diff options
Diffstat (limited to 'lib/libc/stdio/stdio.c')
| -rw-r--r-- | lib/libc/stdio/stdio.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/lib/libc/stdio/stdio.c b/lib/libc/stdio/stdio.c index 57be5bb..58fafcb 100644 --- a/lib/libc/stdio/stdio.c +++ b/lib/libc/stdio/stdio.c @@ -43,6 +43,7 @@ static const char rcsid[] = #endif /* LIBC_SCCS and not lint */ #include "namespace.h" +#include <errno.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> @@ -94,10 +95,24 @@ __sseek(cookie, offset, whence) register FILE *fp = cookie; register off_t ret; + /* + * Disallow negative seeks per POSIX. + * It is needed here to help upper level caller + * (fseek) in the cases it can't detect. + */ + if (whence == SEEK_SET && (off_t)offset < 0) { + errno = EINVAL; + return (-1); + } ret = lseek(fp->_file, (off_t)offset, whence); - if (ret == -1) + if (ret < 0) { + if (ret != -1) { + /* Resulting seek is negative! */ + ret = -1; + errno = EINVAL; + } fp->_flags &= ~__SOFF; - else { + } else { fp->_flags |= __SOFF; fp->_offset = ret; } |
