dyngen.c.svn-base

我们自己开发的一个OSEK操作系统！不知道可不可以？

struct symtab_command 	*symtabcmd = 0;

/* section */
struct section 	*section_hdr;
struct section *text_sec_hdr;
uint8_t 	**sdata;

/* relocs */
struct relocation_info *relocs;

/* symbols */
EXE_SYM			*symtab;
struct nlist 	*symtab_std;
char			*strtab;

/* indirect symbols */
uint32_t 	*tocdylib;

/* Utility functions */

static inline char *find_str_by_index(int index)
{
    return strtab+index;
}

/* Used by dyngen common code */
static char *get_sym_name(EXE_SYM *sym)
{
	char *name = find_str_by_index(sym->n_un.n_strx);

	if ( sym->n_type & N_STAB ) /* Debug symbols are ignored */
		return "debug";

	if(!name)
		return name;
	if(name[0]=='_')
		return name + 1;
	else
		return name;
}

/* find a section index given its segname, sectname */
static int find_mach_sec_index(struct section *section_hdr, int shnum, const char *segname,
                                  const char *sectname)
{
    int i;
    struct section *sec = section_hdr;

    for(i = 0; i < shnum; i++, sec++) {
        if (!sec->segname || !sec->sectname)
            continue;
        if (!strcmp(sec->sectname, sectname) && !strcmp(sec->segname, segname))
            return i;
    }
    return -1;
}

/* find a section header given its segname, sectname */
struct section *find_mach_sec_hdr(struct section *section_hdr, int shnum, const char *segname,
                                  const char *sectname)
{
    int index = find_mach_sec_index(section_hdr, shnum, segname, sectname);
	if(index == -1)
		return NULL;
	return section_hdr+index;
}


static inline void fetch_next_pair_value(struct relocation_info * rel, unsigned int *value)
{
    struct scattered_relocation_info * scarel;

    if(R_SCATTERED & rel->r_address) {
        scarel = (struct scattered_relocation_info*)rel;
        if(scarel->r_type != PPC_RELOC_PAIR)
            error("fetch_next_pair_value: looking for a pair which was not found (1)");
        *value = scarel->r_value;
    } else {
		if(rel->r_type != PPC_RELOC_PAIR)
			error("fetch_next_pair_value: looking for a pair which was not found (2)");
		*value = rel->r_address;
	}
}

/* find a sym name given its value, in a section number */
static const char * find_sym_with_value_and_sec_number( int value, int sectnum, int * offset )
{
	int i, ret = -1;

	for( i = 0 ; i < nb_syms; i++ )
	{
	    if( !(symtab[i].n_type & N_STAB) && (symtab[i].n_type & N_SECT) &&
			 (symtab[i].n_sect ==  sectnum) && (symtab[i].st_value <= value) )
		{
			if( (ret<0) || (symtab[i].st_value >= symtab[ret].st_value) )
				ret = i;
		}
	}
	if( ret < 0 ) {
		*offset = 0;
		return 0;
	} else {
		*offset = value - symtab[ret].st_value;
		return get_sym_name(&symtab[ret]);
	}
}

/*
 *  Find symbol name given a (virtual) address, and a section which is of type
 *  S_NON_LAZY_SYMBOL_POINTERS or S_LAZY_SYMBOL_POINTERS or S_SYMBOL_STUBS
 */
static const char * find_reloc_name_in_sec_ptr(int address, struct section * sec_hdr)
{
    unsigned int tocindex, symindex, size;
    const char *name = 0;

    /* Sanity check */
    if(!( address >= sec_hdr->addr && address < (sec_hdr->addr + sec_hdr->size) ) )
        return (char*)0;

	if( sec_hdr->flags & S_SYMBOL_STUBS ){
		size = sec_hdr->reserved2;
		if(size == 0)
		    error("size = 0");

	}
	else if( sec_hdr->flags & S_LAZY_SYMBOL_POINTERS ||
	            sec_hdr->flags & S_NON_LAZY_SYMBOL_POINTERS)
		size = sizeof(unsigned long);
	else
		return 0;

    /* Compute our index in toc */
	tocindex = (address - sec_hdr->addr)/size;
	symindex = tocdylib[sec_hdr->reserved1 + tocindex];

	name = get_sym_name(&symtab[symindex]);

    return name;
}

static const char * find_reloc_name_given_its_address(int address)
{
    unsigned int i;
    for(i = 0; i < segment->nsects ; i++)
    {
        const char * name = find_reloc_name_in_sec_ptr(address, &section_hdr[i]);
        if((long)name != -1)
            return name;
    }
    return 0;
}

static const char * get_reloc_name(EXE_RELOC * rel, int * sslide)
{
	char * name = 0;
	struct scattered_relocation_info * sca_rel = (struct scattered_relocation_info*)rel;
	int sectnum = rel->r_symbolnum;
	int sectoffset;
	int other_half=0;

