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/* SPDX-License-Identifier: BSD-3-Clause */
/* Copyright (c) 2026 Open-IOV contributors */
/* peek.c - print RIP/RBX/RSP/RDI of every thread of a process (root).
usage: peek PID [lo_off hi_off] (offsets from the libcuda r-xp base)
Flags threads whose RIP is inside [base+lo, base+hi) with SPIN. */
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dirent.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/user.h>
#include <sys/uio.h>
#include <unistd.h>
int main(int argc, char **argv)
{
if (argc < 2) { fprintf(stderr, "usage: peek PID [lo_off hi_off]\n"); return 1; }
int pid = atoi(argv[1]);
unsigned long lo = 0x23f700, hi = 0x23fd10;
if (argc >= 4) { lo = strtoul(argv[2], 0, 16); hi = strtoul(argv[3], 0, 16); }
char path[256];
snprintf(path, sizeof path, "/proc/%d/maps", pid);
FILE *f = fopen(path, "r");
if (!f) { perror("maps"); return 1; }
unsigned long base = 0;
char line[512];
while (fgets(line, sizeof line, f)) {
if (strstr(line, "libcuda") && strstr(line, "r-xp")) {
unsigned long a, b, off; char perms[8], dev[16], name[256]; unsigned long ino;
if (sscanf(line, "%lx-%lx %7s %lx %15s %lu %255s",
&a, &b, perms, &off, dev, &ino, name) >= 6) {
base = a - off;
break;
}
}
}
fclose(f);
printf("libcuda base=0x%lx\n", base);
snprintf(path, sizeof path, "/proc/%d/task", pid);
DIR *d = opendir(path);
if (!d) { perror("task"); return 1; }
struct dirent *e;
while ((e = readdir(d))) {
if (e->d_name[0] == '.') continue;
int tid = atoi(e->d_name);
if (ptrace(PTRACE_ATTACH, tid, 0, 0)) { printf("tid %d attach fail\n", tid); continue; }
int st;
waitpid(tid, &st, 0);
struct user_regs_struct r;
struct iovec io = { &r, sizeof r };
if (ptrace(PTRACE_GETREGSET, tid, (void *)1, &io)) {
printf("tid %d getregs fail\n", tid);
ptrace(PTRACE_DETACH, tid, 0, 0);
continue;
}
printf("tid %d rip=0x%llx rsp=0x%llx rbx=0x%llx rdi=0x%llx%s\n",
tid,
(unsigned long long)r.rip, (unsigned long long)r.rsp,
(unsigned long long)r.rbx, (unsigned long long)r.rdi,
(r.rip >= base + lo && r.rip < base + hi) ? " SPIN" : "");
ptrace(PTRACE_DETACH, tid, 0, 0);
}
closedir(d);
return 0;
}
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