fix swprintf handling of nul character in output

[musl] / src / stdio / fseek.c

diff --git a/src/stdio/fseek.c b/src/stdio/fseek.c
index 8d9da44..c742580 100644 (file)
--- a/src/stdio/fseek.c
+++ b/src/stdio/fseek.c
@@ -1,12 +1,19 @@
 #include "stdio_impl.h"
+#include <errno.h>
 
 int __fseeko_unlocked(FILE *f, off_t off, int whence)
 {
+       /* Fail immediately for invalid whence argument. */
+       if (whence != SEEK_CUR && whence != SEEK_SET && whence != SEEK_END) {
+               errno = EINVAL;
+               return -1;
+       }
+
        /* Adjust relative offset for unread data in buffer, if any. */
-       if (whence == SEEK_CUR) off -= f->rend - f->rpos;
+       if (whence == SEEK_CUR && f->rend) off -= f->rend - f->rpos;
 
        /* Flush write buffer, and report error on failure. */
-       if (f->wpos > f->wbase) {
+       if (f->wpos != f->wbase) {
                f->write(f, 0, 0);
                if (!f->wpos) return -1;
        }
@@ -15,10 +22,7 @@ int __fseeko_unlocked(FILE *f, off_t off, int whence)
        f->wpos = f->wbase = f->wend = 0;
 
        /* Perform the underlying seek. */
-       if (f->seek(f, off, whence) < 0) {
-               f->flags |= F_ERR;
-               return -1;
-       }
+       if (f->seek(f, off, whence) < 0) return -1;
 
        /* If seek succeeded, file is seekable and we discard read buffer. */
        f->rpos = f->rend = 0;
@@ -42,5 +46,3 @@ int fseek(FILE *f, long off, int whence)
 }
 
 weak_alias(__fseeko, fseeko);
-
-LFS64(fseeko);