/*
* Internal routine to determine `proper' buffering for a file.
*/
int
__swhatbuf(FILE *fp, size_t *bufsize, int *couldbetty)
{
struct stat st;
_DIAGASSERT(fp != NULL);
_DIAGASSERT(bufsize != NULL);
_DIAGASSERT(couldbetty != NULL);
if (__sfileno(fp) == -1 || fstat(__sfileno(fp), &st) < 0) {
*couldbetty = 0;
*bufsize = BUFSIZ;
return __SNPT;
}
/* could be a tty iff it is a character device */
*couldbetty = S_ISCHR(st.st_mode);
if (st.st_blksize == 0) {
*bufsize = BUFSIZ;
return __SNPT;
}
/*
* Optimise fseek() only if it is a regular file. (The test for
* __sseek is mainly paranoia.) It is safe to set _blksize
* unconditionally; it will only be used if __SOPT is also set.
*/
*bufsize = st.st_blksize;
fp->_blksize = st.st_blksize;
return (st.st_mode & S_IFMT) == S_IFREG && fp->_seek == __sseek ?
__SOPT : __SNPT;
}
/*
* Allocate a file buffer, or switch to unbuffered I/O.
* Per the ANSI C standard, ALL tty devices default to line buffered.
*
* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
* optimisation) right after the fstat() that finds the buffer size.
*/
void
__smakebuf(FILE *fp)
{
void *p;
int flags;
size_t size;
int couldbetty;
_DIAGASSERT(fp != NULL);
if (fp->_flags & __SNBF) {
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
return;
}
flags = __swhatbuf(fp, &size, &couldbetty);
if ((p = malloc(size)) == NULL) {
fp->_flags |= __SNBF;
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
return;
}
__cleanup = _cleanup;
flags |= __SMBF;
fp->_bf._base = fp->_p = p;
_DIAGASSERT(__type_fit(int, size));
fp->_bf._size = (int)size;
if (couldbetty && isatty(__sfileno(fp)))
flags |= __SLBF;
fp->_flags |= flags;
}
int
fileno(FILE* fp) {
int fd;
FLOCKFILE(fp);
fd = __sfileno(fp);
FUNLOCKFILE(fp);
return (fd);
}
int
fileno(FILE *fp)
{
int ret;
FLOCKFILE(fp);
ret = __sfileno(fp);
FUNLOCKFILE(fp);
return (ret);
}
int fileno
(
FILE * fp /* stream */
)
{
if (OBJ_VERIFY (fp, fpClassId) != OK)
return (ERROR);
return (__sfileno(fp));
}
int
_fileno(FILE *fp)
{
int r;
_DIAGASSERT(fp != NULL);
FLOCKFILE(fp);
r = __sfileno(fp);
FUNLOCKFILE(fp);
return r;
}
int
fileno_unlocked (FILE * f)
{
int result;
CHECK_INIT (_REENT, f);
if (f->_flags)
result = __sfileno (f);
else
{
result = -1;
__errno_r(_REENT) = EBADF;
}
return result;
}
/**
* @brief Maps a stream pointer to a file descriptor.
*
* @details Returns the integer file descriptor associated
* with the stream pointed to by @p f.
*
* @return Returns the integer value of the file descriptor
* associated with @p f. Otherwise, the value -1 is returned
* and errno set to indicate the error.
*/
int fileno(FILE * f)
{
int result;
CHECK_INIT (_REENT, f);
_newlib_flockfile_start (f);
if (f->_flags)
result = __sfileno (f);
else
{
result = -1;
_REENT->_errno = EBADF;
}
_newlib_flockfile_end (f);
return result;
}
/*
* Allocate a file buffer, or switch to unbuffered I/O.
* Per the ANSI C standard, ALL tty devices default to line buffered.
*
* As a side effect, we set __SOPT or __SNPT (en/dis-able fseek
* optimisation) right after the fstat() that finds the buffer size.
