1 /* $NetBSD: filemon_dev.c,v 1.9 2022/03/04 23:17:16 sjg Exp $ */ 2 3 /* 4 * Copyright (c) 2020 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include "filemon.h" 33 34 #include <sys/ioctl.h> 35 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <stdlib.h> 39 #include <unistd.h> 40 41 #ifdef HAVE_FILEMON_H 42 # include <filemon.h> 43 #endif 44 45 #ifndef _PATH_FILEMON 46 #define _PATH_FILEMON "/dev/filemon" 47 #endif 48 49 #ifndef MAKE_ATTR_UNUSED 50 #define MAKE_ATTR_UNUSED __attribute__((__unused__)) 51 #endif 52 53 struct filemon { 54 int fd; 55 }; 56 57 const char * 58 filemon_path(void) 59 { 60 61 return _PATH_FILEMON; 62 } 63 64 struct filemon * 65 filemon_open(void) 66 { 67 struct filemon *F; 68 unsigned i; 69 int error; 70 71 /* Allocate and zero a struct filemon object. */ 72 F = calloc(1, sizeof *F); 73 if (F == NULL) 74 return NULL; 75 76 /* Try opening /dev/filemon, up to six times (cargo cult!). */ 77 for (i = 0; (F->fd = open(_PATH_FILEMON, O_RDWR|O_CLOEXEC)) == -1; i++) { 78 if (i == 5) { 79 error = errno; 80 goto fail0; 81 } 82 } 83 84 /* Success! */ 85 return F; 86 87 fail0: free(F); 88 errno = error; 89 return NULL; 90 } 91 92 int 93 filemon_setfd(struct filemon *F, int fd) 94 { 95 96 /* Point the kernel at this file descriptor. */ 97 if (ioctl(F->fd, FILEMON_SET_FD, &fd) == -1) 98 return -1; 99 100 /* No need for it in userland any more; close it. */ 101 (void)close(fd); 102 103 /* Success! */ 104 return 0; 105 } 106 107 void 108 filemon_setpid_parent(struct filemon *F MAKE_ATTR_UNUSED, pid_t pid MAKE_ATTR_UNUSED) 109 { 110 /* Nothing to do! */ 111 } 112 113 int 114 filemon_setpid_child(const struct filemon *F, pid_t pid) 115 { 116 117 /* Just pass it on to the kernel. */ 118 return ioctl(F->fd, FILEMON_SET_PID, &pid); 119 } 120 121 int 122 filemon_close(struct filemon *F) 123 { 124 int error = 0; 125 126 /* Close the filemon device fd. */ 127 if (close(F->fd) == -1 && error == 0) 128 error = errno; 129 130 /* Free the filemon descriptor. */ 131 free(F); 132 133 /* Set errno and return -1 if anything went wrong. */ 134 if (error != 0) { 135 errno = error; 136 return -1; 137 } 138 139 /* Success! */ 140 return 0; 141 } 142 143 int 144 filemon_readfd(const struct filemon *F MAKE_ATTR_UNUSED) 145 { 146 147 return -1; 148 } 149 150 int 151 filemon_process(struct filemon *F MAKE_ATTR_UNUSED) 152 { 153 154 return 0; 155 } 156