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-rw-r--r--src/stdio/freopen.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/src/stdio/freopen.c b/src/stdio/freopen.c
new file mode 100644
index 00000000..8d3af9fc
--- /dev/null
+++ b/src/stdio/freopen.c
@@ -0,0 +1,47 @@
+#include "stdio_impl.h"
+
+/* The basic idea of this implementation is to open a new FILE,
+ * hack the necessary parts of the new FILE into the old one, then
+ * close the new FILE. */
+
+/* Locking is not necessary because, in the event of failure, the stream
+ * passed to freopen is invalid as soon as freopen is called. */
+
+FILE *freopen(const char *filename, const char *mode, FILE *f)
+{
+ int fl;
+ FILE *f2;
+
+ fflush(f);
+
+ if (!filename) {
+ f2 = fopen("/dev/null", mode);
+ if (!f2) goto fail;
+ fl = __syscall_fcntl(f2->fd, F_GETFL, 0);
+ if (fl < 0 || __syscall_fcntl(f->fd, F_SETFL, fl) < 0)
+ goto fail2;
+ } else {
+ f2 = fopen(filename, mode);
+ if (!f2) goto fail;
+ if (__syscall_dup2(f2->fd, f->fd) < 0)
+ goto fail2;
+ }
+
+ f->flags = (f->flags & F_PERM) | f2->flags;
+ f->read = f2->read;
+ f->write = f2->write;
+ f->seek = f2->seek;
+ f->close = f2->close;
+ f->flush = f2->flush;
+
+ fclose(f2);
+ return f;
+
+fail2:
+ fclose(f2);
+fail:
+ fclose(f);
+ return NULL;
+}
+
+LFS64(freopen);