1 00000000 : %ebp %esp,%ebp Ox8(%ebp),%eax Oxc(%ebp),%ecx (%eax,%eax,4),%eax Ox4 (%ecx,%eax,4),%eax Oxb8 (%ecx),%edx (%ecx),%edx %edx,0x8(%ecx,%eax,4) %ebp 0: 55 push 3 1: 89 e5 mov 4 3: 8b 45 08 mov 5 6: 8b 4d Oc mov 6 9: 8d 04 80 lea 7 C: 03 44 81 04 add 8 10: 8b 91 b8 0o 00 00 mov 16: 03 11 add 10 18: 89 54 81 08 mov 11 1с: 5d pop 12 1d: c3 ret Figure 3.45 Disassembled code for Problem 3.66. The declarations of the compile-time constant CNT and the structure a_struct are in a file for which you do not have the necessary access privilege. Fortunately, you have a copy of the .o' version of code, which you are able to disassemble with the OBJDUMP program, yielding the disassembly shown in Figure 3.45. Using your reverse engineering skills, deduce the following. A. The value of CNT. B. A complete declaration of structure a_struct. Assume that the only fields in this structure are idx and x. 2.
1 00000000 : %ebp %esp,%ebp Ox8(%ebp),%eax Oxc(%ebp),%ecx (%eax,%eax,4),%eax Ox4 (%ecx,%eax,4),%eax Oxb8 (%ecx),%edx (%ecx),%edx %edx,0x8(%ecx,%eax,4) %ebp 0: 55 push 3 1: 89 e5 mov 4 3: 8b 45 08 mov 5 6: 8b 4d Oc mov 6 9: 8d 04 80 lea 7 C: 03 44 81 04 add 8 10: 8b 91 b8 0o 00 00 mov 16: 03 11 add 10 18: 89 54 81 08 mov 11 1с: 5d pop 12 1d: c3 ret Figure 3.45 Disassembled code for Problem 3.66. The declarations of the compile-time constant CNT and the structure a_struct are in a file for which you do not have the necessary access privilege. Fortunately, you have a copy of the .o' version of code, which you are able to disassemble with the OBJDUMP program, yielding the disassembly shown in Figure 3.45. Using your reverse engineering skills, deduce the following. A. The value of CNT. B. A complete declaration of structure a_struct. Assume that the only fields in this structure are idx and x. 2.
Computer Networking: A Top-Down Approach (7th Edition)
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Chapter1: Computer Networks And The Internet
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Related questions
Question
![Computer Systems: A Programmer's Perspective
339
/ 1078
267%
+
3.66
You are charged with maintaining a large C program, and you come across the
following code:
1
typedef struct {
2
int left;
a_struct a [CNT];
int right;
3
4
5
} b_struct;
7
void test (int i, b_struct *bp)
8
{
bp->left + bp->right;
&bp->a[i];
9.
int n =
10
a_struct *ap =
ap->x [ap->idx] = n;
11
12
}
II](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdc985489-c0ba-4ac0-af6b-7f6d1979b950%2F5f054749-b1ab-4242-b79a-799046151e2a%2Fl1veer_processed.png&w=3840&q=75)
Transcribed Image Text:Computer Systems: A Programmer's Perspective
339
/ 1078
267%
+
3.66
You are charged with maintaining a large C program, and you come across the
following code:
1
typedef struct {
2
int left;
a_struct a [CNT];
int right;
3
4
5
} b_struct;
7
void test (int i, b_struct *bp)
8
{
bp->left + bp->right;
&bp->a[i];
9.
int n =
10
a_struct *ap =
ap->x [ap->idx] = n;
11
12
}
II

Transcribed Image Text:Computer Systems: A Programmer's Perspective
340
/ 1078
231%
+
1
00000000 <test>:
%ebp
%esp,%ebp
Ox8(%ebp),%eax
Oxc (%ebp),%ecx
(%eax,%eax,4),%eax
2
0:
55
push
1:
89 e5
mov
4
3:
8b 45 08
mov
6:
8b 4d Oc
mov
9:
8d 04 80
lea
Ох4 (%eсx, %eaах, 4) ,%eax
Oxb8 (%ecx),%edx
(%ecx),%edx
%edx,0x8 (%ecх,%eax,4)
%ebp
03 44 81 04
8b 91 b8 00 00 00
7
C:
add
8
10:
mov
16:
03 11
add
10
18:
89 54 81 O8
mov
11
1c:
5d
роp
12
1d:
c3
ret
Figure 3.45 Disassembled code for Problem 3.66.
The declarations of the compile-time constant CNT and the structure a_struct
are in a file for which you do not have the necessary access privilege. Fortunately,
you have a copy of the .o' version of code, which you are able to disassemble with
the OBJDUMP program, yielding the disassembly shown in Figure 3.45.
Using your reverse engineering skills, deduce the following.
A. The value of CNT.
B. A complete declaration of structure a_struct. Assume that the only fields
in this structure are idx and x.
II
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