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 <string.h> 34 #include <sys/prctl.h> 35 #include <sys/stat.h> 36 #include <sys/types.h> 37 #include <unistd.h> 38 39 #include "private/ErrnoRestorer.h" 40 #include "pthread_internal.h" 41 42 // This value is not exported by kernel headers. 43 #define MAX_TASK_COMM_LEN 16 44 45 static int __open_task_comm_fd(pthread_t t, int flags) { 46 char comm_name[64]; 47 snprintf(comm_name, sizeof(comm_name), "/proc/self/task/%d/comm", pthread_gettid_np(t)); 48 return open(comm_name, O_CLOEXEC | flags); 49 } 50 51 int pthread_getname_np(pthread_t t, char* buf, size_t buf_size) { 52 ErrnoRestorer errno_restorer; 53 54 if (buf_size < MAX_TASK_COMM_LEN) return ERANGE; 55 56 // Getting our own name is an easy special case. 57 if (t == pthread_self()) { 58 return prctl(PR_GET_NAME, buf) ? errno : 0; 59 } 60 61 // We have to get another thread's name. 62 int fd = __open_task_comm_fd(t, O_RDONLY); 63 if (fd == -1) return errno; 64 65 ssize_t n = TEMP_FAILURE_RETRY(read(fd, buf, buf_size)); 66 close(fd); 67 68 if (n == -1) return errno; 69 70 // The kernel adds a trailing '\n' to the /proc file, 71 // so this is actually the normal case for short names. 72 if (n > 0 && buf[n - 1] == '\n') { 73 buf[n - 1] = '\0'; 74 return 0; 75 } 76 77 if (n == static_cast<ssize_t>(buf_size)) return ERANGE; 78 buf[n] = '\0'; 79 return 0; 80 } 81 82 int pthread_setname_np(pthread_t t, const char* thread_name) { 83 ErrnoRestorer errno_restorer; 84 85 size_t thread_name_len = strlen(thread_name); 86 if (thread_name_len >= MAX_TASK_COMM_LEN) return ERANGE; 87 88 // Setting our own name is an easy special case. 89 if (t == pthread_self()) { 90 return prctl(PR_SET_NAME, thread_name) ? errno : 0; 91 } 92 93 // We have to set another thread's name. 94 int fd = __open_task_comm_fd(t, O_WRONLY); 95 if (fd == -1) return errno; 96 97 ssize_t n = TEMP_FAILURE_RETRY(write(fd, thread_name, thread_name_len)); 98 close(fd); 99 100 if (n == -1) return errno; 101 if (n != static_cast<ssize_t>(thread_name_len)) return EIO; 102 return 0; 103 } 104
