Provided by: inn2-dev_2.7.2~20240212-1build3_amd64 
NAME
libinn - InterNetNews library routines
SYNOPSIS
#include "inn/libinn.h"
#define ISWHITE(c) ...
/* Headers-related routines. */
extern char *GenerateMessageID(char *domain);
extern void HeaderCleanFrom(char *from);
extern struct _DDHANDLE *DDstart(FILE *FromServer, FILE *ToServer);
extern void DDcheck(struct _DDHANDLE *h, char *group);
extern char *DDend(struct _DDHANDLE *h);
/* Cancel-Lock routines. */
extern bool gen_cancel_lock(const char *msgid, const char *username,
char **canbuff);
extern bool gen_cancel_key(const char *hdrcontrol,
const char *hdrsupersedes,
const char *username, char **canbuff);
extern bool verify_cancel_key(const char *c_key_header,
const char *c_lock_header);
/* Opening the active file on a client. */
extern FILE *CAopen(FILE *FromServer, FILE *ToServer);
extern FILE *CAlistopen(FILE *FromServer, FILE *ToServer,
const char *request);
extern void CAclose(void);
/* File locking. */
enum inn_locktype
{
INN_LOCK_READ,
INN_LOCK_WRITE,
INN_LOCK_UNLOCK
};
extern bool inn_lock_file(int fd, enum inn_locktype type,
bool block);
/* NNTP functions. */
extern int NNTPlocalopen(FILE **FromServerp, FILE **ToServerp,
char *errbuff, size_t len);
extern int NNTPremoteopen(int port, FILE **FromServerp,
FILE **ToServerp, char *errbuff,
size_t len);
extern int NNTPconnect(const char *host, int port,
FILE **FromServerp, FILE **ToServerp,
char *errbuff, size_t len);
extern int NNTPsendarticle(char *text, FILE *ToServer,
bool terminate);
extern int NNTPsendpassword(char *server, FILE *FromServer,
FILE *ToServer);
/* Hash functions. */
typedef struct {
char hash[16];
} HASH;
extern HASH HashMessageID(const char *MessageID);
/* Other useful functions. */
extern char *inn_getfqdn(const char *domain);
extern char *GetModeratorAddress(FILE *FromServer, FILE *ToServer,
char *group, char *moderatormailer);
/* Miscellaneous. */
extern int GetResourceUsage(double *usertime, double *systime);
extern void Radix32(unsigned long value, char *buff);
extern char *ReadInDescriptor(int fd, struct stat *Sbp);
extern char *ReadInFile(const char *name, struct stat *Sbp);
/* Reserving file descriptors. */
extern bool fdreserve(int fdnum);
extern FILE *Fopen(const char *name, const char *mode, int fdindex);
extern int Fclose(FILE *fp);
/* Determining, setting and checking the limit on open file
descriptors. */
extern int getfdlimit(void);
extern int setfdlimit(unsigned int limit);
extern bool isvalidfd(unsigned int fd);
/* Setting or clearing file descriptor flags. */
#include "inn/fdflag.h"
bool fdflag_close_exec(int fd, bool flag);
bool fdflag_nonblocking(socket_type fd, bool flag);
DESCRIPTION
libinn is a library of utility routines for manipulating Usenet articles and related data.
The whole documentation of libinn routines is split into several specific man pages
besides this one: libinn_clientlib(3), libinn_dbz(3), libinn_inndcomm(3), libinn_list(3),
libinn_qio(3), libinn_tst(3) and libinn_uwildmat(3).
MACROS
"ISWHITE" is a macro which tests whether its char argument is a space or a tabulation.
HEADERS-RELATED ROUTINES
GenerateMessageID uses the current time, nnrpd's process ID, a global static counter
incrementing at each post in the same NNTP session, and a fully qualified domain name,
which is passed as an argument, to create a Message-ID header field that is highly likely
to be unique. The returned value points to static space that is reused on subsequent
calls. If the argument is NULL, inn_getfqdn is called to find a suitable FQDN (using
domain as set in inn.conf to qualify the local host name if local host cannot be resolved
in DNS).
