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/* Report a module to libdwfl based on ELF program headers.
Copyright (C) 2005 Red Hat, Inc.
This program is Open Source software; you can redistribute it and/or
modify it under the terms of the Open Software License version 1.0 as
published by the Open Source Initiative.
You should have received a copy of the Open Software License along
with this program; if not, you may obtain a copy of the Open Software
License version 1.0 from http://www.opensource.org/licenses/osl.php or
by writing the Open Source Initiative c/o Lawrence Rosen, Esq.,
3001 King Ranch Road, Ukiah, CA 95482. */
#include "libdwflP.h"
#include <fcntl.h>
#include <unistd.h>
Dwfl_Module *
dwfl_report_elf (Dwfl *dwfl, const char *name,
const char *file_name, int fd, GElf_Addr base)
{
bool closefd = false;
if (fd < 0)
{
fd = open64 (file_name, O_RDONLY);
if (fd < 0)
{
__libdwfl_seterrno (DWFL_E_ERRNO);
return NULL;
}
closefd = true;
}
Elf *elf = elf_begin (fd, ELF_C_READ_MMAP_PRIVATE, NULL);
GElf_Ehdr ehdr_mem, *ehdr = gelf_getehdr (elf, &ehdr_mem);
if (ehdr == NULL)
{
elf_error:
__libdwfl_seterrno (DWFL_E_LIBELF);
if (closefd)
close (fd);
return NULL;
}
GElf_Addr start = 0, end = 0, bias = 0;
switch (ehdr->e_type)
{
case ET_REL:
/* For a relocatable object, we do an arbitrary section layout.
By updating the section header in place, we leave the layout
information to be found by relocation. */
start = end = base;
Elf_Scn *scn = NULL;
while ((scn = elf_nextscn (elf, scn)) != NULL)
{
GElf_Shdr shdr_mem;
GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem);
if (shdr == NULL)
goto elf_error;
if (shdr->sh_flags & SHF_ALLOC)
{
const GElf_Xword align = shdr->sh_addralign ?: 1;
shdr->sh_addr = (end + align - 1) & -align;
if (end == base)
/* This is the first section assigned a location.
Use its aligned address as the module's base. */
start = shdr->sh_addr;
end = shdr->sh_addr + shdr->sh_size;
if (! gelf_update_shdr (scn, shdr))
goto elf_error;
}
}
if (end == start)
{
__libdwfl_seterrno (DWFL_E_BADELF);
if (closefd)
close (fd);
return NULL;
}
break;
/* Everything else has to have program headers. */
case ET_EXEC:
case ET_CORE:
/* An assigned base address is meaningless for these. */
base = 0;
case ET_DYN:
default:
for (uint_fast16_t i = 0; i < ehdr->e_phnum; ++i)
{
GElf_Phdr phdr_mem, *ph = gelf_getphdr (elf, i, &phdr_mem);
if (ph == NULL)
goto elf_error;
if (ph->p_type == PT_LOAD)
{
if ((base & (ph->p_align - 1)) != 0)
base = (base + ph->p_align - 1) & -ph->p_align;
start = base + (ph->p_vaddr & -ph->p_align);
break;
}
}
bias = base;
for (uint_fast16_t i = ehdr->e_phnum; i-- > 0;)
{
GElf_Phdr phdr_mem, *ph = gelf_getphdr (elf, i, &phdr_mem);
if (ph == NULL)
goto elf_error;
if (ph->p_type == PT_LOAD)
{
end = base + (ph->p_vaddr + ph->p_memsz);
break;
}
}
if (end == 0)
{
__libdwfl_seterrno (DWFL_E_NO_PHDR);
if (closefd)
close (fd);
return NULL;
}
break;
}
Dwfl_Module *m = INTUSE(dwfl_report_module) (dwfl, name, start, end);
if (m != NULL)
{
if (m->main.name == NULL)
{
m->main.name = strdup (file_name);
m->main.fd = fd;
}
else if ((fd >= 0 && m->main.fd != fd)
|| strcmp (m->main.name, file_name))
{
elf_end (elf);
overlap:
if (closefd)
close (fd);
m->gc = true;
__libdwfl_seterrno (DWFL_E_OVERLAP);
m = NULL;
}
/* Preinstall the open ELF handle for the module. */
if (m->main.elf == NULL)
{
m->main.elf = elf;
m->main.bias = bias;
m->e_type = ehdr->e_type;
}
else
{
elf_end (elf);
if (m->main.bias != base)
goto overlap;
}
}
return m;
}
INTDEF (dwfl_report_elf)
|
