libs/bsd: implemented dl_iterate_phdr

dl_iterate_phdr now fills the first four fields of
struct dl_phdr_info. The last four fields remain
unimplemented, as it requires help from the
runtime_loader.

Change-Id: Id96a7c7ac05633a71b9fb62c98b3a40f7d4f255b
Signed-off-by: Augustin Cavalier <waddlesplash@gmail.com>
This commit is contained in:
Trung Nguyen 2022-05-26 20:48:56 +07:00 committed by Augustin Cavalier
parent 045f7a5f3a
commit 908107a15f
2 changed files with 62 additions and 0 deletions

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@ -10,6 +10,7 @@ for architectureObject in [ MultiArchSubDirSetup ] {
SharedLibrary [ MultiArchDefaultGristFiles libbsd.so ] :
daemon.c
dl_iterate_phdr.c
err.c
explicit_bzero.c
fgetln.c

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@ -0,0 +1,61 @@
/*
* Copyright 2022, Haiku, Inc. All rights reserved.
* Distributed under the terms of the MIT License.
*
* Authors:
* Trung Nguyen, trungnt282910@gmail.com
*/
#include <kernel/image.h>
#include <link.h>
#include <stddef.h>
#if B_HAIKU_32_BIT
typedef Elf32_Ehdr Elf_Ehdr;
#elif B_HAIKU_64_BIT
typedef Elf64_Ehdr Elf_Ehdr;
#endif
// While get_next_image_info does not return the address of
// the ELF header, it does return the first page of the image's
// text segment (defined by runtime_loader as the first loaded page
// with read-only protection). For most images produced by
// normal compilers, including Haiku ELF files, the file header
// is always loaded at the beginning of the text segment.
//
// We can therefore take advantage of this fact and populate
// struct dl_phdr_info.
int
dl_iterate_phdr(int (*callback)(struct dl_phdr_info* info, size_t size, void* data), void* data)
{
image_info info;
int32 cookie = 0;
int status;
struct dl_phdr_info phdr_info;
while (get_next_image_info(0, &cookie, &info) == B_OK) {
const Elf_Ehdr* header = (const Elf_Ehdr*)info.text;
// Check for the special commpage info (which is not an ELF image),
// and also guard against any maliciously crafted file which
// does not load its header in memory.
if (!IS_ELF(*header))
continue;
phdr_info.dlpi_addr = (Elf_Addr)info.text;
phdr_info.dlpi_name = info.name;
phdr_info.dlpi_phnum = header->e_phnum;
phdr_info.dlpi_phdr = (const Elf_Phdr*)((const char*)info.text + header->e_phoff);
status = callback(&phdr_info, sizeof(phdr_info), data);
if (status != 0)
return status;
}
return 0;
}