1This file is umask.def, from which is created umask.c. 2It implements the builtin "umask" in Bash. 3 4Copyright (C) 1987-2004 Free Software Foundation, Inc. 5 6This file is part of GNU Bash, the Bourne Again SHell. 7 8Bash is free software; you can redistribute it and/or modify it under 9the terms of the GNU General Public License as published by the Free 10Software Foundation; either version 2, or (at your option) any later 11version. 12 13Bash is distributed in the hope that it will be useful, but WITHOUT ANY 14WARRANTY; without even the implied warranty of MERCHANTABILITY or 15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16for more details. 17 18You should have received a copy of the GNU General Public License along 19with Bash; see the file COPYING. If not, write to the Free Software 20Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. 21 22$PRODUCES umask.c 23 24$BUILTIN umask 25$FUNCTION umask_builtin 26$SHORT_DOC umask [-p] [-S] [mode] 27The user file-creation mask is set to MODE. If MODE is omitted, or if 28`-S' is supplied, the current value of the mask is printed. The `-S' 29option makes the output symbolic; otherwise an octal number is output. 30If `-p' is supplied, and MODE is omitted, the output is in a form 31that may be used as input. If MODE begins with a digit, it is 32interpreted as an octal number, otherwise it is a symbolic mode string 33like that accepted by chmod(1). 34$END 35 36#include <config.h> 37 38#include "../bashtypes.h" 39#include "filecntl.h" 40#if ! defined(_MINIX) && defined (HAVE_SYS_FILE_H) 41# include <sys/file.h> 42#endif 43 44#if defined (HAVE_UNISTD_H) 45#include <unistd.h> 46#endif 47 48#include <stdio.h> 49#include <chartypes.h> 50 51#include "../bashintl.h" 52 53#include "../shell.h" 54#include "posixstat.h" 55#include "common.h" 56#include "bashgetopt.h" 57 58#ifdef __LCC__ 59#define mode_t int 60#endif 61 62/* **************************************************************** */ 63/* */ 64/* UMASK Builtin and Helpers */ 65/* */ 66/* **************************************************************** */ 67 68static void print_symbolic_umask __P((mode_t)); 69static int symbolic_umask __P((WORD_LIST *)); 70 71/* Set or display the mask used by the system when creating files. Flag 72 of -S means display the umask in a symbolic mode. */ 73int 74umask_builtin (list) 75 WORD_LIST *list; 76{ 77 int print_symbolically, opt, umask_value, pflag; 78 mode_t umask_arg; 79 80 print_symbolically = pflag = 0; 81 reset_internal_getopt (); 82 while ((opt = internal_getopt (list, "Sp")) != -1) 83 { 84 switch (opt) 85 { 86 case 'S': 87 print_symbolically++; 88 break; 89 case 'p': 90 pflag++; 91 break; 92 default: 93 builtin_usage (); 94 return (EX_USAGE); 95 } 96 } 97 98 list = loptend; 99 100 if (list) 101 { 102 if (DIGIT (*list->word->word)) 103 { 104 umask_value = read_octal (list->word->word); 105 106 /* Note that other shells just let you set the umask to zero 107 by specifying a number out of range. This is a problem 108 with those shells. We don't change the umask if the input 109 is lousy. */ 110 if (umask_value == -1) 111 { 112 sh_erange (list->word->word, _("octal number")); 113 return (EXECUTION_FAILURE); 114 } 115 } 116 else 117 { 118 umask_value = symbolic_umask (list); 119 if (umask_value == -1) 120 return (EXECUTION_FAILURE); 121 } 122 umask_arg = (mode_t)umask_value; 123 umask (umask_arg); 124 if (print_symbolically) 125 print_symbolic_umask (umask_arg); 126 } 127 else /* Display the UMASK for this user. */ 128 { 129 umask_arg = umask (022); 130 umask (umask_arg); 131 132 if (pflag) 133 printf ("umask%s ", (print_symbolically ? " -S" : "")); 134 if (print_symbolically) 135 print_symbolic_umask (umask_arg); 136 else 137 printf ("%04lo\n", (unsigned long)umask_arg); 138 } 139 140 fflush (stdout); 141 return (EXECUTION_SUCCESS); 142} 143 144/* Print the umask in a symbolic form. In the output, a letter is 145 printed if the corresponding bit is clear in the umask. */ 146static void 147print_symbolic_umask (um) 148 mode_t um; 149{ 150 char ubits[4], gbits[4], obits[4]; /* u=rwx,g=rwx,o=rwx */ 151 int i; 152 153 i = 0; 154 if ((um & S_IRUSR) == 0) 155 ubits[i++] = 'r'; 156 if ((um & S_IWUSR) == 0) 157 ubits[i++] = 'w'; 158 if ((um & S_IXUSR) == 0) 159 ubits[i++] = 'x'; 160 ubits[i] = '\0'; 161 162 i = 0; 163 if ((um & S_IRGRP) == 0) 164 gbits[i++] = 'r'; 165 if ((um & S_IWGRP) == 0) 166 gbits[i++] = 'w'; 167 if ((um & S_IXGRP) == 0) 168 gbits[i++] = 'x'; 169 gbits[i] = '\0'; 170 171 i = 0; 172 if ((um & S_IROTH) == 0) 173 obits[i++] = 'r'; 174 if ((um & S_IWOTH) == 0) 175 obits[i++] = 'w'; 176 if ((um & S_IXOTH) == 0) 177 obits[i++] = 'x'; 178 obits[i] = '\0'; 179 180 printf ("u=%s,g=%s,o=%s\n", ubits, gbits, obits); 181} 182 183int 184parse_symbolic_mode (mode, initial_bits) 185 char *mode; 186 int initial_bits; 187{ 188 int who, op, perm, bits, c; 189 char *s; 190 191 for (s = mode, bits = initial_bits;;) 192 { 193 who = op = perm = 0; 194 195 /* Parse the `who' portion of the symbolic mode clause. */ 196 while (member (*s, "agou")) 197 { 198 switch (c = *s++) 199 { 200 case 'u': 201 who |= S_IRWXU; 202 continue; 203 case 'g': 204 who |= S_IRWXG; 205 continue; 206 case 'o': 207 who |= S_IRWXO; 208 continue; 209 case 'a': 210 who |= S_IRWXU | S_IRWXG | S_IRWXO; 211 continue; 212 default: 213 break; 214 } 215 } 216 217 /* The operation is now sitting in *s. */ 218 op = *s++; 219 switch (op) 220 { 221 case '+': 222 case '-': 223 case '=': 224 break; 225 default: 226 builtin_error (_("`%c': invalid symbolic mode operator"), op); 227 return (-1); 228 } 229 230 /* Parse out the `perm' section of the symbolic mode clause. */ 231 while (member (*s, "rwx")) 232 { 233 c = *s++; 234 235 switch (c) 236 { 237 case 'r': 238 perm |= S_IRUGO; 239 break; 240 case 'w': 241 perm |= S_IWUGO; 242 break; 243 case 'x': 244 perm |= S_IXUGO; 245 break; 246 } 247 } 248 249 /* Now perform the operation or return an error for a 250 bad permission string. */ 251 if (!*s || *s == ',') 252 { 253 if (who) 254 perm &= who; 255 256 switch (op) 257 { 258 case '+': 259 bits |= perm; 260 break; 261 case '-': 262 bits &= ~perm; 263 break; 264 case '=': 265 if (who == 0) 266 who = S_IRWXU | S_IRWXG | S_IRWXO; 267 bits &= ~who; 268 bits |= perm; 269 break; 270 271 /* No other values are possible. */ 272 } 273 274 if (*s == '\0') 275 break; 276 else 277 s++; /* skip past ',' */ 278 } 279 else 280 { 281 builtin_error (_("`%c': invalid symbolic mode character"), *s); 282 return (-1); 283 } 284 } 285 286 return (bits); 287} 288 289/* Set the umask from a symbolic mode string similar to that accepted 290 by chmod. If the -S argument is given, then print the umask in a 291 symbolic form. */ 292static int 293symbolic_umask (list) 294 WORD_LIST *list; 295{ 296 int um, bits; 297 298 /* Get the initial umask. Don't change it yet. */ 299 um = umask (022); 300 umask (um); 301 302 /* All work is done with the complement of the umask -- it's 303 more intuitive and easier to deal with. It is complemented 304 again before being returned. */ 305 bits = parse_symbolic_mode (list->word->word, ~um & 0777); 306 if (bits == -1) 307 return (-1); 308 309 um = ~bits & 0777; 310 return (um); 311} 312