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#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <signal.h>
#include "elf.h"
#include "trace.h"
extern void print_function(const char *, int);
extern void read_config_file(const char *);
int pid;
int debug = 0;
FILE * output = stderr;
unsigned long return_addr;
unsigned char return_value;
struct library_symbol * current_symbol;
static void usage(void)
{
fprintf(stderr," Usage: ltrace [-d][-o output] <program> [<arguments>...]\n");
}
int main(int argc, char **argv)
{
int status;
struct library_symbol * tmp = NULL;
while ((argc>2) && (argv[1][0] == '-') && (argv[1][2] == '\0')) {
switch(argv[1][1]) {
case 'd': debug++;
break;
case 'o': output = fopen(argv[2], "w");
if (!output) {
fprintf(stderr, "Can't open %s for output: %s\n", argv[2], sys_errlist[errno]);
exit(1);
}
argc--; argv++;
break;
default: fprintf(stderr, "Unknown option '%c'\n", argv[1][1]);
usage();
exit(1);
}
argc--; argv++;
}
if (argc<2) {
usage();
exit(1);
}
if (!read_elf(argv[1])) {
fprintf(stderr, "%s: Not dynamically linked\n", argv[1]);
exit(1);
}
pid = attach_process(argv[1], argv+1);
fprintf(output, "pid %u attached\n", pid);
/* Enable breakpoints: */
fprintf(output, "Enabling breakpoints...\n");
enable_all_breakpoints();
fprintf(output, "Reading config file(s)...\n");
read_config_file("/etc/ltrace.cfg");
read_config_file(".ltracerc");
ptrace(PTRACE_CONT, pid, 1, 0);
while(1) {
int eip;
int esp;
int function_seen;
pid = wait4(-1, &status, 0, NULL);
if (pid==-1) {
if (errno == ECHILD) {
fprintf(output, "No more children\n");
exit(0);
}
perror("wait4");
exit(1);
}
if (WIFEXITED(status)) {
fprintf(output, "pid %u exited\n", pid);
continue;
}
if (WIFSIGNALED(status)) {
fprintf(output, "pid %u exited on signal %u\n", pid, WTERMSIG(status));
continue;
}
if (!WIFSTOPPED(status)) {
fprintf(output, "pid %u ???\n", pid);
continue;
}
if (WSTOPSIG(status) != SIGTRAP) {
fprintf(output, "Signal: %u\n", WSTOPSIG(status));
ptrace(PTRACE_CONT, pid, 1, WSTOPSIG(status));
continue;
}
/* pid is stopped... */
eip = ptrace(PTRACE_PEEKUSER, pid, 4*EIP, 0);
esp = ptrace(PTRACE_PEEKUSER, pid, 4*UESP, 0);
#if 0
fprintf(output,"EIP = 0x%08x\n", eip);
fprintf(output,"ESP = 0x%08x\n", esp);
#endif
fprintf(output,"[0x%08x] ", ptrace(PTRACE_PEEKTEXT, pid, esp, 0));
tmp = library_symbols;
function_seen = 0;
while(tmp) {
if (eip == tmp->addr+1) {
function_seen = 1;
print_function(tmp->name, esp);
delete_breakpoint(pid, tmp->addr, tmp->old_value);
ptrace(PTRACE_POKEUSER, pid, 4*EIP, eip-1);
ptrace(PTRACE_SINGLESTEP, pid, 0, 0);
pid = wait4(-1, &status, 0, NULL);
if (pid==-1) {
if (errno == ECHILD) {
fprintf(output, "No more children\n");
exit(0);
}
perror("wait4");
exit(1);
}
insert_breakpoint(pid, tmp->addr, tmp->old_value);
ptrace(PTRACE_CONT, pid, 1, 0);
break;
}
tmp = tmp->next;
}
if (!function_seen) {
fprintf(output, "pid %u stopped; continuing it...\n", pid);
ptrace(PTRACE_CONT, pid, 1, 0);
}
}
exit(0);
}
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