Richard W.M. Jones
2017-Jun-03 08:22 UTC
[Libguestfs] [PATCH 0/3]: daemon: Reimplement ‘file’ API in OCaml.
This patch series is just FYI at the moment. However it does pass the tests. The daemon is a self-contained program. We don't need to write it all in C. Writing parts of it in OCaml would make it simpler and less error-prone. In particular if the daemon was written in a more sane programming language then we could move the inspection code to run entirely inside the appliance, which would be more secure, much faster and much saner for the people implementing it. This patch series allows individual APIs to be rewritten in OCaml (I am _not_ proposing that we would ever reimplement all APIs this way). The third patch reimplements the ?file? API this way, showing that the code ends up smaller, safer and (because we can now use a chroot properly) more accurate. Rich.
Richard W.M. Jones
2017-Jun-03 08:23 UTC
[Libguestfs] [PATCH 1/3] daemon: Allow parts of the daemon to be written in OCaml.
This change allows parts of the daemon to be written in the OCaml
programming language. I am using the ?Main Program in C? method along
with ?-output-obj? to create an object file from the OCaml code /
runtime, as described here:
https://caml.inria.fr/pub/docs/manual-ocaml/intfc.html
This change doesn't make any functional changes yet. There is simply
an empty ?daemon.ml? file.
Note that the OCaml compiler (either ocamlc or ocamlopt) is now
required even for building from tarballs.
---
.gitignore | 9 ++++-
daemon/Makefile.am | 89 +++++++++++++++++++++++++++++++++++++++++++++--
daemon/daemon.ml | 17 +++++++++
daemon/guestfsd.c | 5 +++
docs/guestfs-building.pod | 10 +++---
mllib/Makefile.am | 2 +-
6 files changed, 124 insertions(+), 8 deletions(-)
create mode 100644 daemon/daemon.ml
diff --git a/.gitignore b/.gitignore
index 69e1ae160..08d6e1863 100644
--- a/.gitignore
+++ b/.gitignore
@@ -154,22 +154,29 @@ Makefile.in
/customize/test-settings-*.sh
/customize/virt-customize
/customize/virt-customize.1
+/daemon/.depend
/daemon/actions.h
+/daemon/common_utils.ml
+/daemon/common_utils.mli
/daemon/dispatch.c
+/daemon/guestfs_config.ml
/daemon/guestfsd
/daemon/guestfsd.8
/daemon/guestfsd.exe
/daemon/install-sh
+/daemon/lvm-tokenization.c
/daemon/missing
/daemon/names.c
/daemon/optgroups.c
/daemon/optgroups.h
-/daemon/lvm-tokenization.c
/daemon/stamp-guestfsd.pod
/daemon/structs-cleanups.c
/daemon/structs-cleanups.h
/daemon/stubs-?.c
/daemon/stubs.h
+/daemon/unix_utils-c.c
+/daemon/unix_utils.ml
+/daemon/unix_utils.mli
/depcomp
/df/stamp-virt-df.pod
/df/virt-df
diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index 0d3dde516..1647b1c46 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -38,6 +38,7 @@ BUILT_SOURCES = \
EXTRA_DIST = \
$(BUILT_SOURCES) \
+ $(SOURCES_MLI) $(SOURCES_ML) \
guestfsd.pod
if INSTALL_DAEMON
@@ -165,6 +166,7 @@ guestfsd_SOURCES = \
truncate.c \
umask.c \
upload.c \
+ unix_utils-c.c \
utimens.c \
utsname.c \
uuids.c \
@@ -175,9 +177,11 @@ guestfsd_SOURCES = \
zero.c \
zerofree.c
+guestfsd_LDFLAGS = $(ocaml_ldflags)
guestfsd_LDADD = \
../common/errnostring/liberrnostring.la \
../common/protocol/libprotocol.la \
+ camldaemon.o \
$(ACL_LIBS) \
$(CAP_LIBS) \
$(YAJL_LIBS) \
@@ -196,9 +200,11 @@ guestfsd_LDADD = \
$(PCRE_LIBS) \
$(TSK_LIBS) \
$(RPC_LIBS) \
- $(YARA_LIBS)
+ $(YARA_LIBS) \
+ $(OCAML_LIBS)
guestfsd_CPPFLAGS = \
+ $(ocaml_cppflags) \
-I$(top_srcdir)/gnulib/lib \
-I$(top_builddir)/gnulib/lib \
-I$(top_srcdir)/lib \
@@ -216,6 +222,85 @@ guestfsd_CFLAGS = \
$(YAJL_CFLAGS) \
$(PCRE_CFLAGS)
+# Parts of the daemon are written in OCaml. These are linked into a
+# library and then linked to the daemon. See
+# https://caml.inria.fr/pub/docs/manual-ocaml/intfc.html
+SOURCES_MLI = \
+ common_utils.mli \
+ unix_utils.mli
+
+SOURCES_ML = \
+ guestfs_config.ml \
+ unix_utils.ml \
+ common_utils.ml \
+ daemon.ml
+
+BOBJECTS = $(SOURCES_ML:.ml=.cmo)
+XOBJECTS = $(BOBJECTS:.cmo=.cmx)
+
+OCAMLPACKAGES = -package str,unix,hivex
+
+ocaml_cppflags = \
+ -I$(shell $(OCAMLC) -where) \
+ -I$(shell $(OCAMLC) -where)/hivex
+ocaml_ldflags = \
+ -L$(shell $(OCAMLC) -where) \
+ -L$(shell $(OCAMLC) -where)/hivex
+
+OCAMLFLAGS = $(OCAML_FLAGS) $(OCAML_WARN_FLAGS)
+
+if !HAVE_OCAMLOPT
+OBJECTS = $(BOBJECTS)
+OCAML_LIBS = -lmlhivex -lcamlstr -lunix -lcamlrun -ldl -lm
+else
+OBJECTS = $(XOBJECTS)
+OCAML_LIBS = -lmlhivex -lcamlstr -lunix -lasmrun -ldl -lm
+endif
+
+CLEANFILES += camldaemon.o
+
+camldaemon.o: $(OBJECTS)
+ $(OCAMLFIND) $(BEST) -output-obj -o $@ \
+ $(OCAMLFLAGS) $(OCAMLPACKAGES) -linkpkg $(OBJECTS)
+
+# We share common_utils.ml{,i}, guestfs_config.ml and unix_utils*
+# with the mllib directory.
