load_flat

函数名称：load_flat_file

函数原型：static int load_flat_file(struct linux_binprm *bprm, struct lib_info *libinfo, int id, unsigned long *extra_stack)

返回类型：int

参数：

类型	参数	名称
struct linux_binprm *	bprm
struct lib_info *	libinfo
int	id
unsigned long *	extra_stack

432

__user乘reloc

433

__user乘rp

440

hdr等于buf

442

text_len等于ntohl(Offset of data segment from beginning offile )

443

data_len等于ntohl(Offset of end of data segment from beginningof file )减ntohl(Offset of data segment from beginning offile )

444

bss_len等于ntohl(Offset of end of bss segment from beginningof file )减ntohl(Offset of end of data segment from beginningof file )

445

stack_len等于ntohl(Size of stack, in bytes )

446

如果extra_stack则

447

stack_len加等于extra_stack

448

extra_stack等于stack_len

450

relocs等于ntohl(Number of relocation records )

451

flags等于ntohl(flags)

452

rev等于ntohl(version (as above) )

453

full_data等于data_len加relocs乘sizeof(unsignedlong)

455

如果字符串指定长度比较则

463

ret等于负ENOEXEC

464

转到:err

467

如果flags按位与utput useful kernel trace for debugging 则打印信息("Loading file: %s\n", filename)

495

如果rev不等于FLAT_VERSION则

496

打印错误信息("bad flat file version 0x%x (supported 0x%lx)\n", rev, FLAT_VERSION)

498

ret等于负ENOEXEC

499

转到:err

508

如果text_len按位或data_len按位或bss_len按位或stack_len按位或full_data的值右移28位则

509

打印错误信息("bad header\n")

510

ret等于负ENOEXEC

511

转到:err

515

如果flags按位与all but the header is compressed 按位或ly data/relocs are compressed (for XIP) 的值则

516

打印错误信息("Support for ZFLAT executables is not enabled.\n")

517

ret等于负ENOEXEC

518

转到:err

527

rlim等于rlimit(RLIMIT_DATA)

528

如果rlim大于等于RLIM_INFINITY则rlim等于0的反

530

如果data_len加bss_len大于rlim则

531

ret等于负ENOMEM

532

转到:err

536

如果id恒等于0则

537

ret等于Calling this is the point of no return. None of the failures will be* seen by userspace since either the process is already taking a fatal* signal (via de_thread() or coredump), or will have SEGV raised

538

如果ret则转到:err

542

Change personality of the currently running process.(PER_LINUX_32BIT)

543

setup_new_exec(bprm)

549

extra等于max_t - return maximum of two values, using the specified type*@type: data type to use*@x: first value*@y: second value(unsignedlong, bss_len + stack_len, relocs * sizeof(unsignedlong))

557

如果非IS_ENABLED(CONFIG_FOO) evaluates to 1 if CONFIG_FOO is set to 'y' or 'm',* 0 otherwise.(CONFIG_MMU)且非flags按位与load program entirely into RAM 按位或all but the header is compressed 的值的值则

562

pr_debug("ROM mapping of file (we hope)\n")

564

textpos等于vm_mmap(file, 0, text_len, page can be read | page can be executed , Changes are private | mark it as an executable , 0)

566

如果非textpos或IS_ERR_VALUE(textpos)则

567

ret等于textpos

568

如果非textpos则ret等于负ENOMEM

570

打印错误信息("Unable to mmap process text, errno %d\n", ret)

571

转到:err

574

len等于data_len加extra

575

len等于 align the pointer to the (next) page boundary (len)

576

realdatastart等于vm_mmap(NULL, 0, len, page can be read | page can be written | page can be executed , Changes are private , 0)

579

如果realdatastart恒等于0或IS_ERR_VALUE(realdatastart)则

580

ret等于realdatastart

581

如果非realdatastart则ret等于负ENOMEM

583

打印错误信息("Unable to allocate RAM for process data, errno %d\n", ret)

585

vm_munmap(textpos, text_len)

586

转到:err

588

datapos等于@a is a power of 2 value (realdatastart, User data (data section and bss) needs to be aligned.* We pick 0x20 here because it is the max value elf2flt has always* used in producing FLAT files, and because it seems to be large* enough to make all the gcc alignment related tests happy.)

