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GDB Function Tracer
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void startDebugger ();
void stopDebugger ();
char gdbRead ();
void gdbWrite (char c);
void readUntilPrompt (unsigned char *data); // If data is NULL copy to stdout
void writeDebugger (unsigned char*cmd, unsigned char* answer);
int fd_to_debugger, fd_from_debugger, fd_err_from_debugger;
FILE *pFile2 = NULL;
int fsync_ct = 0;
char **argv_out;
void gdbWrite (char c)
{
write (fd_to_debugger, &c, 1);
fsync (fd_to_debugger);
}
char gdbRead ()
{
char c;
read (fd_from_debugger, &c, 1);
return c;
}
void writeDebugger (unsigned char*cmd, unsigned char *answer)
{
unsigned char a[10000];
if (answer==NULL) answer = a;
fprintf (stderr, " ---COMMAND>%s\n", cmd);
write (fd_to_debugger, cmd, strlen (cmd));
write (fd_to_debugger, "\n", 1);
fsync (fd_to_debugger);
readUntilPrompt (answer);
//fprintf (stderr, "******\n%s\n******\n", answer);
int sln = strlen(answer);
char * a4 = answer+sln-5;
char * a5 = "(gdb)";
if (strcmp(a4 , a5)==0) {
answer[sln-6] = '\0';
}
fprintf (stderr, "%s\n", answer);
if(pFile2==NULL)
pFile2=fopen("myfile2.txt", "a");
if(pFile2==NULL) {
perror("Error opening file.");
} else {
fprintf(pFile2, "%s\n", answer);
fsync_ct++;
fsync(pFile2);
}
}
void readUntilPrompt (unsigned char *data)
{
char buf[256], c;
char *str = "(gdb)";
int nof_read, n = strlen (str);
if (n>255) exit(-1);
memset (buf, 0, 256);
while (1)
{
memmove(buf, buf+1, n-1);
nof_read = read (fd_from_debugger, &c, 1);
if (nof_read!=1) break;
buf[n-1] = c;
if (data!=NULL)
{
*data = c;
data++;
}
else
{
printf ("%c", c);
}
if (buf[n-1]==0) exit(-1);
if (!strcmp (str, buf)) break;
}
if (data!=NULL) *data = 0;
}
void stopDebugger ()
{
close(fd_to_debugger);
close(fd_err_from_debugger);
close(fd_from_debugger);
}
void startDebugger ()
{
unsigned char tmp_string[1024];
int stdin_pipe[2];
int stdout_pipe[2];
int stderr_pipe[2];
int fork_result;
int n, i;
if( (pipe(stdin_pipe) != 0) || (pipe(stdout_pipe) != 0) || (pipe(stderr_pipe) != 0))
{
fprintf (stderr, "Could not create pipes!\n");
exit (-1);
}
fork_result = fork();
if(fork_result == -1)
{
fprintf(stderr, "Fork Failure\n");
exit(-1);
}
if(fork_result == 0)
{
// We are child
close(0); // Close childs stdin
dup(stdin_pipe[0]); // Child now has STDIN that is stdin_pipe[0]
close(stdin_pipe[0]);
close(stdin_pipe[1]);
close(1); // Close childs stdout
dup(stdout_pipe[1]); // Child now has STDOUT that is stdout_pipe[1]
//setvbuf (stdout, (char*)NULL, _IONBF, 0); // Do not buffer stdout!
close(stdout_pipe[0]);
close(stdout_pipe[1]);
close(2); // Close childs STDERR
dup(stderr_pipe[1]);
close(stderr_pipe[0]);
close(stderr_pipe[1]);
execvp("gdb",argv_out);
// If we get here, the execlp failed!
fprintf (stderr, "Execution of gdb failed!\n");
exit(-1);
}
else
{
fd_to_debugger = stdin_pipe[1]; // Write to stdin
fd_from_debugger = stdout_pipe[0]; // Read from stdout
fd_err_from_debugger = stderr_pipe[0]; // Read from stderr
close(stdin_pipe[0]); // No reads from stdin
close(stdout_pipe[1]); // No writes to stdout
close(stderr_pipe[1]); // No writes to stderr
readUntilPrompt (NULL);
}
}
int main (int argc, char **argv)
{
fprintf (stdout, " - gdbwalkthrough - \n");
if (argc<2) {
fprintf (stdout, "Usage: %s <application full path> [application arguments]\n\n",argv[0]);
exit(0);
}
argv_out = malloc(argc+3);
int x=0;
argv_out[x++] = "gdb";
argv_out[x++] = "--args";
int i=0;
while (argc) {
i++;
argv_out[x++] = argv[i];
argc--;
}
argv_out[x++] = NULL;
char ** argv_out2 = argv_out;
fprintf (stdout, "Starting with arguments: \n");
while (*argv_out2) {
fprintf (stdout, ">> %s\n", *argv_out2++);
}
fprintf (stdout, "\n\n");
sleep(2);
startDebugger();
//writeDebugger("info shared", NULL);
writeDebugger("b main", NULL);
writeDebugger("run", NULL);
while(1)
writeDebugger("s",NULL);
stopDebugger();
}
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