elfload.c.svn-base

我们自己开发的一个OSEK操作系统！不知道可不可以？

#ifdef TARGET_ABI32
#undef ELF_CLASS
#define ELF_CLASS ELFCLASS32
#undef bswaptls
#define bswaptls(ptr) bswap32s(ptr)
#endif

#include "elf.h"

struct exec
{
  unsigned int a_info;   /* Use macros N_MAGIC, etc for access */
  unsigned int a_text;   /* length of text, in bytes */
  unsigned int a_data;   /* length of data, in bytes */
  unsigned int a_bss;    /* length of uninitialized data area, in bytes */
  unsigned int a_syms;   /* length of symbol table data in file, in bytes */
  unsigned int a_entry;  /* start address */
  unsigned int a_trsize; /* length of relocation info for text, in bytes */
  unsigned int a_drsize; /* length of relocation info for data, in bytes */
};


#define N_MAGIC(exec) ((exec).a_info & 0xffff)
#define OMAGIC 0407
#define NMAGIC 0410
#define ZMAGIC 0413
#define QMAGIC 0314

/* max code+data+bss space allocated to elf interpreter */
#define INTERP_MAP_SIZE (32 * 1024 * 1024)

/* max code+data+bss+brk space allocated to ET_DYN executables */
#define ET_DYN_MAP_SIZE (128 * 1024 * 1024)

/* Necessary parameters */
#define TARGET_ELF_EXEC_PAGESIZE TARGET_PAGE_SIZE
#define TARGET_ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(TARGET_ELF_EXEC_PAGESIZE-1))
#define TARGET_ELF_PAGEOFFSET(_v) ((_v) & (TARGET_ELF_EXEC_PAGESIZE-1))

#define INTERPRETER_NONE 0
#define INTERPRETER_AOUT 1
#define INTERPRETER_ELF 2

#define DLINFO_ITEMS 12

static inline void memcpy_fromfs(void * to, const void * from, unsigned long n)
{
	memcpy(to, from, n);
}

extern unsigned long x86_stack_size;

static int load_aout_interp(void * exptr, int interp_fd);

#ifdef BSWAP_NEEDED
static void bswap_ehdr(struct elfhdr *ehdr)
{
    bswap16s(&ehdr->e_type);			/* Object file type */
    bswap16s(&ehdr->e_machine);		/* Architecture */
    bswap32s(&ehdr->e_version);		/* Object file version */
    bswaptls(&ehdr->e_entry);		/* Entry point virtual address */
    bswaptls(&ehdr->e_phoff);		/* Program header table file offset */
    bswaptls(&ehdr->e_shoff);		/* Section header table file offset */
    bswap32s(&ehdr->e_flags);		/* Processor-specific flags */
    bswap16s(&ehdr->e_ehsize);		/* ELF header size in bytes */
    bswap16s(&ehdr->e_phentsize);		/* Program header table entry size */
    bswap16s(&ehdr->e_phnum);		/* Program header table entry count */
    bswap16s(&ehdr->e_shentsize);		/* Section header table entry size */
    bswap16s(&ehdr->e_shnum);		/* Section header table entry count */
    bswap16s(&ehdr->e_shstrndx);		/* Section header string table index */
}

static void bswap_phdr(struct elf_phdr *phdr)
{
    bswap32s(&phdr->p_type);			/* Segment type */
    bswaptls(&phdr->p_offset);		/* Segment file offset */
    bswaptls(&phdr->p_vaddr);		/* Segment virtual address */
    bswaptls(&phdr->p_paddr);		/* Segment physical address */
    bswaptls(&phdr->p_filesz);		/* Segment size in file */
    bswaptls(&phdr->p_memsz);		/* Segment size in memory */
    bswap32s(&phdr->p_flags);		/* Segment flags */
    bswaptls(&phdr->p_align);		/* Segment alignment */
}

static void bswap_shdr(struct elf_shdr *shdr)
{
    bswap32s(&shdr->sh_name);
    bswap32s(&shdr->sh_type);
    bswaptls(&shdr->sh_flags);
    bswaptls(&shdr->sh_addr);
    bswaptls(&shdr->sh_offset);
    bswaptls(&shdr->sh_size);
    bswap32s(&shdr->sh_link);
    bswap32s(&shdr->sh_info);
    bswaptls(&shdr->sh_addralign);
    bswaptls(&shdr->sh_entsize);
}

static void bswap_sym(struct elf_sym *sym)
{
    bswap32s(&sym->st_name);
    bswaptls(&sym->st_value);
    bswaptls(&sym->st_size);
    bswap16s(&sym->st_shndx);
}
#endif

