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Revert "Remove text-relocation support for lp32"

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This reverts commit cb00add1b3.

Bug: 20020312
Bug: 20013628
Change-Id: I8baa3d4b6c7fef50c9e2531257d5b96762099eb3
This commit is contained in:
Dimitry Ivanov
2015-04-01 21:18:48 +00:00
parent cb00add1b3
commit 56be6ed9e4
4 changed files with 108 additions and 4 deletions
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64
linker/linker_phdr.cpp
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@@ -412,6 +412,70 @@ bool ElfReader::LoadSegments() {
return true;
}
/* Used internally. Used to set the protection bits of all loaded segments
* with optional extra flags (i.e. really PROT_WRITE). Used by
* phdr_table_protect_segments and phdr_table_unprotect_segments.
*/
static int _phdr_table_set_load_prot(const ElfW(Phdr)* phdr_table, size_t phdr_count,
ElfW(Addr) load_bias, int extra_prot_flags) {
const ElfW(Phdr)* phdr = phdr_table;
const ElfW(Phdr)* phdr_limit = phdr + phdr_count;
for (; phdr < phdr_limit; phdr++) {
if (phdr->p_type != PT_LOAD || (phdr->p_flags & PF_W) != 0) {
continue;
}
ElfW(Addr) seg_page_start = PAGE_START(phdr->p_vaddr) + load_bias;
ElfW(Addr) seg_page_end = PAGE_END(phdr->p_vaddr + phdr->p_memsz) + load_bias;
int ret = mprotect(reinterpret_cast<void*>(seg_page_start),
seg_page_end - seg_page_start,
PFLAGS_TO_PROT(phdr->p_flags) | extra_prot_flags);
if (ret < 0) {
return -1;
}
}
return 0;
}
/* Restore the original protection modes for all loadable segments.
* You should only call this after phdr_table_unprotect_segments and
* applying all relocations.
*
* Input:
* phdr_table -> program header table
* phdr_count -> number of entries in tables
* load_bias -> load bias
* Return:
* 0 on error, -1 on failure (error code in errno).
*/
int phdr_table_protect_segments(const ElfW(Phdr)* phdr_table,
size_t phdr_count, ElfW(Addr) load_bias) {
return _phdr_table_set_load_prot(phdr_table, phdr_count, load_bias, 0);
}
/* Change the protection of all loaded segments in memory to writable.
* This is useful before performing relocations. Once completed, you
* will have to call phdr_table_protect_segments to restore the original
* protection flags on all segments.
*
* Note that some writable segments can also have their content turned
* to read-only by calling phdr_table_protect_gnu_relro. This is no
* performed here.
*
* Input:
* phdr_table -> program header table
* phdr_count -> number of entries in tables
* load_bias -> load bias
* Return:
* 0 on error, -1 on failure (error code in errno).
*/
int phdr_table_unprotect_segments(const ElfW(Phdr)* phdr_table,
size_t phdr_count, ElfW(Addr) load_bias) {
return _phdr_table_set_load_prot(phdr_table, phdr_count, load_bias, PROT_WRITE);
}
/* Used internally by phdr_table_protect_gnu_relro and
* phdr_table_unprotect_gnu_relro.
*/