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5c831bb1eb
New in v2: - As Tom pointed out, we don't need to keep the fd around after mmapping. This simplifies things quite a bit, since we don't need a new class. It's now just a function that returns a scoped_mmap. We already have scoped_mmap, which is a thin RAII layer over mmap. If one simply wants to mmap an entire file for reading, it takes a bit of boilerplate. This patch introduces the mmap_file function to make this easier. gdb/ChangeLog: * Makefile.in (COMMON_SFILES): Add common/scoped_mmap.c. * common/scoped_mmap.c: New file. * common/scoped_mmap.h (destroy): New method. (~scoped_mmap, reset): Use destroy. (scoped_mmap): New move constructor. (mmap_file): New declaration. * unittests/scoped_mmap-selftests.c (test_normal, test_invalid_filename, run_tests): New functions. (_initialize_scoped_mmap_selftests): Register selftest.
96 lines
2.2 KiB
C++
96 lines
2.2 KiB
C++
/* scoped_mmap, automatically unmap files
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Copyright (C) 2018 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program 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
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef SCOPED_MMAP_H
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#define SCOPED_MMAP_H
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#include "config.h"
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#ifdef HAVE_SYS_MMAN_H
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#include <sys/mman.h>
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/* A smart-pointer-like class to mmap() and automatically munmap() a memory
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mapping. */
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class scoped_mmap
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{
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public:
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scoped_mmap () noexcept : m_mem (MAP_FAILED), m_length (0) {}
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scoped_mmap (void *addr, size_t length, int prot, int flags, int fd,
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off_t offset) noexcept : m_length (length)
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{
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m_mem = mmap (addr, m_length, prot, flags, fd, offset);
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}
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~scoped_mmap ()
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{
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destroy ();
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}
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scoped_mmap (scoped_mmap &&rhs)
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{
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destroy ();
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m_mem = rhs.m_mem;
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m_length = rhs.m_length;
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rhs.m_mem = MAP_FAILED;
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rhs.m_length = 0;
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}
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DISABLE_COPY_AND_ASSIGN (scoped_mmap);
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void *release () noexcept
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{
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void *mem = m_mem;
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m_mem = MAP_FAILED;
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m_length = 0;
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return mem;
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}
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void reset (void *addr, size_t length, int prot, int flags, int fd,
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off_t offset) noexcept
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{
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destroy ();
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m_length = length;
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m_mem = mmap (addr, m_length, prot, flags, fd, offset);
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}
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size_t size () const noexcept { return m_length; }
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void *get () const noexcept { return m_mem; }
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private:
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void destroy ()
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{
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if (m_mem != MAP_FAILED)
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munmap (m_mem, m_length);
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}
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void *m_mem;
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size_t m_length;
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};
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/* Map FILENAME in memory. Throw an error if anything goes wrong. */
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scoped_mmap mmap_file (const char *filename);
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#endif /* HAVE_SYS_MMAN_H */
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#endif /* SCOPED_MMAP_H */
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