/* modechange.c -- file mode manipulation
- Copyright (C) 1989, 1990, 1997, 1998, 1999, 2001, 2003, 2004 Free
- Software Foundation, Inc.
+ Copyright (C) 1989, 1990, 1997, 1998, 1999, 2001, 2003, 2004, 2005
+ 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
/* Written by David MacKenzie <djm@ai.mit.edu> */
-/* The ASCII mode string is compiled into a linked list of `struct
+/* The ASCII mode string is compiled into an array 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. */
+ performance gain. */
#if HAVE_CONFIG_H
# include <config.h>
#include "modechange.h"
#include <sys/stat.h>
-#include "xstrtol.h"
-#include <stdbool.h>
-#include <stddef.h>
+#include "stat-macros.h"
+#include "xalloc.h"
#include <stdlib.h>
-#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
-
/* The traditional octal values corresponding to each mode bit. */
#define SUID 04000
#define SGID 02000
#define XOTH 00001
#define ALLM 07777 /* all octal mode bits */
-#ifndef S_ISUID
-# define S_ISUID SUID
-#endif
-#ifndef S_ISGID
-# define S_ISGID SGID
-#endif
-#ifndef S_ISVTX
-# define S_ISVTX SVTX
-#endif
-#ifndef S_IRUSR
-# define S_IRUSR RUSR
-#endif
-#ifndef S_IWUSR
-# define S_IWUSR WUSR
-#endif
-#ifndef S_IXUSR
-# define S_IXUSR XUSR
-#endif
-#ifndef S_IRGRP
-# define S_IRGRP RGRP
-#endif
-#ifndef S_IWGRP
-# define S_IWGRP WGRP
-#endif
-#ifndef S_IXGRP
-# define S_IXGRP XGRP
-#endif
-#ifndef S_IROTH
-# define S_IROTH ROTH
-#endif
-#ifndef S_IWOTH
-# define S_IWOTH WOTH
-#endif
-#ifndef S_IXOTH
-# define S_IXOTH XOTH
-#endif
-#ifndef S_IRWXU
-# define S_IRWXU (S_IRUSR | S_IWUSR | S_IXUSR)
-#endif
-#ifndef S_IRWXG
-# define S_IRWXG (S_IRGRP | S_IWGRP | S_IXGRP)
-#endif
-#ifndef S_IRWXO
-# define S_IRWXO (S_IROTH | S_IWOTH | S_IXOTH)
-#endif
+/* Special operations flags. */
+enum
+ {
+ /* For the sentinel at the end of the mode changes array. */
+ MODE_DONE,
+
+ /* The typical case. */
+ MODE_ORDINARY_CHANGE,
-/* 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)
+ /* In addition to the typical case, affect the execute bits if at
+ least one execute bit is set already, or if the file is a
+ directory. */
+ MODE_X_IF_ANY_X,
-/* Return newly allocated memory to hold one element of type TYPE. */
-#define talloc(type) ((type *) malloc (sizeof (type)))
+ /* Instead of the typical case, copy some existing permissions for
+ u, g, or o onto the other two. Which of u, g, or o is copied
+ is determined by which bits are set in the `value' field. */
+ MODE_COPY_EXISTING
+ };
+
+/* Description of a mode change. */
+struct mode_change
+{
+ char op; /* One of "=+-". */
+ char flag; /* Special operations flag. */
+ mode_t affected; /* Set for u, g, o, or a. */
+ mode_t value; /* Bits to add/remove. */
+};
-/* 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. */
+/* Return a mode_change array with the specified `=ddd'-style
+ mode change operation, where NEW_MODE is `ddd'. */
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;
+ struct mode_change *p = xmalloc (2 * sizeof *p);
p->op = '=';
- p->flags = 0;
+ p->flag = MODE_ORDINARY_CHANGE;
+ p->affected = CHMOD_MODE_BITS;
p->value = new_mode;
- p->affected = CHMOD_MODE_BITS; /* Affect all permissions. */
+ p[1].flag = MODE_DONE;
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
+/* Return a pointer to an array 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. */
+ Return NULL if `mode_string' does not contain a valid
+ representation of file mode change operations. */
struct mode_change *
-mode_compile (const char *mode_string, unsigned int masked_ops)
+mode_compile (char const *mode_string)
{
