source: trunk/athena/bin/delete/pattern.c @ 23667

/*
 * $Id: pattern.c,v 1.28 1999-01-22 23:09:03 ghudson Exp $
 *
 * This program is part of a package including delete, undelete,
 * lsdel, expunge and purge.  The software suite is meant as a
 * replacement for rm which allows for file recovery.
 * 
 * Copyright (c) 1989 by the Massachusetts Institute of Technology.
 * For copying and distribution information, see the file "mit-copying.h."
 */

#if (!defined(lint) && !defined(SABER))
     static char rcsid_pattern_c[] = "$Id: pattern.c,v 1.28 1999-01-22 23:09:03 ghudson Exp $";
#endif

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <sys/param.h>
#include <string.h>
#include <errno.h>
#include <com_err.h>
#include "pattern.h"
#include "util.h"
#include "directories.h"
#include "undelete.h"
#include "shell_regexp.h"
#include "mit-copying.h"
#include "delete_errs.h"
#include "errors.h"
#include "stack.h"

extern char *whoami;

void free_list();


/*
 * add_arrays() takes pointers to two arrays of char **'s and their
 * lengths, merges the two into the first by realloc'ing the first and
 * then free's the second's memory usage.
 */  
int add_arrays(array1, num1, size1, array2, num2)
char ***array1, ***array2;
int *num1, *size1, *num2;
{
     int counter;

     if (! *size1) {
       if (*array1)
         free(*array1);
       *array1 = *array2;
       *num1 = *num2;
       *size1 = *num2;
       return 0;
     }

     while (*size1 < (*num1 + *num2)) {
       *size1 *= 2;
     }

     *array1 = (char **) realloc((char *) *array1, (unsigned)
                                 (sizeof(char *) * *size1));
     if (! *array1) {
          set_error(errno);
          error("realloc");
          return error_code;
     }
     for (counter = *num1; counter < *num1 + *num2; counter++)
          *(*array1 + counter) = *(*array2 + counter - *num1);
     free ((char *) *array2);
     *num1 += *num2;
     return 0;
}






/*
 * Add a string to a list of strings.
 */
int add_str(strs, num, size, str)
char ***strs;
int num, *size;
char *str;
{
     char **ary;

     if (! *size) {
       num = 0;
       *size = 1;
       ary = *strs = (char **) malloc((unsigned) (sizeof(char *)));
     }
     else if (num == *size) {
       *size *= 2;
       ary = *strs = (char **) realloc((char *) *strs, (unsigned)
                                       (sizeof(char *) * *size));
     }
     else {
       ary = *strs;
     }

     if (! *strs) {
          set_error(errno);
          error("realloc");
          return error_code;
     }
     ary[num] = Malloc((unsigned) (strlen(str) + 1));
     if (! ary[num]) {
          set_error(errno);
          error("Malloc");
          return error_code;
     }
     (void) strcpy(ary[num], str);
     return 0;
}