+#
+# For common_utils we have to remove functions which depend on any
+# modules which are not part of the OCaml stdlib.
+common_utils.ml: $(top_srcdir)/mllib/common_utils.ml
+ rm -f $@ $@-t
+ echo '(* This file is generated from mllib/common_utils.ml *)' >
$@-t
+ sed -n '/^(\*<stdlib>\*)$$/,/^(\*<\/stdlib>\*)$$/p' $<
>> $@-t
+ mv $@-t $@
+common_utils.mli: $(top_srcdir)/mllib/common_utils.mli
+ rm -f $@ $@-t
+ echo '(* This file is generated from mllib/common_utils.mli *)' >
$@-t
+ sed -n '/^(\*<stdlib>\*)$$/,/^(\*<\/stdlib>\*)$$/p' $<
>> $@-t
+ mv $@-t $@
+guestfs_config.ml: ../mllib/guestfs_config.ml
+ cp $< $@
+unix_utils-c.c: ../mllib/unix_utils-c.c
+ cp $< $@
+unix_utils.ml: ../mllib/unix_utils.ml
+ cp $< $@
+unix_utils.mli: ../mllib/unix_utils.mli
+ cp $< $@
+
+# OCaml dependencies.
+depend: .depend
+
+.depend: $(wildcard $(abs_srcdir)/*.mli) $(wildcard $(abs_srcdir)/*.ml)
common_utils.ml common_utils.mli guestfs_config.ml
+ rm -f $@ $@-t
+ $(OCAMLFIND) ocamldep -I ../ocaml -I $(abs_srcdir) -I
$(abs_top_builddir)/mllib -I $(abs_top_builddir)/customize $^ | \
+ $(SED) 's/ *$$//' | \
+ $(SED) -e :a -e '/ *\\$$/N; s/ *\\\n */ /; ta' | \
+ $(SED) -e 's,$(abs_srcdir)/,$(builddir)/,g' | \
+ sort > $@-t
+ mv $@-t $@
+
+-include .depend
+
# Manual pages and HTML files for the website.
if INSTALL_DAEMON
man_MANS = guestfsd.8
@@ -237,4 +322,4 @@ stamp-guestfsd.pod: guestfsd.pod
$<
touch $@
-.PHONY: force
+.PHONY: depend force
diff --git a/daemon/daemon.ml b/daemon/daemon.ml
new file mode 100644
index 000000000..27d77a161
--- /dev/null
+++ b/daemon/daemon.ml
@@ -0,0 +1,17 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index db2bb702f..02fc27d32 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -56,6 +56,8 @@
#include <augeas.h>
+#include <caml/callback.h>
+
#include "sockets.h"
#include "c-ctype.h"
#include "ignore-value.h"
@@ -348,6 +350,9 @@ main (int argc, char *argv[])
*/
udev_settle ();
+ /* Initialize the OCaml stubs. */
+ caml_startup (argv);
+
/* Send the magic length message which indicates that
* userspace is up inside the guest.
*/
diff --git a/docs/guestfs-building.pod b/docs/guestfs-building.pod
index 0f9ed2893..4e1ff7df4 100644
--- a/docs/guestfs-building.pod
+++ b/docs/guestfs-building.pod
@@ -120,8 +120,7 @@ I<Required>. Part of Perl core.
=item OCaml findlib
-I<Required> if compiling from git.
-Optional (but recommended) if compiling from tarball.
+I<Required>.
=item autoconf
@@ -594,8 +593,11 @@ See L</USING A PREBUILT BINARY APPLIANCE> below.
Disable specific language bindings, even if C<./configure> finds all
the necessary libraries are installed so that they could be compiled.
-Note that disabling OCaml or Perl will have the knock-on effect of
-disabling large numbers of virt tools and parts of the test suite.
+Note that disabling Perl will have the knock-on effect of disabling
+parts of the test suite and some tools.
+
+Disabling OCaml only disables the bindings and several virt tools.
+OCaml is required to build libguestfs.
=item B<--disable-fuse>
diff --git a/mllib/Makefile.am b/mllib/Makefile.am
index ee2f1a7a8..8e2d3a8a0 100644
--- a/mllib/Makefile.am
+++ b/mllib/Makefile.am
@@ -49,9 +49,9 @@ SOURCES_ML = \
$(OCAML_BYTES_COMPAT_ML) \
libdir.ml \
stringMap.ml \
+ unix_utils.ml \
common_gettext.ml \
getopt.ml \
- unix_utils.ml \
common_utils.ml \
progress.ml \
URI.ml \
--
2.13.0
Richard W.M. Jones
2017-Jun-03 08:23 UTC
[Libguestfs] [PATCH 2/3] generator: Allow APIs to be implemented in OCaml.
Change the generator to allow individual APIs to be implemented in
OCaml. This is picked by setting:
impl = OCaml <ocaml_function>;
The generator creates ?do_function? (the same one you would have to
write by hand in C), with the function calling the named
?ocaml_function? and dealing with marshalling/unmarshalling the OCaml
parameters.
