+++ /dev/null
-/* modechange.c -- file mode manipulation
- Copyright (C) 1989, 1990, 1997, 1998, 1999 Free Software Foundation, Inc.
-
- This program 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.
-
- This program 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 this program; if not, write to the Free Software Foundation,
- Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
-
-/* Written by David MacKenzie <djm@ai.mit.edu> */
-
-/* The ASCII mode string is compiled into a linked list of `struct
- modechange', which can then be applied to each file to be changed.
- We do this instead of re-parsing the ASCII string for each file
- because the compiled form requires less computation to use; when
- changing the mode of many files, this probably results in a
- performance gain. */
-
-#if HAVE_CONFIG_H
-# include <config.h>
-#endif
-
-#include "modechange.h"
-#include <sys/stat.h>
-#include "xstrtol.h"
-
-#if STDC_HEADERS
-# include <stdlib.h>
-#else
-char *malloc ();
-#endif
-
-#ifndef NULL
-# define NULL 0
-#endif
-
-#if STAT_MACROS_BROKEN
-# undef S_ISDIR
-#endif
-
-#if !defined(S_ISDIR) && defined(S_IFDIR)
-# define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
-#endif
-
-#ifndef S_ISUID
-# define S_ISUID 04000
-#endif
-#ifndef S_ISGID
-# define S_ISGID 04000
-#endif
-#ifndef S_ISVTX
-# define S_ISVTX 01000
-#endif
-#ifndef S_IRUSR
-# define S_IRUSR 0400
-#endif
-#ifndef S_IWUSR
-# define S_IWUSR 0200
-#endif
-#ifndef S_IXUSR
-# define S_IXUSR 0100
-#endif
-#ifndef S_IRGRP
-# define S_IRGRP 0040
-#endif
-#ifndef S_IWGRP
-# define S_IWGRP 0020
-#endif
-#ifndef S_IXGRP
-# define S_IXGRP 0010
-#endif
-#ifndef S_IROTH
-# define S_IROTH 0004
-#endif
-#ifndef S_IWOTH
-# define S_IWOTH 0002
-#endif
-#ifndef S_IXOTH
-# define S_IXOTH 0001
-#endif
-#ifndef S_IRWXU
-# define S_IRWXU 0700
-#endif
-#ifndef S_IRWXG
-# define S_IRWXG 0070
-#endif
-#ifndef S_IRWXO
-# define S_IRWXO 0007
-#endif
-
-/* All the mode bits that can be affected by chmod. */
-#define CHMOD_MODE_BITS \
- (S_ISUID | S_ISGID | S_ISVTX | S_IRWXU | S_IRWXG | S_IRWXO)
-
-/* Return newly allocated memory to hold one element of type TYPE. */
-#define talloc(type) ((type *) malloc (sizeof (type)))
-
-/* Create a mode_change entry with the specified `=ddd'-style
- mode change operation, where NEW_MODE is `ddd'. Return the
- new entry, or NULL upon failure. */
-
-static struct mode_change *
-make_node_op_equals (mode_t new_mode)
-{
- struct mode_change *p;
- p = talloc (struct mode_change);
- if (p == NULL)
- return p;
- p->next = NULL;
- p->op = '=';
- p->flags = 0;
- p->value = new_mode;
- p->affected = CHMOD_MODE_BITS; /* Affect all permissions. */
- return p;
-}
-
-/* Append entry E to the end of the link list with the specified
- HEAD and TAIL. */
-
-static void
-mode_append_entry (struct mode_change **head,
- struct mode_change **tail,
- struct mode_change *e)
-{
- if (*head == NULL)
- *head = *tail = e;
- else
- {
- (*tail)->next = e;
- *tail = e;
- }
-}
-
-/* Return a linked list of file mode change operations created from
- MODE_STRING, an ASCII string that contains either an octal number
- specifying an absolute mode, or symbolic mode change operations with
- the form:
- [ugoa...][[+-=][rwxXstugo...]...][,...]
- MASKED_OPS is a bitmask indicating which symbolic mode operators (=+-)
- should not affect bits set in the umask when no users are given.
- Operators not selected in MASKED_OPS ignore the umask.