/*
 * Find_matches will behave unpredictably if you try to use it to find
 * very strange combinations of file types, for example only searching
 * for undeleted files in the top-level directory, while searching
 * recursively for deleted files.  Basically, there are some conflicts
 * between options that I don't list here because I don't think I'll
 * ever need to use those combinations.
 */
/*
 * Function: find_matches(char *name, int *num_found, char ***found,
 *                        int options)
 *
 * Requires: name points to a NULL-terminated string, representing a
 *   filename pattern with regular filename characters, path
 *   separators and shell wildcard characters []*?; num_found points
 *   to a valid int memory storage location; found points to a valid
 *   char ** memory storage location.
 *
 * Effects: Returns a list of all the files in the file hierarchy that
 *   match the options specified in options and that match name.
 *   Options are:
 *
 *   FIND_UNDELETED search for and return undeleted files
 * 
 *   FIND_DELETED search for and return deleted files
 *
 *   FIND_CONTENTS means that if matches are directories (or links to
 *     directories), the contents of the directory should be matched
 *     in addition to the directory itself
 * 
 *   RECURS_FIND_DELETED to search all undeleted subdirectories
 *     recursively of matched directories looking for deleted files
 *
 *   RECURS_FIND_UNDELETED to search all undeleted subdirectories
 *     recursively of matched directories looking for undeleted files
 * 
 *   RECURS_DELETED to recursively return all contents of deleted
 *     directories in addition to the directories themselves
 *   
 *   FOLLW_LINKS to pursue symlinks to directories and continue down
 *     the referenced directories when searching recursively (if the
 *     initial string is an undeleted symlink it is always traversed;
 *     deleted symlinks are never traversed)
 *   
 *   FOLLW_MOUNTPOINTS to traverse mount points when searching
 *     recursively (if the initial string is a mountpoint it is always
 *     traversed)
 *
 *   FIND_DOTFILES forces the system to recognize dot files instead of
 *     discarding them when looking for files
 *
 *   If the first character of name is '/', the search is conducted
 *   absolutely from the root of the hierarchy; else, it is conducted
 *   relative to the current working directory.  The number of
 *   matching files is returned in *num_found, and a list of file
 *   names is returned in *found.  If there are no errors, the return
 *   value is 0; else the return value represents the error code of
 *   the error which occurred.  No matter how many file names are
 *   returned, the memory location addressed in *found is a valid
 *   pointer according to Malloc() and can be released using free()
 *   safely.  However, if an error value is returned, the caller
 *   should not attempt to use the values stored in *num_found or
 *   *found.
 *
 * Modifies: *num_found, *found.
 */
int find_matches(name, num_found, found, options)
char *name;
int *num_found;
char ***found;
int options;
{
     char       **matched_files, **return_files, **recurs_files;
     int        num_matched_files = 0, num_return_files = 0,
                num_recurs_files = 0, return_files_size = 0;
     int        retval;
     int        i;
#ifdef DEBUG
     int        j;
#endif
     int        match_options = 0;

#ifdef DEBUG
     fprintf(stderr, "Entering find_matches, name = %s, options = %d.\n",
             name, options);
#endif
     
     match_options = options & (FIND_DELETED | FIND_UNDELETED);
     if (options & (RECURS_FIND_DELETED | RECURS_FIND_UNDELETED |
                    FIND_CONTENTS))
          match_options |= FIND_UNDELETED;
     
     if (! match_options) {
          set_error(PAT_NO_FILES_REQUESTED);
          error("find_matches");
          return error_code;
     }
     
     retval = do_match(name, &num_matched_files, &matched_files,
                       match_options & FIND_UNDELETED,
                       match_options & FIND_DELETED);
     if (retval) {
          error(name);
          return retval;
     }
     if (num_matched_files == 0) {
          *num_found = num_matched_files;
          *found = matched_files;
#ifdef DEBUG
          fprintf(stderr, "No matches found, returning.\n");
#endif
          return 0;
     }

#ifdef DEBUG
     fprintf(stderr, "The following matches were found:\n");
     for (i = 0; i < num_matched_files; i++)
          fprintf(stderr, "  %s\n", matched_files[i]);
#endif
     
     if (options & RECURS) {
          return_files = (char **) Malloc(0);
          num_return_files = 0;

          for (i = 0; i < num_matched_files; i++) {

               retval = do_recurs(matched_files[i], &num_recurs_files,
                                  &recurs_files, options);
               if (retval) {
                    error(matched_files[i]);
                    return retval;
               }

               if (num_recurs_files) {
                    retval = add_arrays(&return_files, &num_return_files,
                                        &return_files_size, &recurs_files,
                                        &num_recurs_files);
                    if (retval) {
                         error("add_arrays");
                         return retval;
                    }
#ifdef DEBUG
                    fprintf(stderr,
                            "Just added the following to return_files:\n");
                    for (j = num_return_files - num_recurs_files;
                         j < num_return_files; j++)
                         fprintf(stderr, "  %s\n", return_files[j]);
#endif
               }
               
