ish/tools/ptutil.c
2018-01-04 13:55:20 -08:00

94 lines
2.5 KiB
C

#define _GNU_SOURCE
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/personality.h>
#include <sys/wait.h>
#include <sys/ptrace.h>
#include <sys/user.h>
#include <sched.h>
#include <sys/prctl.h>
#include <sys/syscall.h>
#include <asm/prctl.h>
#undef PAGE_SIZE // want definition from emu/memory.h
#include "../misc.h"
long trycall(long res, const char *msg) {
if (res == -1 && errno != 0) {
perror(msg); printf("\r\n"); exit(1);
}
return res;
}
// wow i'm sooo bleeding edge
static int arch_prctl(int code, unsigned long arg) {
return syscall(SYS_arch_prctl, code, arg);
}
int start_tracee(int at, const char *path, char *const argv[], char *const envp[]) {
// shut off aslr
int persona = personality(0xffffffff);
persona |= ADDR_NO_RANDOMIZE;
personality(persona);
int pid = fork();
if (pid < 0) {
perror("fork");
exit(1);
}
if (pid == 0) {
// child
// enable segfaulting on rdtsc and cpuid
trycall(prctl(PR_SET_TSC, PR_TSC_SIGSEGV), "rdtsc faulting");
/* trycall(arch_prctl(ARCH_SET_CPUID, 0), "cpuid faulting"); */
trycall(ptrace(PTRACE_TRACEME, 0, NULL, NULL), "ptrace traceme");
// get rid of signal handlers
for (int sig = 0; sig < SIGRTMIN - 1; sig++)
signal(sig, SIG_DFL);
trycall(fexecve(openat(at, path, O_RDONLY), argv, envp), "execve");
} else {
// parent, wait for child to stop after exec
int status;
trycall(wait(&status), "wait");
if (!WIFSTOPPED(status)) {
fprintf(stderr, "child failed to start\n");
exit(1);
}
}
return pid;
}
int open_mem(int pid) {
char filename[1024];
sprintf(filename, "/proc/%d/mem", pid);
return trycall(open(filename, O_RDWR), "open mem");
}
void pt_readn(int pid, addr_t addr, void *buf, size_t count) {
int fd = open_mem(pid);
trycall(lseek(fd, addr, SEEK_SET), "read seek");
trycall(read(fd, buf, count), "read read");
close(fd);
}
void pt_writen(int pid, addr_t addr, void *buf, size_t count) {
int fd = open_mem(pid);
trycall(lseek(fd, addr, SEEK_SET), "write seek");
trycall(write(fd, buf, count), "write write");
close(fd);
}
dword_t pt_read(int pid, addr_t addr) {
dword_t res;
pt_readn(pid, addr, &res, sizeof(res));
return res;
}
void pt_write(int pid, addr_t addr, dword_t val) {
pt_writen(pid, addr, &val, sizeof(val));
}
void pt_write8(int pid, addr_t addr, byte_t val) {
pt_writen(pid, addr, &val, sizeof(val));
}