/*
 * 'copy_elf_strings()' copies argument/envelope strings from user
 * memory to free pages in kernel mem. These are in a format ready
 * to be put directly into the top of new user memory.
 *
 */
static abi_ulong copy_elf_strings(int argc,char ** argv, void **page,
                                  abi_ulong p)
{
    char *tmp, *tmp1, *pag = NULL;
    int len, offset = 0;

    if (!p) {
	return 0;       /* bullet-proofing */
    }
    while (argc-- > 0) {
        tmp = argv[argc];
        if (!tmp) {
	    fprintf(stderr, "VFS: argc is wrong");
	    exit(-1);
	}
        tmp1 = tmp;
	while (*tmp++);
	len = tmp - tmp1;
	if (p < len) {  /* this shouldn't happen - 128kB */
		return 0;
	}
	while (len) {
	    --p; --tmp; --len;
	    if (--offset < 0) {
		offset = p % TARGET_PAGE_SIZE;
                pag = (char *)page[p/TARGET_PAGE_SIZE];
                if (!pag) {
                    pag = (char *)malloc(TARGET_PAGE_SIZE);
                    memset(pag, 0, TARGET_PAGE_SIZE);
                    page[p/TARGET_PAGE_SIZE] = pag;
                    if (!pag)
                        return 0;
		}
	    }
	    if (len == 0 || offset == 0) {
	        *(pag + offset) = *tmp;
	    }
	    else {
	      int bytes_to_copy = (len > offset) ? offset : len;
	      tmp -= bytes_to_copy;
	      p -= bytes_to_copy;
	      offset -= bytes_to_copy;
	      len -= bytes_to_copy;
	      memcpy_fromfs(pag + offset, tmp, bytes_to_copy + 1);
	    }
	}
    }
    return p;
}

static abi_ulong setup_arg_pages(abi_ulong p, struct linux_binprm *bprm,
                                 struct image_info *info)
{
    abi_ulong stack_base, size, error;
    int i;

    /* Create enough stack to hold everything.  If we don't use
     * it for args, we'll use it for something else...
     */
    size = x86_stack_size;
    if (size < MAX_ARG_PAGES*TARGET_PAGE_SIZE)
        size = MAX_ARG_PAGES*TARGET_PAGE_SIZE;
    error = target_mmap(0,
                        size + qemu_host_page_size,
                        PROT_READ | PROT_WRITE,
                        MAP_PRIVATE | MAP_ANONYMOUS,
                        -1, 0);
    if (error == -1) {
        perror("stk mmap");
        exit(-1);
    }
    /* we reserve one extra page at the top of the stack as guard */
    target_mprotect(error + size, qemu_host_page_size, PROT_NONE);

    stack_base = error + size - MAX_ARG_PAGES*TARGET_PAGE_SIZE;
    p += stack_base;

    for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
	if (bprm->page[i]) {
	    info->rss++;
            /* FIXME - check return value of memcpy_to_target() for failure */
	    memcpy_to_target(stack_base, bprm->page[i], TARGET_PAGE_SIZE);
	    free(bprm->page[i]);
	}
        stack_base += TARGET_PAGE_SIZE;
    }
    return p;
}

static void set_brk(abi_ulong start, abi_ulong end)
{
	/* page-align the start and end addresses... */
        start = HOST_PAGE_ALIGN(start);
        end = HOST_PAGE_ALIGN(end);
        if (end <= start)
                return;
        if(target_mmap(start, end - start,
                       PROT_READ | PROT_WRITE | PROT_EXEC,
                       MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0) == -1) {
	    perror("cannot mmap brk");
	    exit(-1);
	}
}


/* We need to explicitly zero any fractional pages after the data
   section (i.e. bss).  This would contain the junk from the file that
   should not be in memory. */
static void padzero(abi_ulong elf_bss, abi_ulong last_bss)
{
        abi_ulong nbyte;

	if (elf_bss >= last_bss)
		return;

