/* Copyright (c) 1998-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
/* This file defines everything that client code should need to
know to talk to the nscd daemon. */
#ifndef _NSCD_CLIENT_H
#define _NSCD_CLIENT_H 1
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <time.h>
#include <sys/types.h>
#include <atomic.h>
#include <nscd-types.h>
#include <sys/uio.h>
/* Version number of the daemon interface */
#define NSCD_VERSION 2
/* Path of the file where the PID of the running system is stored. */
#define _PATH_NSCDPID "/var/run/nscd/nscd.pid"
/* Path for the Unix domain socket. */
#define _PATH_NSCDSOCKET "/var/run/nscd/socket"
/* Path for the configuration file. */
#define _PATH_NSCDCONF "/etc/nscd.conf"
/* Maximum allowed length for the key. */
#define MAXKEYLEN 1024
/* Available services. */
typedef enum
{
GETPWBYNAME,
GETPWBYUID,
GETGRBYNAME,
GETGRBYGID,
GETHOSTBYNAME,
GETHOSTBYNAMEv6,
GETHOSTBYADDR,
GETHOSTBYADDRv6,
SHUTDOWN, /* Shut the server down. */
GETSTAT, /* Get the server statistic. */
INVALIDATE, /* Invalidate one special cache. */
GETFDPW,
GETFDGR,
GETFDHST,
GETAI,
INITGROUPS,
GETSERVBYNAME,
GETSERVBYPORT,
GETFDSERV,
GETNETGRENT,
INNETGR,
GETFDNETGR,
LASTREQ
} request_type;
/* Header common to all requests */
typedef struct
{
int32_t version; /* Version number of the daemon interface. */
request_type type; /* Service requested. */
int32_t key_len; /* Key length. */
} request_header;
/* Structure sent in reply to password query. Note that this struct is
sent also if the service is disabled or there is no record found. */
typedef struct
{
int32_t version;
int32_t found;
nscd_ssize_t pw_name_len;
nscd_ssize_t pw_passwd_len;
uid_t pw_uid;
gid_t pw_gid;
nscd_ssize_t pw_gecos_len;
nscd_ssize_t pw_dir_len;
nscd_ssize_t pw_shell_len;
} pw_response_header;
/* Structure sent in reply to group query. Note that this struct is
sent also if the service is disabled or there is no record found. */
typedef struct
{
int32_t version;
int32_t found;
nscd_ssize_t gr_name_len;
nscd_ssize_t gr_passwd_len;
gid_t gr_gid;
nscd_ssize_t gr_mem_cnt;
} gr_response_header;
/* Structure sent in reply to host query. Note that this struct is
sent also if the service is disabled or there is no record found. */
typedef struct
{
int32_t version;
int32_t found;
nscd_ssize_t h_name_len;
nscd_ssize_t h_aliases_cnt;
int32_t h_addrtype;
int32_t h_length;
nscd_ssize_t h_addr_list_cnt;
int32_t error;
} hst_response_header;
/* Structure sent in reply to addrinfo query. Note that this struct is
sent also if the service is disabled or there is no record found. */
typedef struct
{
int32_t version;
int32_t found;
nscd_ssize_t naddrs;
nscd_ssize_t addrslen;
nscd_ssize_t canonlen;
int32_t error;
} ai_response_header;
/* Structure filled in by __nscd_getai. */
struct nscd_ai_result
{
int naddrs;
char *canon;
uint8_t *family;
char *addrs;
};
/* Structure sent in reply to initgroups query. Note that this struct is
sent also if the service is disabled or there is no record found. */
typedef struct
{
int32_t version;
int32_t found;
nscd_ssize_t ngrps;
} initgr_response_header;
/* Structure sent in reply to services query. Note that this struct is
sent also if the service is disabled or there is no record found. */
typedef struct
{
int32_t version;
int32_t found;
nscd_ssize_t s_name_len;
nscd_ssize_t s_proto_len;
nscd_ssize_t s_aliases_cnt;
int32_t s_port;
} serv_response_header;
/* Structure send in reply to netgroup query. Note that this struct is
