fix unsynchronized access to FILE structure in fflush(0)

[musl] / src / stdio / fread.c

diff --git a/src/stdio/fread.c b/src/stdio/fread.c
index 3f31af8..aef75f7 100644 (file)
--- a/src/stdio/fread.c
+++ b/src/stdio/fread.c
@@ -1,4 +1,5 @@
 #include "stdio_impl.h"
+#include <string.h>
 
 #define MIN(a,b) ((a)<(b) ? (a) : (b))
 
@@ -6,12 +7,12 @@ size_t fread(void *restrict destv, size_t size, size_t nmemb, FILE *restrict f)
 {
        unsigned char *dest = destv;
        size_t len = size*nmemb, l = len, k;
-
-       /* Never touch the file if length is zero.. */
-       if (!l) return 0;
+       if (!size) nmemb = 0;
 
        FLOCK(f);
 
+       f->mode |= f->mode-1;
+
        if (f->rend - f->rpos > 0) {
                /* First exhaust the buffer. */
                k = MIN(f->rend - f->rpos, l);