bdb.c

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#include "config.h"
#include <db.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <sys/stat.h>
#include <unistd.h>
#include "mutt/lib.h"
#include "lib.h"
 
struct BdbStoreData
{
  DB_ENV *env;
  DB *db;
  int fd;
  struct Buffer lockfile;
};
 
static void bdb_sdata_free(struct BdbStoreData **ptr)
{
  if (!ptr || !*ptr)
    return;
 
  struct BdbStoreData *sdata = *ptr;
  buf_dealloc(&sdata->lockfile);
 
  FREE(ptr);
}
 
static struct BdbStoreData *bdb_sdata_new(void)
{
  struct BdbStoreData *sdata = MUTT_MEM_CALLOC(1, struct BdbStoreData);
 
  buf_alloc(&sdata->lockfile, 128);
 
  return sdata;
}
 
static void dbt_init(DBT *dbt, void *data, size_t len)
{
  dbt->data = data;
  dbt->size = len;
  dbt->ulen = len;
  dbt->dlen = 0;
  dbt->doff = 0;
  dbt->flags = DB_DBT_USERMEM;
}
 
static void dbt_empty_init(DBT *dbt)
{
  dbt->data = NULL;
  dbt->size = 0;
  dbt->ulen = 0;
  dbt->dlen = 0;
  dbt->doff = 0;
  dbt->flags = 0;
}
 
static StoreHandle *store_bdb_open(const char *path, bool create)
{
  if (!path)
    return NULL;
 
  struct BdbStoreData *sdata = bdb_sdata_new();
 
  const int pagesize = 512;
 
  buf_printf(&sdata->lockfile, "%s-lock-hack", path);
 
  sdata->fd = open(buf_string(&sdata->lockfile),
                   O_WRONLY | (create ? O_CREAT : 0), S_IRUSR | S_IWUSR);
  if (sdata->fd < 0)
  {
    bdb_sdata_free(&sdata);
    return NULL;
  }
 
  if (mutt_file_lock(sdata->fd, true, true))
    goto fail_close;
 
  int rc = db_env_create(&sdata->env, 0);
  if (rc)
    goto fail_unlock;
 
  rc = (*sdata->env->open)(sdata->env, NULL, DB_INIT_MPOOL | DB_CREATE | DB_PRIVATE, 0600);
  if (rc)
    goto fail_env;
 
  sdata->db = NULL;
  rc = db_create(&sdata->db, sdata->env, 0);
  if (rc)
    goto fail_env;
 
  uint32_t createflags = DB_CREATE;
  struct stat st = { 0 };
 
  if ((stat(path, &st) != 0) && (errno == ENOENT))
  {
    createflags |= DB_EXCL;
    sdata->db->set_pagesize(sdata->db, pagesize);
  }
 
  rc = (*sdata->db->open)(sdata->db, NULL, path, NULL, DB_BTREE, createflags, 0600);
  if (rc)
    goto fail_db;
 
  // Return an opaque pointer
  return (StoreHandle *) sdata;
 
fail_db:
  sdata->db->close(sdata->db, 0);
fail_env:
  sdata->env->close(sdata->env, 0);
fail_unlock:
  mutt_file_unlock(sdata->fd);
fail_close:
  close(sdata->fd);
  unlink(buf_string(&sdata->lockfile));
  bdb_sdata_free(&sdata);
 
  return NULL;
}
 
static void *store_bdb_fetch(StoreHandle *store, const char *key, size_t klen, size_t *vlen)
{
  if (!store)
    return NULL;
 
  // Decloak an opaque pointer
  struct BdbStoreData *sdata = store;
 
  DBT dkey = { 0 };
  DBT data = { 0 };
 
  dbt_init(&dkey, (void *) key, klen);
  dbt_empty_init(&data);
  data.flags = DB_DBT_MALLOC;
 
  sdata->db->get(sdata->db, NULL, &dkey, &data, 0);
 
  *vlen = data.size;
  return data.data;
}
 
static void store_bdb_free(StoreHandle *store, void **ptr)
{
  FREE(ptr);
}
 
static int store_bdb_store(StoreHandle *store, const char *key, size_t klen,
                           void *value, size_t vlen)
{
  if (!store)
    return -1;
 
  // Decloak an opaque pointer
  struct BdbStoreData *sdata = store;
 
  DBT dkey = { 0 };
  DBT databuf = { 0 };
 
  dbt_init(&dkey, (void *) key, klen);
  dbt_empty_init(&databuf);
  databuf.flags = DB_DBT_USERMEM;
  databuf.data = value;
  databuf.size = vlen;
  databuf.ulen = vlen;
 
  return sdata->db->put(sdata->db, NULL, &dkey, &databuf, 0);
}
 
static int store_bdb_delete_record(StoreHandle *store, const char *key, size_t klen)
{
  if (!store)
    return -1;
 
  // Decloak an opaque pointer
  struct BdbStoreData *sdata = store;
 
  DBT dkey = { 0 };
  dbt_init(&dkey, (void *) key, klen);
  return sdata->db->del(sdata->db, NULL, &dkey, 0);
}
 
static void store_bdb_close(StoreHandle **ptr)
{
  if (!ptr || !*ptr)
    return;
 
  // Decloak an opaque pointer
  struct BdbStoreData *sdata = *ptr;
 
  sdata->db->close(sdata->db, 0);
  sdata->env->close(sdata->env, 0);
  mutt_file_unlock(sdata->fd);
  close(sdata->fd);
  unlink(buf_string(&sdata->lockfile));
 
  bdb_sdata_free((struct BdbStoreData **) ptr);
}
 
static const char *store_bdb_version(void)
{
  return DB_VERSION_STRING;
}
 
STORE_BACKEND_OPS(bdb)