---
.gitignore | 3 +
daemon/Makefile.am | 33 ++++++++--
daemon/chroot.ml | 85 ++++++++++++++++++++++++
daemon/chroot.mli | 35 ++++++++++
daemon/daemon.ml | 4 ++
daemon/guestfsd.c | 40 ++++++++++++
daemon/utils-c.c | 37 +++++++++++
daemon/utils.ml | 158 +++++++++++++++++++++++++++++++++++++++++++++
daemon/utils.mli | 70 ++++++++++++++++++++
docs/guestfs-hacking.pod | 7 ++
generator/actions.ml | 5 ++
generator/actions.mli | 4 ++
generator/daemon.ml | 165 +++++++++++++++++++++++++++++++++++++++++++++++
generator/daemon.mli | 3 +
generator/main.ml | 6 ++
generator/types.ml | 7 +-
16 files changed, 657 insertions(+), 5 deletions(-)
create mode 100644 daemon/chroot.ml
create mode 100644 daemon/chroot.mli
create mode 100644 daemon/utils-c.c
create mode 100644 daemon/utils.ml
create mode 100644 daemon/utils.mli
diff --git a/.gitignore b/.gitignore
index 08d6e1863..69b824a74 100644
--- a/.gitignore
+++ b/.gitignore
@@ -156,6 +156,8 @@ Makefile.in
/customize/virt-customize.1
/daemon/.depend
/daemon/actions.h
+/daemon/callbacks.ml
+/daemon/caml-stubs.c
/daemon/common_utils.ml
/daemon/common_utils.mli
/daemon/dispatch.c
@@ -174,6 +176,7 @@ Makefile.in
/daemon/structs-cleanups.h
/daemon/stubs-?.c
/daemon/stubs.h
+/daemon/types.ml
/daemon/unix_utils-c.c
/daemon/unix_utils.ml
/daemon/unix_utils.mli
diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index 1647b1c46..ba37cbb6b 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -19,6 +19,7 @@ include $(top_srcdir)/subdir-rules.mk
generator_built = \
actions.h \
+ caml-stubs.c \
dispatch.c \
names.c \
lvm-tokenization.c \
@@ -31,13 +32,29 @@ generator_built = \
stubs-4.c \
stubs-5.c \
stubs-6.c \
- stubs.h
+ stubs.h \
+ callbacks.ml \
+ types.ml
BUILT_SOURCES = \
- $(generator_built)
+ actions.h \
+ caml-stubs.c \
+ dispatch.c \
+ names.c \
+ lvm-tokenization.c \
+ structs-cleanups.c \
+ structs-cleanups.h \
+ stubs-0.c \
+ stubs-1.c \
+ stubs-2.c \
+ stubs-3.c \
+ stubs-4.c \
+ stubs-5.c \
+ stubs-6.c \
+ stubs.h
EXTRA_DIST = \
- $(BUILT_SOURCES) \
+ $(generator_built) \
$(SOURCES_MLI) $(SOURCES_ML) \
guestfsd.pod
@@ -60,6 +77,7 @@ guestfsd_SOURCES = \
blkid.c \
blockdev.c \
btrfs.c \
+ caml-stubs.c \
cap.c \
checksum.c \
cleanups.c \
@@ -167,6 +185,7 @@ guestfsd_SOURCES = \
umask.c \
upload.c \
unix_utils-c.c \
+ utils-c.c \
utimens.c \
utsname.c \
uuids.c \
@@ -226,13 +245,19 @@ guestfsd_CFLAGS = \
# library and then linked to the daemon. See
# https://caml.inria.fr/pub/docs/manual-ocaml/intfc.html
SOURCES_MLI = \
+ chroot.mli \
common_utils.mli \
- unix_utils.mli
+ unix_utils.mli \
+ utils.mli
SOURCES_ML = \
guestfs_config.ml \
unix_utils.ml \
common_utils.ml \
+ types.ml \
+ utils.ml \
+ chroot.ml \
+ callbacks.ml \
daemon.ml
BOBJECTS = $(SOURCES_ML:.ml=.cmo)
diff --git a/daemon/chroot.ml b/daemon/chroot.ml
new file mode 100644
index 000000000..14dcbc494
--- /dev/null
+++ b/daemon/chroot.ml
@@ -0,0 +1,85 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+open Printf
+open Unix
+
+open Common_utils
+open Unix_utils
+
+type t = {
+ name : string;
+ chroot : string;
+}
+
+let create ?(name = prog) chroot + { name = name; chroot = chroot }
+
+let f t func arg + if verbose () then
+ eprintf "chroot: %s: running ?%s?\n%!" t.chroot t.name;
+
+ let rfd, wfd = pipe () in
+
+ let pid = fork () in
+ if pid = 0 then (
+ (* Child. *)
+ close rfd;
+
+ chdir t.chroot;
+ chroot t.chroot;
+
+ let ret + try Either (func arg)
+ with exn -> Or exn in
+
+ try
+ let chan = out_channel_of_descr wfd in
+ output_value chan ret;
+ Pervasives.flush chan;
+ Exit._exit 0
+ with
+ exn ->
+ prerr_endline (Printexc.to_string exn);
+ Exit._exit 1
+ );
+
+ (* Parent. *)
+ close wfd;
+
+ let _, status = waitpid [] pid in
+ (match status with
+ | WEXITED 0 -> ()
+ | WEXITED i ->
+ close rfd;
+ failwithf "chroot ?%s? exited with non-zero error %d" t.name i
+ | WSIGNALED i ->
+ close rfd;
+ failwithf "chroot ?%s? killed by signal %d" t.name i
+ | WSTOPPED i ->
+ close rfd;
+ failwithf "chroot ?%s? stopped by signal %d" t.name i
+ );
+
+ let chan = in_channel_of_descr rfd in
+ let ret = input_value chan in
+ close_in chan;
+
+ match ret with
+ | Either ret -> ret
+ | Or exn -> raise exn
diff --git a/daemon/chroot.mli b/daemon/chroot.mli
new file mode 100644
index 000000000..eda3a785f
--- /dev/null
+++ b/daemon/chroot.mli
@@ -0,0 +1,35 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+(** This is a generic module for running functions in a chroot.
