To be added ... gdb a.out [inferior 1 (Process 9718) exited with code] (GDB) listline number is out of range; T.C has lines. (GDB) List one #include2 char foo (char *s) 3 {4 char *c=s;5 return * (c+2); 6}7 int main () 8 {9
Char arr[5]= "abc\n";Ten char B=foo (arr);(gdb) One by one printf ("%c\n", b), printf ("%s\n", arr); 1314} (GDB) Disass/mdump of Assembler code for function Main:8 {0x08048449 <+0>: Push? p 0x0804844a <+1>: mov%esp ,? p 0x0804844c <+3>: and $0xfffffff0,%esp 0x0804844f <+6>: Sub $0x20,%esp 9 char arr [5]= "abc\n"; 0x08048452 <+9>: Movl $0xa636261,
0x1a (%ESP)0x0804845a <+17>: Movb $0x0,0x1e (%ESP) char B=foo (arr);=> 0x0804845f <+22>: Lea 0x1a (% ESP),? x
//eip0x08048463 <+26>: mov x, (%ESP) 0x08048466 <+29>: Call 0x8048434 0x0804846b <+34>: mov %al,0x1f (%ESP) (GDB) Info registers Espesp
0xbfffefb00xbfffefb0#another Shell[email protected]:~> echo $ ((
0xbfffefb0+0X1A))
3221221322[Email protected]:~> echo ' obase=16;base=10;
3221221322' | Bc
BFFFEFCA(GDB) x/s
0XBFFFEFCA0XBFFFEFCA:
" abc\n"//find the "abc\n"(GDB) gdb) help Catchset catchpoints to catch events. list of catch subcommands: catch assert--CATC H failed Ada Assertionscatch catch--Catch an Exceptioncatch exception--catch Ada exceptionscatch exec--catch calls T o Execcatch Fork--catch calls to Forkcatch syscall--catch system calls by their names and/or numberscatch throw--Cat Ch an exceptioncatch vfork--Catch calls to Vfork type ' help catch ' followed by CATCH subcommand name For full Documentation. Type "Apropos word" to search for commands related to "word". Command name abbreviations is allowed if unambiguous. (GDB) (GDB) info breakpoints num type disp Enb Address what7 breakpoint keep y 0x08048440 in foo at t.c:5 Breakpoint already hit 1 time8 catchpoint keep y syscall "" 9 breakpoint keep y exception catch10 catchpoint keep y fork (GDB)
DisableBreakpoints 7 (GDB)
condition
