diff options
Diffstat (limited to 'lib/libc/stdio/ftell.c')
| -rw-r--r-- | lib/libc/stdio/ftell.c | 40 |
1 files changed, 33 insertions, 7 deletions
diff --git a/lib/libc/stdio/ftell.c b/lib/libc/stdio/ftell.c index e4a4e11..38a164e 100644 --- a/lib/libc/stdio/ftell.c +++ b/lib/libc/stdio/ftell.c @@ -44,8 +44,9 @@ static const char rcsid[] = #include "namespace.h" #include <sys/types.h> -#include <stdio.h> #include <errno.h> +#include <limits.h> +#include <stdio.h> #include "un-namespace.h" #include "local.h" #include "libc_private.h" @@ -58,8 +59,9 @@ ftell(fp) register FILE *fp; { register off_t rv; + rv = ftello(fp); - if ((long)rv != rv) { + if (rv > LONG_MAX) { errno = EOVERFLOW; return (-1); } @@ -74,10 +76,11 @@ ftello(fp) register FILE *fp; { register fpos_t pos; + size_t n; if (fp->_seek == NULL) { errno = ESPIPE; /* historic practice */ - return (-1L); + return (-1); } FLOCKFILE(fp); @@ -91,7 +94,7 @@ ftello(fp) pos = (*fp->_seek)(fp->_cookie, (fpos_t)0, SEEK_CUR); if (pos == -1) { FUNLOCKFILE(fp); - return (pos); + return (-1); } } if (fp->_flags & __SRD) { @@ -101,15 +104,38 @@ ftello(fp) * smaller than that in the underlying object. */ pos -= fp->_r; - if (HASUB(fp)) + if (pos < 0) { + if (HASUB(fp)) { + fp->_p -= pos; + fp->_r += pos; + pos = 0; + } else { + errno = EBADF; + FUNLOCKFILE(fp); + return (-1); + } + } + if (HASUB(fp)) { pos -= fp->_ur; - } else if (fp->_flags & __SWR && fp->_p != NULL) { + if (pos < 0) { + errno = EBADF; + FUNLOCKFILE(fp); + return (-1); + } + } + } 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; + n = fp->_p - fp->_bf._base; + if (pos > OFF_MAX - n) { + FUNLOCKFILE(fp); + errno = EOVERFLOW; + return (-1); + } + pos += n; } FUNLOCKFILE(fp); return (pos); |
