bool
SgAsmElfSection::reallocate()
{
bool reallocated = false;
SgAsmElfSectionTableEntry *sechdr = get_section_entry();
SgAsmElfSegmentTableEntry *seghdr = get_segment_entry();
/* Change section size if this section was defined in the ELF Section Table */
if (sechdr!=NULL) {
rose_addr_t need = calculate_sizes(NULL, NULL, NULL, NULL);
if (need < get_size()) {
if (is_mapped()) {
ROSE_ASSERT(get_mapped_size()==get_size());
set_mapped_size(need);
}
set_size(need);
reallocated = true;
} else if (need > get_size()) {
get_file()->shift_extend(this, 0, need-get_size(), SgAsmGenericFile::ADDRSP_ALL, SgAsmGenericFile::ELASTIC_HOLE);
reallocated = true;
}
}
/* Update entry in the ELF Section Table and/or ELF Segment Table */
if (sechdr)
sechdr->update_from_section(this);
if (seghdr)
seghdr->update_from_section(this);
return reallocated;
}
/** Attaches a previously unattached ELF Segment (SgAsmElfSection) to the ELF Segment Table (SgAsmElfSegmentTable). This
* method complements SgAsmElfSection::init_from_segment_table. This method initializes the segment table from the segment
* while init_from_segment_table() initializes the segment from the segment table.
*
* ELF Segments are represented by SgAsmElfSection objects since ELF Segments and ELF Sections overlap very much in their
* features and thus should share an interface. An SgAsmElfSection can appear in the ELF Section Table and/or the ELF Segment
* Table and you can determine where it was located by calling get_section_entry() and get_segment_entry().
*
* Returns the new segment table entry linked into the AST. */
SgAsmElfSegmentTableEntry *
SgAsmElfSegmentTable::add_section(SgAsmElfSection *section)
{
ROSE_ASSERT(section!=NULL);
ROSE_ASSERT(section->get_file()==get_file());
ROSE_ASSERT(section->get_header()==get_header());
ROSE_ASSERT(section->get_segment_entry()==NULL); /* must not be in the segment table yet */
SgAsmElfFileHeader *fhdr = dynamic_cast<SgAsmElfFileHeader*>(get_header());
ROSE_ASSERT(fhdr);
/* Assign a slot in the segment table */
int idx = fhdr->get_e_phnum();
fhdr->set_e_phnum(idx+1);
/* Create a new segment table entry */
SgAsmElfSegmentTableEntry *shdr = new SgAsmElfSegmentTableEntry;
shdr->set_index(idx);
shdr->update_from_section(section);
section->set_segment_entry(shdr);
return shdr;
}
/** Write the segment table to disk. */
void
SgAsmElfSegmentTable::unparse(std::ostream &f) const
{
SgAsmElfFileHeader *fhdr = dynamic_cast<SgAsmElfFileHeader*>(get_header());
ROSE_ASSERT(fhdr!=NULL);
ByteOrder sex = fhdr->get_sex();
SgAsmGenericSectionPtrList sections = fhdr->get_segtab_sections();
/* Write the segments first */
for (size_t i=0; i<sections.size(); i++)
sections[i]->unparse(f);
unparse_holes(f);
/* Calculate sizes. The ELF File Header should have been updated in reallocate() prior to unparsing. */
size_t ent_size, struct_size, opt_size, nentries;
calculate_sizes(&ent_size, &struct_size, &opt_size, &nentries);
ROSE_ASSERT(fhdr->get_phextrasz()==opt_size);
ROSE_ASSERT(fhdr->get_e_phnum()==nentries);
/* Write the segment table entries */
for (size_t i=0; i < sections.size(); ++i) {
SgAsmElfSection *section = dynamic_cast<SgAsmElfSection*>(sections[i]);
ROSE_ASSERT(section!=NULL);
SgAsmElfSegmentTableEntry *shdr = section->get_segment_entry();
ROSE_ASSERT(shdr!=NULL);
ROSE_ASSERT(shdr->get_offset()==section->get_offset()); /*segment table entry should have been updated in reallocate()*/
int id = shdr->get_index();
ROSE_ASSERT(id>=0 && (size_t)id<nentries);
SgAsmElfSegmentTableEntry::Elf32SegmentTableEntry_disk disk32;
SgAsmElfSegmentTableEntry::Elf64SegmentTableEntry_disk disk64;
void *disk = NULL;
if (4==fhdr->get_word_size()) {
disk = shdr->encode(sex, &disk32);
} else if (8==fhdr->get_word_size()) {
disk = shdr->encode(sex, &disk64);
} else {
ROSE_ASSERT(!"invalid word size");
}
/* The disk struct */
rose_addr_t spos = write(f, id*ent_size, struct_size, disk);
