189 lines
7.0 KiB
Diff
189 lines
7.0 KiB
Diff
From a4c3f5f46e850c977cda81c251036475aab8313c Mon Sep 17 00:00:00 2001
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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Date: Thu, 23 Nov 2023 14:29:14 -0300
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Subject: [PATCH] elf: Add a way to check if tunable is set (BZ 27069)
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Content-type: text/plain; charset=UTF-8
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The patch adds two new macros, TUNABLE_GET_DEFAULT and TUNABLE_IS_INITIALIZED,
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here the former get the default value with a signature similar to
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TUNABLE_GET, while the later returns whether the tunable was set by
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the environment variable.
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Checked on x86_64-linux-gnu.
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Reviewed-by: DJ Delorie <dj@redhat.com>
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Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
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Conflicts:
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elf/Versions
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(removed to preserve ABI)
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elf/dl-tunable-types.h
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(line numbers)
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scripts/gen-tunables.awk
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(account for missing TUNABLE_SECLEVEL patch)
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---
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elf/dl-tunable-types.h | 1 +
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elf/dl-tunables.c | 40 ++++++++++++++++++++++++++++++++++++++++
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elf/dl-tunables.h | 28 ++++++++++++++++++++++++++++
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elf/dl-tunables.list | 1 +
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scripts/gen-tunables.awk | 4 ++--
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6 files changed, 73 insertions(+), 2 deletions(-)
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diff -rup a/elf/dl-tunable-types.h b/elf/dl-tunable-types.h
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--- a/elf/dl-tunable-types.h 2021-08-01 21:33:43.000000000 -0400
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+++ b/elf/dl-tunable-types.h 2024-03-26 18:23:22.211504813 -0400
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@@ -61,6 +61,7 @@ struct _tunable
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{
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const char name[TUNABLE_NAME_MAX]; /* Internal name of the tunable. */
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tunable_type_t type; /* Data type of the tunable. */
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+ const tunable_val_t def; /* The value. */
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tunable_val_t val; /* The value. */
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bool initialized; /* Flag to indicate that the tunable is
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initialized. */
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diff -rup a/elf/dl-tunables.c b/elf/dl-tunables.c
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--- a/elf/dl-tunables.c 2024-03-26 18:21:10.090681748 -0400
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+++ b/elf/dl-tunables.c 2024-03-26 18:23:22.214504923 -0400
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@@ -152,6 +152,13 @@ tunable_initialize (tunable_t *cur, cons
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do_tunable_update_val (cur, &val, NULL, NULL);
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}
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+bool
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+__tunable_is_initialized (tunable_id_t id)
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+{
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+ return tunable_list[id].initialized;
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+}
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+rtld_hidden_def (__tunable_is_initialized)
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+
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void
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__tunable_set_val (tunable_id_t id, tunable_val_t *valp, tunable_num_t *minp,
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tunable_num_t *maxp)
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@@ -399,6 +406,39 @@ __tunables_print (void)
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}
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}
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+void
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+__tunable_get_default (tunable_id_t id, void *valp)
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+{
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+ tunable_t *cur = &tunable_list[id];
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+
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+ switch (cur->type.type_code)
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+ {
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+ case TUNABLE_TYPE_UINT_64:
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+ {
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+ *((uint64_t *) valp) = (uint64_t) cur->def.numval;
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+ break;
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+ }
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+ case TUNABLE_TYPE_INT_32:
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+ {
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+ *((int32_t *) valp) = (int32_t) cur->def.numval;
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+ break;
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+ }
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+ case TUNABLE_TYPE_SIZE_T:
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+ {
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+ *((size_t *) valp) = (size_t) cur->def.numval;
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+ break;
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+ }
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+ case TUNABLE_TYPE_STRING:
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+ {
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+ *((const char **)valp) = cur->def.strval;
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+ break;
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+ }
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+ default:
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+ __builtin_unreachable ();
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+ }
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+}
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+rtld_hidden_def (__tunable_get_default)
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+
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/* Set the tunable value. This is called by the module that the tunable exists
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in. */
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void
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diff -rup a/elf/dl-tunables.h b/elf/dl-tunables.h
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--- a/elf/dl-tunables.h 2021-08-01 21:33:43.000000000 -0400
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+++ b/elf/dl-tunables.h 2024-03-26 18:23:22.217505032 -0400
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@@ -53,18 +53,26 @@ typedef void (*tunable_callback_t) (tuna
