1 /* 2 * Copyright (C) 2008 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <pthread.h> 30 31 #include <fcntl.h> 32 #include <stdio.h> // For snprintf. 33 #include <sys/prctl.h> 34 #include <sys/stat.h> 35 #include <sys/types.h> 36 #include <unistd.h> 37 38 #include "pthread_accessor.h" 39 #include "pthread_internal.h" 40 #include "private/ErrnoRestorer.h" 41 42 // This value is not exported by kernel headers. 43 #define MAX_TASK_COMM_LEN 16 44 #define TASK_COMM_FMT "/proc/self/task/%d/comm" 45 46 int pthread_setname_np(pthread_t t, const char* thread_name) { 47 ErrnoRestorer errno_restorer; 48 49 size_t thread_name_len = strlen(thread_name); 50 if (thread_name_len >= MAX_TASK_COMM_LEN) { 51 return ERANGE; 52 } 53 54 // Changing our own name is an easy special case. 55 if (t == pthread_self()) { 56 return prctl(PR_SET_NAME, thread_name) ? errno : 0; 57 } 58 59 // We have to change another thread's name. 60 pid_t tid = 0; 61 { 62 pthread_accessor thread(t); 63 if (thread.get() == NULL) { 64 return ESRCH; 65 } 66 tid = thread->tid; 67 } 68 char comm_name[sizeof(TASK_COMM_FMT) + 8]; 69 snprintf(comm_name, sizeof(comm_name), TASK_COMM_FMT, tid); 70 int fd = open(comm_name, O_WRONLY); 71 if (fd == -1) { 72 return errno; 73 } 74 ssize_t n = TEMP_FAILURE_RETRY(write(fd, thread_name, thread_name_len)); 75 close(fd); 76 77 if (n < 0) { 78 return errno; 79 } else if (n != static_cast<ssize_t>(thread_name_len)) { 80 return EIO; 81 } 82 return 0; 83 } 84