build: Assume __attribute__((cleanup)) always works

All recent compilers support this (except MS compilers which we don't
care about).  Assume it is supported.  We test it in ./configure and
hard fail if it doesn't work.

We still define HAVE_ATTRIBUTE_CLEANUP but you can now assume it is
always defined and don't have to check it.

daemon/daemon.h

@@ -93,11 +93,7 @@ extern char *read_whole_file (const char *filename, size_t *size_r);
 extern char *mountable_to_string (const mountable_t *mountable);
 extern void cleanup_free_mountable (mountable_t *mountable);
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_FREE_MOUNTABLE __attribute__((cleanup(cleanup_free_mountable)))
-#else
-#define CLEANUP_FREE_MOUNTABLE
-#endif
 
 /* cleanups.c */
 /* These functions are used internally by the CLEANUP_* macros.
@@ -106,13 +102,8 @@ extern void cleanup_free_mountable (mountable_t *mountable);
 extern void cleanup_aug_close (void *ptr);
 extern void cleanup_free_stringsbuf (void *ptr);
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_AUG_CLOSE __attribute__((cleanup(cleanup_aug_close)))
 #define CLEANUP_FREE_STRINGSBUF __attribute__((cleanup(cleanup_free_stringsbuf)))
-#else
-#define CLEANUP_AUG_CLOSE
-#define CLEANUP_FREE_STRINGSBUF
-#endif
 
 /* mount.c */
 extern int is_root_mounted (void);

daemon/sh.c

@@ -32,13 +32,8 @@
 
 #include "ignore-value.h"
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_BIND_STATE __attribute__((cleanup(free_bind_state)))
 #define CLEANUP_RESOLVER_STATE __attribute__((cleanup(free_resolver_state)))
-#else
-#define CLEANUP_BIND_STATE
-#define CLEANUP_RESOLVER_STATE
-#endif
 
 struct bind_state {
   bool mounted;

daemon/yara.c

@@ -39,12 +39,8 @@
 
 #include <yara.h>
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_DESTROY_YARA_COMPILER                           \
   __attribute__((cleanup(cleanup_destroy_yara_compiler)))
-#else
-#define CLEANUP_DESTROY_YARA_COMPILER
-#endif
 
 struct write_callback_data {
   int fd;
@@ -208,10 +204,6 @@ compile_rules_file (const char *rules_path)
   }
 
  err:
-#ifndef HAVE_ATTRIBUTE_CLEANUP
-  yr_compiler_destroy (compiler);
-#endif
-
   return ret;
 }
 

generator/c.ml

@@ -817,7 +817,6 @@ and generate_client_structs_cleanups_h () =
 #ifndef GUESTFS_STRUCTS_CLEANUPS_H_
 #define GUESTFS_STRUCTS_CLEANUPS_H_
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 ";
 
   List.iter (
@@ -828,16 +827,7 @@ and generate_client_structs_cleanups_h () =
       pr "  __attribute__((cleanup(guestfs_int_cleanup_free_%s_list)))\n" name
   ) structs;
 
-  pr "#else /* !HAVE_ATTRIBUTE_CLEANUP */\n";
-
-  List.iter (
-    fun { s_name = name } ->
-      pr "#define CLEANUP_FREE_%s\n" (String.uppercase_ascii name);
-      pr "#define CLEANUP_FREE_%s_LIST\n" (String.uppercase_ascii name)
-  ) structs;
-
   pr "\
-#endif /* !HAVE_ATTRIBUTE_CLEANUP */
 
 /* These functions are used internally by the CLEANUP_* macros.
  * Don't call them directly.

generator/daemon.ml

@@ -127,8 +127,6 @@ let generate_daemon_stubs actions () =
                     args_passed_to_daemon in
 
       if args_passed_to_daemon <> [] then (
-        pr "#ifdef HAVE_ATTRIBUTE_CLEANUP\n";
-        pr "\n";
         pr "#define CLEANUP_XDR_FREE_%s_ARGS \\\n" uc_name;
         pr "    __attribute__((cleanup(cleanup_xdr_free_%s_args)))\n" name;
         pr "\n";
@@ -140,9 +138,6 @@ let generate_daemon_stubs actions () =
            name;
         pr "}\n";
         pr "\n";
-        pr "#else /* !HAVE_ATTRIBUTE_CLEANUP */\n";
-        pr "#define CLEANUP_XDR_FREE_%s_ARGS\n" uc_name;
-        pr "#endif /* !HAVE_ATTRIBUTE_CLEANUP */\n";
         pr "\n"
       );
 
@@ -1315,7 +1310,6 @@ let generate_daemon_structs_cleanups_h () =
 #ifndef GUESTFS_DAEMON_STRUCTS_CLEANUPS_H_
 #define GUESTFS_DAEMON_STRUCTS_CLEANUPS_H_
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 ";
 