               if (is_deleted(lastpart(matched_files[i]))) {
                    if (options & FIND_DELETED) {
                         retval = add_str(&return_files, num_return_files,
                                          &return_files_size,
                                          matched_files[i]);
                         if (retval) {
                              error("add_str");
                              return retval;
                         }
                         num_return_files++;
#ifdef DEBUG
                         fprintf(stderr, "Just added %s to return_files.\n",
                                 return_files[num_return_files-1]);
#endif
                    }
               }
               else if (options & FIND_UNDELETED) {
                    retval = add_str(&return_files, num_return_files,
                                     &return_files_size, matched_files[i]);
                    if (retval) {
                         error("add_str");
                         return retval;
                    }
                    num_return_files++;
#ifdef DEBUG
                    fprintf(stderr, "Just added %s to return_files.\n",
                            return_files[num_return_files-1]);
#endif
               }
          }
          free_list(matched_files, num_matched_files);
          *num_found = num_return_files;
          *found = return_files;
     }
     else {
          *num_found = num_matched_files;
          *found = matched_files;
     }

     return 0;
}




          
          
                    
               
#define string_push(str)\
          strsize = strlen(str);\
          retval = push(str, strsize);\
          if (! retval)\
               retval |= push(&strsize, sizeof(int));\
          if (retval) {\
               error("push");\
               (void) popall();\
               return retval;\
          }
#define string_pop(str)\
          retval = pop(&strsize, sizeof(int));\
          if (! retval)\
               retval = pop(str, strsize);\
          if (! retval)\
               str[strsize] = '\0'
          
          




/*
 * Function: do_match(char *name, int *num_found, char ***found,
 *                    Boolean match_undeleted, Boolean match_deleted)
 *
 * Requires: name points to a NULL-terminated string, representing a
 *   filename pattern with regular filename characters, path
 *   separators and shell wildcard characters []*?; num_found points
 *   to a valid int memory storage location; found points to a valid
 *   char ** memory storage location.
 *
 * Effects: Returns a list of all the files in the file hierarchy that
 *   match name.  If match_undeleted is true, will return undeleted
 *   files that match; if match_deleted is true, will return
 *   deleted_files that match.  If the first character of name is '/',
 *   the search is conducted absolutely from the root of the
 *   hierarchy; else, it is conducted relative to the current working
 *   directory.  The number of matching files is returned in
 *   *num_found, and a list of file names is returned in *found.  If
 *   there are no errors, the return value is 0; else the return value
 *   represents the error code of the error which occurred.  No matter
 *   how many file names are returned, the memory location addressed
 *   in *found is a valid pointer according to Malloc() and can be
 *   released using free() safely.  However, if an error value is
 *   returned, the caller should not attempt to use the values stored
 *   in *num_found or *found.
 *
 * Modifies: *num_found, *found.
 *
 * Algorithm:
 *
 * start:
 *   base = "" or "/",
 *   name = name or name + 1
 *   initialze found and num_found
 *   dirp = Opendir(base)
 *   first = firstpart(name, rest) (assigns rest as side-effect)
 *   if (! *first) {
 *     add string to list if appropriate
 *     return
 * 
 * loop:
 *   dp = readdir(dirp)
 *   if (! dp) goto updir
 *   compare dp->d_name to first -- match?
 *     yes - goto downdir
 *     no - are we looking for deleted and is dp->d_name deleted?
 *       yes - compare undeleted dp->d_name to first -- match?
 *         yes - goto downdir
 *         no - goto loop
 *       no - goto loop
 *
 * downdir:
 *   save dirp, rest, first and base on stack
 *   first = firstpart(rest, rest)
 *   base = dp->d_name appended to base
 *   is first an empty string?
 *      yes - put back dirp, rest, first, base
 *            goto loop
 *   try to open dir base - opens?
 *      yes - goto loop
 *      no - is the error ENOTDIR?
 *             yes - don't worry about it
 *             no - report the error
 *           restore dirp, rest, first, base from stack
 *           goto loop
 *
 * updir:
 *   close dirp
 *   restore base, rest, first from stack
 *   STACK_EMPTY?
 *     yes - return from procedure with results
 *   restore dirp from stack
 *   goto loop
 */
int do_match(name, num_found, found, match_undeleted, match_deleted)
char *name;
int *num_found;
char ***found;
Boolean match_undeleted, match_deleted;
{
     char base[MAXPATHLEN];
     struct dirent *dp;
     DIR *dirp;
     char first[MAXNAMLEN], rest[MAXPATHLEN];
     int retval;
     int strsize;
     struct stat statbuf;
#ifdef PATTERN_DEBUG
     int j;
#endif
     int found_size = 0;
     