*/
void
__smakebuf(FILE *fp)
{
void *p;
int flags;
size_t size;
int couldbetty;
_DIAGASSERT(fp != NULL);
if (fp->_flags & __SNBF)
goto unbuf;
flags = __swhatbuf(fp, &size, &couldbetty);
if ((fp->_flags & (__SLBF|__SNBF|__SMBF)) == 0
&& fp->_cookie == fp && fp->_file >= 0) {
flags |= __senvbuf(fp, &size, &couldbetty);
if (flags & __SNBF)
goto unbuf;
}
if ((p = malloc(size)) == NULL)
goto unbuf;
__cleanup = _cleanup;
flags |= __SMBF;
fp->_bf._base = fp->_p = p;
_DIAGASSERT(__type_fit(int, size));
fp->_bf._size = (int)size;
if (couldbetty && isatty(__sfileno(fp)))
flags |= __SLBF;
fp->_flags |= flags;
return;
unbuf:
fp->_flags |= __SNBF;
fp->_bf._base = fp->_p = fp->_nbuf;
fp->_bf._size = 1;
}
/*
* Seek the given file to the given offset.
* `Whence' must be one of the three SEEK_* macros.
*/
int
fseeko(FILE *fp, off_t offset, int whence)
{
fpos_t (*seekfn)(void *, fpos_t, int);
fpos_t target, curoff;
size_t n;
struct stat st;
int havepos;
/* make sure stdio is set up */
if (!__sdidinit)
__sinit();
/*
* Have to be able to seek.
*/
if ((seekfn = fp->_seek) == NULL || isatty(__sfileno(fp))) {
__sseterr(fp, ESPIPE); /* historic practice */
return (EOF);
}
/*
* Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
* After this, whence is either SEEK_SET or SEEK_END.
*/
FLOCKFILE(fp);
switch (whence) {
case SEEK_CUR:
/*
* In order to seek relative to the current stream offset,
* we have to first find the current stream offset a la
* ftell (see ftell for details).
*/
__sflush(fp); /* may adjust seek offset on append stream */
if (fp->_flags & __SOFF)
curoff = fp->_offset;
else {
curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
if (curoff == (fpos_t)-1) {
FUNLOCKFILE(fp);
return (EOF);
}
}
if (fp->_flags & __SRD) {
curoff -= fp->_r;
if (HASUB(fp))
curoff -= fp->_ur;
} else if (fp->_flags & __SWR && fp->_p != NULL)
curoff += fp->_p - fp->_bf._base;
offset += curoff;
whence = SEEK_SET;
havepos = 1;
break;
case SEEK_SET:
case SEEK_END:
curoff = 0; /* XXX just to keep gcc quiet */
havepos = 0;
break;
default:
FUNLOCKFILE(fp);
__sseterr(fp, EINVAL);
return (EOF);
}
/*
* Can only optimise if:
* reading (and not reading-and-writing);
* not unbuffered; and
* this is a `regular' Unix file (and hence seekfn==__sseek).
* We must check __NBF first, because it is possible to have __NBF
* and __SOPT both set.
*/
if (fp->_bf._base == NULL)
__smakebuf(fp);
if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
goto dumb;
if ((fp->_flags & __SOPT) == 0) {
if (seekfn != __sseek ||
fp->_file < 0 || __libc_fstat(fp->_file, &st) ||
(st.st_mode & S_IFMT) != S_IFREG) {
fp->_flags |= __SNPT;
goto dumb;
}
fp->_blksize = st.st_blksize;
fp->_flags |= __SOPT;
}
/*
* We are reading; we can try to optimise.
* Figure out where we are going and where we are now.
*/
if (whence == SEEK_SET)
target = offset;
else {
if (__libc_fstat(fp->_file, &st))
goto dumb;
target = st.st_size + offset;
}
if (!havepos) {
if (fp->_flags & __SOFF)
curoff = fp->_offset;
else {
curoff = (*seekfn)(fp->_cookie, (fpos_t)0, SEEK_CUR);
if (curoff == POS_ERR)
goto dumb;
}
curoff -= fp->_r;
if (HASUB(fp))
curoff -= fp->_ur;
}
/*
* Compute the number of bytes in the input buffer (pretending
* that any ungetc() input has been discarded). Adjust current
* offset backwards by this count so that it represents the
* file offset for the first byte in the current input buffer.
