/* Check GLIBC_TUNABLES parsing.
Copyright (C) 2023-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
. */
#include
/* The test uses the tunable_list size, which is only exported for
ld.so. This will result in a copy of tunable_list, which is ununsed by
the test itself. */
#define TUNABLES_INTERNAL 1
#include
#include
#include
#include
#include
#include
#include
#include
static int restart;
#define CMDLINE_OPTIONS \
{ "restart", no_argument, &restart, 1 },
static struct test_t
{
const char *name;
const char *value;
int32_t expected_malloc_check;
size_t expected_mmap_threshold;
int32_t expected_perturb;
} tests[] =
{
/* Expected tunable format. */
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2",
2,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096",
2,
4096,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.mmap_threshold=-1",
0,
SIZE_MAX,
0,
},
/* Empty tunable are ignored. */
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2::glibc.malloc.mmap_threshold=4096",
2,
4096,
0,
},
/* As well empty values. */
{
"GLIBC_TUNABLES",
"glibc.malloc.check=:glibc.malloc.mmap_threshold=4096",
0,
4096,
0,
},
/* Tunable are processed from left to right, so last one is the one set. */
{
"GLIBC_TUNABLES",
"glibc.malloc.check=1:glibc.malloc.check=2",
2,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=1:glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096",
2,
4096,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096:glibc.malloc.check=1",
1,
4096,
0,
},
/* 0x800 is larger than tunable maxval (0xff), so the tunable is unchanged. */
{
"GLIBC_TUNABLES",
"glibc.malloc.perturb=0x800",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.perturb=0x55",
0,
0,
0x55,
},
/* Out of range values are just ignored. */
{
"GLIBC_TUNABLES",
"glibc.malloc.perturb=0x800:glibc.malloc.mmap_threshold=4096",
0,
4096,
0,
},
/* Invalid keys are ignored. */
{
"GLIBC_TUNABLES",
":glibc.malloc.garbage=2:glibc.malloc.check=1",
1,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.perturb=0x800:not_valid.malloc.check=2:glibc.malloc.mmap_threshold=4096",
0,
4096,
0,
},
{
"GLIBC_TUNABLES",
"glibc.not_valid.check=2:glibc.malloc.mmap_threshold=4096",
0,
4096,
0,
},
{
"GLIBC_TUNABLES",
"not_valid.malloc.check=2:glibc.malloc.mmap_threshold=4096",
0,
4096,
0,
},
/* Invalid subkeys are ignored. */
{
"GLIBC_TUNABLES",
"glibc.malloc.garbage=2:glibc.maoc.mmap_threshold=4096:glibc.malloc.check=2",
2,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=4:glibc.malloc.garbage=2:glibc.maoc.mmap_threshold=4096",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"not_valid.malloc.check=2",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.not_valid.check=2",
0,
0,
0,
},
/* An ill-formatted tunable in the for key=key=value will considere the
value as 'key=value' (which can not be parsed as an integer). */
{
"GLIBC_TUNABLES",
"glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096",
0,
0,
0,
},
/* Ill-formatted tunables string is not parsed. */
{
"GLIBC_TUNABLES",
"glibc.malloc.mmap_threshold=glibc.malloc.mmap_threshold=4096:glibc.malloc.check=2",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2=2",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2=2:glibc.malloc.mmap_threshold=4096",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2=2:glibc.malloc.check=2",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096=4096",
0,
