#include
#include <stdlib.h>
#include
void url_encode_char(char *vj, int va)
{
//1: /x $rsp = 0x7fffffffe168
//2: /x $rbp = 0x7fffffffe180
/*1169: f3 0f 1e fa endbr64
116d: 55 push %rbp // rsp = 0x7fffffffe160
116e: 48 89 e5 mov %rsp,%rbp // rsp=rbp=0x7fffffffe160
1171: 48 83 ec 30 sub $0x30,%rsp // rsp = 0x7fffffffe130
1175: 48 89 7d d8 mov %rdi,-0x28(%rbp) */ // 0x7fffffffe138: 0x00007fffffffe173
char *j = vj;
char var = va;
/*1179: 89 f0 mov %esi,%eax // eax = parameter 2 = 'a' = 0x61
117b: 88 45 d4 mov %al,-0x2c(%rbp) // (rbp-0x2c) = 0x7fffffffe134: 0xffffe17300000061
117e: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax
1185: 00 00
1187: 48 89 45 f8 mov %rax,-0x8(%rbp)
118b: 31 c0 xor %eax,%eax*/
/*118d: 48 b8 30 31 32 33 34 movabs $0x3736353433323130,%rax // rax = "01234567"
1194: 35 36 37
1197: 48 ba 38 39 41 42 43 movabs $0x46444342413938,%rdx // rdx = "89ABCDEF"
119e: 44 46 00 */
char s[] = {'0', '1','2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
/*11a1: 48 89 45 e0 mov %rax,-0x20(%rbp) // (rbp-0x20) = "01234567"
11a5: 48 89 55 e8 mov %rdx,-0x18(%rbp) // (rbp-0x18) = "89ABCDEF"
11a9: 48 8b 45 d8 mov -0x28(%rbp),%rax // rax = parameter1
11ad: c6 00 25 movb $0x25,(%rax) // parameter1 = '%'*/
vj[0] = '%';
/*11b0: 0f b6 45 d4 movzbl -0x2c(%rbp),%eax // eax = 0x61
11b4: c0 f8 04 sar $0x4,%al // al <<= 4 = 0x61>>4 = 0x6
11b7: 0f be c0 movsbl %al,%eax // eax = 0x6
11ba: 83 e0 0f and $0xf,%eax // eax = 0x6
11bd: 89 c1 mov %eax,%ecx // ecx = 0x6
11bf: 48 8b 45 d8 mov -0x28(%rbp),%rax // rax = parameter1
11c3: 48 8d 50 01 lea 0x1(%rax),%rdx // rdx = praramter1 + 1
11c7: 48 63 c1 movslq %ecx,%rax // rax = 0x6
11ca: 0f b6 44 05 e0 movzbl -0x20(%rbp,%rax,1),%eax // eax = s[6] = '6'
11cf: 88 02 mov %al,(%rdx) // (praramter1 + 1) = '6' */
vj[1] = s[va>>4];
/*11d1: 48 8b 45 d8 mov -0x28(%rbp),%rax // rax = parameter1
11d5: 48 83 c0 01 add $0x1,%rax // rax = parameter1 + 1
11d9: 0f b6 00 movzbl (%rax),%eax // eax = 0x36 = '6'
11dc: 0f be c0 movsbl %al,%eax // eax = 0x36
11df: 89 c6 mov %eax,%esi // esi = 0x36
11e1: 48 8d 3d 1c 0e 00 00 lea 0xe1c(%rip),%rdi # 2004 <_IO_stdin_used+0x4>
11e8: b8 00 00 00 00 mov $0x0,%eax
11ed: e8 7e fe ff ff callq 1070
printf("%c\n", j[1]);
/*11f2: 0f be 45 d4 movsbl -0x2c(%rbp),%eax // eax = 0x61
11f6: 83 e0 0f and $0xf,%eax // eax = 0x1
11f9: 89 c1 mov %eax,%ecx // ecx = 1
11fb: 48 8b 45 d8 mov -0x28(%rbp),%rax // rax = parameter1
11ff: 48 8d 50 02 lea 0x2(%rax),%rdx // rdx = parameter1 + 2
1203: 48 63 c1 movslq %ecx,%rax // rax = 1
1206: 0f b6 44 05 e0 movzbl -0x20(%rbp,%rax,1),%eax // eax = s[1] = 0x31 = '1'
120b: 88 02 mov %al,(%rdx)*/ // parameter1 + 2 = '1'
vj[2] = s[va&0xf];
/*120d: 90 nop
120e: 48 8b 45 f8 mov -0x8(%rbp),%rax
