diff options
Diffstat (limited to 'libio/freopen.c')
| -rw-r--r-- | libio/freopen.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/libio/freopen.c b/libio/freopen.c index ad1c848877..980523af48 100644 --- a/libio/freopen.c +++ b/libio/freopen.c @@ -76,17 +76,31 @@ freopen (const char *filename, const char *mode, FILE *fp) /* unbound stream orientation */ result->_mode = 0; - if (fd != -1) + if (fd != -1 && _IO_fileno (result) != fd) { - __dup3 (_IO_fileno (result), fd, - (result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0 - ? O_CLOEXEC : 0); + /* At this point we have both file descriptors already allocated, + so __dup3 will not fail with EBADF, EINVAL, or EMFILE. But + we still need to check for EINVAL and, due Linux internal + implementation, EBUSY. It is because on how it internally opens + the file by splitting the buffer allocation operation and VFS + opening (a dup operation may run when a file is still pending + 'install' on VFS). */ + if (__dup3 (_IO_fileno (result), fd, + (result->_flags2 & _IO_FLAGS2_CLOEXEC) != 0 + ? O_CLOEXEC : 0) == -1) + { + _IO_file_close_it (result); + result = NULL; + goto end; + } __close (_IO_fileno (result)); _IO_fileno (result) = fd; } } else if (fd != -1) __close (fd); + +end: if (filename == NULL) free ((char *) gfilename); |