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author | Simon Marchi <simon.marchi@ericsson.com> | 2018-08-07 18:10:29 -0400 |
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committer | Simon Marchi <simon.marchi@ericsson.com> | 2018-08-07 18:10:29 -0400 |
commit | 5c831bb1eb6b22cd1705b98188b7d1b0633e7c54 (patch) | |
tree | 4c8000b9288db41ff690633006361b0f69a370a7 /gdb/common | |
parent | 4485a1c1d8d2b4a20fca2e2b7d1aabcff383b222 (diff) | |
download | binutils-5c831bb1eb6b22cd1705b98188b7d1b0633e7c54.zip binutils-5c831bb1eb6b22cd1705b98188b7d1b0633e7c54.tar.gz binutils-5c831bb1eb6b22cd1705b98188b7d1b0633e7c54.tar.bz2 |
Introduce mmap_file function
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.
Diffstat (limited to 'gdb/common')
-rw-r--r-- | gdb/common/scoped_mmap.c | 48 | ||||
-rw-r--r-- | gdb/common/scoped_mmap.h | 26 |
2 files changed, 70 insertions, 4 deletions
diff --git a/gdb/common/scoped_mmap.c b/gdb/common/scoped_mmap.c new file mode 100644 index 0000000..aa2f703 --- /dev/null +++ b/gdb/common/scoped_mmap.c @@ -0,0 +1,48 @@ +/* scoped_mmap, automatically unmap files + + Copyright (C) 2018 Free Software Foundation, Inc. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include "defs.h" +#include "scoped_mmap.h" +#include "scoped_fd.h" + +#ifdef HAVE_SYS_MMAN_H + +scoped_mmap +mmap_file (const char *filename) +{ + scoped_fd fd (open (filename, O_RDONLY)); + if (fd.get () < 0) + perror_with_name ("open"); + + off_t size = lseek (fd.get (), 0, SEEK_END); + if (size < 0) + perror_with_name ("lseek"); + + /* We can't map an empty file. */ + if (size == 0) + error (_("file to mmap is empty")); + + scoped_mmap mmapped_file (nullptr, size, PROT_READ, MAP_PRIVATE, fd.get (), 0); + if (mmapped_file.get () == MAP_FAILED) + perror_with_name ("mmap"); + + return mmapped_file; +} + +#endif /* HAVE_SYS_MMAN_H */ diff --git a/gdb/common/scoped_mmap.h b/gdb/common/scoped_mmap.h index 6070c37..b446163 100644 --- a/gdb/common/scoped_mmap.h +++ b/gdb/common/scoped_mmap.h @@ -41,8 +41,18 @@ public: ~scoped_mmap () { - if (m_mem != MAP_FAILED) - munmap (m_mem, m_length); + destroy (); + } + + scoped_mmap (scoped_mmap &&rhs) + { + destroy (); + + m_mem = rhs.m_mem; + m_length = rhs.m_length; + + rhs.m_mem = MAP_FAILED; + rhs.m_length = 0; } DISABLE_COPY_AND_ASSIGN (scoped_mmap); @@ -58,8 +68,7 @@ public: void reset (void *addr, size_t length, int prot, int flags, int fd, off_t offset) noexcept { - if (m_mem != MAP_FAILED) - munmap (m_mem, m_length); + destroy (); m_length = length; m_mem = mmap (addr, m_length, prot, flags, fd, offset); @@ -69,9 +78,18 @@ public: void *get () const noexcept { return m_mem; } private: + void destroy () + { + if (m_mem != MAP_FAILED) + munmap (m_mem, m_length); + } + void *m_mem; size_t m_length; }; +/* Map FILENAME in memory. Throw an error if anything goes wrong. */ +scoped_mmap mmap_file (const char *filename); + #endif /* HAVE_SYS_MMAN_H */ #endif /* SCOPED_MMAP_H */ |