sent also if the service is disabled or there is no record found. */
typedef struct
{
int32_t version;
int32_t found;
nscd_ssize_t nresults;
nscd_ssize_t result_len;
} netgroup_response_header;
typedef struct
{
int32_t version;
int32_t found;
int32_t result;
} innetgroup_response_header;
/* Type for offsets in data part of database. */
typedef uint32_t ref_t;
/* Value for invalid/no reference. */
#define ENDREF UINT32_MAX
/* Timestamp type. */
typedef uint64_t nscd_time_t;
/* Maximum timestamp. */
#define MAX_TIMEOUT_VALUE \
(sizeof (time_t) == sizeof (long int) ? LONG_MAX : INT_MAX)
/* Alignment requirement of the beginning of the data region. */
#define ALIGN 16
/* Head of record in data part of database. */
struct datahead
{
nscd_ssize_t allocsize; /* Allocated Bytes. */
nscd_ssize_t recsize; /* Size of the record. */
nscd_time_t timeout; /* Time when this entry becomes invalid. */
uint8_t notfound; /* Nonzero if data has not been found. */
uint8_t nreloads; /* Reloads without use. */
uint8_t usable; /* False if the entry must be ignored. */
uint8_t unused; /* Unused. */
uint32_t ttl; /* TTL value used. */
/* We need to have the following element aligned for the response
header data types and their use in the 'struct dataset' types
defined in the XXXcache.c files. */
union
{
pw_response_header pwdata;
gr_response_header grdata;
hst_response_header hstdata;
ai_response_header aidata;
initgr_response_header initgrdata;
serv_response_header servdata;
netgroup_response_header netgroupdata;
innetgroup_response_header innetgroupdata;
nscd_ssize_t align1;
nscd_time_t align2;
} data[0];
};
static inline time_t
datahead_init_common (struct datahead *head, nscd_ssize_t allocsize,
nscd_ssize_t recsize, uint32_t ttl)
{
/* Initialize so that we don't write out junk in uninitialized data to the
cache. */
memset (head, 0, sizeof (*head));
head->allocsize = allocsize;
head->recsize = recsize;
head->usable = true;
head->ttl = ttl;
/* Compute and return the timeout time. */
return head->timeout = time (NULL) + ttl;
}
static inline time_t
datahead_init_pos (struct datahead *head, nscd_ssize_t allocsize,
nscd_ssize_t recsize, uint8_t nreloads, uint32_t ttl)
{
time_t ret = datahead_init_common (head, allocsize, recsize, ttl);
head->notfound = false;
head->nreloads = nreloads;
return ret;
}
static inline time_t
datahead_init_neg (struct datahead *head, nscd_ssize_t allocsize,
nscd_ssize_t recsize, uint32_t ttl)
{
time_t ret = datahead_init_common (head, allocsize, recsize, ttl);
/* We don't need to touch nreloads here since it is set to our desired value
(0) when we clear the structure. */
head->notfound = true;
return ret;
}
/* Structure for one hash table entry. */
struct hashentry
{
request_type type:8; /* Which type of dataset. */
bool first; /* True if this was the original key. */
nscd_ssize_t len; /* Length of key. */
ref_t key; /* Pointer to key. */
int32_t owner; /* If secure table, this is the owner. */
ref_t next; /* Next entry in this hash bucket list. */
ref_t packet; /* Records for the result. */
union
{
struct hashentry *dellist; /* Next record to be deleted. This can be a
pointer since only nscd uses this field. */
ref_t *prevp; /* Pointer to field containing forward
reference. */
};
};
/* Current persistent database version. */
#define DB_VERSION 2
/* Maximum time allowed between updates of the timestamp. */
#define MAPPING_TIMEOUT (5 * 60)
/* Used indices for the EXTRA_DATA element of 'database_pers_head'.
