diff options
Diffstat (limited to 'bfd/mmap.c')
| -rw-r--r-- | bfd/mmap.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/bfd/mmap.c b/bfd/mmap.c new file mode 100644 index 0000000..a28dd6a --- /dev/null +++ b/bfd/mmap.c @@ -0,0 +1,227 @@ +/* BFD library -- mmap of file descriptors. + Copyright (C) 2016 Free Software Foundation, Inc. + This file is part of BFD, the Binary File Descriptor library. + + 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, write to the Free Software + Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, + MA 02110-1301, USA. */ + +#include "sysdep.h" + +#ifdef HAVE_MMAP +#include "bfd.h" +#include "libbfd.h" +#include "libiberty.h" +#include "bfd_stdint.h" + +#include <sys/mman.h> + +static file_ptr +mmap_btell (struct bfd *abfd) +{ + return abfd->where; +} + +/* Copied and modified from gold_fallocate in gold. */ + +static int +mmap_fallocate (int fd, file_ptr offset, file_ptr len) +{ +#ifdef HAVE_FALLOCATE + if (fallocate (fd, 0, offset, len) == 0) + return 0; +#endif +#ifdef HAVE_POSIX_FALLOCATE + return posix_fallocate (fd, offset, len); +#endif + if (ftruncate (fd, offset + len) < 0) + return errno; + return 0; +} + +static int +mmap_resize (bfd *abfd, file_ptr size) +{ + if (mmap_fallocate (abfd->mmap_fd, 0, size) != 0) + { +syscall_error: + bfd_set_error (bfd_error_system_call); + abfd->mmap_size = 0; + return -1; + } + if (abfd->mmap_size != 0) + { +#ifdef HAVE_MREMAP + abfd->iostream = mremap (abfd->iostream, abfd->mmap_size, + size, MREMAP_MAYMOVE); + if (abfd->iostream == MAP_FAILED) + goto syscall_error; + else + goto success; +#else + if (munmap (abfd->iostream, abfd->mmap_size) != 0) + goto syscall_error; +#endif + } + abfd->iostream = mmap (NULL, size, PROT_READ | PROT_WRITE, + MAP_SHARED, abfd->mmap_fd, 0); + if (abfd->iostream == MAP_FAILED) + goto syscall_error; + +success: + abfd->mmap_size = size; + return 0; +} + +static int +mmap_bseek (bfd *abfd, file_ptr position, int direction) +{ + file_ptr nwhere; + + if (direction == SEEK_SET) + nwhere = position; + else + nwhere = abfd->where + position; + + if (nwhere < 0) + { + abfd->where = 0; + errno = EINVAL; + return -1; + } + else if (nwhere >= abfd->mmap_size && mmap_resize (abfd, nwhere) != 0) + return -1; + + return 0; +} + +static file_ptr +mmap_bread (struct bfd *abfd, void *buf, file_ptr size) +{ + memcpy (buf, abfd->iostream + abfd->where, size); + return size; +} + +static file_ptr +mmap_bwrite (bfd *abfd, const void *ptr, file_ptr size) +{ + file_ptr filesize = abfd->where + size; + + if (filesize > abfd->mmap_size && mmap_resize (abfd, filesize) != 0) + { + bfd_set_error (bfd_error_system_call); + return 0; + } + + memcpy (abfd->iostream + abfd->where, ptr, size); + return size; +} + +static int +mmap_bclose (struct bfd *abfd) +{ + int status = munmap (abfd->iostream, abfd->mmap_size); + if (status == 0) + status = close (abfd->mmap_fd); + if (status != 0) + bfd_set_error (bfd_error_system_call); + + abfd->iostream = MAP_FAILED; + abfd->mmap_size = 0; + abfd->mmap_fd = -1; + + return status; +} + +static int +mmap_bflush (struct bfd *abfd ATTRIBUTE_UNUSED) +{ +#ifdef HAVE_MSYNC + int status = msync (abfd->iostream, abfd->mmap_size, MS_SYNC); + if (status != 0) + bfd_set_error (bfd_error_system_call); + return status; +#else + return 0; +#endif +} + +static int +mmap_bstat (struct bfd *abfd ATTRIBUTE_UNUSED, struct stat *sb) +{ + int status; + status = fstat (abfd->mmap_fd, sb); + if (status < 0) + bfd_set_error (bfd_error_system_call); + return status; +} + +static void * +mmap_bmmap (struct bfd *abfd ATTRIBUTE_UNUSED, + void *addr ATTRIBUTE_UNUSED, + bfd_size_type len ATTRIBUTE_UNUSED, + int prot ATTRIBUTE_UNUSED, + int flags ATTRIBUTE_UNUSED, + file_ptr offset ATTRIBUTE_UNUSED, + void **map_addr ATTRIBUTE_UNUSED, + bfd_size_type *map_len ATTRIBUTE_UNUSED) +{ + /* Unsupported. */ + abort (); + return 0; +} + +static const struct bfd_iovec mmap_iovec = +{ + &mmap_bread, &mmap_bwrite, &mmap_btell, &mmap_bseek, + &mmap_bclose, &mmap_bflush, &mmap_bstat, &mmap_bmmap +}; +#endif + +/* +INTERNAL_FUNCTION + bfd_mmap_init + +SYNOPSIS + bfd_boolean bfd_mmap_init (bfd *abfd); + +DESCRIPTION + Use mmap on BFD. Fallback to bfd_cache_init. +*/ + +bfd_boolean +bfd_mmap_init (bfd *abfd) +{ +#ifdef HAVE_MMAP + /* Only suport write before writing starts. */ + if (abfd->direction == write_direction + && !abfd->output_has_begun) + { + if (abfd->mmap_size != 0 || abfd->iostream == NULL) + abort (); + + abfd->mmap_fd = dup (fileno (abfd->iostream)); + if (abfd->mmap_fd < 0) + { + bfd_set_error (bfd_error_system_call); + return FALSE; + } + + abfd->iovec = &mmap_iovec; + return TRUE; + } +#endif + + return bfd_cache_init (abfd); +} |