jt_pqueue* jt_pqueue_new(void)
{
jt_pqueue* pq = jt_new(jt_pqueue);
pq->item = jt_newarray(jt_pqueueitem*, 4);
pq->length = 0;
pq->size = 4;
return pq;
}
jt_pqueueitem* jt_pqueue_newitem(uint5 priority)
{
jt_pqueueitem* pqi = jt_new(jt_pqueueitem);
pqi->priority = priority;
pqi->data = 0;
return pqi;
}
/* add symbols in object file to local symbol map */
void readsymbols(section* symtab, section* strtab, jt_map** symbolmap)
{
int i;
Elf32_Sym* thissym;
for (i=1; i<symtab->content->length/sizeof(Elf32_Sym); i++)
{
mapentry* mentry = jt_new(mapentry);
thissym = buffer_IDX(symtab->content, Elf32_Sym, i);
mentry->name = symbolname(thissym, strtab);
mentry->binding = ELF32_ST_BIND(thissym->st_info);
mentry->symtabentry = i;
mentry->backpatches = 0;
#ifdef DEBUG
/* fprintf(stderr, "Read symbol %s\n", mentry->name);*/
#endif
jt_map_insert(symbolmap, mentry->name, mentry);
}
}
/*
Must match write_elf in asm/elfutil.c
*/
image* loadimage(FILE* f, int inlibrary)
{
image* img = jt_new(image);
uint5 total = 0;
section* sections[SHN_COUNT];
const uint5 numsections = sizeof(sections)/sizeof(section*);
uint5 i;
/* yucky innit. */
sections[0] = &img->null;
sections[1] = &img->shstrtab;
sections[2] = &img->text;
sections[3] = &img->data;
sections[4] = &img->rodata;
sections[5] = &img->bss;
sections[6] = &img->symtab;
sections[7] = &img->strtab;
sections[8] = &img->reltext;
sections[9] = &img->reldata;
sections[10] = &img->relrodata;
sections[11] = &img->relbss;
img->symbolmap = 0;
total += fread(&img->ehdr, sizeof(Elf32_Ehdr), 1, f) * sizeof(Elf32_Ehdr);
if (img->ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
img->ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
img->ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
img->ehdr.e_ident[EI_MAG3] != ELFMAG3)
{
fprintf(stderr, "Unrecognized file format\n");
exit(1);
}
// read section headers
for (i=0; i<numsections; i++)
{
total += fread(§ions[i]->header, sizeof(Elf32_Shdr), 1, f) *
sizeof(Elf32_Shdr);
fixshdr(§ions[i]->header);
}
// read section data
for (i=0; i<numsections; i++)
{
total += loadsection(sections[i], f);
}
#ifdef DEBUG
fprintf(stderr, "Read %d bytes total\n", total);
#endif
/* fiddle symtab to make it host byte order */
fixsymtab(img->symtab.content->buffer,
img->symtab.content->length / sizeof(Elf32_Sym));
img->used = IMAGE_UNUSED;
img->library = inlibrary;
return img;
}
/* find global symbols defined in an object file, add to global symbol map.
Overrides weak symbols with global symbols.
