1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "qemu_pipe.h" 18 19 #include <unistd.h> 20 #include <fcntl.h> 21 #include <string.h> 22 #include <errno.h> 23 #include <stdio.h> 24 25 #include <android-base/file.h> 26 27 using android::base::ReadFully; 28 using android::base::WriteFully; 29 30 // Define QEMU_PIPE_DEBUG if you want to print error messages when an error 31 // occurs during pipe operations. The macro should simply take a printf-style 32 // formatting string followed by optional arguments. 33 #ifndef QEMU_PIPE_DEBUG 34 # define QEMU_PIPE_DEBUG(...) (void)0 35 #endif 36 37 int qemu_pipe_open(const char* pipeName) { 38 // Sanity check. 39 if (!pipeName) { 40 errno = EINVAL; 41 return -1; 42 } 43 44 int fd = TEMP_FAILURE_RETRY(open("/dev/qemu_pipe", O_RDWR)); 45 if (fd < 0) { 46 QEMU_PIPE_DEBUG("%s: Could not open /dev/qemu_pipe: %s", __FUNCTION__, 47 strerror(errno)); 48 return -1; 49 } 50 51 // Write the pipe name, *including* the trailing zero which is necessary. 52 size_t pipeNameLen = strlen(pipeName); 53 if (WriteFully(fd, pipeName, pipeNameLen + 1U)) { 54 return fd; 55 } 56 57 // now, add 'pipe:' prefix and try again 58 // Note: host side will wait for the trailing '\0' to start 59 // service lookup. 60 const char pipe_prefix[] = "pipe:"; 61 if (WriteFully(fd, pipe_prefix, strlen(pipe_prefix)) && 62 WriteFully(fd, pipeName, pipeNameLen + 1U)) { 63 return fd; 64 } 65 QEMU_PIPE_DEBUG("%s: Could not write to %s pipe service: %s", 66 __FUNCTION__, pipeName, strerror(errno)); 67 close(fd); 68 return -1; 69 } 70 71 int qemu_pipe_frame_send(int fd, const void* buff, size_t len) { 72 char header[5]; 73 snprintf(header, sizeof(header), "%04zx", len); 74 if (!WriteFully(fd, header, 4)) { 75 QEMU_PIPE_DEBUG("Can't write qemud frame header: %s", strerror(errno)); 76 return -1; 77 } 78 if (!WriteFully(fd, buff, len)) { 79 QEMU_PIPE_DEBUG("Can't write qemud frame payload: %s", strerror(errno)); 80 return -1; 81 } 82 return 0; 83 } 84 85 int qemu_pipe_frame_recv(int fd, void* buff, size_t len) { 86 char header[5]; 87 if (!ReadFully(fd, header, 4)) { 88 QEMU_PIPE_DEBUG("Can't read qemud frame header: %s", strerror(errno)); 89 return -1; 90 } 91 header[4] = '\0'; 92 size_t size; 93 if (sscanf(header, "%04zx", &size) != 1) { 94 QEMU_PIPE_DEBUG("Malformed qemud frame header: [%.*s]", 4, header); 95 return -1; 96 } 97 if (size > len) { 98 QEMU_PIPE_DEBUG("Oversized qemud frame (% bytes, expected <= %)", size, 99 len); 100 return -1; 101 } 102 if (!ReadFully(fd, buff, size)) { 103 QEMU_PIPE_DEBUG("Could not read qemud frame payload: %s", 104 strerror(errno)); 105 return -1; 106 } 107 return size; 108 } 109