#ifdef DEBUG
     printf("do_match: looking for %s\n", name);
#endif

     /* start: */
     
     if (*name == '/') {
          *base = '/';
          *(base + 1) = '\0';
          name++;
     }
     else 
          *base = '\0';

     *found = (char **) Malloc(0);
     *num_found = 0;
     
     dirp = Opendir(base);
     if (! dirp) {
          set_error(errno);
          error(base);
#ifdef PATTERN_DEBUG
          fprintf(stderr, "do_match: return 2.\n");
#endif
          return error_code;
     }
     (void) strcpy(first, firstpart(name, rest));
     if ((! *first) && (match_undeleted)) {
          retval = add_str(found, *num_found, &found_size, base);
          if (retval) {
               error("add_str");
               (void) popall();
#ifdef PATTERN_DEBUG
               fprintf(stderr, "do_match: return 3.\n");
#endif
               return retval;
          }
          (*num_found)++;
#ifdef PATTERN_DEBUG
          fprintf(stderr, "do_match: return 4.\n");
#endif
          return 0;
     }
     
     while (1) {
          dp = readdir(dirp);
          if (! dp) goto updir;

          retval = reg_cmp(first, dp->d_name);
#ifdef PATTERN_DEBUG
        fprintf(stderr, "do_match: comparing %s to %s returns %d.\n",
                first, dp->d_name, retval);
#endif
          if (retval < 0) {
               error("reg_cmp");
               goto updir;
          }

          if (retval == REGEXP_MATCH) goto downdir;

          if (is_deleted(dp->d_name) && match_deleted) {
               retval = reg_cmp(first, &dp->d_name[2]);
#ifdef PATTERN_DEBUG
               fprintf(stderr,
                       "do_match: deleted compare of %s to %s returns %d.\n",
                       first, &dp->d_name[2], retval);
#endif
               if (retval < 0) {
                    error("reg_cmp");
                    goto updir;
               }

               if (retval == REGEXP_MATCH)
                    goto downdir;
               else
                    continue;
          }
          else
               continue;

     downdir:
#ifdef PATTERN_DEBUG
          fprintf(stderr, "do_match: downdir\n");
#endif
          retval = push(&dirp, sizeof(DIR *));
          if (retval) {
               error("push");
               (void) popall();
#ifdef PATTERN_DEBUG
               fprintf(stderr, "do_match: return 5.\n");
#endif
               return retval;
          }
#ifdef PATTERN_DEBUG
          fprintf(stderr, "do_match: pushing %s, %s, %s\n", first, rest, base);
#endif
          string_push(first);
          string_push(rest);
          string_push(base);
          (void) strcpy(base, append(base, dp->d_name));
          (void) strcpy(first, firstpart(rest, rest));
          if (! *first) {
               if (is_deleted(lastpart(base))) {
                    if (match_deleted) {
                         retval = add_str(found, *num_found, &found_size,
                                          base);
                         if (retval) {
                              error("add_str");
                              (void) popall();
#ifdef PATTERN_DEBUG
                              fprintf(stderr, "do_match: return 6.\n");
#endif
                              return retval;
                         }
                         (*num_found)++;
                    }
               }
               else if (match_undeleted) {
                    retval = add_str(found, *num_found, &found_size, base);
                    if (retval) {
                         error("add_str");
                         (void) popall();
#ifdef PATTERN_DEBUG
                         fprintf(stderr, "do_match: return 7.\n");
#endif
                         return retval;
                    }
                    (*num_found)++;
               }
               string_pop(base);
               string_pop(rest);
               string_pop(first);
#ifdef PATTERN_DEBUG
               fprintf(stderr, "do_match: popped %s, %s, %s\n", first,
                       rest, base);
#endif
               (void) pop(&dirp, sizeof(DIR *));
               continue;
          }

