mca_base_component_find.c

MPI stands for the Message Passing Interface. Written by the MPI Forum (a large committee comprising

/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
 *                         University Research and Technology
 *                         Corporation.  All rights reserved.
 * Copyright (c) 2004-2005 The University of Tennessee and The University
 *                         of Tennessee Research Foundation.  All rights
 *                         reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */

#include "opal_config.h"

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

#if OMPI_WANT_LIBLTDL
#include "opal/libltdl/ltdl.h"
#endif

#include "opal/util/output.h"
#include "opal/class/opal_list.h"
#include "opal/mca/mca.h"
#include "opal/mca/base/base.h"
#include "opal/mca/base/mca_base_component_repository.h"
#include "opal/constants.h"


/*
 * Private types
 */
typedef enum component_status {
  UNVISITED,
  FAILED_TO_LOAD,
  CHECKING_CYCLE,
  LOADED,

  STATUS_MAX
} component_status_t;

struct component_file_item_t {
  opal_list_item_t super;

  char type[MCA_BASE_MAX_TYPE_NAME_LEN];
  char name[MCA_BASE_MAX_COMPONENT_NAME_LEN];
  char basename[OMPI_PATH_MAX];
  char filename[OMPI_PATH_MAX];
  component_status_t status;
};
typedef struct component_file_item_t component_file_item_t;

static OBJ_CLASS_INSTANCE(component_file_item_t, opal_list_item_t, NULL, NULL);

struct dependency_item_t {
  opal_list_item_t super;

  component_file_item_t *di_component_file_item;
};
typedef struct dependency_item_t dependency_item_t;

static OBJ_CLASS_INSTANCE(dependency_item_t, opal_list_item_t, NULL, NULL);

struct ltfn_data_holder_t {
  char type[MCA_BASE_MAX_TYPE_NAME_LEN];
  char name[MCA_BASE_MAX_COMPONENT_NAME_LEN];
};
typedef struct ltfn_data_holder_t ltfn_data_holder_t;


#if OMPI_WANT_LIBLTDL
/*
 * Private functions
 */
static void find_dyn_components(const char *path, const char *type, 
                             const char *name, opal_list_t *found_components);
static int save_filename(const char *filename, lt_ptr data);
static int open_component(component_file_item_t *target_file, 
                       opal_list_t *found_components);
static int check_ompi_info(component_file_item_t *target_file, 
                         opal_list_t *dependencies,
                         opal_list_t *found_components);
static int check_dependency(char *line, component_file_item_t *target_file, 
                            opal_list_t *dependencies, 
                            opal_list_t *found_components);
static void free_dependency_list(opal_list_t *dependencies);


/*
 * Private variables
 */
static const char *ompi_info_suffix = ".ompi_info";
static const char *key_dependency = "dependency=";
static const char component_template[] = "mca_%s_";
static opal_list_t found_files;
#endif /* OMPI_WANT_LIBLTDL */

/*
 * Function to find as many components of a given type as possible.  This
 * includes statically-linked in components as well as opening up a
 * directory and looking for shared-library MCA components of the
 * appropriate type (load them if available).
 *
 * Return one consolidated array of (mca_base_component_t*) pointing to all
 * available components.
 */
int mca_base_component_find(const char *directory, const char *type, 
                         const mca_base_component_t *static_components[], 
                            opal_list_t *found_components,
                            bool open_dso_components)
{
  int i;
  mca_base_component_list_item_t *cli;

  /* Find all the components that were statically linked in */

  OBJ_CONSTRUCT(found_components, opal_list_t);
  for (i = 0; NULL != static_components[i]; ++i) {
    cli = OBJ_NEW(mca_base_component_list_item_t);
    if (NULL == cli) {
      return OPAL_ERR_OUT_OF_RESOURCE;
    }
    cli->cli_component = static_components[i];
    opal_list_append(found_components, (opal_list_item_t *) cli);
  }

#if OMPI_WANT_LIBLTDL
  /* Find any available dynamic components in the specified directory */
  if (open_dso_components) {
      int param, param_disable_dlopen;
      param = mca_base_param_find("mca", NULL, "component_disable_dlopen");
      mca_base_param_lookup_int(param, &param_disable_dlopen);

      if (0 == param_disable_dlopen) {
          find_dyn_components(directory, type, NULL, found_components);
      }
  } else {
    opal_output_verbose(40, 0, 
                        "mca: base: component_find: dso loading for %s MCA components disabled", 
                        type);
  }
#endif

  /* All done */

  return OPAL_SUCCESS;
}

#if OMPI_WANT_LIBLTDL

/*
 * Open up all directories in a given path and search for components of
 * the specified type (and possibly of a given name).
 *
 * Note that we use our own path iteration functionality (vs. ltdl's
 * lt_dladdsearchdir() functionality) because we need to look at
 * companion .ompi_info files in the same directory as the library to
 * generate dependencies, etc.  If we use the plain lt_dlopen()
 * functionality, we would not get the directory name of the file
 * finally opened in recursive dependency traversals.
 */
static void find_dyn_components(const char *path, const char *type_name, 
                                const char *name,
                                opal_list_t *found_components)
{
  ltfn_data_holder_t params;
  char *path_to_use, *dir, *end, *param;
  component_file_item_t *file;
  opal_list_item_t *cur;

  strcpy(params.type, type_name);

  if (NULL == name) {
    params.name[0] = '\0';
    opal_output_verbose(40, 0, "mca: base: component_find: looking for all dynamic %s MCA components", 
                       type_name, NULL);
  } else {
    strcpy(params.name, name);
    opal_output_verbose(40, 0,
                       "mca: base: component_find: looking for dynamic %s MCA component named \"%s\"",
                       type_name, name, NULL);
  }