	/* init the slide value */
	*sslide = 0;

	if(R_SCATTERED & rel->r_address)
		return (char *)find_reloc_name_given_its_address(sca_rel->r_value);

	if(rel->r_extern)
	{
		/* ignore debug sym */
		if ( symtab[rel->r_symbolnum].n_type & N_STAB )
			return 0;
		return get_sym_name(&symtab[rel->r_symbolnum]);
	}

	/* Intruction contains an offset to the symbols pointed to, in the rel->r_symbolnum section */
	sectoffset = *(uint32_t *)(text + rel->r_address) & 0xffff;

	if(sectnum==0xffffff)
		return 0;

	/* Sanity Check */
	if(sectnum > segment->nsects)
		error("sectnum > segment->nsects");

	switch(rel->r_type)
	{
		case PPC_RELOC_LO16: fetch_next_pair_value(rel+1, &other_half); sectoffset |= (other_half << 16);
			break;
		case PPC_RELOC_HI16: fetch_next_pair_value(rel+1, &other_half); sectoffset = (sectoffset << 16) | (uint16_t)(other_half & 0xffff);
			break;
		case PPC_RELOC_HA16: fetch_next_pair_value(rel+1, &other_half); sectoffset = (sectoffset << 16) + (int16_t)(other_half & 0xffff);
			break;
		case PPC_RELOC_BR24:
			sectoffset = ( *(uint32_t *)(text + rel->r_address) & 0x03fffffc );
			if (sectoffset & 0x02000000) sectoffset |= 0xfc000000;
			break;
		default:
			error("switch(rel->type) not found");
	}

	if(rel->r_pcrel)
		sectoffset += rel->r_address;

	if (rel->r_type == PPC_RELOC_BR24)
		name = (char *)find_reloc_name_in_sec_ptr((int)sectoffset, &section_hdr[sectnum-1]);

	/* search it in the full symbol list, if not found */
	if(!name)
		name = (char *)find_sym_with_value_and_sec_number(sectoffset, sectnum, sslide);

	return name;
}

/* Used by dyngen common code */
static const char * get_rel_sym_name(EXE_RELOC * rel)
{
	int sslide;
	return get_reloc_name( rel, &sslide);
}

/* Used by dyngen common code */
static host_ulong get_rel_offset(EXE_RELOC *rel)
{
	struct scattered_relocation_info * sca_rel = (struct scattered_relocation_info*)rel;
    if(R_SCATTERED & rel->r_address)
		return sca_rel->r_address;
	else
		return rel->r_address;
}

/* load a mach-o object file */
int load_object(const char *filename)
{
	int fd;
	unsigned int offset_to_segment = 0;
    unsigned int offset_to_dysymtab = 0;
    unsigned int offset_to_symtab = 0;
    struct load_command lc;
    unsigned int i, j;
	EXE_SYM *sym;
	struct nlist *syment;

	fd = open(filename, O_RDONLY);
    if (fd < 0)
        error("can't open file '%s'", filename);

    /* Read Mach header.  */
    if (read(fd, &mach_hdr, sizeof (mach_hdr)) != sizeof (mach_hdr))
        error("unable to read file header");

    /* Check Mach identification.  */
    if (!check_mach_header(mach_hdr)) {
        error("bad Mach header");
    }

    if (mach_hdr.cputype != CPU_TYPE_POWERPC)
        error("Unsupported CPU");

    if (mach_hdr.filetype != MH_OBJECT)
        error("Unsupported Mach Object");

    /* read segment headers */
    for(i=0, j=sizeof(mach_hdr); i<mach_hdr.ncmds ; i++)
    {
        if(read(fd, &lc, sizeof(struct load_command)) != sizeof(struct load_command))
            error("unable to read load_command");
        if(lc.cmd == LC_SEGMENT)
        {
            offset_to_segment = j;
            lseek(fd, offset_to_segment, SEEK_SET);
            segment = malloc(sizeof(struct segment_command));
            if(read(fd, segment, sizeof(struct segment_command)) != sizeof(struct segment_command))
                error("unable to read LC_SEGMENT");
        }
        if(lc.cmd == LC_DYSYMTAB)
        {
            offset_to_dysymtab = j;
            lseek(fd, offset_to_dysymtab, SEEK_SET);
            dysymtabcmd = malloc(sizeof(struct dysymtab_command));
            if(read(fd, dysymtabcmd, sizeof(struct dysymtab_command)) != sizeof(struct dysymtab_command))
                error("unable to read LC_DYSYMTAB");
        }
        if(lc.cmd == LC_SYMTAB)
        {
            offset_to_symtab = j;
            lseek(fd, offset_to_symtab, SEEK_SET);
            symtabcmd = malloc(sizeof(struct symtab_command));
            if(read(fd, symtabcmd, sizeof(struct symtab_command)) != sizeof(struct symtab_command))
                error("unable to read LC_SYMTAB");
        }
        j+=lc.cmdsize;

        lseek(fd, j, SEEK_SET);
    }

    if(!segment)
        error("unable to find LC_SEGMENT");

