Include stat-macros.h, xalloc.h.

(S_ISDIR, S_ISUID, S_ISGID, S_ISVTX, S_IRUSR, S_IWUSR, S_IXUSR):
(S_IRGRP, S_IWGRP, S_IXGRP, S_IROTH, S_IWOTH, S_IXOTH, S_IRXWU):
(S_IRWXG, S_IRWXO, CHMOD_MODE_BITS):
Remove.  This is now stat-macros.h's job.
(talloc): Remove.  All callers replaced by xalloc, so that
our invokers don't have to worry about reporting memory failures.
(make_node_op_equals): Remove.
(MODE_ORDINARY_CHAGE, MODE_X_IF_ANY_X, MODE_COPY_EXISTING):
New constants.
(struct mode_change): Moved here from modechange.h.
(mode_append_entry): Remove.
(mode_compile): Remove MASKED_OPS arg, since it encouraged
apps to have incorrect behavior.  Use simpler algorithm for head
and tail.  Don't futz with umask; that's now the job of mode_adjust.
Detect more invalid usages rather than having somewhat-random behavior.
Don't insert an "a=" action, as that leads to incorrect behavior.
(mode_compile, mode_create_from_ref): Return NULL on error instead
of an enum, since now there's only one way to have an error.  All
callers changed.
(mode_adjust): Accept new arg UMASK_VALUE, and interpret it
at the correct time.  Simplify calculation of "+u" and its ilk.
Don't mishandle "+X".
(mode_free): Remove "register" and localize decls.

1 files changed, 175 insertions, 299 deletions

diff --git a/lib/modechange.c b/lib/modechange.c
index 991235b09..8880ec09a 100644
--- a/lib/modechange.c
+++ b/lib/modechange.c
@@ -1,7 +1,7 @@
 /* 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
@@ -24,7 +24,7 @@
    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>
@@ -32,19 +32,13 @@
 
 #include "modechange.h"
 #include <sys/stat.h>
+#include "stat-macros.h"
+#include "xalloc.h"
 #include "xstrtol.h"
 #include <stdbool.h>
 #include <stddef.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
@@ -60,127 +54,54 @@
 #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
-
-/* 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)
+/* Special operations flags.  */
+enum
+  {
+    /* The typical case.  */
+    MODE_ORDINARY_CHANGE,
+
+    /* 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,
+
+    /* 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
 {
-  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;
-    }
-}
+  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.  */
+  struct mode_change *next;	/* Link to next change in list.  */
+};
 
 /* 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. */
+   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. */
+  struct mode_change *head;	/* First element of the linked list.  */
+  struct mode_change **tail = &head;  /* Pointer to list end.  */
   unsigned long octal_value;	/* The mode value, if octal.  */
-  mode_t umask_value;		/* The umask value (surprise). */
-
-  head = NULL;
-#ifdef lint
-  tail = NULL;
-#endif
 
   if (xstrtoul (mode_string, NULL, 8, &octal_value, "") == LONGINT_OK)
     {
-      struct mode_change *p;
       mode_t mode;
       if (octal_value != (octal_value & ALLM))
-	return MODE_INVALID;
+	return NULL;
 
       /* Help the compiler optimize the usual case where mode_t uses
 	 the traditional octal representation.  */
@@ -202,166 +123,132 @@ mode_compile (const char *mode_string, unsigned int masked_ops)
 			  | (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);
+      head = xmalloc (sizeof *head);
+      head->op = '=';
+      head->flag = MODE_ORDINARY_CHANGE;
+      head->affected = CHMOD_MODE_BITS;
+      head->value = mode;
+      head->next = NULL;
       return head;
     }
 
-  umask_value = umask (0);
-  umask (umask_value);		/* Restore the old value. */
-
-  /* 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)
 	  {
 	  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;
+	  default:
+	    goto invalid;
 	  }
+    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;
+	  change = xmalloc (sizeof *change);
+	  change->op = op;
+	  change->flag = flag;
+	  change->affected = affected;
+	  change->value = value;
 
-	  /* 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:;
+	  *tail = change;
+	  tail = &change->next;
 	}
+      while (*mode_string == '=' || *mode_string == '+'
+	     || *mode_string == '-');
 
       if (*mode_string != ',')
 	break;
     }
 
   if (*mode_string == 0)
-    return head;
+    {
+      *tail = NULL;
+      return head;
+    }
+
 invalid:
+  *tail = NULL;
   mode_free (head);
-  return MODE_INVALID;
+  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)
@@ -369,16 +256,12 @@ 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;
+  if (stat (ref_file, &ref_stats) != 0)
+    return NULL;
 
+  change = xmalloc (sizeof *change);
   change->op = '=';
-  change->flags = 0;
+  change->flag = MODE_ORDINARY_CHANGE;
   change->affected = CHMOD_MODE_BITS;
   change->value = ref_stats.st_mode;
   change->next = NULL;
@@ -387,90 +270,83 @@ mode_create_from_ref (const char *ref_file)
 }
 
 /* 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)
     {
-      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. */
+   CHANGES.  */
 
 void
-mode_free (register struct mode_change *changes)
+mode_free (struct mode_change *changes)
 {
-  register struct mode_change *next;
-
   while (changes)
     {
-      next = changes->next;
+      struct mode_change *next = changes->next;
       free (changes);
       changes = next;
     }