-
- Return MODE_INVALID if `mode_string' does not contain a valid
- representation of file mode change operations;
- return MODE_MEMORY_EXHAUSTED if there is insufficient memory. */
-
-struct mode_change *
-mode_compile (const char *mode_string, unsigned int masked_ops)
-{
- struct mode_change *head; /* First element of the linked list. */
- struct mode_change *tail; /* An element of the linked list. */
- uintmax_t mode_value; /* The mode value, if octal. */
- char *string_end; /* Pointer to end of parsed value. */
- mode_t umask_value; /* The umask value (surprise). */
-
- head = NULL;
-#ifdef lint
- tail = NULL;
-#endif
-
- if (xstrtoumax (mode_string, &string_end, 8, &mode_value, "") == LONGINT_OK)
- {
- struct mode_change *p;
- if (mode_value != (mode_value & CHMOD_MODE_BITS))
- return MODE_INVALID;
- p = make_node_op_equals ((mode_t) mode_value);
- if (p == NULL)
- return MODE_MEMORY_EXHAUSTED;
- mode_append_entry (&head, &tail, p);
- return head;
- }
-
- umask_value = umask (0);
- umask (umask_value); /* Restore the old value. */
- --mode_string;
-
- /* One loop iteration for each "ugoa...=+-rwxXstugo...[=+-rwxXstugo...]". */
- do
- {
- /* Which bits in the mode are operated on. */
- mode_t affected_bits = 0;
- /* `affected_bits' modified by umask. */
- mode_t affected_masked;
- /* Operators to actually use umask on. */
- unsigned ops_to_mask = 0;
-
- int who_specified_p;
-
- affected_bits = 0;
- ops_to_mask = 0;
- /* Turn on all the bits in `affected_bits' for each group given. */
- for (++mode_string;; ++mode_string)
- switch (*mode_string)
- {
- case 'u':
- affected_bits |= S_ISUID | S_IRWXU;
- break;
- case 'g':
- affected_bits |= S_ISGID | S_IRWXG;
- break;
- case 'o':
- affected_bits |= S_ISVTX | S_IRWXO;
- break;
- case 'a':
- affected_bits |= CHMOD_MODE_BITS;
- break;
- default:
- goto no_more_affected;
- }
-
- no_more_affected:
- /* If none specified, affect all bits, except perhaps those
- set in the umask. */
- if (affected_bits)
- who_specified_p = 1;
- else
- {
- who_specified_p = 0;
- affected_bits = CHMOD_MODE_BITS;
- ops_to_mask = masked_ops;
- }
-
- while (*mode_string == '=' || *mode_string == '+' || *mode_string == '-')
- {
- struct mode_change *change = talloc (struct mode_change);
- if (change == NULL)
- {
- mode_free (head);
- return MODE_MEMORY_EXHAUSTED;
- }
-
- change->next = NULL;
- change->op = *mode_string; /* One of "=+-". */
- affected_masked = affected_bits;
-
- /* Per the Single Unix Spec, if `who' is not specified and the
- `=' operator is used, then clear all the bits first. */
- if (!who_specified_p &&
- ops_to_mask & (*mode_string == '=' ? MODE_MASK_EQUALS : 0))
- {
- struct mode_change *p = make_node_op_equals (0);
- if (p == NULL)
- return MODE_MEMORY_EXHAUSTED;
- mode_append_entry (&head, &tail, p);
- }
-
- if (ops_to_mask & (*mode_string == '=' ? MODE_MASK_EQUALS
- : *mode_string == '+' ? MODE_MASK_PLUS
- : MODE_MASK_MINUS))
- affected_masked &= ~umask_value;
- change->affected = affected_masked;
- change->value = 0;
- change->flags = 0;
-
- /* Add the element to the tail of the list, so the operations
- are performed in the correct order. */
- mode_append_entry (&head, &tail, change);
-
- /* Set `value' according to the bits set in `affected_masked'. */
- for (++mode_string;; ++mode_string)
- switch (*mode_string)
- {
- case 'r':
- change->value |= ((S_IRUSR | S_IRGRP | S_IROTH)
- & affected_masked);
- break;
- case 'w':
- change->value |= ((S_IWUSR | S_IWGRP | S_IWOTH)
- & affected_masked);
- break;
- case 'X':
- change->flags |= MODE_X_IF_ANY_X;
- /* Fall through. */
- case 'x':
- change->value |= ((S_IXUSR | S_IXGRP | S_IXOTH)
- & affected_masked);
- break;
- case 's':
- /* Set the setuid/gid bits if `u' or `g' is selected. */
- change->value |= (S_ISUID | S_ISGID) & affected_masked;
- break;
- case 't':
- /* Set the "save text image" bit if `o' is selected. */
- change->value |= S_ISVTX & affected_masked;
- break;
- case 'u':
- /* Set the affected bits to the value of the `u' bits
- on the same file. */