590

pr_debug("Allocated data+bss+stack (%u bytes): %lx\n", data_len + bss_len + stack_len, datapos)

593

fpos等于ntohl(Offset of data segment from beginning offile )

601

result等于read_code(file, datapos, fpos, full_data)

604

如果IS_ERR_VALUE(result)则

605

ret等于result

606

打印错误信息("Unable to read data+bss, errno %d\n", ret)

607

vm_munmap(textpos, text_len)

608

vm_munmap(realdatastart, len)

609

转到:err

612

reloc乘__user等于datapos加ntohl(Offset of relocation records from beginning offile )减text_len

614

memp等于realdatastart

615

memp_size等于len

616

否则

618

len等于text_len加data_len加extra

619

len等于 align the pointer to the (next) page boundary (len)

620

textpos等于vm_mmap(NULL, 0, len, page can be read | page can be executed | page can be written , Changes are private , 0)

623

如果非textpos或IS_ERR_VALUE(textpos)则

624

ret等于textpos

625

如果非textpos则ret等于负ENOMEM

627

打印错误信息("Unable to allocate RAM for process text/data, errno %d\n", ret)

629

转到:err

632

realdatastart等于textpos加ntohl(Offset of data segment from beginning offile )

633

635

reloc乘__user等于datapos加ntohl(Offset of relocation records from beginning offile )减text_len

637

memp等于textpos

638

memp_size等于len

699

result等于read_code(file, textpos, 0, text_len)

700

如果非IS_ERR_VALUE(result)则result等于read_code(file, datapos, ntohl(Offset of data segment from beginning offile ), full_data)

705

如果IS_ERR_VALUE(result)则

706

ret等于result

707

打印错误信息("Unable to read code+data+bss, errno %d\n", ret)

708

vm_munmap(textpos, text_len + data_len + extra)

709

转到:err

713

start_code等于textpos加sizeof(structflat_hdr)

714

end_code等于textpos加text_len

715

text_len减等于sizeof(structflat_hdr)

718

如果id恒等于0则

719

start_code等于start_code

720

end_code等于end_code

721

start_data等于datapos

722

end_data等于datapos加data_len

730

start_brk等于datapos加data_len加bss_len

731

brk等于start_brk加3按位与3的反

737

如果flags按位与utput useful kernel trace for debugging 则

738

打印信息("Mapping is %lx, Entry point is %x, data_start is %x\n", textpos, 0x00ffffff & ntohl(Offset of first executable instructionwith text segment from beginning of file ), ntohl(Offset of data segment from beginning offile ))

740

打印信息("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", id ? "Lib" : "Load", filename, start_code, end_code, datapos, datapos + data_len, datapos + data_len, (datapos + data_len + bss_len + 3) & ~3)

747

Start of text segment 等于start_code

748

Start of data segment 等于datapos

749

End of data segment 等于datapos加data_len加bss_len

750

Length of text segment 等于text_len

751

Has this library been loaded? 等于1

752

Start address for this module 等于0x00ffffff按位与ntohl(Offset of first executable instructionwith text segment from beginning of file )的值加textpos

753

When this one was compiled 等于ntohl(When the program/library was built )

767

如果flags按位与program is PIC with GOT 则

768

循环

770

如果Careful: we have to cast the result to the type of the pointer* for sign reasons(rp_val, rp)则返回:负EFAULT

772

如果rp_val恒等于0xffffffff则退出

774

如果rp_val则

775

addr等于calc_reloc(rp_val, libinfo, id, 0)

776

如果addr恒等于Relocation incorrect somewhere 则

777

ret等于负ENOEXEC

778

转到:err

780

如果put_user - Write a simple value into user space(addr, rp)则返回:负EFAULT

797

如果rev大于While it would be nice to keep this header clean, users of older* tools still need this support in the kernel. So this section is* purely for compatibility with old tool chains.* DO NOT make changes or enhancements to the old format please, just work则

798

以i小于relocs 循环

807

如果Careful: we have to cast the result to the type of the pointer* for sign reasons(tmp, reloc + i)则返回:负EFAULT

809

relval等于ntohl(tmp)

810

addr等于flat_get_relocate_addr(relval)

811

rp等于calc_reloc(addr, libinfo, id, 1)

812

如果rp恒等于Relocation incorrect somewhere 则

813

ret等于负ENOEXEC

814

转到:err

818

ret等于flat_get_addr_from_rp(rp, relval, flags, & addr)

819

如果此条件成立可能性小(为编译器优化)(ret)则转到:err

822

如果addr不等于0则

827

如果flags按位与program is PIC with GOT 的值恒等于0则

832

addr等于ntohl((__force __be32)addr)

834

addr等于calc_reloc(addr, libinfo, id, 0)

835

如果addr恒等于Relocation incorrect somewhere 则

836

ret等于负ENOEXEC

837

转到:err

841

ret等于flat_put_addr_at_rp(rp, addr, relval)

842

如果此条件成立可能性小(为编译器优化)(ret)则转到:err

857

flush_icache_range(start_code, end_code)

860

如果用户内存块清零则返回:负EFAULT

866

返回:0

867

err :

868

返回:ret

**调用者**
名称	描述
load_flat_binary	These are the functions used to load flat style executables and shared* libraries. There is no binary dependent code anywhere else.

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