*/
if (HASUB(fp)) {
curoff += fp->_r; /* kill off ungetc */
n = fp->_up - fp->_bf._base;
curoff -= n;
n += fp->_ur;
} else {
n = fp->_p - fp->_bf._base;
curoff -= n;
n += fp->_r;
}
/*
* If the target offset is within the current buffer,
* simply adjust the pointers, clear EOF, undo ungetc(),
* and return. (If the buffer was modified, we have to
* skip this; see fgetln.c.)
*/
if ((fp->_flags & __SMOD) == 0 &&
target >= curoff && target < curoff + n) {
int o = target - curoff;
fp->_p = fp->_bf._base + o;
fp->_r = n - o;
if (HASUB(fp))
FREEUB(fp);
fp->_flags &= ~__SEOF;
FUNLOCKFILE(fp);
return (0);
}
/*
* The place we want to get to is not within the current buffer,
* but we can still be kind to the kernel copyout mechanism.
* By aligning the file offset to a block boundary, we can let
* the kernel use the VM hardware to map pages instead of
* copying bytes laboriously. Using a block boundary also
* ensures that we only read one block, rather than two.
*/
curoff = target & ~(fp->_blksize - 1);
if ((*seekfn)(fp->_cookie, curoff, SEEK_SET) == POS_ERR)
goto dumb;
fp->_r = 0;
fp->_p = fp->_bf._base;
if (HASUB(fp))
FREEUB(fp);
fp->_flags &= ~__SEOF;
n = target - curoff;
if (n) {
if (__srefill(fp) || fp->_r < n)
goto dumb;
fp->_p += n;
fp->_r -= n;
}
FUNLOCKFILE(fp);
return (0);
/*
* We get here if we cannot optimise the seek ... just
* do it. Allow the seek function to change fp->_bf._base.
*/
dumb:
if (__sflush(fp) ||
(*seekfn)(fp->_cookie, (fpos_t)offset, whence) == POS_ERR) {
FUNLOCKFILE(fp);
return (EOF);
}
/* success: clear EOF indicator and discard ungetc() data */
if (HASUB(fp))
FREEUB(fp);
fp->_p = fp->_bf._base;
fp->_r = 0;
/* fp->_w = 0; */ /* unnecessary (I think...) */
fp->_flags &= ~__SEOF;
FUNLOCKFILE(fp);
return (0);
}
int
fileno_unlocked(FILE *fp)
{
return (__sfileno(fp));
}
DESCRIPTION
You can use <<fileno>> to return the file descriptor identified by <[fp]>.
RETURNS
<<fileno>> returns a non-negative integer when successful.
If <[fp]> is not an open stream, <<fileno>> returns -1.
PORTABILITY
<<fileno>> is not part of ANSI C.
POSIX requires <<fileno>>.
Supporting OS subroutines required: none.
*/
#include <_ansi.h>
#include <stdio.h>
#include "local.h"
int
_DEFUN(fileno, (f),
FILE * f)
{
int result;
CHECK_INIT (_REENT);
_flockfile (f);
result = __sfileno (f);
_funlockfile (f);
return result;
}
int
pd_fileno_unlocked_p(FILEpd *fp)
{
return (__sfileno(fp));
}
int fileno(FILE *f)
{
CHECK_INIT(f);
return __sfileno(f);
}
/*
* Re-direct an existing, open (probably) file to some other file.
* ANSI is written such that the original file gets closed if at
* all possible, no matter what.