- struct mode_change *head; /* First element of the linked list. */
- struct mode_change *tail; /* An element of the linked list. */
- unsigned long octal_value; /* The mode value, if octal. */
- mode_t umask_value; /* The umask value (surprise). */
-
- head = NULL;
-#ifdef lint
- tail = NULL;
-#endif
+ /* The array of mode-change directives to be returned. */
+ struct mode_change *mc;
+ size_t used = 0;
- if (xstrtoul (mode_string, NULL, 8, &octal_value, "") == LONGINT_OK)
+ if ('0' <= *mode_string && *mode_string < '8')
{
- struct mode_change *p;
mode_t mode;
- if (octal_value != (octal_value & ALLM))
- return MODE_INVALID;
+ unsigned int octal_value = 0;
+
+ do
+ {
+ octal_value = 8 * octal_value + *mode_string++ - '0';
+ if (ALLM < octal_value)
+ return NULL;
+ }
+ while ('0' <= *mode_string && *mode_string < '8');
/* Help the compiler optimize the usual case where mode_t uses
the traditional octal representation. */
| (octal_value & WOTH ? S_IWOTH : 0)
| (octal_value & XOTH ? S_IXOTH : 0)));
- p = make_node_op_equals (mode);
- if (p == NULL)
- return MODE_MEMORY_EXHAUSTED;
- mode_append_entry (&head, &tail, p);
- return head;
+ return make_node_op_equals (mode);
}
- umask_value = umask (0);
- umask (umask_value); /* Restore the old value. */
+ /* Allocate enough space to hold the result. */
+ {
+ size_t needed = 1;
+ char const *p;
+ for (p = mode_string; *p; p++)
+ needed += (*p == '=' || *p == '+' || *p == '-');
+ mc = xnmalloc (needed, sizeof *mc);
+ }
- /* One loop iteration for each "ugoa...=+-rwxXstugo...[=+-rwxXstugo...]". */
+ /* One loop iteration for each `[ugoa]*([-+=]([rwxXst]*|[ugo]))+'. */
for (;; mode_string++)
{
- /* 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 int ops_to_mask = 0;
+ /* Which bits in the mode are operated on. */
+ mode_t affected = 0;
- bool who_specified_p;
-
- /* Turn on all the bits in `affected_bits' for each group given. */
+ /* Turn on all the bits in `affected' for each group given. */
for (;; mode_string++)
switch (*mode_string)
{
+ default:
+ goto invalid;
case 'u':
- affected_bits |= S_ISUID | S_IRWXU;
+ affected |= S_ISUID | S_IRWXU;
break;
case 'g':
- affected_bits |= S_ISGID | S_IRWXG;
+ affected |= S_ISGID | S_IRWXG;
break;
case 'o':
- affected_bits |= S_ISVTX | S_IRWXO;
+ affected |= S_ISVTX | S_IRWXO;
break;
case 'a':
- affected_bits |= CHMOD_MODE_BITS;
+ affected |= CHMOD_MODE_BITS;
break;
- default:
+ case '=': case '+': case '-':
goto no_more_affected;
}
+ 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 = true;
- else
+ do
{
- who_specified_p = false;
- affected_bits = CHMOD_MODE_BITS;
- ops_to_mask = masked_ops;
- }
+ char op = *mode_string++;
+ mode_t value;
+ char flag = MODE_COPY_EXISTING;
+ struct mode_change *change;
- while (*mode_string == '=' || *mode_string == '+' || *mode_string == '-')
- {
- struct mode_change *change = talloc (struct mode_change);
- if (change == NULL)
+ switch (*mode_string++)
{
- mode_free (head);
- return MODE_MEMORY_EXHAUSTED;
+ case 'u':
+ /* Set the affected bits to the value of the `u' bits
+ on the same file. */
+ value = S_IRWXU;
+ break;
+ case 'g':
+ /* Set the affected bits to the value of the `g' bits
+ on the same file. */
+ value = S_IRWXG;
+ break;
+ case 'o':
+ /* Set the affected bits to the value of the `o' bits
+ on the same file. */
+ value = S_IRWXO;
+ break;
+
+ default:
+ value = 0;
+ flag = MODE_ORDINARY_CHANGE;
+
+ for (mode_string--;; mode_string++)
+ switch (*mode_string)
+ {
+ case 'r':
+ value |= S_IRUSR | S_IRGRP | S_IROTH;
+ break;
+ case 'w':
+ value |= S_IWUSR | S_IWGRP | S_IWOTH;
+ break;
+ case 'x':