0,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2:glibc.malloc.mmap_threshold=4096=4096",
0,
0,
0,
},
/* Invalid numbers are ignored. */
{
"GLIBC_TUNABLES",
"glibc.malloc.check=abc:glibc.malloc.mmap_threshold=4096",
0,
4096,
0,
},
{
"GLIBC_TUNABLES",
"glibc.malloc.check=2:glibc.malloc.mmap_threshold=abc",
2,
0,
0,
},
{
"GLIBC_TUNABLES",
/* SIZE_MAX + 1 */
"glibc.malloc.mmap_threshold=18446744073709551616",
0,
0,
0,
},
/* Also check some tunable aliases. */
{
"MALLOC_CHECK_",
"2",
2,
0,
0,
},
{
"MALLOC_MMAP_THRESHOLD_",
"4096",
0,
4096,
0,
},
{
"MALLOC_PERTURB_",
"0x55",
0,
0,
0x55,
},
/* 0x800 is larger than tunable maxval (0xff), so the tunable is unchanged. */
{
"MALLOC_PERTURB_",
"0x800",
0,
0,
0,
},
/* Also check for repeated tunables with a count larger than the total number
of tunables. */
{
"GLIBC_TUNABLES",
NULL,
2,
0,
0,
},
{
"GLIBC_TUNABLES",
NULL,
1,
0,
0,
},
{
"GLIBC_TUNABLES",
NULL,
0,
0,
0,
},
};
static int
handle_restart (int i)
{
TEST_COMPARE (tests[i].expected_malloc_check,
TUNABLE_GET_FULL (glibc, malloc, check, int32_t, NULL));
TEST_COMPARE (tests[i].expected_mmap_threshold,
TUNABLE_GET_FULL (glibc, malloc, mmap_threshold, size_t, NULL));
TEST_COMPARE (tests[i].expected_perturb,
TUNABLE_GET_FULL (glibc, malloc, perturb, int32_t, NULL));
return 0;
}
static int
do_test (int argc, char *argv[])
{
/* We must have either:
- One our fource parameters left if called initially:
+ path to ld.so optional
+ "--library-path" optional
+ the library path optional
+ the application name
+ the test to check */
TEST_VERIFY_EXIT (argc == 2 || argc == 5);
if (restart)
return handle_restart (atoi (argv[1]));
char nteststr[INT_BUFSIZE_BOUND (int)];
char *spargv[10];
{
int i = 0;
for (; i < argc - 1; i++)
spargv[i] = argv[i + 1];
spargv[i++] = (char *) "--direct";
spargv[i++] = (char *) "--restart";
spargv[i++] = nteststr;
spargv[i] = NULL;
}
/* Create a tunable line with the duplicate values with a total number
larger than the different number of tunables. */
{
enum { tunables_list_size = array_length (tunable_list) };
const char *value = "";
for (int i = 0; i < tunables_list_size; i++)
value = xasprintf ("%sglibc.malloc.check=2%c",
value,
i == (tunables_list_size - 1) ? '\0' : ':');
tests[33].value = value;
}
/* Same as before, but the last tunable values is differen than the
rest. */
{
enum { tunables_list_size = array_length (tunable_list) };
const char *value = "";
for (int i = 0; i < tunables_list_size - 1; i++)
value = xasprintf ("%sglibc.malloc.check=2:", value);
value = xasprintf ("%sglibc.malloc.check=1", value);
tests[34].value = value;
}
/* Same as before, but with an invalid last entry. */
{
enum { tunables_list_size = array_length (tunable_list) };
const char *value = "";
for (int i = 0; i < tunables_list_size - 1; i++)
value = xasprintf ("%sglibc.malloc.check=2:", value);
value = xasprintf ("%sglibc.malloc.check=1=1", value);
tests[35].value = value;
}
for (int i = 0; i < array_length (tests); i++)
{
snprintf (nteststr, sizeof nteststr, "%d", i);
printf ("[%d] Spawned test for %s=%s\n",
i,
tests[i].name,
tests[i].value);
setenv (tests[i].name, tests[i].value, 1);
struct support_capture_subprocess result
= support_capture_subprogram (spargv[0], spargv, NULL);
support_capture_subprocess_check (&result, "tst-tunables", 0,
sc_allow_stderr);
support_capture_subprocess_free (&result);
unsetenv (tests[i].name);
}
return 0;
}
#define TEST_FUNCTION_ARGV do_test
#include