Compiler construction 启动期间生成的ELF可执行文件错误
我正在生成一个ELF可执行文件,其中.text部分加载到加载段中。它可以很好地进行反汇编,但在启动程序期间,如果试图在Compiler construction 启动期间生成的ELF可执行文件错误,compiler-construction,posix,elf,Compiler Construction,Posix,Elf,我正在生成一个ELF可执行文件,其中.text部分加载到加载段中。它可以很好地进行反汇编,但在启动程序期间,如果试图在gdb下运行它,程序将以信号SIGSEGV终止,出现分段故障。 readelf给出: ELF Header: Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 Class: ELF64 Data:
gdb
下运行它,程序将以信号SIGSEGV终止,出现分段故障。
readelf
给出:
ELF Header:
Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
Class: ELF64
Data: 2's complement, little endian
Version: 1 (current)
OS/ABI: UNIX - System V
ABI Version: 0
Type: EXEC (Executable file)
Machine: Advanced Micro Devices X86-64
Version: 0x1
Entry point address: 0x400056
Start of program headers: 759 (bytes into file)
Start of section headers: 503 (bytes into file)
Flags: 0x0
Size of this header: 64 (bytes)
Size of program headers: 56 (bytes)
Number of program headers: 1
Size of section headers: 64 (bytes)
Number of section headers: 4
Section header string table index: 2
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] .text PROGBITS 0000000000400040 00000040
000000000000005b 0000000000000000 AX 0 0 16
[ 2] .strtab STRTAB 0000000000000000 0000009b
000000000000009c 0000000000000000 0 0 4
[ 3] .symtab SYMTAB 0000000000000000 00000137
00000000000000c0 0000000000000018 2 1 4
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), l (large)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)
There are no section groups in this file.
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x0000000000000040 0x0000000000400000 0x0000000000400000
0x000000000000009b 0x000000000000009b R E 200000
Section to Segment mapping:
Segment Sections...
00 .text
There is no dynamic section in this file.
There are no relocations in this file.
The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.
Symbol table '.symtab' contains 8 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FUNC GLOBAL DEFAULT 1
2: 0000000000400040 16 FUNC GLOBAL DEFAULT 1 _R_Potato
3: 0000000000400050 6 FUNC GLOBAL DEFAULT 1 _R_Main
4: 0000000000000000 0 SECTION LOCAL DEFAULT 1
5: 0000000000400056 18 FUNC GLOBAL DEFAULT 1 _start
6: 0000000000400068 25 FUNC GLOBAL DEFAULT 1 GetStringLength
7: 0000000000400081 26 FUNC GLOBAL DEFAULT 1 _R_Print
如果需要,可以找到hextump。
我假设问题在于内核试图从加载段映射内容,但我没有看到问题。这是怎么回事
Program Headers:
Type Offset VirtAddr PhysAddr
FileSiz MemSiz Flags Align
LOAD 0x0000000000000040 0x0000000000400000 0x0000000000400000
0x000000000000009b 0x000000000000009b R E 200000
这就是你的问题所在:你要求内核执行一个等价的mmap(0x400000,0x9b,PROT_READ,PROT_EXEC,MAP_FIXED,$fd,0x40)
,但是这样的mmap
调用总是会在EINVAL
中失败,因为地址和偏移量不是等价的模对齐
您希望文件偏移量为0
,而不是0x40
。也就是说,您的加载
段应同时涵盖Elf64_Ehdr
和程序.text
(您的加载
段的大小已经包括这两个部分)