          /*
           * The logic here in this attempt to descend is as follows:
           *
           * Try to stat base.  Succeeds?
           * Yes:
           *   Is it a directory?
           *   Yes:
           *     Try to open it.
           *     Does the open succeed?
           *     Yes:
           *       Continue the loop.
           *     No:
           *       Print an error, and pop up to the last directory.
           *   No:
           *     Pop up to the last directory.
           * No:
           *   Try to lstat base.  Succeeds?
           *   Yes:
           *     Is it a directory?
           *     Yes: see above.  *** this should never happen ***
           *     No:
           *       Pop up to the last directory.
           *   No:
           *     Print an error, and pop up to the last directory.
           *
           * The reason for the lstat is that we don't want to print
           * errors when we can't descend because we're trying to go
           * into a symlink pointing nowhere; a symlink pointing
           * nowhere is not an error when matching, it just means that
           * we can't descend.
           */
          dirp = NULL;
          if (((! (retval = stat(base, &statbuf))) ||
               (! (retval = lstat(base, &statbuf)))) &&
              ((statbuf.st_mode & S_IFMT) == S_IFDIR))
               dirp = Opendir(base);
          if (! dirp) {
               if (retval || ((statbuf.st_mode & S_IFMT) == S_IFDIR)) {
                    set_error(errno);
                    error(base);
               }
               string_pop(base);
               string_pop(rest);
               string_pop(first);
#ifdef PATTERN_DEBUG
               fprintf(stderr, "do_match: popped %s, %s, %s\n", first,
                       rest, base);
#endif
               (void) pop(&dirp, sizeof(DIR *));
               continue;
          }
          else 
               continue;

     updir:
#ifdef PATTERN_DEBUG
          fprintf(stderr, "do_match: updir\n");
#endif
          closedir(dirp);
          string_pop(base);
#ifdef PATTERN_DEBUG
          fprintf(stderr, "do_match: popped %s\n", base);
#endif
          if (retval) {
               if (retval != STACK_EMPTY) {
                    error("pop");
                    (void) popall();
#ifdef PATTERN_DEBUG
                    fprintf(stderr, "do_match: return 8.\n");
#endif
                    return retval;
               }
#ifdef PATTERN_DEBUG
               fprintf(stderr, "Returning %d word%s from do_match:\n",
                       *num_found,
                       *num_found == 1 ? "" : "s");
               for (j = 0; j < *num_found; j++)
                    fprintf(stderr, "\t%s\n", (*found)[j]);
               fprintf(stderr, "do_match: return 9.\n");
#endif
               return 0;
          }
          string_pop(rest);
          string_pop(first);
#ifdef PATTERN_DEBUG
          fprintf(stderr, "do_match: popped %s, %s\n", rest, first);
#endif
          retval = pop(&dirp, sizeof(DIR *));
          if (retval) {
               error("pop");
               (void) popall();
#ifdef PATTERN_DEBUG
               fprintf(stderr, "do_match: return 10.\n");
#endif
               return retval;
          }
          continue;
     }
}