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extern void __tunables_init (char **);
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extern void __tunables_print (void);
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+extern bool __tunable_is_initialized (tunable_id_t);
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extern void __tunable_get_val (tunable_id_t, void *, tunable_callback_t);
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extern void __tunable_set_val (tunable_id_t, tunable_val_t *, tunable_num_t *,
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tunable_num_t *);
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+extern void __tunable_get_default (tunable_id_t id, void *valp);
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rtld_hidden_proto (__tunables_init)
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rtld_hidden_proto (__tunables_print)
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+rtld_hidden_proto (__tunable_is_initialized)
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rtld_hidden_proto (__tunable_get_val)
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rtld_hidden_proto (__tunable_set_val)
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+rtld_hidden_proto (__tunable_get_default)
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/* Define TUNABLE_GET and TUNABLE_SET in short form if TOP_NAMESPACE and
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TUNABLE_NAMESPACE are defined. This is useful shorthand to get and set
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tunables within a module. */
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#if defined TOP_NAMESPACE && defined TUNABLE_NAMESPACE
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+# define TUNABLE_IS_INITIALIZED(__id) \
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+ TUNABLE_IS_INITIALIZED_FULL(TOP_NAMESPACE, TUNABLE_NAMESPACE, __id)
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+# define TUNABLE_GET_DEFAULT(__id, __type) \
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+ TUNABLE_GET_DEFAULT_FULL(TOP_NAMESPACE, TUNABLE_NAMESPACE,__id, __type)
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# define TUNABLE_GET(__id, __type, __cb) \
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TUNABLE_GET_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, __type, __cb)
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# define TUNABLE_SET(__id, __val) \
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@@ -73,6 +81,10 @@ rtld_hidden_proto (__tunable_set_val)
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TUNABLE_SET_WITH_BOUNDS_FULL (TOP_NAMESPACE, TUNABLE_NAMESPACE, __id, \
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__val, __min, __max)
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#else
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+# define TUNABLE_IS_INITIALIZED(__top, __ns, __id) \
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+ TUNABLE_IS_INITIALIZED_FULL(__top, __ns, __id)
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+# define TUNABLE_GET_DEFAULT(__top, __ns, __type) \
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+ TUNABLE_GET_DEFAULT_FULL(__top, __ns, __id, __type)
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# define TUNABLE_GET(__top, __ns, __id, __type, __cb) \
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TUNABLE_GET_FULL (__top, __ns, __id, __type, __cb)
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# define TUNABLE_SET(__top, __ns, __id, __val) \
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@@ -81,6 +93,22 @@ rtld_hidden_proto (__tunable_set_val)
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TUNABLE_SET_WITH_BOUNDS_FULL (__top, __ns, __id, __val, __min, __max)
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#endif
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+/* Return whether the tunable was initialized by the environment variable. */
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+#define TUNABLE_IS_INITIALIZED_FULL(__top, __ns, __id) \
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+({ \
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+ tunable_id_t id = TUNABLE_ENUM_NAME (__top, __ns, __id); \
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+ __tunable_is_initialized (id); \
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+})
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+
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+/* Return the default value of the tunable. */
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+#define TUNABLE_GET_DEFAULT_FULL(__top, __ns, __id, __type) \
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+({ \
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+ tunable_id_t id = TUNABLE_ENUM_NAME (__top, __ns, __id); \
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+ __type __ret; \
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+ __tunable_get_default (id, &__ret); \
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+ __ret; \
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+})
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+
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/* Get and return a tunable value. If the tunable was set externally and __CB
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is defined then call __CB before returning the value. */
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# define TUNABLE_GET_FULL(__top, __ns, __id, __type, __cb) \
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diff -rup a/elf/dl-tunables.list b/elf/dl-tunables.list
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--- a/elf/dl-tunables.list 2024-03-26 18:21:09.664666196 -0400
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+++ b/elf/dl-tunables.list 2024-03-26 18:23:22.220505142 -0400
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@@ -20,6 +20,7 @@
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# type: Defaults to STRING
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# minval: Optional minimum acceptable value
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# maxval: Optional maximum acceptable value
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+# default: Optional default value (if not specified it will be 0 or "")
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# env_alias: An alias environment variable
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# security_level: Specify security level of the tunable for AT_SECURE binaries.
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# Valid values are:
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diff -rup a/scripts/gen-tunables.awk b/scripts/gen-tunables.awk
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--- a/scripts/gen-tunables.awk 2024-03-26 18:21:09.523661049 -0400
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+++ b/scripts/gen-tunables.awk 2024-03-26 18:34:45.385462341 -0400
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@@ -236,8 +236,8 @@ END {
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n = indices[2];
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m = indices[3];
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printf (" {TUNABLE_NAME_S(%s, %s, %s)", t, n, m)
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- printf (", {TUNABLE_TYPE_%s, %s, %s}, {%s}, NULL, TUNABLE_SECLEVEL_%s, %s},\n",
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- types[t,n,m], minvals[t,n,m], maxvals[t,n,m],
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+ printf (", {TUNABLE_TYPE_%s, %s, %s}, {%s}, {%s}, NULL, TUNABLE_SECLEVEL_%s, %s},\n",
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+ types[t,n,m], minvals[t,n,m], maxvals[t,n,m],default_val[t,n,m],
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default_val[t,n,m], security_level[t,n,m], env_alias[t,n,m]);
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}
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print "};"
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