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#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(SYS_fcntl, f2->fd, F_GETFL, 0);
if (fl < 0 || syscall(SYS_fcntl, f->fd, F_SETFL, fl) < 0)
goto fail2;
} else {
f2 = fopen(filename, mode);
if (!f2) goto fail;
if (syscall(SYS_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);
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