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+This file is umask.def, from which is created umask.c.
+It implements the builtin "umask" in Bash.
+
+Copyright (C) 1987-2020 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
+
+$PRODUCES umask.c
+
+$BUILTIN umask
+$FUNCTION umask_builtin
+$SHORT_DOC umask [-p] [-S] [mode]
+Display or set file mode mask.
+
+Sets the user file-creation mask to MODE. If MODE is omitted, prints
+the current value of the mask.
+
+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).
+
+Options:
+ -p if MODE is omitted, output in a form that may be reused as input
+ -S makes the output symbolic; otherwise an octal number is output
+
+Exit Status:
+Returns success unless MODE is invalid or an invalid option is given.
+$END
+
+#include <config.h>
+
+#include "../bashtypes.h"
+#include "filecntl.h"
+#if ! defined(_MINIX) && defined (HAVE_SYS_FILE_H)
+# include <sys/file.h>
+#endif
+
+#if defined (HAVE_UNISTD_H)
+#include <unistd.h>
+#endif
+
+#include <stdio.h>
+#include <chartypes.h>
+
+#include "../bashintl.h"
+
+#include "../shell.h"
+#include "posixstat.h"
+#include "common.h"
+#include "bashgetopt.h"
+
+/* **************************************************************** */
+/* */
+/* UMASK Builtin and Helpers */
+/* */
+/* **************************************************************** */
+
+static void print_symbolic_umask PARAMS((mode_t));
+static int symbolic_umask PARAMS((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;
+ CASE_HELPOPT;
+ 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);
+ }
+
+ return (sh_chkwrite (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
+#if defined (__STDC__)
+print_symbolic_umask (mode_t um)
+#else
+print_symbolic_umask (um)
+ mode_t um;
+#endif
+{
+ 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);
+}