diff options
Diffstat (limited to 'nis/nis_cache.c')
| -rw-r--r-- | nis/nis_cache.c | 275 |
1 files changed, 269 insertions, 6 deletions
diff --git a/nis/nis_cache.c b/nis/nis_cache.c index 8e1d583003..4c0ea7b186 100644 --- a/nis/nis_cache.c +++ b/nis/nis_cache.c @@ -20,25 +20,288 @@ #include <fcntl.h> #include <unistd.h> #include <syslog.h> +#include <string.h> #include <sys/stat.h> #include <sys/mman.h> #include <rpcsvc/nis.h> -#include <rpcsvc/nislib.h> #include <rpcsvc/nis_cache.h> #include <bits/libc-lock.h> #include "nis_intern.h" -/* XXX Only dummy functions in the moment. The real implementation - will follow, if we have a working nis_cachemgr */ +static struct timeval TIMEOUT = {10, 0}; + +#define HEADER_MAGIC 0x07021971 +#define SPACER_MAGIC 0x07654321 + +#define CACHE_VERSION 0x00000001 + +struct cache_header +{ + u_long magic; /* Magic number */ + u_long vers; /* Cache file format version */ + u_short tcp_port; /* tcp port of nis_cachemgr */ + u_short udp_port; /* udp port of nis_cachemgr */ + u_long entries; /* Number of cached objs. */ + off_t used; /* How many space are used ? */ +}; +typedef struct cache_header cache_header; + +struct cache_spacer +{ + u_long magic; /* Magic number */ + u_long hashval; + time_t ctime; /* time we have created this object */ + time_t ttl; /* time to life of this object */ + off_t next_offset; +}; +typedef struct cache_spacer cache_spacer; + +static int cache_fd = -1; +static int clnt_sock; +static caddr_t maddr = NULL; +static size_t msize; +static CLIENT *cache_clnt = NULL; + +/* If there is no cachemgr, we shouldn't use NIS_SHARED_DIRCACHE, if + there is no NIS_SHARED_DIRCACHE, we couldn't use nis_cachemgr. + So, if the clnt_call to nis_cachemgr fails, we also close the cache file. + But another thread could read the cache => lock the cache_fd and cache_clnt + variables with the same lock */ +__libc_lock_define_initialized (static, mgrlock) + +/* close file handles and nis_cachemgr connection */ +static void +__cache_close (void) +{ + if (cache_fd != -1) + { + close (cache_fd); + cache_fd = -1; + } + if (cache_clnt != NULL) + { + clnt_destroy (cache_clnt); + close (clnt_sock); + cache_clnt = NULL; + } +} + +/* open the cache file and connect to nis_cachemgr */ +static bool_t +__cache_open (void) +{ + struct sockaddr_in sin; + cache_header hptr; + + if ((cache_fd = open (CACHEFILE, O_RDONLY)) == -1) + return FALSE; + + if (read (cache_fd, &hptr, sizeof (cache_header)) == -1 + || lseek (cache_fd, 0, SEEK_SET) < 0) + { + close (cache_fd); + cache_fd = -1; + return FALSE; + } + if (hptr.magic != HEADER_MAGIC) + { + close (cache_fd); + cache_fd = -1; + syslog (LOG_ERR, _("NIS+: cache file is corrupt!")); + return FALSE; + } + + memset (&sin, '\0', sizeof (sin)); + sin.sin_family = AF_INET; + clnt_sock = RPC_ANYSOCK; + sin.sin_addr.s_addr = htonl (INADDR_LOOPBACK); + sin.sin_port = htons (hptr.tcp_port); + cache_clnt = clnttcp_create (&sin, CACHEPROG, CACHE_VER_1, &clnt_sock, 0, 0); + if (cache_clnt == NULL) + { + close (cache_fd); + cache_fd = -1; + return FALSE; + } + /* If the program exists, close the socket */ + if (fcntl (clnt_sock, F_SETFD, FD_CLOEXEC) == -1) + perror (_("fcntl: F_SETFD")); + return TRUE; +} + +/* Ask the cache manager to update directory 'name' + for us (because the ttl has expired). */ +static nis_error +__cache_refresh (nis_name name) +{ + char clnt_res = 0; + nis_error result = NIS_SUCCESS; + + __libc_lock_lock (mgrlock); + + if (cache_clnt == NULL) + result = NIS_FAIL; + else if (clnt_call (cache_clnt, NIS_CACHE_REFRESH_ENTRY, + (xdrproc_t) xdr_wrapstring, (caddr_t) name, + (xdrproc_t) xdr_void, &clnt_res, TIMEOUT) + != RPC_SUCCESS) + { + __cache_close (); + result = NIS_FAIL; + } + + __libc_lock_unlock (mgrlock); + + return result; +} + +static nis_error +__cache_find (const_nis_name name, directory_obj **obj) +{ + unsigned long hash; + struct cache_header *hptr; + struct cache_spacer *cs; + struct directory_obj *dir; + XDR xdrs; + caddr_t addr, ptr; + time_t now = time (NULL); + + if (maddr == NULL) + return NIS_FAIL; + + hash = __nis_hash (name, strlen(name)); + hptr = (cache_header *)maddr; + if ((hptr->magic != HEADER_MAGIC) || (hptr->vers != CACHE_VERSION)) + { + syslog (LOG_ERR, _("NIS+: cache file is corrupt!")); + return NIS_SYSTEMERROR; + } + cs = (cache_spacer *)(maddr + sizeof (cache_header)); + while (cs->next_offset) + { + if (cs->magic != SPACER_MAGIC) + { + syslog (LOG_ERR, _("NIS+: cache file is corrupt!")); + return NIS_SYSTEMERROR; + } + if (cs->hashval == hash) + { + if ((now - cs->ctime) > cs->ttl) + return NIS_CACHEEXPIRED; + dir = calloc (1, sizeof (directory_obj)); + addr = (caddr_t)cs + sizeof (cache_spacer); + xdrmem_create (&xdrs, addr, cs->next_offset, XDR_DECODE); + xdr_directory_obj (&xdrs, dir); + xdr_destroy (&xdrs); + *obj = dir; + return NIS_SUCCESS; + } + ptr = (caddr_t)cs; + ptr += cs->next_offset + sizeof (struct cache_spacer); + cs = (struct cache_spacer *)ptr; + } + return NIS_NOTFOUND; +} + +static directory_obj * +internal_cache_search (const_nis_name name) +{ + directory_obj *dir; + nis_error res; + int second_refresh = 0; + struct stat s; + + if (cache_fd == -1) + if (__cache_open () == FALSE) + return NULL; + + again: + /* This lock is for nis_cachemgr, so it couldn't write a new cache + file if we reading it */ + if (__nis_lock_cache () == -1) + return NULL; + + if (maddr != NULL) + munmap (maddr, msize); + if (fstat (cache_fd, &s) < 0) + maddr = MAP_FAILED; + else + { + msize = s.st_size; + maddr = mmap (0, msize, PROT_READ, MAP_SHARED, cache_fd, 0); + } + if (maddr == MAP_FAILED) + { + __nis_unlock_cache (); + return NULL; + } + + res = __cache_find (name, &dir); + + munmap (maddr, msize); + maddr = NULL; + /* Allow nis_cachemgr to write a new cachefile */ + __nis_unlock_cache (); + + switch(res) + { + case NIS_CACHEEXPIRED: + if (second_refresh) + { + __cache_close (); + syslog (LOG_WARNING, + _("NIS+: nis_cachemgr failed to refresh object for us")); + return NULL; + } + ++second_refresh; + if (__cache_refresh ((char *) name) != NIS_SUCCESS) + return NULL; + goto again; + break; + case NIS_SUCCESS: + return dir; + default: + return NULL; + } +} + directory_obj * __cache_search (const_nis_name name) { - return NULL; + directory_obj *dir; + + __libc_lock_lock (mgrlock); + + dir = internal_cache_search (name); + + __libc_lock_unlock (mgrlock); + + return dir; } -nis_error +nis_error __cache_add (fd_result *fd) { - return NIS_FAIL; + char clnt_res = 0; + nis_error result = NIS_SUCCESS; + + __libc_lock_lock (mgrlock); + + if (cache_clnt == NULL) + if (__cache_open () == FALSE) + result = NIS_FAIL; + + if (cache_clnt != NULL && + (clnt_call (cache_clnt, NIS_CACHE_ADD_ENTRY, (xdrproc_t) xdr_fd_result, + (caddr_t)fd, (xdrproc_t) xdr_void, &clnt_res, TIMEOUT) + != RPC_SUCCESS)) + { + __cache_close (); + result = NIS_RPCERROR; + } + + __libc_lock_unlock (mgrlock); + + return result; } |