+ The function runs in a forked subprocess too so that we can
+ restore the root afterwards.
+
+ It handles passing the parmeter, forking, running the
+ function and marshalling the result or any exceptions. *)
+
+type t
+
+val create : ?name:string -> string -> t
+(** Create a chroot handle. [?name] is an optional name used in
+ debugging and error messages. The string is the chroot
+ directory. *)
+
+val f : t -> ('a -> 'b) -> 'a -> 'b
+(** Run a function in the chroot, returning the result or re-raising
+ any exception thrown. *)
diff --git a/daemon/daemon.ml b/daemon/daemon.ml
index 27d77a161..466459912 100644
--- a/daemon/daemon.ml
+++ b/daemon/daemon.ml
@@ -15,3 +15,7 @@
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*)
+
+let () + (* Register the callbacks which are used to call OCaml code from C.
*)
+ Callbacks.init_callbacks ()
diff --git a/daemon/guestfsd.c b/daemon/guestfsd.c
index 02fc27d32..9b6ae02b1 100644
--- a/daemon/guestfsd.c
+++ b/daemon/guestfsd.c
@@ -57,6 +57,8 @@
#include <augeas.h>
#include <caml/callback.h>
+#include <caml/mlvalues.h>
+#include <caml/unixsupport.h>
#include "sockets.h"
#include "c-ctype.h"
@@ -1274,3 +1276,41 @@ cleanup_free_mountable (mountable_t *mountable)
free (mountable->volume);
}
}
+
+/* Convert an OCaml exception to a reply_with_error_errno call
+ * as best we can.
+ */
+extern void ocaml_exn_to_reply_with_error (const char *func, value exn);
+
+void
+ocaml_exn_to_reply_with_error (const char *func, value exn)
+{
+ const char *exn_name;
+
+ /* This is not the official way to do this, but I could not get the
+ * official way to work, and this way does work. See
+ *
http://caml.inria.fr/pub/ml-archives/caml-list/2006/05/097f63cfb39a80418f95c70c3c520aa8.en.html
+ *
http://caml.inria.fr/pub/ml-archives/caml-list/2009/06/797e2f797f57b8ea2a2c0e431a2df312.en.html
+ */
+ exn_name = String_val (Field (Field (exn, 0), 0));
+ if (verbose)
+ fprintf (stderr, "ocaml_exn: '%s' raised '%s'
exception\n",
+ func, exn_name);
+
+ if (STREQ (exn_name, "Unix.Unix_error")) {
+ int errcode = code_of_unix_error (Field (exn, 1));
+ reply_with_perror_errno (errcode, "%s: %s",
+ String_val (Field (exn, 2)),
+ String_val (Field (exn, 3)));
+ }
+ else if (STREQ (exn_name, "Failure"))
+ reply_with_error ("%s", String_val (Field (exn, 1)));
+ else if (STREQ (exn_name, "Sys_error"))
+ reply_with_error ("%s", String_val (Field (exn, 1)));
+ else if (STREQ (exn_name, "Invalid_argument"))
+ reply_with_error ("invalid argument: %s",
+ String_val (Field (exn, 1)));
+ else
+ reply_with_error ("internal error: %s: unknown exception thrown:
%s",
+ func, exn_name);
+}
diff --git a/daemon/utils-c.c b/daemon/utils-c.c
new file mode 100644
index 000000000..ad31d36ee
--- /dev/null
+++ b/daemon/utils-c.c
@@ -0,0 +1,37 @@
+/* guestfs-inspection
+ * Copyright (C) 2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
USA.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <caml/alloc.h>
+#include <caml/fail.h>
+#include <caml/memory.h>
+#include <caml/mlvalues.h>
+
+#include "daemon.h"
+
+extern value guestfs_int_daemon_sysroot (value unitv);
+
+value
+guestfs_int_daemon_sysroot (value unitv)
+{
+ return caml_copy_string (sysroot);
+}
diff --git a/daemon/utils.ml b/daemon/utils.ml
new file mode 100644
index 000000000..049df6f12
--- /dev/null
+++ b/daemon/utils.ml
@@ -0,0 +1,158 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+open Unix
+open Printf
+
+open Common_utils
+
+external sysroot : unit -> string = "guestfs_int_daemon_sysroot"
+
+let prog_exists prog + try ignore (which prog); true
+ with Executable_not_found _ -> false
+
+let commandr prog args + if verbose () then
+ eprintf "command: %s %s\n"
+ prog (String.concat " " args);
+
+ let argv = Array.of_list (prog :: args) in
+
+ let stdout_file, stdout_chan = Filename.open_temp_file "cmd"
".out" in
+ let stderr_file, stderr_chan = Filename.open_temp_file "cmd"
".err" in
+ let stdout_fd = descr_of_out_channel stdout_chan in
+ let stderr_fd = descr_of_out_channel stderr_chan in
+ let stdin_fd = openfile "/dev/null" [O_RDONLY] 0 in
+
+ let pid = fork () in
+ if pid = 0 then (
+ (* Child process. *)
+ dup2 stdin_fd stdin;
+ close stdin_fd;
+ dup2 stdout_fd stdout;
+ close stdout_fd;
+ dup2 stderr_fd stderr;
+ close stderr_fd;
+
+ execvp prog argv
+ );
+
+ (* Parent process. *)
+ close stdin_fd;
+ close stdout_fd;
+ close stderr_fd;
+ let _, status = waitpid [] pid in
+ let r + match status with
+ | WEXITED i -> i
+ | WSIGNALED i ->
+ failwithf "external command ?%s? killed by signal %d" prog i
+ | WSTOPPED i ->
+ failwithf "external command ?%s? stopped by signal %d" prog i
in
+
+ if verbose () then
+ eprintf "command: %s returned %d\n" prog r;
+
+ let stdout = read_whole_file stdout_file in
