我们以可执行src文件为例
删除所有的符号和重定位信息：
strip -s src
查看段(Section)头部信息：
root@000d3fada0b3:~/go/src# readelf -S src
There are 13 section headers, starting at offset 0x127768:
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 0000000000401000 00001000
0000000000081258 0000000000000000 AX 0 0 16
[ 2] .rodata PROGBITS 0000000000483000 00083000
0000000000041a5b 0000000000000000 A 0 0 32
[ 3] .typelink PROGBITS 00000000004c4b80 000c4b80
0000000000000b48 0000000000000000 A 0 0 32
[ 4] .itablink PROGBITS 00000000004c56c8 000c56c8
0000000000000040 0000000000000000 A 0 0 8
[ 5] .gosymtab PROGBITS 00000000004c5708 000c5708
0000000000000000 0000000000000000 A 0 0 1
[ 6] .gopclntab PROGBITS 00000000004c5720 000c5720
000000000004e0e7 0000000000000000 A 0 0 32
[ 7] .noptrdata PROGBITS 0000000000514000 00114000
000000000000cbdc 0000000000000000 WA 0 0 32
[ 8] .data PROGBITS 0000000000520be0 00120be0
0000000000006b10 0000000000000000 WA 0 0 32
[ 9] .bss NOBITS 0000000000527700 001276f0
000000000001c688 0000000000000000 WA 0 0 32
[10] .noptrbss NOBITS 0000000000543da0 001276f0
0000000000002698 0000000000000000 WA 0 0 32
[11] .note.go.buildid NOTE 0000000000400f9c 00000f9c
0000000000000064 0000000000000000 A 0 0 4
[12] .shstrtab STRTAB 0000000000000000 001276f0
0000000000000073 0000000000000000 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
L (link order), O (extra OS processing required), G (group), T (TLS),
C (compressed), x (unknown), o (OS specific), E (exclude),
l (large), p (processor specific)
添加一个新的段(Section)，并写入信息。之后生成一个新的可执行文件src2
root@000d3fada0b3:~/go/src# objcopy --add-section .xxx=o.md --set-section-flags .xxx=noload,readonly src src2
查看src2的段(Section)头部的信息：
root@000d3fada0b3:~/go/src# readelf -S src2
There are 14 section headers, starting at offset 0x128900:
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 0000000000401000 00001000
0000000000081258 0000000000000000 AX 0 0 16
[ 2] .rodata PROGBITS 0000000000483000 00083000
0000000000041a5b 0000000000000000 A 0 0 32
[ 3] .typelink PROGBITS 00000000004c4b80 000c4b80
0000000000000b48 0000000000000000 A 0 0 32
[ 4] .itablink PROGBITS 00000000004c56c8 000c56c8
0000000000000040 0000000000000000 A 0 0 8
[ 5] .gosymtab PROGBITS 00000000004c5708 000c5708
0000000000000000 0000000000000000 A 0 0 1
[ 6] .gopclntab PROGBITS 00000000004c5720 000c5720
000000000004e0e7 0000000000000000 A 0 0 32
[ 7] .noptrdata PROGBITS 0000000000514000 00114000
000000000000cbdc 0000000000000000 WA 0 0 32
[ 8] .data PROGBITS 0000000000520be0 00120be0
0000000000006b10 0000000000000000 WA 0 0 32
[ 9] .bss NOBITS 0000000000527700 001276f0
000000000001c688 0000000000000000 WA 0 0 32
[10] .noptrbss NOBITS 0000000000543da0 001276f0
0000000000002698 0000000000000000 WA 0 0 32
[11] .note.go.buildid NOTE 0000000000400f9c 00000f9c
0000000000000064 0000000000000000 A 0 0 4
[12] .xxx PROGBITS 0000000000000000 001276f0
0000000000001191 0000000000000000 0 0 1
[13] .shstrtab STRTAB 0000000000000000 00128881
0000000000000078 0000000000000000 0 0 1
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
L (link order), O (extra OS processing required), G (group), T (TLS),
C (compressed), x (unknown), o (OS specific), E (exclude),
l (large), p (processor specific)
与src段(Section)信息相对比，发现多了一个.xxx的段。
其他命令
更新段(Section)信息：
objcopy --update-section .abc=data2 dst
重命名：
objcopy --rename-section .abc=.demo dst
删除段信息：
objcopy --remove-section .demo dst
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