*/
void findglobals(image* in, jt_map** global)
{
uint5 i;
for (i=1; i<in->symtab.content->length/sizeof(Elf32_Sym); i++)
{
Elf32_Sym* sym = buffer_IDX(in->symtab.content, Elf32_Sym, i);
char* name = symbolname(sym, &in->strtab);
mapentry* oldmsym = jt_map_find(*global, name);
uint5 newbinding = ELF32_ST_BIND(sym->st_info);
if ((newbinding!=STB_GLOBAL && newbinding!=STB_WEAK) ||
sym->st_shndx==SHN_UNDEF) continue;
if (oldmsym)
{
if (!in->library)
{
/* We have a symbol with this name already */
switch (oldmsym->binding)
{
case STB_GLOBAL:
if (newbinding==STB_GLOBAL)
{
fprintf(stderr, "Multiply-defined global symbol %s\n", name);
exit(1);
}
/* Else new symbol is weak, we can ignore it */
break;
case STB_WEAK:
if (newbinding==STB_WEAK)
{
#ifdef DEBUG2
fprintf(stderr, "Warning: multiply-defined weak symbol %s\n", name);
#endif
}
else
{
/* Override old weak symbol */
oldmsym->binding = STB_GLOBAL;
oldmsym->symtabentry = i;
oldmsym->in_image = in;
}
break;
default:
fprintf(stderr, "Non-global symbol in global symbol map? (%s)\n",
name);
exit(1);
}
}
}
else
{
/* Generate a new global map entry */
mapentry* msym = jt_new(mapentry);
msym->name = name;
msym->binding = newbinding;
msym->symtabentry = i;
msym->in_image = in;
msym->index = -1u;
msym->backpatches = 0;
jt_map_insert(global, name, msym);
}
}
}
void loadarchive(FILE* ar, program* prog, jt_clist* objects)
{
char armagic[SARMAG];
struct ar_hdr arheader;
int entry = 0;
int havesymtab = 0;
fread(armagic, 1, SARMAG, ar);
if (strncmp(armagic, ARMAG, SARMAG) != 0)
{
fprintf(stderr, "This does not look like an archive file\n");
exit(1);
}
#ifdef DEBUG
fprintf(stderr, "Got archive file!\n");
#endif
while (!feof(ar))
{
long posn = ftell(ar);
int size;
if ((posn & 1) == 1)
{
/* odd byte boundary, we must read another character, a newline */
int c = fgetc(ar);
if (c != '\n')
{
fprintf(stderr, "Was expecting newline padding for header\n");
exit(1);
}
}
/* first thing we try to read from the file this iteration: if it
* fails, we've hit the end of the file (feof() didn't seem to work)
*/
if (fread(&arheader, 1, sizeof(arheader), ar) != sizeof(arheader))
break;
if (strncmp(arheader.ar_fmag, ARFMAG, sizeof(ARFMAG)-1) != 0)
{
fprintf(stderr, "Bad archive header\n");
exit(1);
}
sscanf(arheader.ar_size, "%d", &size);
posn = ftell(ar);
#ifdef DEBUG
fprintf(stderr, "Good archive header, length=%d\n", size);
#endif
if (entry==0 && !havesymtab && arheader.ar_name[0] == '/' &&
arheader.ar_name[1] == ' ')
{
archive_symtab* symtab = jt_new(archive_symtab);
/* unnamed first entry is probably a symtab */
if (readsymtab(ar, &arheader, symtab))
{
fprintf(stderr, "Error reading symbol table\n");
exit(1);
}
havesymtab = 1;
/* don't really want one of those, was just being polite */
free(symtab->loc);
free(symtab->name);
free(symtab->nameidx);
free(symtab);
}
else if (arheader.ar_name[0] == '/' && arheader.ar_name[1] == '/')
{
int posn = ftell(ar), size;
#ifdef DEBUG
fprintf(stderr, "Detected long filename section\n");
#endif
sscanf(arheader.ar_size, "%d", &size);
fseek(ar, posn+size, SEEK_SET);
#ifdef DEBUG
fprintf(stderr, "Skipped %d bytes\n", size);
#endif
}
else
{
jt_clist* newobj = jt_clist_append(objects);
image* img;
#ifdef DEBUG
uint5 i;
#endif
/* read a file from the archive */
#ifdef DEBUG
fprintf(stderr, "Original filename: ");
if (arheader.ar_name[0]=='/')
{
fprintf(stderr, "(long)\n");
}
else
{
for (i=0; i<16; i++)
{
if (arheader.ar_name[i]=='/') break;
fputc(arheader.ar_name[i], stderr);
}
fputc('\n', stderr);
}
#endif
newobj->data = img = loadimage(ar, 1);
readsymbols(&img->symtab, &img->strtab, &img->symbolmap);
findglobals(img, &prog->globalsymbolmap);
}
/* position over file */
fseek(ar, posn+size, SEEK_SET);
entry++;
}
#ifdef DEBUG
fprintf(stderr, "Read library, returning...\n");
#endif
}
