ape/stdio: make fopen() quasi threadsafe for python

python uses processes sharing memory. it requires at least fopen() to
be called by multiple threads at once so we introduce _IO_newfile()
which allocates the FILE structure slot under a lock.

1 files changed, 5 insertions, 4 deletions

diff --git a/sys/src/ape/lib/ap/stdio/fopen.c b/sys/src/ape/lib/ap/stdio/fopen.c
index edf27172c..a10da3a42 100644
--- a/sys/src/ape/lib/ap/stdio/fopen.c
+++ b/sys/src/ape/lib/ap/stdio/fopen.c
@@ -2,10 +2,11 @@
  * pANS stdio -- fopen
  */
 #include "iolib.h"
+
 FILE *fopen(const char *name, const char *mode){
 	FILE *f;
-	for(f=_IO_stream;f!=&_IO_stream[FOPEN_MAX];f++)
-		if(f->state==CLOSED)
-			return freopen(name, mode, f);
-	return NULL;
+
+	if((f = _IO_newfile()) == NULL)
+		return NULL;
+	return freopen(name, mode, f);
 }