source: trunk/athena/lib/athdir/src/athdir.c @ 25907

/* Copyright 1998 by the Massachusetts Institute of Technology.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.
 *
 * * Neither the name of the M.I.T nor the names of its contributors
 *   may be used to endorse or promote products derived from this
 *   software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* This file implements the main athdir library calls. */

static const char rcsid[] = "$Id: athdir.c,v 1.6 1999-10-23 19:28:46 danw Exp $";

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>          /* MAXPATHLEN */
#include <sys/types.h>
#include <sys/stat.h>
#include "athdir.h"
#include "stringlist.h"
#include "config.h"

/* HOSTTYPE should always be defined when we get here, because
   configure is responsible for getting it to us. Nonetheless, this
   codepath is beign left in for legacy reasons, like the rest of this
   entire file... */
#ifdef HOSTTYPE
char *hosttype = HOSTTYPE;
#else
char *hosttype = NULL;
#endif

/* Definition of known conventions and what flavors they are.  */

typedef struct {
  char *name;
  int flavor;
} Convention;

#define ARCHflavor (1<<0)
#define MACHflavor (1<<1)
#define PLAINflavor (1<<2)
#define SYSflavor (1<<3)
#define DEPENDENTflavor (1<<8)
#define INDEPENDENTflavor (1<<9)
#define ATSYSflag (1<<16)

#define NUMCONVENTIONS 5

Convention conventions[NUMCONVENTIONS] = {
  { NULL,               ARCHflavor | MACHflavor | PLAINflavor |
                        DEPENDENTflavor | INDEPENDENTflavor },
  { "%p/arch/%s/%t",    ARCHflavor | DEPENDENTflavor | ATSYSflag },
  { "%p/%s/%t",         SYSflavor | DEPENDENTflavor | ATSYSflag },
  { "%p/%m%t",          MACHflavor | DEPENDENTflavor },
  { "%p/%t",            PLAINflavor | INDEPENDENTflavor }
};

/* Editorial tagging for what conventions are acceptable or
 * preferable for what types.
 */

typedef struct {
  char *type;
  int allowedFlavors;   /* searching parameters */
  int preferredFlavor;  /* creating paramaters */
} Editorial;

Editorial editorials[] = {
  { "bin",      ARCHflavor | SYSflavor | MACHflavor,    DEPENDENTflavor },
  { "lib",      ARCHflavor | SYSflavor | MACHflavor,    DEPENDENTflavor },
  { "etc",      ARCHflavor | SYSflavor | MACHflavor,    DEPENDENTflavor },
  { "man",      ARCHflavor | PLAINflavor,               INDEPENDENTflavor },
  { "include",  ARCHflavor | PLAINflavor,               INDEPENDENTflavor },
  { NULL,       ARCHflavor | PLAINflavor,               DEPENDENTflavor }
};

/* path = template(dir, type, sys, machine)
 *      %p = path (dir)
 *      %t = type
 *      %s = sys
 *      %m = machine
 * %foo is inserted if the corresponding string is NULL.
 * If this happens, expand returns 1 (not a valid path).
 * If expand runs out of memory, it returns -1 (and path is NULL).
 * Otherwise, expand returns 0.
 */
static int expand(char **path, char *template, char *dir,
           char *type, char *sys, char *machine)
{
  char *src, *dst, *oldpath;
  int somenull = 0, size;

  src = template;
  size = strlen(template) + 1;
  dst = oldpath = *path = malloc(size);
  *dst = '\0';

  while (*src != '\0')
    {
      if (*src != '%')
        *dst++ = *src++;
      else
        {

#define copystring(casec, cases, string)                        \
        case casec:                                             \
          src++;                                                \
          if (string)                                           \
            {                                                   \
              *path = realloc(*path, size += strlen(string));   \
              if (!*path)                                       \
                return -1;                                      \
              dst = *path + (dst - oldpath);                    \
              oldpath = *path;                                  \
              strcpy(dst, string);                              \
              dst += strlen(string);                            \
            }                                                   \
          else                                                  \
            {                                                   \
              strcpy(dst, cases);                               \
              dst += 2;                                         \
              somenull = 1;                                     \
            }                                                   \
          break;

          src++;
          switch(*src)
            {
              copystring('p', "%p", dir);
              copystring('t', "%t", type);
              copystring('s', "%s", sys);
              copystring('m', "%m", machine);

#undef copystring

            case '\0':
              break;

            default:
              *dst++ = '%';
              *dst++ = *src++;
              break;
            }
        }
    }

  *dst = '\0';
  return somenull;
}

static int template_flavor(char *template)
{
  int flavor = ARCHflavor | MACHflavor | PLAINflavor
    | DEPENDENTflavor | INDEPENDENTflavor;
  char *ptr;

  if (template == NULL)
    return 0;

  for (ptr = strchr(template, '%'); ptr != NULL; ptr = strchr(ptr + 1, '%'))
    {
      if (*(ptr+1) == 's')
        flavor |= ATSYSflag;
    }

  return flavor;
}

int athdir_native(char *what, char *sys)
{
  char *ptr;

