Hi,
$ cat func_globalvar.c
int globalVar;
static int globalStaticVar;
int func() {
static int localStaticVar;
return globalVar;
}
$ gcc -c -o func_globalvar_abs.o func_globalvar.c
I have the above object file. If I understand it correctly, the Ndx in
the following output should be the index of the string in the
.shstrtab table as shown below?
1 -> .symtab
3 -> .shstrtab
4 -> .rela.text
6 -> .bss
7 -> .comment
5 -> .data
$ readelf -s func_globalvar_abs.o
Symbol table '.symtab' contains 12 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FILE LOCAL DEFAULT ABS func_globalvar.c
2: 0000000000000000 0 SECTION LOCAL DEFAULT 1
3: 0000000000000000 0 SECTION LOCAL DEFAULT 3
4: 0000000000000000 0 SECTION LOCAL DEFAULT 4
5: 0000000000000004 4 OBJECT LOCAL DEFAULT 4 globalStaticVar
6: 0000000000000008 4 OBJECT LOCAL DEFAULT 4 localStaticVar.0
7: 0000000000000000 0 SECTION LOCAL DEFAULT 6
8: 0000000000000000 0 SECTION LOCAL DEFAULT 7
9: 0000000000000000 0 SECTION LOCAL DEFAULT 5
10: 0000000000000000 4 OBJECT GLOBAL DEFAULT 4 globalVar
11: 0000000000000000 12 FUNC GLOBAL DEFAULT 1 func
$ readelf -p .shstrtab func_globalvar_abs.o
String dump of section '.shstrtab':
[ 1] .symtab
[ 9] .strtab
[ 11] .shstrtab
[ 1b] .rela.text
[ 26] .data
[ 2c] .bss
[ 31] .comment
[ 3a] .note.GNU-stack
[ 4a] .rela.eh_frame
Why these sections are in the symbol table, given that they are
already in the section headers?
$ readelf -SW func_globalvar_abs.o
There are 12 section headers, starting at offset 0x2a8:
Section Headers:
[Nr] Name Type Address Off Size
ES Flg Lk Inf Al
[ 0] NULL 0000000000000000 000000
000000 00 0 0 0
[ 1] .text PROGBITS 0000000000000000 000040
00000c 00 AX 0 0 1
[ 2] .rela.text RELA 0000000000000000 000218
000018 18 I 9 1 8
[ 3] .data PROGBITS 0000000000000000 00004c
000000 00 WA 0 0 1
[ 4] .bss NOBITS 0000000000000000 00004c
00000c 00 WA 0 0 4
[ 5] .comment PROGBITS 0000000000000000 00004c
000028 01 MS 0 0 1
[ 6] .note.GNU-stack PROGBITS 0000000000000000 000074
000000 00 0 0 1
[ 7] .eh_frame PROGBITS 0000000000000000 000078
000038 00 A 0 0 8
[ 8] .rela.eh_frame RELA 0000000000000000 000230
000018 18 I 9 7 8
[ 9] .symtab SYMTAB 0000000000000000 0000b0
000120 18 10 10 8
[10] .strtab STRTAB 0000000000000000 0001d0
000042 00 0 0 1
[11] .shstrtab STRTAB 0000000000000000 000248
000059 00 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)
--
Regards,
Peng
