[Libguestfs] [PATCH] mllib: Add a binding for realpath(3).

[Richard W.M. Jones]

This is a copy of the supermin binding:

https://github.com/libguestfs/supermin/tree/master/src realpath*
---
 mllib/unix_utils-c.c | 18 ++++++++++++++++++
 mllib/unix_utils.ml  |  4 ++++
 mllib/unix_utils.mli |  5 +++++
 3 files changed, 27 insertions(+)

diff --git a/mllib/unix_utils-c.c b/mllib/unix_utils-c.c
index f5aaaf6..7e90541 100644
--- a/mllib/unix_utils-c.c
+++ b/mllib/unix_utils-c.c
@@ -25,6 +25,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <fnmatch.h>
+#include <limits.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/statvfs.h>
@@ -57,6 +58,7 @@ extern value guestfs_int_mllib_fnmatch (value patternv, value strv, value flagsv
 extern value guestfs_int_mllib_sync (value unitv);
 extern value guestfs_int_mllib_fsync_file (value filenamev);
 extern value guestfs_int_mllib_mkdtemp (value val_pattern);
+extern value guestfs_int_mllib_realpath (value pathv);
 extern value guestfs_int_mllib_statvfs_free_space (value pathv);
 
 /* NB: This is a "noalloc" call. */
@@ -196,6 +198,22 @@ guestfs_int_mllib_mkdtemp (value val_pattern)
 }
 
 value
+guestfs_int_mllib_realpath (value pathv)
+{
+  CAMLparam1 (pathv);
+  CAMLlocal1 (rv);
+  char *r;
+
+  r = realpath (String_val (pathv), NULL);
+  if (r == NULL)
+    unix_error (errno, (char *) "realpath", pathv);
+
+  rv = caml_copy_string (r);
+  free (r);
+  CAMLreturn (rv);
+}
+
+value
 guestfs_int_mllib_statvfs_free_space (value pathv)
 {
   CAMLparam1 (pathv);
diff --git a/mllib/unix_utils.ml b/mllib/unix_utils.ml
index 66b6e4f..8ac3683 100644
--- a/mllib/unix_utils.ml
+++ b/mllib/unix_utils.ml
@@ -56,6 +56,10 @@ module Mkdtemp = struct
     mkdtemp (Filename.concat base_dir (prefix ^ "XXXXXX" ^ suffix))
 end
 
+module Realpath = struct
+  external realpath : string -> string = "guestfs_int_mllib_realpath"
+end
+
 module StatVFS = struct
   external free_space : string -> int64 =
     "guestfs_int_mllib_statvfs_free_space"
diff --git a/mllib/unix_utils.mli b/mllib/unix_utils.mli
index 0a4c1b3..4795cb3 100644
--- a/mllib/unix_utils.mli
+++ b/mllib/unix_utils.mli
@@ -88,6 +88,11 @@ module Mkdtemp : sig
       [Filename.temp_dir_name] is used. *)
 end
 
+module Realpath : sig
+  val realpath : string -> string
+  (** [realpath(3)] returns the canonicalized absolute pathname. *)
+end
+
 module StatVFS : sig
   val free_space : string -> int64
   (** [free_space path] returns the free space available on the
-- 
2.9.3