal(SIGHUP, SIG_IGN);
	istat = signal(SIGINT, SIG_IGN);
	qstat = signal(SIGQUIT, SIG_IGN);
	for (;;) {
#ifdef NeXT
		pid = wait((union wait *)&status);
#else
		pid = wait(&status);
#endif /* NeXT */
		if (interesting && pid == interesting) {
			break;
		} else if (pid != -1) {
			for (redp = red_head; redp != NULL; redp = redp->next)
				if (pid == redp->pid) {
					redp->pid = -1;
					redp->status = status;
					if (redp->fp) {
						pclose(redp->fp);
						redp->fp = 0;
					}
					if (redp->iop) {
						(void) iop_close(redp->iop);
						redp->iop = 0;
					}
					break;
				}
		}
		if (pid == -1 && errno == ECHILD)
			break;
	}
	signal(SIGHUP, hstat);
	signal(SIGINT, istat);
	signal(SIGQUIT, qstat);
	return(status);
}

static IOBUF *
gawk_popen(cmd, rp)
char *cmd;
struct redirect *rp;
{
	int p[2];
	register int pid;

	/* used to wait for any children to synchronize input and output,
	 * but this could cause gawk to hang when it is started in a pipeline
	 * and thus has a child process feeding it input (shell dependant)
	 */
	/*(void) wait_any(0);*/	/* wait for outstanding processes */

	if (pipe(p) < 0)
		fatal("cannot open pipe \"%s\" (%s)", cmd, strerror(errno));
	if ((pid = fork()) == 0) {
		if (close(1) == -1)
			fatal("close of stdout in child failed (%s)",
				strerror(errno));
		if (dup(p[1]) != 1)
			fatal("dup of pipe failed (%s)", strerror(errno));
		if (close(p[0]) == -1 || close(p[1]) == -1)
			fatal("close of pipe failed (%s)", strerror(errno));
		if (close(0) == -1)
			fatal("close of stdin in child failed (%s)",
				strerror(errno));
		execl("/bin/sh", "sh", "-c", cmd, 0);
		_exit(127);
	}
	if (pid == -1)
		fatal("cannot fork for \"%s\" (%s)", cmd, strerror(errno));
	rp->pid = pid;
	if (close(p[1]) == -1)
		fatal("close of pipe failed (%s)", strerror(errno));
	return (rp->iop = iop_alloc(p[0]));
}

static int
gawk_pclose(rp)
struct redirect *rp;
{
	(void) iop_close(rp->iop);
	rp->iop = NULL;

	/* process previously found, return stored status */
	if (rp->pid == -1)
		return (rp->status >> 8) & 0xFF;
	rp->status = wait_any(rp->pid);
	rp->pid = -1;
	return (rp->status >> 8) & 0xFF;
}

#else	/* PIPES_SIMULATED */
	/* use temporary file rather than pipe */

#ifdef VMS
static IOBUF *
gawk_popen(cmd, rp)
char *cmd;
struct redirect *rp;
{
	FILE *current;

	if ((current = popen(cmd, "r")) == NULL)
		return NULL;
	return (rp->iop = iop_alloc(fileno(current)));
}

static int
gawk_pclose(rp)
struct redirect *rp;
{
	int rval, aval, fd = rp->iop->fd;
	FILE *kludge = fdopen(fd, "r"); /* pclose needs FILE* w/ right fileno */

	rp->iop->fd = dup(fd);	  /* kludge to allow close() + pclose() */
	rval = iop_close(rp->iop);
	rp->iop = NULL;
	aval = pclose(kludge);
	return (rval < 0 ? rval : aval);
}
#else	/* VMS */

static
struct {
	char *command;
	char *name;
} pipes[_NFILE];

static IOBUF *
gawk_popen(cmd, rp)
char *cmd;
struct redirect *rp;
{
	extern char *strdup(const char *);
	int current;
	char *name;
	static char cmdbuf[256];

	/* get a name to use.  */
	if ((name = tempnam(".", "pip")) == NULL)
		return NULL;
	sprintf(cmdbuf,"%s > %s", cmd, name);
	system(cmdbuf);
	if ((current = open(name,O_RDONLY)) == INVALID_HANDLE)
		return NULL;
	pipes[current].name = name;
	pipes[current].command = strdup(cmd);
	rp->iop = iop_alloc(current);
	return (rp->iop = iop_alloc(current));
}

static int
gawk_pclose(rp)
struct redirect *rp;
{
	int cur = rp->iop->fd;
	int rval;

	rval = iop_close(rp->iop);
	rp->iop = NULL;

	/* check for an open file  */
	if (pipes[cur].name == NULL)
		return -1;
	unlink(pipes[cur].name);
	free(pipes[cur].name);
	pipes[cur].name = NULL;
	free(pipes[cur].command);
	return rval;
}
#endif	/* VMS */