   List.iter (
@@ -1326,16 +1320,7 @@ let generate_daemon_structs_cleanups_h () =
       pr "  __attribute__((cleanup(cleanup_free_int_%s_list)))\n" name
   ) structs;
 
-  pr "#else /* !HAVE_ATTRIBUTE_CLEANUP */\n";
-
-  List.iter (
-    fun { s_name = name } ->
-      pr "#define CLEANUP_FREE_%s\n" (String.uppercase_ascii name);
-      pr "#define CLEANUP_FREE_%s_LIST\n" (String.uppercase_ascii name)
-  ) structs;
-
   pr "\
-#endif /* !HAVE_ATTRIBUTE_CLEANUP */
 
 /* These functions are used internally by the CLEANUP_* macros.
  * Don't call them directly.

lib/guestfs-internal.h

@@ -661,11 +661,7 @@ extern void guestfs_int_end_stringsbuf (guestfs_h *g, struct stringsbuf *sb);
 
 extern void guestfs_int_free_stringsbuf (struct stringsbuf *sb);
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_FREE_STRINGSBUF __attribute__((cleanup(guestfs_int_cleanup_free_stringsbuf)))
-#else
-#define CLEANUP_FREE_STRINGSBUF
-#endif
 extern void guestfs_int_cleanup_free_stringsbuf (struct stringsbuf *sb);
 
 /* proto.c */
@@ -785,11 +781,7 @@ extern int guestfs_int_cmd_pipe_run (struct command *cmd, const char *mode);
 extern int guestfs_int_cmd_pipe_wait (struct command *cmd);
 extern char *guestfs_int_cmd_get_pipe_errors (struct command *cmd);
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_CMD_CLOSE __attribute__((cleanup(guestfs_int_cleanup_cmd_close)))
-#else
-#define CLEANUP_CMD_CLOSE
-#endif
 extern void guestfs_int_cleanup_cmd_close (struct command **);
 
 /* launch-*.c constructors */

lib/info.c

@@ -43,7 +43,6 @@
 #include "guestfs-internal.h"
 #include "guestfs-internal-actions.h"
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_JSON_T_DECREF __attribute__((cleanup(cleanup_json_t_decref)))
 
 static void
@@ -52,10 +51,6 @@ cleanup_json_t_decref (void *ptr)
   json_decref (* (json_t **) ptr);
 }
 
-#else
-#define CLEANUP_JSON_T_DECREF
-#endif
-
 static json_t *get_json_output (guestfs_h *g, const char *filename);
 static int qemu_img_supports_U_option (guestfs_h *g);
 static void set_child_rlimits (struct command *);

lib/launch-libvirt.c

@@ -97,7 +97,6 @@ xmlBufferDetach (xmlBufferPtr buf)
 }
 #endif
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_VIRSECRETFREE __attribute__((cleanup(cleanup_virSecretFree)))
 
 static void
@@ -108,10 +107,6 @@ cleanup_virSecretFree (void *ptr)
     virSecretFree (secret_obj);
 }
 
-#else /* !HAVE_ATTRIBUTE_CLEANUP */
-#define CLEANUP_VIRSECRETFREE
-#endif
-
 /* List used to store a mapping of secret to libvirt secret UUID. */
 struct secret {
   char *secret;

lib/qemu.c

@@ -46,7 +46,6 @@
 #include "guestfs-internal.h"
 #include "guestfs_protocol.h"
 
-#ifdef HAVE_ATTRIBUTE_CLEANUP
 #define CLEANUP_JSON_T_DECREF __attribute__((cleanup(cleanup_json_t_decref)))
 
 static void
@@ -55,10 +54,6 @@ cleanup_json_t_decref (void *ptr)
   json_decref (* (json_t **) ptr);
 }
 
-#else
-#define CLEANUP_JSON_T_DECREF
-#endif
-
 struct qemu_data {
   int generation;               /* MEMO_GENERATION read from qemu.stat */
   uint64_t prev_size;           /* Size of qemu binary when cached. */

m4/guestfs-c.m4

@@ -109,15 +109,12 @@ main (int argc, char *argv[])
     AC_MSG_RESULT([yes])
     AC_DEFINE([HAVE_ATTRIBUTE_CLEANUP],[1],[Define to 1 if '__attribute__((cleanup(...)))' works with this compiler.])
     ],[
-    AC_MSG_WARN(
+    AC_MSG_ERROR(
 ['__attribute__((cleanup(...)))' does not work.
 
 You may not be using a sufficiently recent version of GCC or CLANG, or
 you may be using a C compiler which does not support this attribute,
-or the configure test may be wrong.
-
-The code will still compile, but is likely to leak memory and other
-resources when it runs.])])
+or the configure test may be wrong.])])
 dnl restore CFLAGS
 CFLAGS="${acx_nbdkit_save_CFLAGS}"