HeaderCleanFrom removes the extraneous information from the value of a From or Reply-To
header field and leaves just the official mailing address. In particular, the following
transformations are made to the from parameter:
• address --> address
• address (stuff) --> address
• stuff <address> --> address
The transformations are simple, based on RFC 5536 which limits the format of the header
field.
DDstart, DDcheck, and DDend are used to set the Distribution header field; the "DD" stands
for Default Distribution. The distrib.pats file is consulted to determine the proper
value for the Distribution header field after all newsgroups have been checked. DDstart
begins the parsing. It returns a pointer to an opaque handle that should be used on
subsequent calls. The FromServer and ToServer parameters should be "FILE"'s connected to
the NNTP server for input and output, respectively. If either parameter is NULL, then an
empty default will ultimately be returned if the file is not locally available.
DDcheck should be called with the handle, h, returned by DDstart and a newsgroup, group,
to check. It can be called as often as necessary.
DDend releases any state maintained in the handle and returns an allocated copy of the
text that should be used for the Distribution header field.
CANCEL-LOCK
These routines are available in libinn if INN was built with Cancel-Lock support
(otherwise they are stub functions which are always returning false). The "configure"
script automatically enables that support if it finds libcanlock.
gen_cancel_lock expects a Message-ID, a username (possibly NULL) and the address of a
pointer where it will write elements suitable for the body of a Cancel-Lock header field.
gen_cancel_key expects a Control header field body (possibly NULL), a Supersedes header
field body (possibly NULL), a username (possibly NULL) and the address of a pointer where
it will write elements suitable for the body of a Cancel-Key header field. This function
extracts the Message-ID from the Control header field body or, if NULL, from the
Supersedes header field body. If the header field used for that extraction is not
correctly formatted, or they are both NULL, or no Message-ID is found, it will result in a
failure.
These functions return true if all the elements were written, false on failure. The
canbuff string will be allocated by these functions, unless they return false. The caller
is responsible for freeing it.
For each admin secret in the canlockadmin vector set in inn.conf, and for each user secret
set in the canlockuser vector set in inn.conf if username is not NULL, gen_cancel_lock
will generate in canbuff both sha1 and sha256 Base64-encoded hashes. Regarding
gen_cancel_key, it will be for each admin secret in the canlockadmin vector if username is
NULL or for each user secret in the canlockuser vector if username is not NULL.
verify_cancel_lock expects pointers to Cancel-Key and Cancel-Lock header field bodies.
This function verifies that c_key_header contains an element matching one of those present
in c_lock_header. It returns true if at least one element matches. Otherwise, false is
returned, that is to say the cancel or supersede request cannot be authenticated.
CLIENT ACTIVE FILE
CAopen and CAclose provide news clients with access to the active file; the "CA" stands
for Client Active. CAopen opens the active file for reading. It returns a pointer to an
open "FILE", or NULL on error. If a local or NFS-mounted copy exists, CAopen will use
that file. The FromServer and ToServer parameters should be "FILE"'s connected to the
NNTP server for input and output, respectively. See NNTPremoteopen or NNTPlocalopen,
below. If either parameter is NULL, then CAopen will just return NULL if the file is not
locally available. If they are not NULL, CAopen will use them to query the NNTP server
using the LIST command to make a local temporary copy.
The CAlistopen sends a LIST command to the server and returns a temporary file containing
the results. The request parameter, if not NULL, will be sent as an argument to the
command. Unlike CAopen, this routine will never use a locally-available copy of the
active file.
CAclose closes the active file and removes any temporary file that might have been created
by CAopen or CAlistopen.
