backend/filedescriptor.h File Reference

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Detailed Description

Filedescriptors.

Filedescriptors are the underlying working horse in accessing files. All information associated with managing a file is kept here.

Definition in file filedescriptor.h.

#include "lib/mutex.h"
#include "lib/psplay.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "backend/filehandle.h"
#include "backend/file.h"

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Classes
struct	lumiera_filedescriptor_struct
Typedefs
typedef struct lumiera_filedescriptor_struct	lumiera_filedescriptor
typedef lumiera_filedescriptor *	LumieraFiledescriptor
Functions
LumieraFiledescriptor	lumiera_filedescriptor_acquire (const char *name, int flags)
	Find existing filedescriptor or create one.
void	lumiera_filedescriptor_delete (LumieraFiledescriptor self)
	Delete a filedescriptor Called whenever its reference count drops to zero.
LumieraFiledescriptor	lumiera_filedescriptor_new (LumieraFiledescriptor template)
	Allocate a new filedescriptor cloned from a template.
void	lumiera_filedescriptor_registry_destroy (void)
	Destroy and free the global filedescriptor registry.
void	lumiera_filedescriptor_registry_init (void)
	Initialize the global filedescriptor registry.
void	lumiera_filedescriptor_release (LumieraFiledescriptor self)
	Release a filedescriptor.

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Function Documentation

void lumiera_filedescriptor_registry_init

(

void

)

Initialize the global filedescriptor registry.

All filedescriptors are looked up by dev/ino/open-flags in a hashtable. Opening hardlinked files will be targeted to the same filedescriptor. This function never fails but dies on error.

Definition at line 89 of file filedescriptor.c.

References LUMIERA_DIE.

{
  NOBUG_INIT_FLAG (filedescriptor);
  TRACE (filedescriptor);
  REQUIRE (!registry);

  registry = psplay_new (cmp_fn, key_fn, delete_fn);
  if (!registry)
    LUMIERA_DIE (NO_MEMORY);

  TODO ("LumieraMutex lumiera_mutex_init (LumieraMutex self, const char* purpose, struct nobug_flag* flag);");

  //  RESOURCE_HANDLE_INIT (registry_mutex.rh);
  RESOURCE_ANNOUNCE (filedescriptor, "mutex", "filedescriptor registry", &registry, registry_mutex.rh);
}

void lumiera_filedescriptor_registry_destroy

(

void

)

Destroy and free the global filedescriptor registry.

Never fails.

Definition at line 106 of file filedescriptor.c.

References psplay_nelements().

{
  TRACE (filedescriptor);
  REQUIRE (!psplay_nelements (registry));

  RESOURCE_FORGET (filedescriptor, registry_mutex.rh);

  TODO ("LumieraMutex lumiera_mutex_destroy (LumieraMutex self, struct nobug_flag* flag);");

  if (registry)
    psplay_destroy (registry);
  registry = NULL;
}

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LumieraFiledescriptor lumiera_filedescriptor_acquire	(	const char *	name,
		int	flags
	)

Find existing filedescriptor or create one.

Parameters:

	name	name of the file
	flags	opening flags for the filedescriptor

Returns:

descriptor on success or NULL on error

Definition at line 122 of file filedescriptor.c.

References LUMIERA_ERROR_SET, and LUMIERA_MUTEX_SECTION.

{
  TRACE (filedescriptor, "%s", name);
  REQUIRE (registry, "not initialized");

  LumieraFiledescriptor dest = NULL;

  LUMIERA_MUTEX_SECTION (filedescriptor, &registry_mutex)
    {
      lumiera_filedescriptor fdesc;
      fdesc.flags = flags;

      if (stat (name, &fdesc.stat) != 0)
        {
          if (errno == ENOENT && flags&O_CREAT)
            {
              char* dir = lumiera_tmpbuf_strndup (name, PATH_MAX);
              char* slash = dir;
              while ((slash = strchr (slash+1, '/')))
                {
                  *slash = '\0';
                  INFO (filedescriptor, "try creating dir: %s", dir);
                  if (mkdir (dir, 0777) == -1 && errno != EEXIST)
                    {
                      LUMIERA_ERROR_SET (filedescriptor, ERRNO);
                      goto error;
                    }
                  *slash = '/';
                }
              int fd;
              INFO (filedescriptor, "try creating file: %s", name);
              fd = creat (name, 0777);
              if (fd == -1)
                {
                  LUMIERA_ERROR_SET (filedescriptor, ERRNO);
                  goto error;
                }
              close (fd);
              if (stat (name, &fdesc.stat) != 0)
                {
                  /* finally, no luck */
                  LUMIERA_ERROR_SET (filedescriptor, ERRNO);
                  goto error;
                }
            }
        }

      /* lookup/create descriptor */
      dest = (LumieraFiledescriptor) psplay_find (registry, &fdesc, 100);

      if (!dest)
        {
          TRACE (filedescriptor, "Descriptor not found");

          dest = lumiera_filedescriptor_new (&fdesc);
          if (!dest)
            goto error;

          psplay_insert (registry, &dest->node, 100);
        }
      else
        {
          TRACE (filedescriptor, "Descriptor already existing");
          ++dest->refcount;
        }
    error: ;
    }

  return dest;
}

void lumiera_filedescriptor_release

(

LumieraFiledescriptor

self

)

Release a filedescriptor.

Parameters:

self

filedescriptor to be released

Definition at line 195 of file filedescriptor.c.

{
  TRACE (filedescriptor, "%p", self);
  if (!--self->refcount)
    lumiera_filedescriptor_delete (self);
}

LumieraFiledescriptor lumiera_filedescriptor_new

(

LumieraFiledescriptor

template

)

Allocate a new filedescriptor cloned from a template.

Parameters:

template

the source filedescriptor

Returns:

the constrccted filedescriptor

Definition at line 204 of file filedescriptor.c.

References lumiera_mutex_init().

{
  LumieraFiledescriptor self = lumiera_malloc (sizeof (lumiera_filedescriptor));
  TRACE (filedescriptor, "at %p", self);

  psplaynode_init (&self->node);
  self->stat = template->stat;

  self->flags = template->flags;
  self->refcount = 1;
  self->handle = 0;

  lumiera_mutex_init (&self->lock, "filedescriptor", &NOBUG_FLAG (filedescriptor));

  return self;
}

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void lumiera_filedescriptor_delete

(

LumieraFiledescriptor

self

)

Delete a filedescriptor Called whenever its reference count drops to zero.

Parameters:

self

the filedescriptor to be deleted

Definition at line 223 of file filedescriptor.c.

References lumiera_free(), lumiera_mutex_destroy(), and LUMIERA_MUTEX_SECTION.

{
  TRACE (filedescriptor, "%p", self);

  LUMIERA_MUTEX_SECTION (filedescriptor, &registry_mutex)
    {
      REQUIRE (self->refcount == 0);

      psplay_remove (registry, &self->node);

      TODO ("destruct other members (WIP)");


      TODO ("release filehandle");

      lumiera_mutex_destroy (&self->lock, &NOBUG_FLAG (filedescriptor));
      lumiera_free (self);
    }
}

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