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/* Utilities functions to name memory mappings.
Copyright (C) 2023 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
<https://www.gnu.org/licenses/>. */
#include <ldsodefs.h>
#include <setvmaname.h>
#include <sys/prctl.h>
#include <sysdep.h>
#include <elf/dl-tunables.h>
/* If PR_SET_VMA_ANON_NAME is not supported by the kernel, prctl returns
EINVAL. However, it also returns the same error for invalid argument.
Since it is an internal-only API, it assumes well formatted input:
aligned START, with (START, START+LEN) being a valid memory range,
and NAME with a limit of 80 characters without invalid one ("\\`$[]"). */
void
__set_vma_name (void *start, size_t len, const char *name)
{
static int prctl_supported = 1;
if (atomic_load_relaxed (&prctl_supported) == 0)
return;
/* Set the prctl as not supported to avoid checking the tunable on every
call. */
if (TUNABLE_GET (glibc, mem, decorate_maps, int32_t, NULL) != 0)
{
int r = INTERNAL_SYSCALL_CALL (prctl, PR_SET_VMA, PR_SET_VMA_ANON_NAME,
start, len, name);
if (r == 0 || r != -EINVAL)
return;
}
atomic_store_relaxed (&prctl_supported, 0);
return;
}
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