if (shdr->get_extra().size() > 0)
write(f, spos, shdr->get_extra());
}
}
/** Parses an ELF Segment (Program Header) Table and constructs and parses all segments reachable from the table. The section
* is extended as necessary based on the number of entries and teh size of each entry. */
SgAsmElfSegmentTable *
SgAsmElfSegmentTable::parse()
{
SgAsmGenericSection::parse();
SgAsmElfFileHeader *fhdr = dynamic_cast<SgAsmElfFileHeader*>(get_header());
ROSE_ASSERT(fhdr!=NULL);
ByteOrder sex = fhdr->get_sex();
size_t ent_size, struct_size, opt_size, nentries;
calculate_sizes(&ent_size, &struct_size, &opt_size, &nentries);
ROSE_ASSERT(opt_size==fhdr->get_phextrasz() && nentries==fhdr->get_e_phnum());
/* If the current size is very small (0 or 1 byte) then we're coming straight from the constructor and the parsing should
* also extend this section to hold all the entries. Otherwise the caller must have assigned a specific size for a good
* reason and we should leave that alone, reading zeros if the entries extend beyond the defined size. */
if (get_size()<=1 && get_size()<nentries*ent_size)
extend(nentries*ent_size - get_size());
rose_addr_t offset=0; /* w.r.t. the beginning of this section */
for (size_t i=0; i<nentries; i++, offset+=ent_size) {
/* Read/decode the segment header */
SgAsmElfSegmentTableEntry *shdr = NULL;
if (4==fhdr->get_word_size()) {
SgAsmElfSegmentTableEntry::Elf32SegmentTableEntry_disk disk;
read_content_local(offset, &disk, struct_size);
shdr = new SgAsmElfSegmentTableEntry(sex, &disk);
} else {
SgAsmElfSegmentTableEntry::Elf64SegmentTableEntry_disk disk;
read_content_local(offset, &disk, struct_size);
shdr = new SgAsmElfSegmentTableEntry(sex, &disk);
}
shdr->set_index(i);
if (opt_size>0)
shdr->get_extra() = read_content_local_ucl(offset+struct_size, opt_size);
/* Null segments are just unused slots in the table; no real section to create */
if (SgAsmElfSegmentTableEntry::PT_NULL == shdr->get_type())
continue;
/* Create SgAsmElfSection objects for each ELF Segment. However, if the ELF Segment Table describes a segment
* that's the same offset and size as a section from the Elf Section Table (and the memory mappings are
* consistent) then use the preexisting section instead of creating a new one. */
SgAsmElfSection *s = NULL;
SgAsmGenericSectionPtrList possible = fhdr->get_file()->get_sections_by_offset(shdr->get_offset(), shdr->get_filesz());
for (size_t j=0; !s && j<possible.size(); j++) {
if (possible[j]->get_offset()!=shdr->get_offset() || possible[j]->get_size()!=shdr->get_filesz())
continue; /*different file extent*/
if (possible[j]->is_mapped()) {
if (possible[j]->get_mapped_preferred_rva()!=shdr->get_vaddr() ||
possible[j]->get_mapped_size()!=shdr->get_memsz())
continue; /*different mapped address or size*/
unsigned section_perms = (possible[j]->get_mapped_rperm() ? 0x01 : 0x00) |
(possible[j]->get_mapped_wperm() ? 0x02 : 0x00) |
(possible[j]->get_mapped_xperm() ? 0x04 : 0x00);
unsigned segment_perms = (shdr->get_flags() & SgAsmElfSegmentTableEntry::PF_RPERM ? 0x01 : 0x00) |
(shdr->get_flags() & SgAsmElfSegmentTableEntry::PF_WPERM ? 0x02 : 0x00) |
(shdr->get_flags() & SgAsmElfSegmentTableEntry::PF_XPERM ? 0x04 : 0x00);
if (section_perms != segment_perms)
continue; /*different mapped permissions*/
}
/* Found a match. Set memory mapping params only. */
s = dynamic_cast<SgAsmElfSection*>(possible[j]);
if (!s) continue; /*potential match was not from the ELF Section or Segment table*/
if (s->get_segment_entry()) continue; /*potential match is assigned to some other segment table entry*/
s->init_from_segment_table(shdr, true); /*true=>set memory mapping params only*/
}
/* Create a new segment if no matching section was found. */
if (!s) {
if (SgAsmElfSegmentTableEntry::PT_NOTE == shdr->get_type()) {
s = new SgAsmElfNoteSection(fhdr);
} else {
s = new SgAsmElfSection(fhdr);
}
s->init_from_segment_table(shdr);
s->parse();
}
}
return this;
}