Each database has its own indices. */
#define NSCD_HST_IDX_CONF_TIMESTAMP 0
/* Header of persistent database file. */
struct database_pers_head
{
int32_t version;
int32_t header_size;
volatile int32_t gc_cycle;
volatile int32_t nscd_certainly_running;
volatile nscd_time_t timestamp;
/* Room for extensions. */
volatile uint32_t extra_data[4];
nscd_ssize_t module;
nscd_ssize_t data_size;
nscd_ssize_t first_free; /* Offset of first free byte in data area. */
nscd_ssize_t nentries;
nscd_ssize_t maxnentries;
nscd_ssize_t maxnsearched;
uint64_t poshit;
uint64_t neghit;
uint64_t posmiss;
uint64_t negmiss;
uint64_t rdlockdelayed;
uint64_t wrlockdelayed;
uint64_t addfailed;
ref_t array[0];
};
/* Mapped database record. */
struct mapped_database
{
const struct database_pers_head *head;
const char *data;
size_t mapsize;
int counter; /* > 0 indicates it is usable. */
size_t datasize;
};
#define NO_MAPPING ((struct mapped_database *) -1l)
struct locked_map_ptr
{
int lock;
struct mapped_database *mapped;
};
#define libc_locked_map_ptr(class, name) class struct locked_map_ptr name
/* Try acquiring lock for mapptr, returns true if it succeeds, false
if not. */
static inline bool
__nscd_acquire_maplock (volatile struct locked_map_ptr *mapptr)
{
int cnt = 0;
while (__builtin_expect (atomic_compare_and_exchange_val_acq (&mapptr->lock,
1, 0) != 0, 0))
{
// XXX Best number of rounds?
if (__glibc_unlikely (++cnt > 5))
return false;
atomic_spin_nop ();
}
return true;
}
/* Open socket connection to nscd server. */
extern int __nscd_open_socket (const char *key, size_t keylen,
request_type type, void *response,
size_t responselen) attribute_hidden;
/* Try to get a file descriptor for the shared meory segment
containing the database. */
extern struct mapped_database *__nscd_get_mapping (request_type type,
const char *key,
struct mapped_database **mappedp) attribute_hidden;
/* Get reference of mapping. */
extern struct mapped_database *__nscd_get_map_ref (request_type type,
const char *name,
volatile struct locked_map_ptr *mapptr,
int *gc_cyclep)
attribute_hidden;
/* Unmap database. */
extern void __nscd_unmap (struct mapped_database *mapped)
attribute_hidden;
/* Drop reference of mapping. */
static int
__attribute__ ((unused))
__nscd_drop_map_ref (struct mapped_database *map, int *gc_cycle)
{
if (map != NO_MAPPING)
{
int now_cycle = map->head->gc_cycle;
if (__glibc_unlikely (now_cycle != *gc_cycle))
{
/* We might have read inconsistent data. */
*gc_cycle = now_cycle;
return -1;
}
if (atomic_decrement_val (&map->counter) == 0)
__nscd_unmap (map);
}
return 0;
}
/* Search the mapped database. */
extern struct datahead *__nscd_cache_search (request_type type,
const char *key,
size_t keylen,
const struct mapped_database *mapped,
size_t datalen)
attribute_hidden;
/* Wrappers around read, readv and write that only read/write less than LEN
bytes on error or EOF. */
extern ssize_t __readall (int fd, void *buf, size_t len)
attribute_hidden;
extern ssize_t __readvall (int fd, const struct iovec *iov, int iovcnt)
attribute_hidden;
extern ssize_t writeall (int fd, const void *buf, size_t len)
attribute_hidden;
/* Get netlink timestamp counter from mapped area or zero. */
extern uint32_t __nscd_get_nl_timestamp (void)
attribute_hidden;
#endif /* nscd.h */