+ value |= S_IXUSR | S_IXGRP | S_IXOTH;
+ break;
+ case 'X':
+ flag = MODE_X_IF_ANY_X;
+ break;
+ case 's':
+ /* Set the setuid/gid bits if `u' or `g' is selected. */
+ value |= S_ISUID | S_ISGID;
+ break;
+ case 't':
+ /* Set the "save text image" bit if `o' is selected. */
+ value |= S_ISVTX;
+ break;
+ default:
+ goto no_more_values;
+ }
+ no_more_values:;
}
- 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:;
+ change = &mc[used++];
+ change->op = op;
+ change->flag = flag;
+ change->affected = affected;
+ change->value = value;
}
+ while (*mode_string == '=' || *mode_string == '+'
+ || *mode_string == '-');
if (*mode_string != ',')
break;
}
if (*mode_string == 0)
- return head;
+ {
+ mc[used].flag = MODE_DONE;
+ return mc;
+ }
+
invalid:
- mode_free (head);
- return MODE_INVALID;
+ free (mc);
+ return NULL;
}
/* 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. */
+ of REF_FILE. Return NULL (setting errno) 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;
+ if (stat (ref_file, &ref_stats) != 0)
+ return NULL;
+ return make_node_op_equals (ref_stats.st_mode);
}
/* Return file mode OLDMODE, adjusted as indicated by the list of change
- operations CHANGES. If OLDMODE is a directory, the type `X'
+ operations CHANGES, which are interpreted assuming the umask is
+ UMASK_VALUE. 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. */
+ The returned value has the S_IFMT bits cleared. */
mode_t
-mode_adjust (mode_t oldmode, const struct mode_change *changes)
+mode_adjust (mode_t oldmode, struct mode_change const *changes,
+ mode_t umask_value)
{
- mode_t newmode; /* The adjusted mode and one operand. */
- mode_t value; /* The other operand. */
-
- newmode = oldmode & CHMOD_MODE_BITS;
+ /* The adjusted mode. */
+ mode_t newmode = oldmode & CHMOD_MODE_BITS;
- for (; changes; changes = changes->next)
+ for (; changes->flag != MODE_DONE; changes++)
{
- 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_IWOTH : 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_IWOTH : 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_IWGRP : 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 cannot 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
+ mode_t affected = changes->affected;
+ mode_t value = changes->value;
+
+ switch (changes->flag)
{
- 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);
+ case MODE_ORDINARY_CHANGE:
+ break;
+
+ case MODE_COPY_EXISTING:
+ /* Isolate in `value' the bits in `newmode' to copy. */
+ value &= newmode;
+
+ /* Copy the isolated bits to the other two parts. */
+ value |= ((value & (S_IRUSR | S_IRGRP | S_IROTH)
+ ? S_IRUSR | S_IRGRP | S_IROTH : 0)
+ | (value & (S_IWUSR | S_IWGRP | S_IWOTH)
+ ? S_IWUSR | S_IWGRP | S_IWOTH : 0)
+ | (value & (S_IXUSR | S_IXGRP | S_IXOTH)
+ ? S_IXUSR | S_IXGRP | S_IXOTH : 0));
+ break;
+
+ case MODE_X_IF_ANY_X:
+ /* Affect the execute bits if execute bits are already set
+ or if the file is a directory. */
+ if ((newmode & (S_IXUSR | S_IXGRP | S_IXOTH)) || S_ISDIR (oldmode))
+ value |= S_IXUSR | S_IXGRP | S_IXOTH;
+ break;
}
+ /* If WHO was specified, limit the change to the affected bits.
+ Otherwise, apply the umask. */
+ value &= (affected ? affected : ~umask_value);
+
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;
+ /* If WHO was specified, preserve the previous values of
+ bits that are not affected by this change operation.
+ Otherwise, clear all the bits. */
+ newmode = (affected ? newmode & ~affected : 0);
+ /* Fall through. */
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;
- }
+ return newmode;
}
projects / gnulib.git / blobdiff