#endif	/* PIPES_SIMULATED */

NODE *
do_getline(tree)
NODE *tree;
{
	struct redirect *rp = NULL;
	IOBUF *iop;
	int cnt = EOF;
	char *s = NULL;
	int errcode;

	while (cnt == EOF) {
		if (tree->rnode == NULL) {	 /* no redirection */
			iop = nextfile(0);
			if (iop == NULL)		/* end of input */
				return tmp_number((AWKNUM) 0.0);
		} else {
			int redir_error = 0;

			rp = redirect(tree->rnode, &redir_error);
			if (rp == NULL && redir_error) { /* failed redirect */
				if (! do_unix) {
					char *s = strerror(redir_error);

					unref(ERRNO_node->var_value);
					ERRNO_node->var_value =
						make_string(s, strlen(s));
				}
				return tmp_number((AWKNUM) -1.0);
			}
			iop = rp->iop;
			if (iop == NULL)		/* end of input */
				return tmp_number((AWKNUM) 0.0);
		}
		errcode = 0;
		cnt = get_a_record(&s, iop, *RS, & errcode);
		if (! do_unix && errcode != 0) {
			char *s = strerror(errcode);

			unref(ERRNO_node->var_value);
			ERRNO_node->var_value = make_string(s, strlen(s));
			return tmp_number((AWKNUM) -1.0);
		}
		if (cnt == EOF) {
			if (rp) {
				/*
				 * Don't do iop_close() here if we are
				 * reading from a pipe; otherwise
				 * gawk_pclose will not be called.
				 */
				if (!(rp->flag & RED_PIPE)) {
					(void) iop_close(iop);
					rp->iop = NULL;
				}
				rp->flag |= RED_EOF;	/* sticky EOF */
				return tmp_number((AWKNUM) 0.0);
			} else
				continue;	/* try another file */
		}
		if (!rp) {
			NR += 1;
			FNR += 1;
		}
		if (tree->lnode == NULL)	/* no optional var. */
			set_record(s, cnt, 1);
		else {			/* assignment to variable */
			Func_ptr after_assign = NULL;
			NODE **lhs;

			lhs = get_lhs(tree->lnode, &after_assign);
			unref(*lhs);
			*lhs = make_string(s, strlen(s));
			(*lhs)->flags |= MAYBE_NUM;
			/* we may have to regenerate $0 here! */
			if (after_assign)
				(*after_assign)();
		}
	}
	return tmp_number((AWKNUM) 1.0);
}

int
pathopen (file)
char *file;
{
	int fd = do_pathopen(file);

#ifdef DEFAULT_FILETYPE
	if (! do_unix && fd <= INVALID_HANDLE) {
		char *file_awk;
		int save = errno;
#ifdef VMS
		int vms_save = vaxc$errno;
#endif

		/* append ".awk" and try again */
		emalloc(file_awk, char *, strlen(file) +
			sizeof(DEFAULT_FILETYPE) + 1, "pathopen");
		sprintf(file_awk, "%s%s", file, DEFAULT_FILETYPE);
		fd = do_pathopen(file_awk);
		free(file_awk);
		if (fd <= INVALID_HANDLE) {
			errno = save;
#ifdef VMS
			vaxc$errno = vms_save;
#endif
		}
	}
#endif	/*DEFAULT_FILETYPE*/

	return fd;
}

static int
do_pathopen (file)
char *file;
{
	static char *savepath = DEFPATH;	/* defined in config.h */
	static int first = 1;
	char *awkpath, *cp;
	char trypath[BUFSIZ];
	int fd;

	if (STREQ(file, "-"))
		return (0);

	if (do_unix)
		return (devopen(file, "r"));

	if (first) {
		first = 0;
		if ((awkpath = getenv ("AWKPATH")) != NULL && *awkpath)
			savepath = awkpath;	/* used for restarting */
	}
	awkpath = savepath;

	/* some kind of path name, no search */
#ifdef VMS	/* (strchr not equal implies either or both not NULL) */
	if (strchr(file, ':') != strchr(file, ']')
	 || strchr(file, '>') != strchr(file, '/'))
#else /*!VMS*/
#ifdef MSDOS
	if (strchr(file, '/') != strchr(file, '\\')
	 || strchr(file, ':') != NULL)
#else
	if (strchr(file, '/') != NULL)
#endif	/*MSDOS*/
#endif	/*VMS*/
		return (devopen(file, "r"));

	do {
		trypath[0] = '\0';
		/* this should take into account limits on size of trypath */
		for (cp = trypath; *awkpath && *awkpath != ENVSEP; )
			*cp++ = *awkpath++;

		if (cp != trypath) {	/* nun-null element in path */
			/* add directory punctuation only if needed */
#ifdef VMS
			if (strchr(":]>/", *(cp-1)) == NULL)
#else
#ifdef MSDOS
			if (strchr(":\\/", *(cp-1)) == NULL)
#else
			if (*(cp-1) != '/')
#endif
#endif
				*cp++ = '/';
			/* append filename */
			strcpy (cp, file);
		} else
			strcpy (trypath, file);
		if ((fd = devopen(trypath, "r")) >= 0)
			return (fd);

		/* no luck, keep going */
		if(*awkpath == ENVSEP && awkpath[1] != '\0')
			awkpath++;	/* skip colon */
	} while (*awkpath);
	/*
	 * You might have one of the awk
	 * paths defined, WITHOUT the current working directory in it.
	 * Therefore try to open the file in the current directory.
	 */
	return (devopen(file, "r"));
}