From 5eb0d33ec0f08b123c5c10877d6258d05fa9453a Mon Sep 17 00:00:00 2001
From: Rich Felker <dalias@aerifal.cx>
Date: Sat, 12 Mar 2011 21:55:45 -0500
Subject: implement flockfile api, rework stdio locking

---
 src/stdio/__lockfile.c   | 19 +++++++++++++++++++
 src/stdio/__ofl.c        |  3 ---
 src/stdio/flockfile.c    |  9 +++++++++
 src/stdio/ftrylockfile.c | 18 ++++++++++++++++++
 src/stdio/funlockfile.c  |  7 +++++++
 src/stdio/vsnprintf.c    |  1 +
 6 files changed, 54 insertions(+), 3 deletions(-)
 create mode 100644 src/stdio/__lockfile.c
 delete mode 100644 src/stdio/__ofl.c
 create mode 100644 src/stdio/flockfile.c
 create mode 100644 src/stdio/ftrylockfile.c
 create mode 100644 src/stdio/funlockfile.c

(limited to 'src/stdio')

diff --git a/src/stdio/__lockfile.c b/src/stdio/__lockfile.c
new file mode 100644
index 00000000..82f50b42
--- /dev/null
+++ b/src/stdio/__lockfile.c
@@ -0,0 +1,19 @@
+#include "stdio_impl.h"
+#include "pthread_impl.h"
+
+void __lockfile(FILE *f)
+{
+	int spins;
+	if (f->owner < 0) return;
+	if (f->owner && f->owner == __pthread_self()->tid) {
+		while (f->lockcount == INT_MAX);
+		f->lockcount++;
+		return;
+	}
+	spins = 100000;
+	while (a_swap(&f->lock, 1))
+		if (spins) spins--, a_spin();
+		else syscall0(__NR_sched_yield);
+	f->owner = __pthread_self()->tid;
+	f->lockcount = 1;
+}
diff --git a/src/stdio/__ofl.c b/src/stdio/__ofl.c
deleted file mode 100644
index 7d9652c8..00000000
--- a/src/stdio/__ofl.c
+++ /dev/null
@@ -1,3 +0,0 @@
-#include "stdio_impl.h"
-
-struct ofl __ofl;
diff --git a/src/stdio/flockfile.c b/src/stdio/flockfile.c
new file mode 100644
index 00000000..1b6ef580
--- /dev/null
+++ b/src/stdio/flockfile.c
@@ -0,0 +1,9 @@
+#include "stdio_impl.h"
+#include "pthread_impl.h"
+
+void flockfile(FILE *f)
+{
+	pthread_self();
+	libc.lockfile = __lockfile;
+	__lockfile(f);
+}
diff --git a/src/stdio/ftrylockfile.c b/src/stdio/ftrylockfile.c
new file mode 100644
index 00000000..725b66e7
--- /dev/null
+++ b/src/stdio/ftrylockfile.c
@@ -0,0 +1,18 @@
+#include "stdio_impl.h"
+#include "pthread_impl.h"
+
+int ftrylockfile(FILE *f)
+{
+	libc.lockfile = __lockfile;
+	if (f->owner && f->owner == pthread_self()->tid) {
+		if (f->lockcount == INT_MAX)
+			return -1;
+		f->lockcount++;
+		return 0;
+	}
+	if (a_swap(&f->lock, 1))
+		return -1;
+	f->owner = pthread_self()->tid;
+	f->lockcount = 1;
+	return 0;
+}
diff --git a/src/stdio/funlockfile.c b/src/stdio/funlockfile.c
new file mode 100644
index 00000000..d69f68ee
--- /dev/null
+++ b/src/stdio/funlockfile.c
@@ -0,0 +1,7 @@
+#include "stdio_impl.h"
+#include "pthread_impl.h"
+
+void funlockfile(FILE *f)
+{
+	FUNLOCK(f);
+}
diff --git a/src/stdio/vsnprintf.c b/src/stdio/vsnprintf.c
index bda6b49b..ff792e17 100644
--- a/src/stdio/vsnprintf.c
+++ b/src/stdio/vsnprintf.c
@@ -17,6 +17,7 @@ int vsnprintf(char *s, size_t n, const char *fmt, va_list ap)
 	f.write = sn_write;
 	f.buf_size = 1;
 	f.buf = buf;
+	f.owner = -1;
 	if (n > INT_MAX) {
 		errno = EOVERFLOW;
 		return -1;
-- 
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