*/
FILE *
freopen(const char *file, const char *mode, FILE *fp)
{
int f;
int flags, isopen, oflags, sverrno, wantfd;
_DIAGASSERT(file != NULL);
_DIAGASSERT(mode != NULL);
_DIAGASSERT(fp != NULL);
if ((flags = __sflags(mode, &oflags)) == 0) {
(void) fclose(fp);
return NULL;
}
if (!__sdidinit)
__sinit();
/*
* There are actually programs that depend on being able to "freopen"
* descriptors that weren't originally open. Keep this from breaking.
* Remember whether the stream was open to begin with, and which file
* descriptor (if any) was associated with it. If it was attached to
* a descriptor, defer closing it; freopen("/dev/stdin", "r", stdin)
* should work. This is unnecessary if it was not a Unix file.
*/
if (fp->_flags == 0) {
fp->_flags = __SEOF; /* hold on to it */
isopen = 0;
wantfd = -1;
} else {
/* flush the stream; ANSI doesn't require this. */
if (fp->_flags & __SWR)
(void)__sflush(fp);
/* if close is NULL, closing is a no-op, hence pointless */
isopen = fp->_close != NULL;
if ((wantfd = __sfileno(fp)) == -1 && isopen) {
(void) (*fp->_close)(fp->_cookie);
isopen = 0;
}
}
/* Get a new descriptor to refer to the new file. */
f = open(file, oflags, DEFFILEMODE);
if (f < 0 && isopen) {
/* If out of fd's close the old one and try again. */
if (errno == ENFILE || errno == EMFILE) {
(void) (*fp->_close)(fp->_cookie);
isopen = 0;
f = open(file, oflags, DEFFILEMODE);
}
}
sverrno = errno;
/*
* Finish closing fp. Even if the open succeeded above, we cannot
* keep fp->_base: it may be the wrong size. This loses the effect
* of any setbuffer calls, but stdio has always done this before.
*/
if (isopen && f != wantfd)
(void) (*fp->_close)(fp->_cookie);
if (fp->_flags & __SMBF)
free((char *)fp->_bf._base);
fp->_w = 0;
fp->_r = 0;
fp->_p = NULL;
fp->_bf._base = NULL;
fp->_bf._size = 0;
fp->_lbfsize = 0;
if (HASUB(fp))
FREEUB(fp);
WCIO_FREE(fp);
_UB(fp)._size = 0;
FREELB(fp);
if (f < 0) { /* did not get it after all */
fp->_flags = 0; /* set it free */
errno = sverrno; /* restore in case _close clobbered */
return NULL;
}
if (oflags & O_NONBLOCK) {
struct stat st;
if (fstat(f, &st) == -1) {
sverrno = errno;
(void)close(f);
errno = sverrno;
return NULL;
}
if (!S_ISREG(st.st_mode)) {
(void)close(f);
errno = EFTYPE;
return NULL;
}
}
/*
* If reopening something that was open before on a real file, try
* to maintain the descriptor. Various C library routines (perror)
* assume stderr is always fd STDERR_FILENO, even if being freopen'd.
*/
if (wantfd >= 0 && f != wantfd) {
if (dup2(f, wantfd) >= 0) {
(void) close(f);
f = wantfd;
}
}
/*
* File descriptors are a full int, but _file is only a short.
* If we get a valid file descriptor that is greater or equal to
* USHRT_MAX, then the fd will get sign-extended into an
* invalid file descriptor. Handle this case by failing the
* open. (We treat the short as unsigned, and special-case -1).
*/
if (f >= USHRT_MAX) {
(void)close(f);
errno = EMFILE;
return NULL;
}
fp->_flags = flags;
fp->_file = f;
fp->_cookie = fp;
fp->_read = __sread;
fp->_write = __swrite;
fp->_seek = __sseek;
fp->_close = __sclose;
/*
* When reopening in append mode, even though we use O_APPEND,
* we need to seek to the end so that ftell() gets the right
* answer. If the user then alters the seek pointer, or
* the file extends, this will fail, but there is not much
* we can do about this. (We could set __SAPP and check in
* fseek and ftell.)
*/
if (oflags & O_APPEND)
(void) __sseek((void *)fp, (off_t)0, SEEK_END);
return fp;
}