+ let stderr = read_whole_file stderr_file in
+
+ if verbose () then (
+ if stdout <> "" then (
+ eprintf "command: %s: stdout:\n%s" prog stdout;
+ if not (String.is_suffix stdout "\n") then eprintf
"\n"
+ );
+ if stderr <> "" then (
+ eprintf "command: %s: stderr:\n%s" prog stderr;
+ if not (String.is_suffix stderr "\n") then eprintf
"\n"
+ )
+ );
+
+ (* Strip trailing \n from stderr but NOT from stdout. *)
+ let stderr + let n = String.length stderr in
+ if n > 0 && stderr.[n-1] = '\n' then
+ String.sub stderr 0 (n-1)
+ else
+ stderr in
+
+ (r, stdout, stderr)
+
+let command prog args + let r, stdout, stderr = commandr prog args in
+ if r <> 0 then
+ failwithf "%s exited with status %d: %s" prog r stderr;
+ stdout
+
+let udev_settle ?filename () + let args = ref [] in
+ if verbose () then
+ push_back args "--debug";
+ push_back args "settle";
+ (match filename with
+ | None -> ()
+ | Some filename ->
+ push_back args "-E";
+ push_back args filename
+ );
+ let args = !args in
+ let r, _, err = commandr "udevadm" args in
+ if r <> 0 then
+ eprintf "udevadm settle: %s\n" err
+
+let root_device = lazy ((stat "/").st_dev)
+
+let is_root_device_stat statbuf + statbuf.st_rdev = Lazy.force root_device
+
+let is_root_device device + udev_settle ~filename:device ();
+ try
+ let statbuf = stat device in
+ is_root_device_stat statbuf
+ with
+ Unix_error (err, func, arg) ->
+ eprintf "is_root_device: %s: %s: %s: %s\n"
+ device func arg (error_message err);
+ false
+
+let proc_unmangle_path path + let n = String.length path in
+ let b = Buffer.create n in
+ let rec loop i + if i < n-3 && path.[i] = '\\' then (
+ let to_int c = Char.code c - Char.code '0' in
+ let v + (to_int path.[i+1] lsl 6) lor
+ (to_int path.[i+2] lsl 3) lor
+ to_int path.[i+3] in
+ Buffer.add_char b (Char.chr v);
+ loop (i+4)
+ )
+ else if i < n then (
+ Buffer.add_char b path.[i];
+ loop (i+1)
+ )
+ else
+ Buffer.contents b
+ in
+ loop 0
+
+let is_small_file path + is_regular_file path &&
+ (stat path).st_size <= 2 * 1048 * 1024
diff --git a/daemon/utils.mli b/daemon/utils.mli
new file mode 100644
index 000000000..9fe053825
--- /dev/null
+++ b/daemon/utils.mli
@@ -0,0 +1,70 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+val sysroot : unit -> string
+(** Return the current sysroot path where filesystems are mounted.
+ This comes from the daemon command line ([-r] option) or a built
+ in default. *)
+
+val prog_exists : string -> bool
+(** Return true iff the program is found on [$PATH]. *)
+
+val udev_settle : ?filename:string -> unit -> unit
+(**
+ * LVM and other commands aren't synchronous, especially when udev is
+ * involved. eg. You can create or remove some device, but the
+ * [/dev] device node won't appear until some time later. This means
+ * that you get an error if you run one command followed by another.
+ *
+ * Use [udevadm settle] after certain commands, but don't be too
+ * fussed if it fails.
+ *
+ * The optional [?filename] passes the [udevadm settle -E filename]
+ * option, which means udevadm stops waiting as soon as the named
+ * file is created (or if it exists at the start).
+ *)
+
+val is_root_device : string -> bool
+(** Return true if this is the root (appliance) device. *)
+
+val is_root_device_stat : Unix.stats -> bool
+(** As for {!is_root_device} but operates on a statbuf instead of
+ a device name. *)
+
+val proc_unmangle_path : string -> string
+(** Reverse kernel path escaping done in fs/seq_file.c:mangle_path.
+ This is inconsistently used for /proc fields. *)
+
+val command : string -> string list -> string
+(** Run an external command without using the shell, and collect
+ stdout and stderr separately. Returns stdout if the command
+ runs successfully.
+
+ On failure of the command, this throws an exception containing
+ the stderr from the command. *)
+
+val commandr : string -> string list -> (int * string * string)
+(** Run an external command without using the shell, and collect
+ stdout and stderr separately.
+
+ Returns [status, stdout, stderr]. As with the C function in
+ [daemon/command.c], this strips the trailing [\n] from stderr,
+ but {b not} from stdout. *)
+
+val is_small_file : string -> bool
+(** Return true if the path is a small regular file. *)
diff --git a/docs/guestfs-hacking.pod b/docs/guestfs-hacking.pod
index 098869bbd..2d3eb46c6 100644
--- a/docs/guestfs-hacking.pod
+++ b/docs/guestfs-hacking.pod
@@ -386,6 +386,13 @@ in the C<lib/> directory.
In either case, use another function as an example of what to do.
+=item 3.
+
+As an alternative to step 2: Since libguestfs 1.37.15, daemon actions
+can be implemented in OCaml. You have to set the C<impl = OCaml ...>
+flag in the generator. Take a look at F<daemon/file.ml> for an
+example.