  /* If path is NULL, iterate over the set of directories specified by
     the MCA param mca_base_component_path.  If path is not NULL, then
     use that as the path. */

  param = NULL;
  if (NULL == path) {
    mca_base_param_lookup_string(mca_base_param_component_path, &param);
    if (NULL == param) {
      /* If there's no path, then there's nothing to search -- we're
         done */
      return;
    } else {
      path_to_use = strdup(param);
    }
  } else {
    path_to_use = strdup(path);
  }

  /* Iterate over all the files in the directories in the path and
     make a master array of all the matching filenames that we
     find. */

  OBJ_CONSTRUCT(&found_files, opal_list_t);
  dir = path_to_use;
  if (NULL != dir) {
    do {
      end = strchr(dir, OPAL_ENV_SEP);
      if (NULL != end) {
        *end = '\0';
      }
      if (0 != lt_dlforeachfile(dir, save_filename, &params)) {
        break;
      }
      dir = end + 1;
    } while (NULL != end);
  }

  /* Iterate through all the filenames that we found.  Since one
     component may [try to] call another to be loaded, only try to load
     the UNVISITED files.  Also, ignore the return code -- basically,
     give every file one chance to try to load.  If they load, great.
     If not, great. */

  for (cur = opal_list_get_first(&found_files); 
       opal_list_get_end(&found_files) != cur;
       cur = opal_list_get_next(cur)) {
    file = (component_file_item_t *) cur;
    if (UNVISITED == file->status) {
      open_component(file, found_components);
    }
  }

  /* So now we have a final list of loaded components.  We can free all
     the file information. */
  
  for (cur = opal_list_remove_first(&found_files); 
       NULL != cur;
       cur = opal_list_remove_first(&found_files)) {
    OBJ_RELEASE(cur);
  }

  /* All done */

  if (NULL != param) {
    free(param);
  }
  if (NULL != path_to_use) {
    free(path_to_use);
  }
  OBJ_DESTRUCT(&found_files);
}


/*
 * Given a filename, see if it appears to be of the proper filename
 * format.  If so, save it in the array so that we can process it
 * later.
 */
static int save_filename(const char *filename, lt_ptr data)
{
  size_t len, prefix_len, total_len;
  char *prefix;
  const char *basename;
  component_file_item_t *component_file;
  ltfn_data_holder_t *params = (ltfn_data_holder_t *) data;

  /* Check to see if the file is named what we expect it to be
     named */

  len = sizeof(component_template) + strlen(params->type) + 32;
  if (NULL != params->name) {
    len += strlen(params->name);
  }
  prefix = (char*)malloc(len);
  snprintf(prefix, len, component_template, params->type);
  prefix_len = strlen(prefix);
  if (NULL != params->name) {
    strcat(prefix, params->name);
  }
  total_len = strlen(prefix);

  basename = strrchr(filename, '/');
  if (NULL == basename) {
    basename = filename;
  } else {
    basename += 1;
  }

  if (0 != strncmp(basename, prefix, total_len)) {
    free(prefix);
    return 0;
  }

  /* Save all the info and put it in the list of found components */

  component_file = OBJ_NEW(component_file_item_t);
  if (NULL == component_file) {
    return OPAL_ERR_OUT_OF_RESOURCE;
  }
  strcpy(component_file->type, params->type);
  strcpy(component_file->name, basename + prefix_len);
  strcpy(component_file->basename, basename);
  strcpy(component_file->filename, filename);
  component_file->status = UNVISITED;
  opal_list_append(&found_files, (opal_list_item_t *) component_file);

  /* All done */

  free(prefix);
  return 0;
}


/*
 * Open a component, chasing down its dependencies first, if possible.
 */
static int open_component(component_file_item_t *target_file, 
                       opal_list_t *found_components)
{
  int show_errors, param;
  lt_dlhandle component_handle;
  mca_base_component_t *component_struct;
  char *struct_name, *err;
  opal_list_t dependencies;
  opal_list_item_t *cur;
  mca_base_component_list_item_t *mitem;
  dependency_item_t *ditem;
  size_t len;

  opal_output_verbose(40, 0, "mca: base: component_find: examining dyanmic %s MCA component \"%s\"",
                     target_file->type, target_file->name, NULL);
  opal_output_verbose(40, 0, "mca: base: component_find: %s", target_file->filename, NULL);
  param = mca_base_param_find("mca", NULL, "component_show_load_errors");
  mca_base_param_lookup_int(param, &show_errors);

  /* Was this component already loaded (e.g., via dependency)? */

  if (LOADED == target_file->status) {
    opal_output_verbose(40, 0, "mca: base: component_find: already loaded (ignored)", NULL);
    return OPAL_SUCCESS;
  }

  /* Ensure that this component is not already loaded (should only happen
     if it was statically loaded).  It's an error if it's already
     loaded because we're evaluating this file -- not this component.