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78ed8bdf4f
Linux 5.17 added support to naming anonymous virtual memory areas
through the prctl syscall. The __set_vma_name is a wrapper to avoid
optimizing the prctl call if the kernel does not support it.
If the kernel does not support PR_SET_VMA_ANON_NAME, prctl returns
EINVAL. And it also returns the same error for an 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 an invalid one
("\\`$[]").
Reviewed-by: DJ Delorie <dj@redhat.com>
44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
/* Utilities functions to name memory mappings.
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Copyright (C) 2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <ldsodefs.h>
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#include <setvmaname.h>
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#include <sys/prctl.h>
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#include <sysdep.h>
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/* If PR_SET_VMA_ANON_NAME is not supported by the kernel, prctl returns
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EINVAL. However, it also returns the same error for invalid argument.
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Since it is an internal-only API, it assumes well formatted input:
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aligned START, with (START, START+LEN) being a valid memory range,
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and NAME with a limit of 80 characters without invalid one ("\\`$[]"). */
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void
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__set_vma_name (void *start, size_t len, const char *name)
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{
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static int prctl_supported = 1;
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if (atomic_load_relaxed (&prctl_supported) == 0)
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return;
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int r = INTERNAL_SYSCALL_CALL (prctl, PR_SET_VMA, PR_SET_VMA_ANON_NAME,
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start, len, name);
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if (r == 0 || r != -EINVAL)
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return;
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atomic_store_relaxed (&prctl_supported, 0);
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return;
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}
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