        /* XXX: this is really a hack : if the real host page size is
           smaller than the target page size, some pages after the end
           of the file may not be mapped. A better fix would be to
           patch target_mmap(), but it is more complicated as the file
           size must be known */
        if (qemu_real_host_page_size < qemu_host_page_size) {
            abi_ulong end_addr, end_addr1;
            end_addr1 = (elf_bss + qemu_real_host_page_size - 1) &
                ~(qemu_real_host_page_size - 1);
            end_addr = HOST_PAGE_ALIGN(elf_bss);
            if (end_addr1 < end_addr) {
                mmap((void *)g2h(end_addr1), end_addr - end_addr1,
                     PROT_READ|PROT_WRITE|PROT_EXEC,
                     MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
            }
        }

        nbyte = elf_bss & (qemu_host_page_size-1);
        if (nbyte) {
	    nbyte = qemu_host_page_size - nbyte;
	    do {
                /* FIXME - what to do if put_user() fails? */
		put_user_u8(0, elf_bss);
                elf_bss++;
	    } while (--nbyte);
        }
}


static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
                                   struct elfhdr * exec,
                                   abi_ulong load_addr,
                                   abi_ulong load_bias,
                                   abi_ulong interp_load_addr, int ibcs,
                                   struct image_info *info)
{
        abi_ulong sp;
        int size;
        abi_ulong u_platform;
        const char *k_platform;
        const int n = sizeof(elf_addr_t);

        sp = p;
        u_platform = 0;
        k_platform = ELF_PLATFORM;
        if (k_platform) {
            size_t len = strlen(k_platform) + 1;
            sp -= (len + n - 1) & ~(n - 1);
            u_platform = sp;
            /* FIXME - check return value of memcpy_to_target() for failure */
            memcpy_to_target(sp, k_platform, len);
        }
	/*
	 * Force 16 byte _final_ alignment here for generality.
	 */
        sp = sp &~ (abi_ulong)15;
        size = (DLINFO_ITEMS + 1) * 2;
        if (k_platform)
          size += 2;
#ifdef DLINFO_ARCH_ITEMS
	size += DLINFO_ARCH_ITEMS * 2;
#endif
        size += envc + argc + 2;
	size += (!ibcs ? 3 : 1);	/* argc itself */
        size *= n;
        if (size & 15)
            sp -= 16 - (size & 15);

        /* This is correct because Linux defines
         * elf_addr_t as Elf32_Off / Elf64_Off
         */
#define NEW_AUX_ENT(id, val) do {		\
            sp -= n; put_user_ual(val, sp);	\
            sp -= n; put_user_ual(id, sp);	\
          } while(0)

        NEW_AUX_ENT (AT_NULL, 0);

        /* There must be exactly DLINFO_ITEMS entries here.  */
        NEW_AUX_ENT(AT_PHDR, (abi_ulong)(load_addr + exec->e_phoff));
        NEW_AUX_ENT(AT_PHENT, (abi_ulong)(sizeof (struct elf_phdr)));
        NEW_AUX_ENT(AT_PHNUM, (abi_ulong)(exec->e_phnum));
        NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(TARGET_PAGE_SIZE));
        NEW_AUX_ENT(AT_BASE, (abi_ulong)(interp_load_addr));
        NEW_AUX_ENT(AT_FLAGS, (abi_ulong)0);
        NEW_AUX_ENT(AT_ENTRY, load_bias + exec->e_entry);
        NEW_AUX_ENT(AT_UID, (abi_ulong) getuid());
        NEW_AUX_ENT(AT_EUID, (abi_ulong) geteuid());
        NEW_AUX_ENT(AT_GID, (abi_ulong) getgid());
        NEW_AUX_ENT(AT_EGID, (abi_ulong) getegid());
        NEW_AUX_ENT(AT_HWCAP, (abi_ulong) ELF_HWCAP);
        if (k_platform)
            NEW_AUX_ENT(AT_PLATFORM, u_platform);
#ifdef ARCH_DLINFO
	/*
	 * ARCH_DLINFO must come last so platform specific code can enforce
	 * special alignment requirements on the AUXV if necessary (eg. PPC).
	 */
        ARCH_DLINFO;
#endif
#undef NEW_AUX_ENT

        sp = loader_build_argptr(envc, argc, sp, p, !ibcs);
        return sp;
}


static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex,
                                 int interpreter_fd,
                                 abi_ulong *interp_load_addr)
{
	struct elf_phdr *elf_phdata  =  NULL;
	struct elf_phdr *eppnt;
	abi_ulong load_addr = 0;
	int load_addr_set = 0;
	int retval;
	abi_ulong last_bss, elf_bss;
	abi_ulong error;
	int i;

	elf_bss = 0;
	last_bss = 0;
	error = 0;