  /* If sys is NULL, fall back to ATHENA_SYS if it's set, otherwise
   * use the compiled-in value.
   */
  if (sys == NULL)
    {
      sys = getenv("ATHENA_SYS");
      if (sys == NULL || strchr(sys, '/') != NULL)
        sys = ATHSYS;
    }

  for (ptr = strchr(what, sys[0]); ptr != NULL; ptr = strchr(ptr + 1, sys[0]))
    {
      if (!strncmp(ptr, sys, strlen(sys)))
        return 1;
    }

  return 0;
}

/* You are in a twisty little maze of interconnecting flags, all different.
 */
char **athdir_get_paths(char *base_path, char *type,
                        char *sys, char **syscompat, char *machine,
                        char *aux, int flags)
{
  char *path;
  string_list *path_list = NULL, *compat_list = NULL;
  int t, j, complete, preferredFlavor, want_break;
  struct stat statbuf;
  char **current_compat, **mysyscompat = NULL, *compat_env;

  /* If sys is NULL, fall back to ATHENA_SYS if it's set, otherwise
   * use the compiled-in value.
   */
  if (sys == NULL)
    {
      sys = getenv("ATHENA_SYS");
      if (sys == NULL || strchr(sys, '/') != NULL)
        sys = ATHSYS;
    }

  /* Generate the syscompat array from the environment if it wasn't
   * passed in.
   */
  if (syscompat == NULL)
    {
      /* We're compatible with ourselves. */
      if (athdir__add_string(&compat_list, sys, 0))
        return NULL;
      compat_env = getenv("ATHENA_SYS_COMPAT");
      if (compat_env != NULL && !strchr(compat_env, '/'))
        {
          if (athdir__parse_string(&compat_list, compat_env, ':'))
            return NULL;
        }
      syscompat = mysyscompat = athdir__make_string_array(&compat_list);
    }

  /* If machine is NULL, use whatever was compiled in. */
  if (machine == NULL)
    machine = hosttype;

  /* Zeroeth convention is optionally provided by the caller. */
  conventions[0].name = aux;
  conventions[0].flavor = template_flavor(aux);

  /* Find matching editorial for the type of directory requested
   * (to be consulted later).
   */
  for (t = 0; editorials[t].type != NULL; t++)
    {
      if (type != NULL && !strcmp(type, editorials[t].type))
        break;
    }

  if (flags & ATHDIR_MACHINEDEPENDENT)
    preferredFlavor = DEPENDENTflavor;
  else
    {
      if (flags & ATHDIR_MACHINEINDEPENDENT)
        preferredFlavor = INDEPENDENTflavor;
      else
        preferredFlavor = editorials[t].preferredFlavor;
    }

  /* Cycle through matching conventions */
  for (j = 0; j < NUMCONVENTIONS; j++)
    {
      if (conventions[j].name == NULL)
        continue; /* conventions[0], the caller specified convention,
                   * is not set. */
      want_break = 0;

      if (
          /* If the editorial says this is a reasonable convention
           * for this type
           */
          (editorials[t].allowedFlavors & conventions[j].flavor) ||

          /* or we don't care what the editorials say */
          (flags & ATHDIR_SUPPRESSEDITORIALS) || 

          /* or something more explicit than the editorials has been
           * specified
           */
          (((ATHDIR_MACHINEDEPENDENT | ATHDIR_MACHINEINDEPENDENT) & flags) &&
           (flags & ATHDIR_SUPPRESSSEARCH)))
        {
          /* If we're looking for a specific flavor (machine dependent/
           * machine independent) and this isn't it, keep going.
           */
          if ((ATHDIR_SUPPRESSSEARCH & flags) &&
              !(preferredFlavor & conventions[j].flavor))
            continue;

          for (current_compat = syscompat; *current_compat != NULL;
               current_compat++)
            {
              complete = !expand(&path, conventions[j].name,
                                 base_path, type, *current_compat, hosttype);

              if (!path)
                return NULL;

              /* If we're listing everything, or we only care about the
               * first match for creation purposes (both cases where we
               * don't want to stat()), store this match.
               */
              if ((flags & ATHDIR_LISTSEARCHDIRECTORIES) ||
                  ((flags & ATHDIR_SUPPRESSSEARCH) && complete))
                {
                  if (athdir__add_string(&path_list, path, 0))
                    {
                      free(path);
                      return NULL;
                    }
                  free(path);
                  
                  /* In this case (first match for creation) we're done. */
                  if (flags & ATHDIR_SUPPRESSSEARCH)
                    {
                      want_break = 1;
                      break;
                    }
                }
              else /* If it's there, store it and be done. */
                if (complete && !stat(path, &statbuf))
                  {
                    if (athdir__add_string(&path_list, path, 0))
                      {
                        free(path);
                        return NULL;
                      }
                    free(path);
                    want_break = 1;
                    break;
                  }
              else
                free(path);

              /* Don't loop over @sys values unless ATSYSflag. */
              if (!(conventions[j].flavor & ATSYSflag))
                break;
            }
        }

      if (want_break)
        break;
    }

  athdir__free_string_array(mysyscompat);
  return athdir__make_string_array(&path_list);
}

void athdir_free_paths(char **paths)
{
  athdir__free_string_array(paths);
}