fileio: add an openat() flavour for fopen()

This adds xfopenat() which is to fopen() what xopendirat() is to
opendir(), i.e. the "at" counterpart to fopen().

(Similar to the xopendir() case, we prefix this with "x", in case libc
gains this natively eventually.)

1 files changed, 1 insertions, 0 deletions

diff --git a/src/basic/fileio.h b/src/basic/fileio.h
index 31bfef33ac..d5bfe1f0fa 100644
--- a/src/basic/fileio.h
+++ b/src/basic/fileio.h
@@ -69,6 +69,7 @@ int executable_is_script(const char *path, char **interpreter);
 int get_proc_field(const char *filename, const char *pattern, const char *terminator, char **field);
 
 DIR *xopendirat(int dirfd, const char *name, int flags);
+int xfopenat(int dir_fd, const char *path, const char *mode, int flags, FILE **ret);
 
 int search_and_fopen(const char *path, const char *mode, const char *root, const char **search, FILE **_f);
 int search_and_fopen_nulstr(const char *path, const char *mode, const char *root, const char *search, FILE **_f);