189 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright 2014, Michael Ellerman, IBM Corp.4 */5 6#define _GNU_SOURCE /* For CPU_ZERO etc. */7 8#include <errno.h>9#include <sched.h>10#include <setjmp.h>11#include <stdlib.h>12#include <sys/wait.h>13 14#include "utils.h"15#include "lib.h"16 17#define PARENT_TOKEN 0xAA18#define CHILD_TOKEN 0x5519 20int sync_with_child(union pipe read_pipe, union pipe write_pipe)21{22 char c = PARENT_TOKEN;23 24 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);25 FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);26 if (c != CHILD_TOKEN) /* sometimes expected */27 return 1;28 29 return 0;30}31 32int wait_for_parent(union pipe read_pipe)33{34 char c;35 36 FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);37 FAIL_IF(c != PARENT_TOKEN);38 39 return 0;40}41 42int notify_parent(union pipe write_pipe)43{44 char c = CHILD_TOKEN;45 46 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);47 48 return 0;49}50 51int notify_parent_of_error(union pipe write_pipe)52{53 char c = ~CHILD_TOKEN;54 55 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);56 57 return 0;58}59 60int wait_for_child(pid_t child_pid)61{62 int rc;63 64 if (waitpid(child_pid, &rc, 0) == -1) {65 perror("waitpid");66 return 1;67 }68 69 if (WIFEXITED(rc))70 rc = WEXITSTATUS(rc);71 else72 rc = 1; /* Signal or other */73 74 return rc;75}76 77int kill_child_and_wait(pid_t child_pid)78{79 kill(child_pid, SIGTERM);80 81 return wait_for_child(child_pid);82}83 84static int eat_cpu_child(union pipe read_pipe, union pipe write_pipe)85{86 volatile int i = 0;87 88 /*89 * We are just here to eat cpu and die. So make sure we can be killed,90 * and also don't do any custom SIGTERM handling.91 */92 signal(SIGTERM, SIG_DFL);93 94 notify_parent(write_pipe);95 wait_for_parent(read_pipe);96 97 /* Soak up cpu forever */98 while (1) i++;99 100 return 0;101}102 103pid_t eat_cpu(int (test_function)(void))104{105 union pipe read_pipe, write_pipe;106 int rc;107 pid_t pid;108 109 FAIL_IF(bind_to_cpu(BIND_CPU_ANY) < 0);110 111 if (pipe(read_pipe.fds) == -1)112 return -1;113 114 if (pipe(write_pipe.fds) == -1)115 return -1;116 117 pid = fork();118 if (pid == 0)119 exit(eat_cpu_child(write_pipe, read_pipe));120 121 if (sync_with_child(read_pipe, write_pipe)) {122 rc = -1;123 goto out;124 }125 126 printf("main test running as pid %d\n", getpid());127 128 rc = test_function();129out:130 kill(pid, SIGKILL);131 132 return rc;133}134 135struct addr_range libc, vdso;136 137int parse_proc_maps(void)138{139 unsigned long start, end;140 char execute, name[128];141 FILE *f;142 int rc;143 144 f = fopen("/proc/self/maps", "r");145 if (!f) {146 perror("fopen");147 return -1;148 }149 150 do {151 /* This skips line with no executable which is what we want */152 rc = fscanf(f, "%lx-%lx %*c%*c%c%*c %*x %*d:%*d %*d %127s\n",153 &start, &end, &execute, name);154 if (rc <= 0)155 break;156 157 if (execute != 'x')158 continue;159 160 if (strstr(name, "libc")) {161 libc.first = start;162 libc.last = end - 1;163 } else if (strstr(name, "[vdso]")) {164 vdso.first = start;165 vdso.last = end - 1;166 }167 } while(1);168 169 fclose(f);170 171 return 0;172}173 174#define PARANOID_PATH "/proc/sys/kernel/perf_event_paranoid"175 176bool require_paranoia_below(int level)177{178 int err;179 long current;180 181 err = read_long(PARANOID_PATH, ¤t, 10);182 if (err) {183 printf("Couldn't parse " PARANOID_PATH "?\n");184 return false;185 }186 187 return current < level;188}189