acmecert: Fixed order invocation error.

[utils.git] / pstack.c

#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <libunwind.h>
#include <libunwind-ptrace.h>

static void usage(FILE *out)
{
    fprintf(out, "usage: pstack [-h] PID\n");
}

static int dumpstack(pid_t pid)
{
    int rv, s;
    unw_addr_space_t rps;
    unw_cursor_t uw;
    unw_word_t reg, pcoff;
    void *ptd;
    char pnm[64];
    
    rps = unw_create_addr_space(&_UPT_accessors, 0);
    ptd = _UPT_create(pid);
    rv = 0;
    if((s = unw_init_remote(&uw, rps, ptd)) != 0) {
	fprintf(stderr, "pstack: init_remote: %i\n", s);
	rv = 1;
	goto out;
    }
    do {
	if(!(s = unw_get_proc_name(&uw, pnm, sizeof(pnm), &pcoff)) || (s == -UNW_ENOMEM)) {
	    pnm[sizeof(pnm) - 1] = 0;
	    printf("%s+%jx\n", pnm, (intmax_t)pcoff);
	} else {
	    unw_get_reg(&uw, UNW_REG_IP, &reg);
	    printf("%jx\n", (intmax_t)reg);
	}
    } while((s = unw_step(&uw)) > 0);
    if(s < 0) {
	fprintf(stderr, "pstack: step: %i\n", s);
    }
out:
    _UPT_destroy(ptd);
    unw_destroy_addr_space(rps);
    return(rv);
}

int main(int argc, char **argv)
{
    int c, s;
    pid_t pid;
    
    while((c = getopt(argc, argv, "h")) != -1) {
	switch(c) {
	case 'h':
	    usage(stdout);
	    exit(0);
	default:
	    usage(stderr);
	    exit(1);
	}
    }
    if(argc - optind < 1) {
	usage(stderr);
	exit(1);
    }
    pid = atoi(argv[optind]);
    if(ptrace(PTRACE_ATTACH, pid, NULL, NULL)) {
	fprintf(stderr, "pstack: attach %i: %s\n", pid, strerror(errno));
	exit(1);
    }
    while(1) {
	if(waitpid(pid, &s, 0) < 0) {
	    fprintf(stderr, "pstack: wait: %s\n", strerror(errno));
	    exit(1);
	}
	if(WIFSTOPPED(s))
	    break;
    }
    dumpstack(pid);
    if(ptrace(PTRACE_DETACH, pid, NULL, NULL)) {
	fprintf(stderr, "pstack: detach: %s\n", strerror(errno));
    }
    return(0);
}

/*
 * Local Variables:
 * compile-command: "gcc -Wall -g -o pstack pstack.c -lunwind-ptrace -lunwind-x86_64"
 * End:
 */