FILE *
fopen(const char *file, const char *mode)
{
FILE *fp;
int f;
int flags, oflags;
if ((flags = __sflags(mode, &oflags)) == 0)
return (NULL);
if ((fp = __sfp()) == NULL)
return (NULL);
if ((f = open(file, oflags, DEFFILEMODE)) < 0) {
fp->_flags = 0; /* release */
return (NULL);
}
fp->_file = f;
fp->_flags = flags;
fp->_cookie = fp;
fp->_read = __sread;
fp->_write = __swrite;
fp->_seek = __sseek;
fp->_close = __sclose;
/*
* When opening 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, (fpos_t)0, SEEK_END);
return (fp);
}
FILE *
fopen(const char *file, const char *mode)
{
FILE *fp;
int f;
int flags, oflags;
_DIAGASSERT(file != NULL);
if ((flags = __sflags(mode, &oflags)) == 0)
return (NULL);
if ((fp = __sfp()) == NULL)
return (NULL);
if ((f = open(file, oflags, DEFFILEMODE)) < 0)
goto release;
if (oflags & O_NONBLOCK) {
struct stat st;
if (fstat(f, &st) == -1) {
int sverrno = errno;
(void)close(f);
errno = sverrno;
goto release;
}
if (!S_ISREG(st.st_mode)) {
(void)close(f);
errno = EFTYPE;
goto release;
}
}
fp->_file = (short)f;
fp->_flags = (unsigned short)flags;
fp->_cookie = fp;
fp->_read = __sread;
fp->_write = __swrite;
fp->_seek = __sseek;
fp->_close = __sclose;
/*
* When opening 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, (fpos_t)0, SEEK_END);
return (fp);
release:
fp->_flags = 0; /* release */
return (NULL);
}
long ftell
(
FAST FILE * fp /* stream */
)
{
FAST fpos_t pos;
if (OBJ_VERIFY (fp, fpClassId) != OK)
return (ERROR);
/*
* Find offset of underlying I/O object, then
* adjust for buffered bytes.
*/
if (fp->_flags & __SOFF)
pos = fp->_offset;
else
{
pos = __sseek (fp, (fpos_t)0, SEEK_CUR);
if (pos == -1L)
return (pos);
}
if (fp->_flags & __SRD)
{
/*
* Reading. Any unread characters (including
* those from ungetc) cause the position to be
* smaller than that in the underlying object.
*/
pos -= fp->_r;
if (HASUB(fp))
pos -= fp->_ur;
}
else if (fp->_flags & __SWR && fp->_p != NULL)
{
/*
* Writing. Any buffered characters cause the
* position to be greater than that in the
* underlying object.
*/
pos += fp->_p - fp->_bf._base;
}
return (pos);
}
/*
* 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;
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 = fp->_file) < 0 && 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);
_UB(fp)._size = 0;
WCIO_FREE(fp);
if (HASLB(fp))
FREELB(fp);
fp->_lb._size = 0;
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 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;
}
}
fp->_flags = flags;
fp->_file = f;
fp->_cookie = fp;
fp->_read = __sread;
fp->_write = __swrite;
fp->_seek = __sseek;
fp->_close = __sclose;
/*
* When opening 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, (fpos_t)0, SEEK_END);
return (fp);
}
int fseek
(
FAST FILE * fp, /* stream */
long offset, /* offset from <whence> */
int whence /* position to offset from: */
/* SEEK_SET = beginning */
/* SEEK_CUR = current position */
/* SEEK_END = end-of-file */
)
{
fpos_t target;
fpos_t curoff;
size_t n;
struct stat st;
int havepos;
BOOL doStat;
if (OBJ_VERIFY (fp, fpClassId) != OK)
return (ERROR);
/*
* Change any SEEK_CUR to SEEK_SET, and check `whence' argument.
* After this, whence is either SEEK_SET or SEEK_END.
*/
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).
*/
if (fp->_flags & __SOFF)
curoff = fp->_offset;
else
{
curoff = __sseek (fp, (fpos_t)0, SEEK_CUR);
if (curoff == -1L)
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:
errno = 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;
doStat = ioctl (fp->_file, FIOFSTATGET, (int)&st);
if ((fp->_flags & __SOPT) == 0)
{
if ((fp->_file < 0 || (doStat) ||
(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 (doStat)
goto dumb;
target = st.st_size + offset;
}
if (!havepos)
{
if (fp->_flags & __SOFF)
curoff = fp->_offset;
else
{
curoff = __sseek (fp, 0L, 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))
{
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 fgetline.c.)
*/
if (((fp->_flags & __SMOD) == 0) &&
(target >= curoff) &&
(target < (curoff + n)))
{
FAST int o = target - curoff;
fp->_p = fp->_bf._base + o;
fp->_r = n - o;
if (HASUB(fp))
FREEUB(fp);
fp->_flags &= ~__SEOF;
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 (__sseek (fp, curoff, SEEK_SET) == POS_ERR)
goto dumb;
fp->_r = 0;
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;
}
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)) || (__sseek (fp, offset, whence) == POS_ERR))
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;
return (0);
}