/*
 * Function: do_recurs(char *name, int *num_found, char ***found,
 *                     int options)
 *
 * Requires: name points to a NULL-terminated string, representing a
 *   filename; points to a valid int memory storage location; found
 *   points to a valid char ** memory storage location.
 *
 * Effects: Returns a list of all the files in the file hierarchy that
 *   are underneath the specified file, governed by the options set in
 *   options.  Options are as described in the find_matches() description.
 *   RECURS_FIND_DELETED and RECURS_DELETED imply FIND_DELETED.
 *   RECURS_FIND_UNDELETED implies FIND_UNDELETED.
 *
 * Modifies: *num_found, *found.
 *
 * Algorithm:
 *
 * start:
 *   initialze found and num_found
 *   strcopy(base, name)
 *   check if we just opened a deleted symlink and return if we did
 *   dirp = Opendir(base)
 *   check RECURS options and set FIND options as appropriate
 * 
 * loop:
 *   dp = readdir(dirp)
 *   if (! dp) goto updir
 *   is dp deleted?
 *     yes - is FIND_DELETED set?
 *             yes - add to list
 *                   is RECURS_DELETED set?
 *                     yes - goto downdir
 *                     no - goto loop
 *             no - goto loop
 *     no - is FIND_UNDELETED set?
 *            yes - is the file a dotfile?
 *                    yes - is FIND_DOTFILES set?
 *                            yes - add to list
 *                          goto loop
 *                    no - add to list
 *                  are RECURS_FIND_DELETED and FIND_DELETED set?
 *                    yes - goto downdir
 *                  is RECURS_FIND_UNDELETED set?
 *                    yes - goto downdir
 *                    no - goto loop
 *            no - goto loop
 *             
 * downdir:
 *   save dirp, base on stack
 *   base = dp->d_name appended to base
 *   try to open base -- opens?
 *     yes - is FOLLW_LINKS set?
 *             yes - is it deleted?
 *                   yes - is it a link?
 *                         yes - close the directory
 *                               restore base and dirp
 *                               goto loop
 *             no - is it a link?
 *                     yes - close the directory
 *                           restore base and dirp
 *                           goto loop
 *           is FOLLW_MOUNTPOINTS set?
 *             no - is it a mountpoint?
 *                     yes - close the directory
 *                           restore base and dirp
 *                           goto loop
 *     no - is the error ENOTDIR?
 *            yes - don't worry about it
 *            no - report the error
 *          restore base and dirp
 *          goto loop
 * 
 * updir:
 *   close dirp
 *   restore base from stack
 *   STACK_EMPTY?
 *     yes - return from procedure with results
 *   restore dirp from stack
 *   goto loop
 */
int do_recurs(name, num_found, found, options)
char *name;
int *num_found;
char ***found;
int options;
{
     char base[MAXPATHLEN];
     struct dirent *dp;
     DIR *dirp;
     int retval;
     int strsize;
     struct stat statbuf;
     int use_stat;
     int found_size = 0;

#ifdef DEBUG
     fprintf(stderr, "do_recurs: opening %s\n", name);
#endif

     /* start: */
     
     *found = (char **) Malloc(0);
     *num_found = 0;
     strcpy(base, name);

     if (lstat(base, &statbuf)) {
          set_error(errno);
          error(base);
          return error_code;
     }
         
#ifdef S_IFLNK
     if (is_link(base, &statbuf)) {
          /* Never follow deleted symlinks */
          if (is_deleted(lastpart(base))) {
               return 0;
          }
          if (stat(base, &statbuf)) {
               if (errno == ENOENT) {
                    extern int readlink();
                    char pathbuf[MAXPATHLEN];
                    int cc;
                    
                    /* What the link is pointing to does not exist; */
                    /* this is a warning, not an error.             */
                    set_warning(errno);
                    cc = readlink(base, pathbuf, MAXPATHLEN);
                    if (cc > 0) {
                         char error_buf[2*MAXPATHLEN+20];

                         pathbuf[(cc == MAXPATHLEN) ? (cc - 1) : cc] = '\0';
                         sprintf(error_buf, "%s (pointed to by %s)", pathbuf,
                                 base);
                         error(error_buf);
                    }
                    else {
                         error(base);
                    }

                    return 0;
               }
               else {
                    set_error(errno);
                    error(base);
                    return error_code;
               }
          }
     }
#endif

     if ((statbuf.st_mode & S_IFMT) != S_IFDIR)
          return 0;
     
     dirp = Opendir(base);
     if (! dirp) {
#ifdef DEBUG
          fprintf(stderr, "Couldn't open %s.\n", base);
#endif
          set_error(errno);
          error(base);
          return error_code;
     }

     if (options & (RECURS_FIND_DELETED | RECURS_DELETED))
          options |= FIND_DELETED;
     if (options & RECURS_FIND_UNDELETED)
          options |= FIND_UNDELETED;
     
     while (1) {
          dp = readdir(dirp);
          if (! dp) goto updir;

          if (is_deleted(dp->d_name)) {
               if (options & FIND_DELETED) {
                    retval = add_str(found, *num_found, &found_size,
                                     append(base, dp->d_name));
                    if (retval) {
                         error("add_str");
                         (void) popall();
                         return retval;
                    }
                    (*num_found)++;
                    if (options & RECURS_DELETED)
                         goto downdir;
                    else
                         continue;
               }
               else
                    continue;
          }