    /* read section headers */
    section_hdr = load_data(fd, offset_to_segment + sizeof(struct segment_command), segment->nsects * sizeof(struct section));

    /* read all section data */
    sdata = (uint8_t **)malloc(sizeof(void *) * segment->nsects);
    memset(sdata, 0, sizeof(void *) * segment->nsects);

	/* Load the data in section data */
	for(i = 0; i < segment->nsects; i++) {
        sdata[i] = load_data(fd, section_hdr[i].offset, section_hdr[i].size);
    }

    /* text section */
	text_sec_hdr = find_mach_sec_hdr(section_hdr, segment->nsects, SEG_TEXT, SECT_TEXT);
	i = find_mach_sec_index(section_hdr, segment->nsects, SEG_TEXT, SECT_TEXT);
	if (i == -1 || !text_sec_hdr)
        error("could not find __TEXT,__text section");
    text = sdata[i];

    /* Make sure dysym was loaded */
    if(!(int)dysymtabcmd)
        error("could not find __DYSYMTAB segment");

    /* read the table of content of the indirect sym */
    tocdylib = load_data( fd, dysymtabcmd->indirectsymoff, dysymtabcmd->nindirectsyms * sizeof(uint32_t) );

    /* Make sure symtab was loaded  */
    if(!(int)symtabcmd)
        error("could not find __SYMTAB segment");
    nb_syms = symtabcmd->nsyms;

    symtab_std = load_data(fd, symtabcmd->symoff, symtabcmd->nsyms * sizeof(struct nlist));
    strtab = load_data(fd, symtabcmd->stroff, symtabcmd->strsize);

	symtab = malloc(sizeof(EXE_SYM) * nb_syms);

	/* Now transform the symtab, to an extended version, with the sym size, and the C name */
	for(i = 0, sym = symtab, syment = symtab_std; i < nb_syms; i++, sym++, syment++) {
        struct nlist *sym_follow, *sym_next = 0;
        unsigned int j;
		memset(sym, 0, sizeof(*sym));

		if ( syment->n_type & N_STAB ) /* Debug symbols are skipped */
            continue;

		memcpy(sym, syment, sizeof(*syment));

		/* Find the following symbol in order to get the current symbol size */
        for(j = 0, sym_follow = symtab_std; j < nb_syms; j++, sym_follow++) {
            if ( sym_follow->n_sect != 1 || sym_follow->n_type & N_STAB || !(sym_follow->n_value > sym->st_value))
                continue;
            if(!sym_next) {
                sym_next = sym_follow;
                continue;
            }
            if(!(sym_next->n_value > sym_follow->n_value))
                continue;
            sym_next = sym_follow;
        }
		if(sym_next)
            sym->st_size = sym_next->n_value - sym->st_value;
		else
            sym->st_size = text_sec_hdr->size - sym->st_value;
	}

    /* Find Reloc */
    relocs = load_data(fd, text_sec_hdr->reloff, text_sec_hdr->nreloc * sizeof(struct relocation_info));
    nb_relocs = text_sec_hdr->nreloc;

	close(fd);
	return 0;
}

#endif /* CONFIG_FORMAT_MACH */

void get_reloc_expr(char *name, int name_size, const char *sym_name)
{
    const char *p;

    if (strstart(sym_name, "__op_param", &p)) {
        snprintf(name, name_size, "param%s", p);
    } else if (strstart(sym_name, "__op_gen_label", &p)) {
        snprintf(name, name_size, "gen_labels[param%s]", p);
    } else {
#ifdef HOST_SPARC
        if (sym_name[0] == '.')
            snprintf(name, name_size,
                     "(long)(&__dot_%s)",
                     sym_name + 1);
        else
#endif
            snprintf(name, name_size, "(long)(&%s)", sym_name);
    }
}

#ifdef HOST_IA64

#define PLT_ENTRY_SIZE	16	/* 1 bundle containing "brl" */

struct plt_entry {
    struct plt_entry *next;
    const char *name;
    unsigned long addend;
} *plt_list;

static int
get_plt_index (const char *name, unsigned long addend)
{
    struct plt_entry *plt, *prev= NULL;
    int index = 0;

    /* see if we already have an entry for this target: */
    for (plt = plt_list; plt; ++index, prev = plt, plt = plt->next)
	if (strcmp(plt->name, name) == 0 && plt->addend == addend)
	    return index;

    /* nope; create a new PLT entry: */

    plt = malloc(sizeof(*plt));
    if (!plt) {
	perror("malloc");