+
=back
After making these changes, use C<make> to compile.
diff --git a/generator/actions.ml b/generator/actions.ml
index 2722f3dcd..db69321e4 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -185,6 +185,11 @@ let is_fish { visibility = v; style = (_, args, _) }
not (List.exists (function Pointer _ -> true | _ -> false) args)
let fish_functions = List.filter is_fish
+let is_ocaml_function = function
+ | { impl = OCaml _ } -> true
+ | { impl = C } -> false
+let impl_ocaml_functions = List.filter is_ocaml_function
+
(* In some places we want the functions to be displayed sorted
* alphabetically, so this is useful:
*)
diff --git a/generator/actions.mli b/generator/actions.mli
index 0d326b609..82217cbdc 100644
--- a/generator/actions.mli
+++ b/generator/actions.mli
@@ -40,6 +40,10 @@ val internal_functions : Types.action list -> Types.action
list
val fish_functions : Types.action list -> Types.action list
(** Filter {!actions}, returning only functions in guestfish. *)
+val impl_ocaml_functions : Types.action list -> Types.action list
+(** Filter {!actions}, returning only functions implemented
+ in OCaml (in the daemon). *)
+
val documented_functions : Types.action list -> Types.action list
(** Filter {!actions}, returning only functions requiring documentation. *)
diff --git a/generator/daemon.ml b/generator/daemon.ml
index 84686973c..b44406d79 100644
--- a/generator/daemon.ml
+++ b/generator/daemon.ml
@@ -471,6 +471,171 @@ let generate_daemon_stubs actions () pr
"}\n\n";
) (actions |> daemon_functions |> sort)
+let generate_daemon_caml_types_ml () + generate_header OCamlStyle GPLv2plus
+
+let generate_daemon_caml_callbacks_ml () + generate_header OCamlStyle
GPLv2plus;
+
+ pr "let init_callbacks () =\n";
+ pr " (* Initialize callbacks to OCaml code. *)\n";
+ List.iter (
+ fun ({ name = name; style = ret, args, optargs } as f) ->
+ let ocaml_function + match f.impl with
+ | OCaml f -> f
+ | C -> assert false in
+
+ pr " Callback.register %S %s;\n" ocaml_function ocaml_function
+ ) (actions |> impl_ocaml_functions |> sort)
+
+(* Generate stubs for the functions implemented in OCaml.
+ * Basically we implement the do_<name> function here, and
+ * have it call out to OCaml code.
+ *)
+let generate_daemon_caml_stubs () + generate_header CStyle GPLv2plus;
+
+ pr "\
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <inttypes.h>
+#include <errno.h>
+
+#include <caml/alloc.h>
+#include <caml/callback.h>
+#include <caml/fail.h>
+#include <caml/memory.h>
+#include <caml/mlvalues.h>
+
+#include \"daemon.h\"
+#include \"actions.h\"
+
+/* This is not declared in <daemon.h> because we don't want to
+ * include the OCaml headers (to get 'value') for the whole daemon.
+ */
+extern void ocaml_exn_to_reply_with_error (const char *func, value exn);
+
+";
+
+ List.iter (
+ fun ({ name = name; style = ret, args, optargs } as f) ->
+ let ocaml_function + match f.impl with
+ | OCaml f -> f
+ | C -> assert false in
+
+ pr "/* Wrapper for OCaml function ?%s?. */\n" ocaml_function;
+
+ let args_do_function = args @ args_of_optargs optargs in
+ let args_do_function + List.filter (function
+ | String ((FileIn|FileOut), _) -> false | _ -> true)
+ args_do_function in
+ let style = ret, args_do_function, [] in
+ generate_prototype ~extern:false ~semicolon:false
+ ~single_line:false ~newline:false
+ ~in_daemon:true ~prefix:"do_"
+ name style;
+ pr "\n";
+
+ pr "{\n";
+ pr " static value *cb = NULL;\n";
+ pr " CAMLparam0 ();\n";
+ pr " CAMLlocal2 (v, retv);\n";
+ let nr_args = List.length args_do_function in
+ pr " CAMLlocalN (args, %d);\n" nr_args;
+ pr "\n";
+ pr " if (cb == NULL)\n";
+ pr " cb = caml_named_value (\"%s\");\n"
ocaml_function;
+ pr "\n";
+
+ (* Construct the actual call, but note that we want to pass
+ * the optional arguments first in the list.
