Avoid pathological behavior in OpenBSD's fread.
(cherry picked from commit 20841a137beac5caa824e3586c7bd91d879ff92e)
Bug: https://code.google.com/p/android/issues/detail?id=81155
Bug: 18556607
Change-Id: Ibdfebc20dce4c34ad565014523c9b074e90ea665
diff --git a/libc/Android.mk b/libc/Android.mk
index 045556e..3005092 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -61,6 +61,7 @@
bionic/sigsetmask.c \
bionic/system_properties_compat.c \
stdio/findfp.c \
+ stdio/fread.c \
stdio/snprintf.c\
stdio/sprintf.c \
@@ -396,7 +397,6 @@
upstream-openbsd/lib/libc/stdio/fputs.c \
upstream-openbsd/lib/libc/stdio/fputwc.c \
upstream-openbsd/lib/libc/stdio/fputws.c \
- upstream-openbsd/lib/libc/stdio/fread.c \
upstream-openbsd/lib/libc/stdio/freopen.c \
upstream-openbsd/lib/libc/stdio/fscanf.c \
upstream-openbsd/lib/libc/stdio/fseek.c \
diff --git a/libc/upstream-openbsd/lib/libc/stdio/fread.c b/libc/stdio/fread.c
similarity index 84%
rename from libc/upstream-openbsd/lib/libc/stdio/fread.c
rename to libc/stdio/fread.c
index 8a592f6..e052128 100644
--- a/libc/upstream-openbsd/lib/libc/stdio/fread.c
+++ b/libc/stdio/fread.c
@@ -68,7 +68,23 @@
fp->_r = 0;
total = resid;
p = buf;
- while (resid > (r = fp->_r)) {
+
+ // BEGIN android-added
+ // Avoid pathological behavior on unbuffered files. OpenBSD
+ // will loop reading one byte then memcpying one byte!
+ if ((fp->_flags & __SNBF) != 0) {
+ // We know if we're unbuffered that our buffer is empty, so
+ // we can just read directly.
+ while (resid > 0 && (r = (*fp->_read)(fp->_cookie, p, resid)) > 0) {
+ p += r;
+ resid -= r;
+ }
+ FUNLOCKFILE(fp);
+ return ((total - resid) / size);
+ }
+ // END android-added
+
+ while (resid > (size_t)(r = fp->_r)) {
(void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
fp->_p += r;
/* fp->_r = 0 ... done in __srefill */