FILE LOCKING
inn_lock_file tries to lock the file descriptor fd. If block is true, it will block until
the lock can be made, otherwise it will return false if the file cannot be locked. type
is one of "INN_LOCK_READ", "INN_LOCK_WRITE" or "INN_LOCK_UNLOCK". It returns false on
failure or true on success.
NNTP FUNCTIONS
NNTPlocalopen opens a connection to the private port of an InterNetNews server running on
the local host, if "HAVE_UNIX_DOMAIN_SOCKETS" in include/config.h is defined. It returns
"-1" on failure, or "0" on success. FromServerp and ToServerp will be filled in with
"FILE"'s which can be used to communicate with the server. errbuff can either be NULL or
a pointer to a buffer at least 512 bytes long. If not NULL, and the server refuses the
connection, then it will be filled in with the text of the server's reply. len should be
the length of the errbuff buffer. This routine is not for general use. If
"HAVE_UNIX_DOMAIN_SOCKETS" in include/config.h is not defined, this is a stub routine, for
compatibility with systems that have Unix-domain stream sockets, and it then always
returns "-1".
NNTPremoteopen does the same, except that it uses the server parameter set in inn.conf as
the local server, and opens a connection to the port. Any client program can use this
routine. It returns "-1" on failure, or "0" on success.
NNTPconnect is the same as NNTPremoteopen except that the desired host is given as the
host parameter.
NNTPsendarticle writes text on ToServer using NNTP conventions for line termination. The
text should consist of one or more lines ending with a newline. If terminate is true,
then the routine will also write the NNTP data-termination marker on the stream. It
returns "-1" on failure, or "0" on success.
NNTPsendpassword sends authentication information to an NNTP server by finding the
appropriate entry in the passwd.nntp file. server contains the name of the host; the
server parameter in inn.conf will be used if server is NULL. FromServer and ToServer
should be "FILE"'s that are connected to the server. No action is taken if the specified
host is not listed in the password file.
HASHES
HashMessageID returns hashed Message-ID using MD5.
OTHER USEFUL FUNCTIONS
inn_getfqdn returns the fully qualified domain name of the local host. domain is used to
qualify the local host name if local host cannot be resolved in DNS. The returned value
points to newly-allocated memory that the caller is responsible for freeing, or NULL on
error.
GetModeratorAddress returns the mailing address of the moderator for specified group or
NULL on error. moderatormailer is used as its address, if there is no matched moderator.
See moderators(5) for details on how the address is determined. GetModeratorAddress does
no checking to see if the specified group is actually moderated. The returned value
points to static space that is reused on subsequent calls. The FromServer and ToServer
parameters should be "FILE"'s connected to the NNTP server for input and output,
respectively. If either of these parameters is NULL, then an attempt to get the list from
a local copy is made.
MISCELLANEOUS
GetResourceUsage fills in the usertime and systime parameters with the total user and
system time used by the current process and any children it may have spawned. If
"HAVE_GETRUSAGE" in include/config.h is defined, it gets the values by doing a
getrusage(2) system call; otherwise it calls times(2). It returns "-1" on failure, or "0"
on success.
Radix32 converts the number in value into a radix-32 string into the buffer pointed to by
buff. The number is split into five-bit pieces and each piece is converted into a
character using the alphabet "0..9a..v" to represent the numbers "0..32". Only the lowest
32 bits of value are used, so buff needs only pointing to a buffer of eight bytes (seven
characters and the trailing "\0").
ReadInFile reads the file named name into allocated memory, appending a terminating "\0"
byte. It returns a pointer to the space, or NULL on error. If Sbp is not NULL, it is
taken as the address of a place to store the results of a stat(2) call.
ReadInDescriptor performs the same function as ReadInFile except that fd refers to an
already-open file.
