external/ibm-public/postfix/dist/src/util/scan_dir.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      scan_dir 3
   6 /* SUMMARY
   7 /*      directory scanning
   8 /* SYNOPSIS
   9 /*      #include <scan_dir.h>
  10 /*
  11 /*      SCAN_DIR *scan_dir_open(path)
  12 /*      const char *path;
  13 /*
  14 /*      char    *scan_dir_next(scan)
  15 /*      SCAN_DIR *scan;
  16 /*
  17 /*      char    *scan_dir_path(scan)
  18 /*      SCAN_DIR *scan;
  19 /*
  20 /*      void    scan_push(scan, entry)
  21 /*      SCAN_DIR *scan;
  22 /*      const char *entry;
  23 /*
  24 /*      SCAN_DIR *scan_pop(scan)
  25 /*      SCAN_DIR *scan;
  26 /*
  27 /*      SCAN_DIR *scan_dir_close(scan)
  28 /*      SCAN_DIR *scan;
  29 /* DESCRIPTION
  30 /*      These functions scan directories for names. The "." and
  31 /*      ".." names are skipped. Essentially, this is <dirent>
  32 /*      extended with error handling and with knowledge of the
  33 /*      name of the directory being scanned.
  34 /*
  35 /*      scan_dir_open() opens the named directory and
  36 /*      returns a handle for subsequent use.
  37 /*
  38 /*      scan_dir_close() terminates the directory scan, cleans up
  39 /*      and returns a null pointer.
  40 /*
  41 /*      scan_dir_next() returns the next requested object in the specified
  42 /*      directory. It skips the "." and ".." entries.
  43 /*
  44 /*      scan_dir_path() returns the name of the directory being scanned.
  45 /*
  46 /*      scan_dir_push() causes the specified directory scan to enter the
  47 /*      named subdirectory.
  48 /*
  49 /*      scan_dir_pop() leaves the directory being scanned and returns
  50 /*      to the previous one. The result is the argument, null if no
  51 /*      previous directory information is available.
  52 /* DIAGNOSTICS
  53 /*      All errors are fatal.
  54 /* LICENSE
  55 /* .ad
  56 /* .fi
  57 /*      The Secure Mailer license must be distributed with this software.
  58 /* AUTHOR(S)
  59 /*      Wietse Venema
  60 /*      IBM T.J. Watson Research
  61 /*      P.O. Box 704
  62 /*      Yorktown Heights, NY 10598, USA
  63 /*--*/
  64
  65 /* System library. */
  66
  67 #include <sys_defs.h>
  68 #ifdef HAVE_DIRENT_H
  69 #include <dirent.h>
  70 #else
  71 #define dirent direct
  72 #ifdef HAVE_SYS_NDIR_H
  73 #include <sys/ndir.h>
  74 #endif
  75 #ifdef HAVE_SYS_DIR_H
  76 #include <sys/dir.h>
  77 #endif
  78 #ifdef HAVE_NDIR_H
  79 #include <ndir.h>
  80 #endif
  81 #endif
  82 #include <string.h>
  83
  84 /* Utility library. */
  85
  86 #include "msg.h"
  87 #include "mymalloc.h"
  88 #include "stringops.h"
  89 #include "vstring.h"
  90 #include "scan_dir.h"
  91
  92  /*
  93   * The interface is based on an opaque structure, so we don't have to expose
  94   * the user to the guts. Subdirectory info sits in front of parent directory
  95   * info: a simple last-in, first-out list.
  96   */
  97 typedef struct SCAN_INFO SCAN_INFO;
  98
  99 struct SCAN_INFO {
 100     char   *path;                       /* directory name */
 101     DIR    *dir;                        /* directory structure */
 102     SCAN_INFO *parent;                  /* linkage */
 103 };
 104 struct SCAN_DIR {
 105     SCAN_INFO *current;                 /* current scan */
 106 };
 107
 108 #define SCAN_DIR_PATH(scan)     (scan->current->path)
 109 #define STR(x)                  vstring_str(x)
 110
 111 /* scan_dir_path - return the path of the directory being read.  */
 112
 113 char   *scan_dir_path(SCAN_DIR *scan)
 114 {
 115     return (SCAN_DIR_PATH(scan));
 116 }
 117
 118 /* scan_dir_push - enter directory */
 119
 120 void    scan_dir_push(SCAN_DIR *scan, const char *path)
 121 {
 122     const char *myname = "scan_dir_push";
 123     SCAN_INFO *info;
 124
 125     info = (SCAN_INFO *) mymalloc(sizeof(*info));
 126     if (scan->current)
 127         info->path = concatenate(SCAN_DIR_PATH(scan), "/", path, (char *) 0);
 128     else
 129         info->path = mystrdup(path);
 130     if ((info->dir = opendir(info->path)) == 0)
 131         msg_fatal("%s: open directory %s: %m", myname, info->path);
 132     if (msg_verbose > 1)
 133         msg_info("%s: open %s", myname, info->path);
 134     info->parent = scan->current;
 135     scan->current = info;
 136 }
 137
 138 /* scan_dir_pop - leave directory */
 139
 140 SCAN_DIR *scan_dir_pop(SCAN_DIR *scan)
 141 {
 142     const char *myname = "scan_dir_pop";
 143     SCAN_INFO *info = scan->current;
 144     SCAN_INFO *parent;
 145
 146     if (info == 0)
 147         return (0);
 148     parent = info->parent;
 149     if (closedir(info->dir))
 150         msg_fatal("%s: close directory %s: %m", myname, info->path);
 151     if (msg_verbose > 1)
 152         msg_info("%s: close %s", myname, info->path);
 153     myfree(info->path);
 154     myfree((char *) info);
 155     scan->current = parent;
 156     return (parent ? scan : 0);
 157 }
 158
 159 /* scan_dir_open - start directory scan */
 160
 161 SCAN_DIR *scan_dir_open(const char *path)
 162 {
 163     SCAN_DIR *scan;
 164
 165     scan = (SCAN_DIR *) mymalloc(sizeof(*scan));
 166     scan->current = 0;
 167     scan_dir_push(scan, path);
 168     return (scan);
 169 }
 170
 171 /* scan_dir_next - find next entry */
 172
 173 char   *scan_dir_next(SCAN_DIR *scan)
 174 {
 175     const char *myname = "scan_dir_next";
 176     SCAN_INFO *info = scan->current;
 177     struct dirent *dp;
 178
 179 #define STREQ(x,y)      (strcmp((x),(y)) == 0)
 180
 181     if (info) {
 182         while ((dp = readdir(info->dir)) != 0) {
 183             if (STREQ(dp->d_name, ".") || STREQ(dp->d_name, "..")) {
 184                 if (msg_verbose > 1)
 185                     msg_info("%s: skip %s", myname, dp->d_name);
 186                 continue;
 187             } else {
 188                 if (msg_verbose > 1)
 189                     msg_info("%s: found %s", myname, dp->d_name);
 190                 return (dp->d_name);
 191             }
 192         }
 193     }
 194     return (0);
 195 }
 196
 197 /* scan_dir_close - terminate directory scan */
 198
 199 SCAN_DIR *scan_dir_close(SCAN_DIR *scan)
 200 {
 201     while (scan->current)
 202         scan_dir_pop(scan);
 203     myfree((char *) scan);
 204     return (0);
 205 }