diff options
| author | Ulf Hermann <ulf.hermann@qt.io> | 2019-01-17 15:55:02 +0100 |
|---|---|---|
| committer | Ulf Hermann <ulf.hermann@qt.io> | 2019-01-18 09:46:20 +0000 |
| commit | 1f1bb33622a517fb674953fedd247fc0d0198f19 (patch) | |
| tree | 0d2c78664d291ab6f0cd2f7ab6fd634aa64ce427 | |
| parent | 5fdac838ae86f536d12c0b5e7631172d049bd556 (diff) | |
Use file-based ELF update strategy if posix_fallocate is absent
The whole idea of extending the file and the mmap in place is rather
fragile and only works on rather specific setups. If we can't even extend
the file, we will likely not be able to extend the mapping that refers to
it, either. In that case we might still be able to write the formally
undefined memory behind the end of the file because the OS actually maps
whole pages, but that is an unspeakable horror.
The file based strategy is slower, but robust.
Change-Id: I995a173d60cfd70dde08ff78b7a97182e83b4727
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
| -rw-r--r-- | libelf/elf_update.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/libelf/elf_update.c b/libelf/elf_update.c index 4ed899ff..3ac38a85 100644 --- a/libelf/elf_update.c +++ b/libelf/elf_update.c @@ -67,6 +67,7 @@ write_file (Elf *elf, off_t size, int change_bo, size_t shnum) return -1; } +#if HAVE_DECL_POSIX_FALLOCATE /* Try to map the file if this isn't done yet. */ if (elf->map_address == NULL && elf->cmd == ELF_C_WRITE_MMAP) { @@ -95,14 +96,12 @@ write_file (Elf *elf, off_t size, int change_bo, size_t shnum) && (elf->maximum_size == ~((size_t) 0) || (size_t) size > elf->maximum_size)) { -#if HAVE_DECL_POSIX_FALLOCATE if (unlikely (posix_fallocate (elf->fildes, 0, size) != 0)) if (errno == ENOSPC) { __libelf_seterrno (ELF_E_WRITE_ERROR); return -1; } -#endif /* Extend the mmap address if needed. */ if (elf->cmd == ELF_C_RDWR_MMAP @@ -127,6 +126,7 @@ write_file (Elf *elf, off_t size, int change_bo, size_t shnum) size = -1; } else +#endif { /* The file is not mmaped. */ if ((class == ELFCLASS32 |