          if (options & FIND_UNDELETED) {
               if (is_dotfile(dp->d_name)) {
                    if (options & FIND_DOTFILES) {
                         retval = add_str(found, *num_found, &found_size,
                                          append(base, dp->d_name));
                         if (retval) {
                              error("add_str");
                              (void) popall();
                              return retval;
                         }
                    }
                    continue;
               }
               else {
                    retval = add_str(found, *num_found, &found_size,
                                     append(base, dp->d_name));
                    if (retval) {
                         error("add_str");
                         (void) popall();
                         return retval;
                    }
                    (*num_found)++;
               }
          }

          if (! is_dotfile(dp->d_name)) {
               if (options & RECURS_FIND_DELETED)
                    goto downdir;
               if (options & RECURS_FIND_UNDELETED)
                    goto downdir;
          }
          
          continue;
          
               
     downdir:
          retval = push(&dirp, sizeof(DIR *));
          if (retval) {
               error("push");
               (void) popall();
               return retval;
          }
          string_push(base);
          (void) strcpy(base, append(base, dp->d_name));

          /*
           * Originally, I did an Opendir() right at the start and
           * then only checked things if the Opendir resulted in an
           * error.  However, this is inefficient, because the
           * Opendir() procedure works by first calling open() on the
           * file, and *then* calling fstat on the file descriptor
           * that is returned.  since most of the time we will be
           * trying to open things that are not directory, it is much
           * more effecient to do the stat first here and to do the
           * Opendir only if the stat results are satisfactory.
           */
          use_stat = (options & FOLLW_LINKS) && (! is_deleted(lastpart(base)));
          if (use_stat)
               retval = stat(base, &statbuf);
          else
               retval = lstat(base, &statbuf);
          if (retval == -1) {
               set_error(errno);
               error(base);
               string_pop(base);
               (void) pop(&dirp, sizeof(DIR *));
               continue;
          }
          /* It's not a directory, so punt it and continue. */
          if ((statbuf.st_mode & S_IFMT) != S_IFDIR) {
               string_pop(base);
               (void) pop(&dirp, sizeof(DIR *));
               continue;
          }

          /* Actually try to open it. */
          dirp = Opendir(base);
          if (! dirp) {
               set_error(errno);
               error(base);
               string_pop(base);
               (void) pop(&dirp, sizeof(DIR *));
               continue;
          }
          
          if (! (options & FOLLW_MOUNTPOINTS)) {
               if (is_mountpoint(base, use_stat ? (struct stat *) NULL :
                                 &statbuf)) {
                    closedir(dirp);
                    set_warning(PAT_IS_MOUNT);
                    error(base);
                    string_pop(base);
                    (void) pop(&dirp, sizeof(DIR *));
                    continue;
               }
#ifdef DEBUG
               else {
                    fprintf(stderr,
                            "do_recurs: %s isn't a mountpoint, following.\n",
                            base);
               }
#endif
          }
#ifdef DEBUG
          printf("do_recurs: opening %s\n", base);
#endif
          continue;
          
     updir:
          closedir(dirp);
          string_pop(base);
          if (retval) {
               if (retval != STACK_EMPTY) {
                    error("pop");
                    (void) popall();
                    return retval;
               }
               return 0;
          }
          retval = pop(&dirp, sizeof(DIR *));
          if (retval) {
               error("pop");
               (void) popall();
               return retval;
          }
          continue;
     }
}


void free_list(list, num)
char **list;
int num;
{
     int i;

     for (i = 0; i < num; i++)
          free(list[i]);

     free((char *) list);
}






/*
 * returns true if the filename has no globbing wildcards in it.  That
 * means no non-quoted question marks, asterisks, or open square
 * braces.  Assumes a null-terminated string, and a valid globbing
 */
int no_wildcards(name)
char *name;
{
     do {
          switch (*name) {
          case '\\':
               name++;
               break;
          case '?':
               return(0);
          case '*':
               return(0);
          case '[':
               return(0);
          }
     } while (*++name);
     return(1);
}