1212: 64 48 33 04 25 28 00 xor %fs:0x28,%rax
1219: 00 00
121b: 74 05 je 1222
121d: e8 3e fe ff ff callq 1060 <__stack_chk_fail@plt>
1222: c9 leaveq
1223: c3 retq */
}
int main()
{
//1: $rsp = (void *) 0x7fffffffe188
//2: $rbp = (void *) 0x0
/*1224: f3 0f 1e fa endbr64 // $rsp = (void *) 0x7fffffffe188
1228: 55 push %rbp // $rsp = (void *) 0x7fffffffe180 $rbp = (void *) 0x0
1229: 48 89 e5 mov %rsp,%rbp // rsp=rbp=0x7fffffffe180
122c: 48 83 ec 10 sub $0x10,%rsp // $rsp = (void *) 0x7fffffffe170
1230: 64 48 8b 04 25 28 00 mov %fs:0x28,%rax // rax=0xf1579181adc48600 eax=0xadc48600
1237: 00 00
1239: 48 89 45 f8 mov %rax,-0x8(%rbp) // 0x7fffffffe178: 0xf1579181adc48600
123d: 31 c0 xor %eax,%eax*/ // eax=0 rax=0
/*(gdb) x/16b $rbp-0xd
0x7fffffffe173: 0xff 0xff 0x7f 0x00 0x00 0x00 0x86 0xc4
0x7fffffffe17b: 0xad 0x81 0x91 0x57 0xf1 0x00 0x00 0x00
(gdb) x/16b $rbp-0x10
0x7fffffffe170: 0x70 0xe2 0xff 0xff 0xff 0x7f 0x00 0x00
0x7fffffffe178: 0x00 0x86 0xc4 0xad 0x81 0x91 0x57 0xf1*/
//123f: c7 45 f3 00 00 00 00 movl $0x0,-0xd(%rbp) // 0x7fffffffe173: 0xc486000000000000
/*(gdb) x/16b $rbp-0xd
0x7fffffffe173: [0x00 0x00 0x00 0x00] 0x00 0x00 0x86 0xc4
0x7fffffffe17b: 0xad 0x81 0x91 0x57 0xf1 0x00 0x00 0x00
(gdb) x/24b $rbp-0x10
0x7fffffffe170: 0x70 0xe2 0xff [0x00 0x00 0x00 0x00] 0x00
0x7fffffffe178: 0x00 0x86 0xc4 0xad 0x81 0x91 0x57 0xf1
0x7fffffffe180: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00*/
char j[5] = {0};
//1246: c6 45 f7 00 movb $0x0,-0x9(%rbp) // 0x7fffffffe177: 0x00
/*(gdb) x/24b $rbp-0x10
0x7fffffffe170: 0x70 0xe2 0xff 0x00 0x00 0x00 0x00 [0x00]
0x7fffffffe178: 0x00 0x86 0xc4 0xad 0x81 0x91 0x57 0xf1
0x7fffffffe180: 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00*/
//char i = 0;
/*124a: 48 8d 45 f3 lea -0xd(%rbp),%rax
124e: be 61 00 00 00 mov $0x61,%esi
1253: 48 89 c7 mov %rax,%rdi
1256: e8 0e ff ff ff callq 1169
url_encode_char(j, 'a');
/*125b: 48 8d 45 f3 lea -0xd(%rbp),%rax
125f: 48 89 c6 mov %rax,%rsi
1262: 48 8d 3d 9f 0d 00 00 lea 0xd9f(%rip),%rdi # 2008 <_IO_stdin_used+0x8>
1269: b8 00 00 00 00 mov $0x0,%eax
126e: e8 fd fd ff ff callq 1070
printf("%s\n", j);
/*1273: b8 00 00 00 00 mov $0x0,%eax
1278: 48 8b 55 f8 mov -0x8(%rbp),%rdx
127c: 64 48 33 14 25 28 00 xor %fs:0x28,%rdx
1283: 00 00
1285: 74 05 je 128c
1287: e8 d4 fd ff ff callq 1060 <__stack_chk_fail@plt>
128c: c9 leaveq
128d: c3 retq
128e: 66 90 xchg %ax,%ax*/
return 0;
}
// code
static void url_encode_char(char *b, char c)
{
char hex_table[] = "0123456789ABCDF";
b[0] = '%';
b[1] = hex_table[(c >> 4) & 0x0F];
printf("%c\n", b[1]); // 6
b[2] = hex_table[c & 0x0F];
}
int main()
{
char b[5] = {0};
url_encode_char(b, 'a');
printf("main = %s \n", b); // %61
return 0;
}