From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 12 Feb 2011 00:22:29 -0500 Subject: initial check-in, version 0.5.0 --- src/stdio/freopen.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 src/stdio/freopen.c (limited to 'src/stdio/freopen.c') 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); -- cgit v1.2.1