This file is umask.def, from which is created umask.c. It implements the builtin "umask" in Bash. Copyright (C) 1987-2004 Free Software Foundation, Inc. This file is part of GNU Bash, the Bourne Again SHell. Bash is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. Bash is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Bash; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. $PRODUCES umask.c $BUILTIN umask $FUNCTION umask_builtin $SHORT_DOC umask [-p] [-S] [mode] The user file-creation mask is set to MODE. If MODE is omitted, or if `-S' is supplied, the current value of the mask is printed. The `-S' option makes the output symbolic; otherwise an octal number is output. If `-p' is supplied, and MODE is omitted, the output is in a form that may be used as input. If MODE begins with a digit, it is interpreted as an octal number, otherwise it is a symbolic mode string like that accepted by chmod(1). $END #include #include "../bashtypes.h" #include "filecntl.h" #if ! defined(_MINIX) && defined (HAVE_SYS_FILE_H) # include #endif #if defined (HAVE_UNISTD_H) #include #endif #include #include #include "../bashintl.h" #include "../shell.h" #include "posixstat.h" #include "common.h" #include "bashgetopt.h" #ifdef __LCC__ #define mode_t int #endif /* **************************************************************** */ /* */ /* UMASK Builtin and Helpers */ /* */ /* **************************************************************** */ static void print_symbolic_umask __P((mode_t)); static int symbolic_umask __P((WORD_LIST *)); /* Set or display the mask used by the system when creating files. Flag of -S means display the umask in a symbolic mode. */ int umask_builtin (list) WORD_LIST *list; { int print_symbolically, opt, umask_value, pflag; mode_t umask_arg; print_symbolically = pflag = 0; reset_internal_getopt (); while ((opt = internal_getopt (list, "Sp")) != -1) { switch (opt) { case 'S': print_symbolically++; break; case 'p': pflag++; break; default: builtin_usage (); return (EX_USAGE); } } list = loptend; if (list) { if (DIGIT (*list->word->word)) { umask_value = read_octal (list->word->word); /* Note that other shells just let you set the umask to zero by specifying a number out of range. This is a problem with those shells. We don't change the umask if the input is lousy. */ if (umask_value == -1) { sh_erange (list->word->word, _("octal number")); return (EXECUTION_FAILURE); } } else { umask_value = symbolic_umask (list); if (umask_value == -1) return (EXECUTION_FAILURE); } umask_arg = (mode_t)umask_value; umask (umask_arg); if (print_symbolically) print_symbolic_umask (umask_arg); } else /* Display the UMASK for this user. */ { umask_arg = umask (022); umask (umask_arg); if (pflag) printf ("umask%s ", (print_symbolically ? " -S" : "")); if (print_symbolically) print_symbolic_umask (umask_arg); else printf ("%04lo\n", (unsigned long)umask_arg); } fflush (stdout); return (EXECUTION_SUCCESS); } /* Print the umask in a symbolic form. In the output, a letter is printed if the corresponding bit is clear in the umask. */ static void print_symbolic_umask (um) mode_t um; { char ubits[4], gbits[4], obits[4]; /* u=rwx,g=rwx,o=rwx */ int i; i = 0; if ((um & S_IRUSR) == 0) ubits[i++] = 'r'; if ((um & S_IWUSR) == 0) ubits[i++] = 'w'; if ((um & S_IXUSR) == 0) ubits[i++] = 'x'; ubits[i] = '\0'; i = 0; if ((um & S_IRGRP) == 0) gbits[i++] = 'r'; if ((um & S_IWGRP) == 0) gbits[i++] = 'w'; if ((um & S_IXGRP) == 0) gbits[i++] = 'x'; gbits[i] = '\0'; i = 0; if ((um & S_IROTH) == 0) obits[i++] = 'r'; if ((um & S_IWOTH) == 0) obits[i++] = 'w'; if ((um & S_IXOTH) == 0) obits[i++] = 'x'; obits[i] = '\0'; printf ("u=%s,g=%s,o=%s\n", ubits, gbits, obits); } int parse_symbolic_mode (mode, initial_bits) char *mode; int initial_bits; { int who, op, perm, bits, c; char *s; for (s = mode, bits = initial_bits;;) { who = op = perm = 0; /* Parse the `who' portion of the symbolic mode clause. */ while (member (*s, "agou")) { switch (c = *s++) { case 'u': who |= S_IRWXU; continue; case 'g': who |= S_IRWXG; continue; case 'o': who |= S_IRWXO; continue; case 'a': who |= S_IRWXU | S_IRWXG | S_IRWXO; continue; default: break; } } /* The operation is now sitting in *s. */ op = *s++; switch (op) { case '+': case '-': case '=': break; default: builtin_error (_("`%c': invalid symbolic mode operator"), op); return (-1); } /* Parse out the `perm' section of the symbolic mode clause. */ while (member (*s, "rwx")) { c = *s++; switch (c) { case 'r': perm |= S_IRUGO; break; case 'w': perm |= S_IWUGO; break; case 'x': perm |= S_IXUGO; break; } } /* Now perform the operation or return an error for a bad permission string. */ if (!*s || *s == ',') { if (who) perm &= who; switch (op) { case '+': bits |= perm; break; case '-': bits &= ~perm; break; case '=': if (who == 0) who = S_IRWXU | S_IRWXG | S_IRWXO; bits &= ~who; bits |= perm; break; /* No other values are possible. */ } if (*s == '\0') break; else s++; /* skip past ',' */ } else { builtin_error (_("`%c': invalid symbolic mode character"), *s); return (-1); } } return (bits); } /* Set the umask from a symbolic mode string similar to that accepted by chmod. If the -S argument is given, then print the umask in a symbolic form. */ static int symbolic_umask (list) WORD_LIST *list; { int um, bits; /* Get the initial umask. Don't change it yet. */ um = umask (022); umask (um); /* All work is done with the complement of the umask -- it's more intuitive and easier to deal with. It is complemented again before being returned. */ bits = parse_symbolic_mode (list->word->word, ~um & 0777); if (bits == -1) return (-1); um = ~bits & 0777; return (um); }