- if (change->value)
- goto invalid;
- change->value = S_IRWXU;
- change->flags |= MODE_COPY_EXISTING;
- break;
- case 'g':
- /* Set the affected bits to the value of the `g' bits
- on the same file. */
- if (change->value)
- goto invalid;
- change->value = S_IRWXG;
- change->flags |= MODE_COPY_EXISTING;
- break;
- case 'o':
- /* Set the affected bits to the value of the `o' bits
- on the same file. */
- if (change->value)
- goto invalid;
- change->value = S_IRWXO;
- change->flags |= MODE_COPY_EXISTING;
- break;
- default:
- goto no_more_values;
- }
- no_more_values:;
- }
- } while (*mode_string == ',');
- if (*mode_string == 0)
- return head;
-invalid:
- mode_free (head);
- return MODE_INVALID;
-}
-
-/* Return a file mode change operation that sets permissions to match those
- of REF_FILE. Return MODE_BAD_REFERENCE if REF_FILE can't be accessed. */
-
-struct mode_change *
-mode_create_from_ref (const char *ref_file)
-{
- struct mode_change *change; /* the only change element */
- struct stat ref_stats;
-
- if (stat (ref_file, &ref_stats))
- return MODE_BAD_REFERENCE;
-
- change = talloc (struct mode_change);
-
- if (change == NULL)
- return MODE_MEMORY_EXHAUSTED;
-
- change->op = '=';
- change->flags = 0;
- change->affected = CHMOD_MODE_BITS;
- change->value = ref_stats.st_mode;
- change->next = NULL;
-
- return change;
-}
-
-/* Return file mode OLDMODE, adjusted as indicated by the list of change
- operations CHANGES. If OLDMODE is a directory, the type `X'
- change affects it even if no execute bits were set in OLDMODE.
- The returned value has the S_IFMT bits cleared. */
-
-mode_t
-mode_adjust (mode_t oldmode, const struct mode_change *changes)
-{
- mode_t newmode; /* The adjusted mode and one operand. */
- mode_t value; /* The other operand. */
-
- newmode = oldmode & CHMOD_MODE_BITS;
-
- for (; changes; changes = changes->next)
- {
- if (changes->flags & MODE_COPY_EXISTING)
- {
- /* Isolate in `value' the bits in `newmode' to copy, given in
- the mask `changes->value'. */
- value = newmode & changes->value;
-
- if (changes->value & S_IRWXU)
- /* Copy `u' permissions onto `g' and `o'. */
- value |= ((value & S_IRUSR ? S_IRGRP | S_IROTH : 0)
- | (value & S_IWUSR ? S_IWGRP | S_IROTH : 0)
- | (value & S_IXUSR ? S_IXGRP | S_IXOTH : 0));
- else if (changes->value & S_IRWXG)
- /* Copy `g' permissions onto `u' and `o'. */
- value |= ((value & S_IRGRP ? S_IRUSR | S_IROTH : 0)
- | (value & S_IWGRP ? S_IWUSR | S_IROTH : 0)
- | (value & S_IXGRP ? S_IXUSR | S_IXOTH : 0));
- else
- /* Copy `o' permissions onto `u' and `g'. */
- value |= ((value & S_IROTH ? S_IRUSR | S_IRGRP : 0)
- | (value & S_IWOTH ? S_IWUSR | S_IRGRP : 0)
- | (value & S_IXOTH ? S_IXUSR | S_IXGRP : 0));
-
- /* In order to change only `u', `g', or `o' permissions,
- or some combination thereof, clear unselected bits.
- This can not be done in mode_compile because the value
- to which the `changes->affected' mask is applied depends
- on the old mode of each file. */
- value &= changes->affected;
- }
- else
- {
- value = changes->value;
- /* If `X', do not affect the execute bits if the file is not a
- directory and no execute bits are already set. */
- if ((changes->flags & MODE_X_IF_ANY_X)
- && !S_ISDIR (oldmode)
- && (newmode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)
- /* Clear the execute bits. */
- value &= ~ (S_IXUSR | S_IXGRP | S_IXOTH);
- }
-
- switch (changes->op)
- {
- case '=':
- /* Preserve the previous values in `newmode' of bits that are
- not affected by this change operation. */
- newmode = (newmode & ~changes->affected) | value;
- break;
- case '+':
- newmode |= value;
- break;
- case '-':
- newmode &= ~value;
- break;
- }
- }
- return newmode;
-}
-
-/* Free the memory used by the list of file mode change operations
- CHANGES. */
-
-void
-mode_free (register struct mode_change *changes)
-{
- register struct mode_change *next;
-
- while (changes)
- {
- next = changes->next;
- free (changes);
- changes = next;
- }
-}
projects / chaz / tar / blobdiff