#ifdef BSWAP_NEEDED
        bswap_ehdr(interp_elf_ex);
#endif
	/* First of all, some simple consistency checks */
	if ((interp_elf_ex->e_type != ET_EXEC &&
             interp_elf_ex->e_type != ET_DYN) ||
	   !elf_check_arch(interp_elf_ex->e_machine)) {
		return ~((abi_ulong)0UL);
	}


	/* Now read in all of the header information */

	if (sizeof(struct elf_phdr) * interp_elf_ex->e_phnum > TARGET_PAGE_SIZE)
	    return ~(abi_ulong)0UL;

	elf_phdata =  (struct elf_phdr *)
		malloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);

	if (!elf_phdata)
	  return ~((abi_ulong)0UL);

	/*
	 * If the size of this structure has changed, then punt, since
	 * we will be doing the wrong thing.
	 */
	if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr)) {
	    free(elf_phdata);
	    return ~((abi_ulong)0UL);
        }

	retval = lseek(interpreter_fd, interp_elf_ex->e_phoff, SEEK_SET);
	if(retval >= 0) {
	    retval = read(interpreter_fd,
			   (char *) elf_phdata,
			   sizeof(struct elf_phdr) * interp_elf_ex->e_phnum);
	}
	if (retval < 0) {
		perror("load_elf_interp");
		exit(-1);
		free (elf_phdata);
		return retval;
 	}
#ifdef BSWAP_NEEDED
	eppnt = elf_phdata;
	for (i=0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
            bswap_phdr(eppnt);
        }
#endif

        if (interp_elf_ex->e_type == ET_DYN) {
            /* in order to avoid hardcoding the interpreter load
               address in qemu, we allocate a big enough memory zone */
            error = target_mmap(0, INTERP_MAP_SIZE,
                                PROT_NONE, MAP_PRIVATE | MAP_ANON,
                                -1, 0);
            if (error == -1) {
                perror("mmap");
                exit(-1);
            }
            load_addr = error;
            load_addr_set = 1;
        }

	eppnt = elf_phdata;
	for(i=0; i<interp_elf_ex->e_phnum; i++, eppnt++)
	  if (eppnt->p_type == PT_LOAD) {
	    int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
	    int elf_prot = 0;
	    abi_ulong vaddr = 0;
	    abi_ulong k;

	    if (eppnt->p_flags & PF_R) elf_prot =  PROT_READ;
	    if (eppnt->p_flags & PF_W) elf_prot |= PROT_WRITE;
	    if (eppnt->p_flags & PF_X) elf_prot |= PROT_EXEC;
	    if (interp_elf_ex->e_type == ET_EXEC || load_addr_set) {
	    	elf_type |= MAP_FIXED;
	    	vaddr = eppnt->p_vaddr;
	    }
	    error = target_mmap(load_addr+TARGET_ELF_PAGESTART(vaddr),
		 eppnt->p_filesz + TARGET_ELF_PAGEOFFSET(eppnt->p_vaddr),
		 elf_prot,
		 elf_type,
		 interpreter_fd,
		 eppnt->p_offset - TARGET_ELF_PAGEOFFSET(eppnt->p_vaddr));

	    if (error == -1) {
	      /* Real error */
	      close(interpreter_fd);
	      free(elf_phdata);
	      return ~((abi_ulong)0UL);
	    }

	    if (!load_addr_set && interp_elf_ex->e_type == ET_DYN) {
	      load_addr = error;
	      load_addr_set = 1;
	    }

	    /*
	     * Find the end of the file  mapping for this phdr, and keep
	     * track of the largest address we see for this.
	     */
	    k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
	    if (k > elf_bss) elf_bss = k;

	    /*
	     * Do the same thing for the memory mapping - between
	     * elf_bss and last_bss is the bss section.
	     */
	    k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
	    if (k > last_bss) last_bss = k;
	  }

	/* Now use mmap to map the library into memory. */

	close(interpreter_fd);

	/*
	 * Now fill out the bss section.  First pad the last page up
	 * to the page boundary, and then perform a mmap to make sure
	 * that there are zeromapped pages up to and including the last
	 * bss page.
	 */
	padzero(elf_bss, last_bss);
	elf_bss = TARGET_ELF_PAGESTART(elf_bss + qemu_host_page_size - 1); /* What we have mapped so far */

	/* Map the last of the bss segment */
	if (last_bss > elf_bss) {
            target_mmap(elf_bss, last_bss-elf_bss,
                        PROT_READ|PROT_WRITE|PROT_EXEC,
                        MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
	}
	free(elf_phdata);