FILE DESCRIPTOR RESERVATION
fdreserve permits reserving fdnum file descriptors for future use. On platforms that have
a stdio limitation, such as 64-bit Solaris versions prior to 11.0, all 32-bit Solaris
versions and 32-bit applications running on 64-bit Solaris, low-numbered file descriptors
can then be kept and re-used for stdio. Without this mechanism, some essential files like
the history file may not have any file descriptor left when being reopened after a closure
for some operations, and stdio would fail.
These file descriptors all read "/dev/null", until Fopen is called on them. If fdnum is
"0" or negative, all reserved file descriptors are closed. Otherwise, fdnum file
descriptors are reserved. If this function is called again with a higher fdnum value, it
reserves more file descriptors; with a lower fdnum value, it closes the supernumerary
reserved file descriptors. It returns true when all the file descriptors have been
successfully reserved, and false otherwise, in which case all the reserved file
descriptors are closed, even if some of them were previously in use.
Fopen opens the file name in the given mode, using the file descriptor in position fdindex
in the reserved file descriptors. If fdindex is lower than the number of reserved file
descriptors, Fopen uses the corresponding one. Otherwise, it just calls fopen(2) without
re-using a reserved file descriptor. It returns a pointer to a FILE struct, or NULL on
failure.
Fclose closes the file descriptor used for fp without keeping it, unless this file
descriptor was a reserved one, in which case it is kept (and read "/dev/null"). It
returns "0" on success. Any other value (like EOF) is a failure.
FILE DESCRIPTOR LIMITS
getfdlimit returns the limit on open file descriptors. It uses the getrlimit(2) function
when available. If not, it tries sysconf(2), then getdtablesize(2), then ulimit(2), then
a possible hard-coded "NOFILE" constant in the sys/param.h system header, or then falls
back to the POSIX-guaranteed minimum of 20.
setfdlimit sets the limit on open file descriptors to the given parameter limit. It uses
the setrlimit(2) function when available. It returns "1" on success, and "-1" on failure
(when setrlimit(2) is not available or limit is higher than select(2) can handle, checking
against "FD_SETSIZE").
isvalidfd returns true if fd is not higher than the system supports, and false otherwise.
FILE DESCRIPTOR FLAGS
fdflag_close_exec can make a descriptor close-on-exec so that it is not shared with any
child processes. If the flag is true, the file is so marked; if false, the close-on-exec
mode is cleared. It returns false on failure (or when the function is unsupported) or
true on success.
fdflag_nonblocking enables (if flag is true) or disables (if flag is false) non-blocking
I/O on the indicated "socket_type" (which can be a non-socket file descriptor on UNIX
systems, but a "socket_type" is expected on Windows). It returns false on failure or true
on success.
EXAMPLES
#include "inn/fdflag.h"
#include "inn/libinn.h"
char *p;
char frombuff[256], errbuff[256];
FILE *F;
FILE *ToServer;
FILE *FromServer;
int port = 119;
strlcpy(frombuff, HDR(HDR__FROM), sizeof(frombuff));
HeaderCleanFrom(frombuff);
if ((F = CAopen(FromServer, ToServer)) == NULL)
Fatal("Can't open active file");
/* Don't pass the file on to our children. */
fdflag_close_exec(fileno(F), true);
/* Make a local copy. */
p = ReadInDescriptor(fileno(F), (struct stat *) NULL);
/* Close the file. */
CAclose();
if (NNTPremoteopen(port, &FromServer, &ToServer, errbuff,
sizeof(errbuff)) < 0)
Fatal("Can't connect to server");
if ((p = GetModeratorAddress(NULL, NULL, "comp.sources.unix",
"%s@example.com")) == NULL)
Fatal("Can't find moderator's address");
HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews. Rewritten into POD by Julien
Elie.
SEE ALSO
active(5), inn.conf(5), libinn_clientlib(3), libinn_dbz(3), libinn_inndcomm(3),
libinn_list(3), libinn_qio(3), libinn_tst(3), libinn_uwildmat(3), moderators(5),
passwd.nntp(5).