+ *)
+ let i = ref 0 in
+ List.iter (
+ fun optarg ->
+ let n = name_of_optargt optarg in
+ let uc_n = String.uppercase_ascii n in
+
+ (* optargs are all passed as [None|Some _] *)
+ pr " if ((optargs_bitmask & %s_%s_BITMASK) == 0)\n"
+ f.c_optarg_prefix uc_n;
+ pr " args[%d] = Val_int (0); /* None */\n" !i;
+ pr " else {\n";
+ pr " v = ";
+ (match optarg with
+ | OBool _ ->
+ pr "Val_bool (%s)" n;
+ | OInt _ -> assert false
+ | OInt64 _ -> assert false
+ | OString _ -> assert false
+ | OStringList _ -> assert false
+ );
+ pr ";\n";
+ pr " args[%d] = caml_alloc (1, 0);\n" !i;
+ pr " Store_field (args[%d], 0, v);\n" !i;
+ pr " }\n";
+ incr i
+ ) optargs;
+ List.iter (
+ fun arg ->
+ pr " args[%d] = " !i;
+ (match arg with
+ | Bool n -> pr "Val_bool (%s)" n
+ | Int n -> pr "Val_int (%s)" n
+ | Int64 n -> pr "caml_copy_int64 (%s)" n
+ | String (_, n) -> pr "caml_copy_string (%s)" n
+ | OptString _ -> assert false
+ | StringList _ -> assert false
+ | BufferIn _ -> assert false
+ | Pointer _ -> assert false
+ );
+ pr ";\n";
+ incr i
+ ) args;
+ assert (!i = nr_args);
+
+ pr " retv = caml_callbackN_exn (*cb, %d, args);\n" nr_args;
+ pr "\n";
+ pr " if (Is_exception_result (retv)) {\n";
+ pr " retv = Extract_exception (retv);\n";
+ pr " ocaml_exn_to_reply_with_error (%S, retv);\n" name;
+ (match errcode_of_ret ret with
+ | `CannotReturnError ->
+ pr " CAMLreturn0;\n"
+ | `ErrorIsMinusOne ->
+ pr " CAMLreturnT (int, -1);\n"
+ | `ErrorIsNULL ->
+ pr " CAMLreturnT (void *, NULL);\n"
+ );
+ pr " }\n";
+
+ (match ret with
+ | RErr -> assert false
+ | RInt _ -> assert false
+ | RInt64 _ -> assert false
+ | RBool _ -> assert false
+ | RConstString _ -> assert false
+ | RConstOptString _ -> assert false
+ | RString _ ->
+ pr " char *ret = strdup (String_val (retv));\n";
+ pr " CAMLreturnT (char *, ret); /* caller frees */\n"
+ | RStringList _ -> assert false
+ | RStruct _ -> assert false
+ | RStructList _ -> assert false
+ | RHashtable _ -> assert false
+ | RBufferOut _ -> assert false
+ );
+ pr "}\n";
+ pr "\n"
+ ) (actions |> impl_ocaml_functions |> sort)
+
let generate_daemon_dispatch () generate_header CStyle GPLv2plus;
diff --git a/generator/daemon.mli b/generator/daemon.mli
index ff008bf85..314a6da8f 100644
--- a/generator/daemon.mli
+++ b/generator/daemon.mli
@@ -19,6 +19,9 @@
val generate_daemon_actions_h : unit -> unit
val generate_daemon_stubs_h : unit -> unit
val generate_daemon_stubs : Types.action list -> unit -> unit
+val generate_daemon_caml_stubs : unit -> unit
+val generate_daemon_caml_callbacks_ml : unit -> unit
+val generate_daemon_caml_types_ml : unit -> unit
val generate_daemon_dispatch : unit -> unit
val generate_daemon_lvm_tokenization : unit -> unit
val generate_daemon_names : unit -> unit
diff --git a/generator/main.ml b/generator/main.ml
index d4316c085..cb39cb610 100644
--- a/generator/main.ml
+++ b/generator/main.ml
@@ -133,6 +133,12 @@ Run it from the top source directory using the command
Daemon.generate_daemon_stubs_h;
output_to_subset "daemon/stubs-%d.c"
Daemon.generate_daemon_stubs;
+ output_to "daemon/caml-stubs.c"
+ Daemon.generate_daemon_caml_stubs;
+ output_to "daemon/callbacks.ml"
+ Daemon.generate_daemon_caml_callbacks_ml;
+ output_to "daemon/types.ml"
+ Daemon.generate_daemon_caml_types_ml;
output_to "daemon/dispatch.c"
Daemon.generate_daemon_dispatch;
output_to "daemon/names.c"
diff --git a/generator/types.ml b/generator/types.ml
index 740bc7750..fb6c3bc06 100644
--- a/generator/types.ml
+++ b/generator/types.ml
@@ -379,11 +379,16 @@ type deprecated_by | Replaced_by of string (*
replaced by another function *)
| Deprecated_no_replacement (* deprecated with no replacement *)
+type impl + | C (* implemented in C by
"do_<name>" *)
+ | OCaml of string (* implemented in OCaml by named function *)
+
(* Type of an action as declared in Actions module. *)
type action = {
name : string; (* name, not including "guestfs_"
*)
added : version; (* which version was the API first added *)
style : style; (* args and return value *)
+ impl : impl; (* implementation language (C or OCaml) *)
proc_nr : int option; (* proc number, None for non-daemon *)
tests : c_api_tests; (* C API tests *)
test_excuse : string; (* if there's no tests ... *)
@@ -439,7 +444,7 @@ type action = {
*)
let defaults = { name = "";
added = (-1,-1,-1);
- style = RErr, [], []; proc_nr = None;
+ style = RErr, [], []; impl = C; proc_nr = None;
tests = []; test_excuse = "";
shortdesc = ""; longdesc = "";
protocol_limit_warning = false; fish_alias = [];
--
2.13.0
Richard W.M. Jones
2017-Jun-03 08:23 UTC
[Libguestfs] [PATCH 3/3] daemon: Reimplement ‘file’ API in OCaml.
?file? is a small, self-contained API which runs a single command, so
it's a good test case for reimplementing APIs.
---
daemon/Makefile.am | 2 ++
daemon/file.c | 80 -----------------------------------------------
daemon/file.ml | 60 +++++++++++++++++++++++++++++++++++
daemon/file.mli | 19 +++++++++++
generator/actions_core.ml | 1 +
5 files changed, 82 insertions(+), 80 deletions(-)
create mode 100644 daemon/file.ml
create mode 100644 daemon/file.mli
diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index ba37cbb6b..5a800bbcf 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -247,6 +247,7 @@ guestfsd_CFLAGS = \
SOURCES_MLI = \
chroot.mli \
common_utils.mli \
+ file.mli \
unix_utils.mli \
utils.mli
@@ -257,6 +258,7 @@ SOURCES_ML = \
types.ml \
utils.ml \
chroot.ml \
+ file.ml \
callbacks.ml \
daemon.ml
diff --git a/daemon/file.c b/daemon/file.c
index 84874dc6f..ee79eb507 100644
--- a/daemon/file.c
+++ b/daemon/file.c
@@ -30,7 +30,6 @@
#include "actions.h"
#include "optgroups.h"
-GUESTFSD_EXT_CMD(str_file, file);
GUESTFSD_EXT_CMD(str_zcat, zcat);
GUESTFSD_EXT_CMD(str_bzcat, bzcat);
@@ -449,85 +448,6 @@ do_pwrite_device (const char *device, const char *content,
size_t size,
return pwrite_fd (fd, content, size, offset, device, 1);
}
-/* This runs the 'file' command. */
-char *
-do_file (const char *path)
-{
- CLEANUP_FREE char *buf = NULL;
- const char *display_path = path;
- const int is_dev = STRPREFIX (path, "/dev/");
- struct stat statbuf;
-
- if (!is_dev) {
- buf = sysroot_path (path);
- if (!buf) {
- reply_with_perror ("malloc");
- return NULL;
- }
- path = buf;
-
- /* For non-dev, check this is a regular file, else just return the
- * file type as a string (RHBZ#582484).
