1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 27 #pragma ident "%Z%%M% %I% %E% SMI" 28 29 /* 30 * Internal utility routines for the ZFS library. 31 */ 32 33 #include <errno.h> 34 #include <fcntl.h> 35 #include <libintl.h> 36 #include <stdarg.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <strings.h> 40 #include <unistd.h> 41 #include <sys/mnttab.h> 42 43 #include <libzfs.h> 44 45 #include "libzfs_impl.h" 46 47 int zfs_fd; 48 49 void (*error_func)(const char *, va_list); 50 51 /* 52 * All error handling is kept within libzfs where we have the most information 53 * immediately available. While this may not be suitable for a general purpose 54 * library, it greatly simplifies our commands. This command name is used to 55 * prefix all error messages appropriately. 56 */ 57 void 58 zfs_error(const char *fmt, ...) 59 { 60 va_list ap; 61 62 va_start(ap, fmt); 63 64 if (error_func != NULL) { 65 error_func(fmt, ap); 66 } else { 67 (void) vfprintf(stderr, fmt, ap); 68 (void) fprintf(stderr, "\n"); 69 } 70 71 va_end(ap); 72 } 73 74 /* 75 * An internal error is something that we cannot recover from, and should never 76 * happen (such as running out of memory). It should only be used in 77 * exceptional circumstances. 78 */ 79 void 80 zfs_fatal(const char *fmt, ...) 81 { 82 va_list ap; 83 84 va_start(ap, fmt); 85 86 if (error_func != NULL) { 87 error_func(fmt, ap); 88 } else { 89 (void) vfprintf(stderr, fmt, ap); 90 (void) fprintf(stderr, "\n"); 91 } 92 93 va_end(ap); 94 95 exit(1); 96 } 97 98 /* 99 * Consumers (such as the JNI interface) that need to capture error output can 100 * override the default error handler using this function. 101 */ 102 void 103 zfs_set_error_handler(void (*func)(const char *, va_list)) 104 { 105 error_func = func; 106 } 107 108 /* 109 * Display an out of memory error message and abort the current program. 110 */ 111 void 112 no_memory(void) 113 { 114 assert(errno == ENOMEM); 115 zfs_fatal(dgettext(TEXT_DOMAIN, "internal error: out of memory\n")); 116 } 117 118 /* 119 * A safe form of malloc() which will die if the allocation fails. 120 */ 121 void * 122 zfs_malloc(size_t size) 123 { 124 void *data; 125 126 if ((data = calloc(1, size)) == NULL) 127 no_memory(); 128 129 return (data); 130 } 131 132 /* 133 * A safe form of strdup() which will die if the allocation fails. 134 */ 135 char * 136 zfs_strdup(const char *str) 137 { 138 char *ret; 139 140 if ((ret = strdup(str)) == NULL) 141 no_memory(); 142 143 return (ret); 144 } 145 146 /* 147 * Initialize the library. Sets the command name used when reporting errors. 148 * This command name is used to prefix all error messages appropriately. 149 * Also opens /dev/zfs and dies if it cannot be opened. 150 */ 151 #pragma init(zfs_init) 152 void 153 zfs_init(void) 154 { 155 if ((zfs_fd = open(ZFS_DEV, O_RDWR)) < 0) 156 zfs_fatal(dgettext(TEXT_DOMAIN, 157 "internal error: cannot open zfs device")); 158 159 if ((mnttab_file = fopen(MNTTAB, "r")) == NULL) 160 zfs_fatal(dgettext(TEXT_DOMAIN, "internal error: unable to " 161 "open %s\n"), MNTTAB); 162 163 sharetab_file = fopen("/etc/dfs/sharetab", "r"); 164 } 165 166 /* 167 * Cleanup function for library. Simply close the file descriptors that we 168 * opened as part of libzfs_init(). 169 */ 170 #pragma fini(zfs_fini) 171 void 172 zfs_fini(void) 173 { 174 (void) close(zfs_fd); 175 } 176 177 /* 178 * Convert a number to an appropriately human-readable output. 179 */ 180 void 181 zfs_nicenum(uint64_t num, char *buf, size_t buflen) 182 { 183 uint64_t n = num; 184 int index = 0; 185 char u; 186 187 while (n >= 1024) { 188 n /= 1024; 189 index++; 190 } 191 192 u = " KMGTPE"[index]; 193 194 if (index == 0) { 195 (void) snprintf(buf, buflen, "%llu", n); 196 } else if ((num & ((1ULL << 10 * index) - 1)) == 0) { 197 /* 198 * If this is an even multiple of the base, always display 199 * without any decimal precision. 200 */ 201 (void) snprintf(buf, buflen, "%llu%c", n, u); 202 } else { 203 /* 204 * We want to choose a precision that reflects the best choice 205 * for fitting in 5 characters. This can get rather tricky when 206 * we have numbers that are very close to an order of magnitude. 207 * For example, when displaying 10239 (which is really 9.999K), 208 * we want only a single place of precision for 10.0K. We could 209 * develop some complex heuristics for this, but it's much 210 * easier just to try each combination in turn. 211 */ 212 int i; 213 for (i = 2; i >= 0; i--) { 214 (void) snprintf(buf, buflen, "%.*f%c", i, 215 (double)num / (1ULL << 10 * index), u); 216 if (strlen(buf) <= 5) 217 break; 218 } 219 } 220 } 221