- */
- if (lstat (path, &statbuf) == -1) {
- reply_with_perror ("lstat: %s", display_path);
- return NULL;
- }
-
- if (! S_ISREG (statbuf.st_mode)) {
- char *ret;
-
- if (S_ISDIR (statbuf.st_mode))
- ret = strdup ("directory");
- else if (S_ISCHR (statbuf.st_mode))
- ret = strdup ("character device");
- else if (S_ISBLK (statbuf.st_mode))
- ret = strdup ("block device");
- else if (S_ISFIFO (statbuf.st_mode))
- ret = strdup ("FIFO");
- else if (S_ISLNK (statbuf.st_mode))
- ret = strdup ("symbolic link");
- else if (S_ISSOCK (statbuf.st_mode))
- ret = strdup ("socket");
- else
- ret = strdup ("unknown, not regular file");
-
- if (ret == NULL)
- reply_with_perror ("strdup");
- return ret;
- }
- }
-
- /* Which flags to use? For /dev paths, follow links because
- * /dev/VG/LV is a symbolic link.
- */
- const char *flags = is_dev ? "-zbsL" : "-zb";
-
- char *out;
- CLEANUP_FREE char *err = NULL;
- int r = command (&out, &err, str_file, flags, path, NULL);
-
- if (r == -1) {
- free (out);
- reply_with_error ("%s: %s", display_path, err);
- return NULL;
- }
-
- /* We need to remove the trailing \n from output of file(1). */
- size_t len = strlen (out);
- if (len > 0 && out[len-1] == '\n')
- out[--len] = '\0';
-
- /* Some upstream versions of file add a space at the end of the
- * output. This is fixed in the Fedora version, but we might as
- * well fix it here too. (RHBZ#928995).
- */
- if (len > 0 && out[len-1] == ' ')
- out[--len] = '\0';
-
- return out; /* caller frees */
-}
-
/* zcat | file */
char *
do_zfile (const char *method, const char *path)
diff --git a/daemon/file.ml b/daemon/file.ml
new file mode 100644
index 000000000..05e315212
--- /dev/null
+++ b/daemon/file.ml
@@ -0,0 +1,60 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+open Unix
+open Printf
+
+open Common_utils
+
+open Utils
+
+(* This runs the [file] command. *)
+let file path + let is_dev = String.is_prefix path "/dev/" in
+
+ (* For non-dev, check this is a regular file, else just return the
+ * file type as a string (RHBZ#582484).
+ *)
+ if not is_dev then (
+ let sysroot = sysroot () in
+ let chroot = Chroot.create sysroot ~name:(sprintf "file: %s"
path) in
+
+ let statbuf = Chroot.f chroot lstat path in
+ match statbuf.st_kind with
+ | S_DIR -> "directory"
+ | S_CHR -> "character device"
+ | S_BLK -> "block device"
+ | S_FIFO -> "FIFO"
+ | S_LNK -> "symbolic link"
+ | S_SOCK -> "socket"
+ | S_REG ->
+ (* Regular file, so now run [file] on it. *)
+ let out = command "file" ["-zb"; sysroot // path] in
+
+ (* We need to remove the trailing \n from output of file(1).
+ *
+ * Some upstream versions of file add a space at the end of the
+ * output. This is fixed in the Fedora version, but we might as
+ * well fix it here too. (RHBZ#928995).
+ *)
+ String.trimr out
+ )
+ else (* it's a device *) (
+ let out = command "file" ["-zbsL"; path] in
+ String.trimr out
+ )
diff --git a/daemon/file.mli b/daemon/file.mli
new file mode 100644
index 000000000..bd49bad0b
--- /dev/null
+++ b/daemon/file.mli
@@ -0,0 +1,19 @@
+(* guestfs-inspection
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *)
+
+val file : string -> string
diff --git a/generator/actions_core.ml b/generator/actions_core.ml
index 0e667eff1..26ed1274e 100644
--- a/generator/actions_core.ml
+++ b/generator/actions_core.ml
@@ -2321,6 +2321,7 @@ and physical volumes." };
{ defaults with
name = "file"; added = (1, 9, 1);
style = RString (RPlainString, "description"), [String
(Dev_or_Path, "path")], [];
+ impl = OCaml "File.file";
tests = [
InitISOFS, Always, TestResultString (
[["file"; "/empty"]], "empty"), [];
--
2.13.0
Reasonably Related Threads
- [PATCH v2 00/12] Allow APIs to be implemented in OCaml.
- [PATCH v3 00/19] Allow APIs to be implemented in OCaml.
- [PATCH v5 00/32] Refactor utilities, implement some APIs in OCaml.
- [PATCH 00/27] Reimplement many daemon APIs in OCaml.
- [PATCH v3 00/23] Reimplement many daemon APIs in OCaml.