LIBINN(3)

NAME
libinn - InterNetNews library routines

SYNOPSIS
#include "libinn.h"
typedef struct _TIMEINFO {
    time_t	time;
    long	usec;
    long	tzone;
} TIMEINFO;
char *
GenerateMessageID()
void
HeaderCleanFrom(from)
    char	*from;
char *
HeaderFind(Article, Header, size)
    char	*Article;
    char	*Header;
    int	size;
FILE *
CAopen(FromServer, ToServer)
    FILE	*FromServer;
    FILE	*ToServer;
FILE *
CAlistopen(FromServer, ToServer, request)
    FILE	*FromServer;
    FILE	*ToServer;
    char	*request;
void
CAclose()
struct _DDHANDLE *
DDstart(FromServer, ToServer)
    FILE	*FromServer;
    FILE	*ToServer;
void
DDcheck(h, group)
    DDHANDLE	*h;
    char	*group;
char *
DDend(h)
    DDHANDLE	*h;
void
CloseOnExec(fd, flag)
    int	fd;
    int	flag;
int
SetNonBlocking(fd, flag)
    int	fd;
    int	flag;
int
LockFile(fd, flag)
    int	fd;
    int	flag;
char *
GetConfigValue(value)
    char	*value;
char *
GetFileConfigValue(value)
    char	*value;
char *
GetFQDN()
char *
GetModeratorAddress(FromServer, ToServer, group)
    FILE	*FromServer;
    FILE	*ToServer;
    char	*group;
int
GetResourceUsage(usertime, systime)
    double	*usertime;
    double	*systime;
int
GetTimeInfo(now)
    TIMEINFO	*now;
int
NNTPlocalopen(FromServerp, ToServerp, errbuff)
    FILE	**FromServerp;
    FILE	**ToServerp;
    char	*errbuff;
int
NNTPremoteopen(FromServerp, ToServerp, errbuff)
    FILE	**FromServerp;
    FILE	**ToServerp;
    char	*errbuff;
int
NNTPconnect(host, FromServerp, ToServerp, errbuff)
    char	*host;
    FILE	**FromServerp;
    FILE	**ToServerp;
    char	*errbuff;
int
NNTPcheckarticle(text)
    char	*text;
int
NNTPsendarticle(text, ToServer, Terminate)
    char	*text;
    FILE	*ToServer;
    int	Terminate;
int
NNTPsendpassword(server, FromServer, ToServer)
    char	*server;
    FILE	*FromServer;
    FILE	*ToServer;
void
Radix32(value, p)
    unsigned long	value;
    char	*p;
char *
ReadInFile(name, Sbp)
    char	*name;
    struct stat	*Sbp;
char *
ReadInDescriptor(fd, Sbp)
    int	fd;
    struct stat	*Sbp;
char *
INNVersion()

DESCRIPTION
Libinn is a library of utility routines for manipulating Usenet articles and related data. It is not necessary to use the header file libinn.h; if it is not available, it is only necessary to properly declare the TIMEINFO datatype, as given above.

GenerateMessageID uses the current time, process-ID, and fully-qualified domain name of the local host to create a Message-ID header that is highly likely to be unique. The returned value points to static space that is reused on subsequent calls.

HeaderCleanFrom removes the extraneous information from the value of a ``From'' or ``Reply-To'' header 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 1036 which limits the format of the header.

HeaderFind searches through Article looking for the specified Header. Size should be the length of the header name. It returns a pointer to the value of the header, skipping leading whitespace, or NULL if the header cannot be found. Article should be a standard C string containing the text of the article; the end of the headers is indicated by a blank line — two consecutive \n characters.

CAopen and CAclose provide news clients with access to the active file; the ``CA'' stands for Client Active. CAopen opens the active(5) 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.

CloseOnExec can make a descriptor ``close-on-exec'' so that it is not shared with any child processes. If the flag is non-zero, the file is so marked; if zero, the ``close-on-exec'' mode is cleared.

DDstart, DDcheck, and DDend are used to set the Distribution header; the ``DD'' stands for Default Distribution. The distrib.pats(5) file is consulted to determine the proper value for the Distribution header 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 newgroups, 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.

SetNonBlocking enables (if flag is non-zero) or disables (if flag is zero) non-blocking I/O on the indicated descriptor. It returns -1 on failure or zero on success.

LockFile tries to lock the file descriptor fd. If flag is non-zero it will block until the lock can be made, otherwise it will return -1 if the file cannot be locked. It returns -1 on failure or zero on success.

GetConfigValue returns the value of the specified configuration parameter. See inn.conf(5) for details on the parameters and their interpretation. The returned value points to static space that is reused on subsequent calls.

GetFileConfigValue returns the specified configuration parameter from the inn.conf file without checking for any defaults. The returned value points to static space that is reused on subsequent calls, or NULL if the value is not present.

GetFQDN returns the fully-qualified domain name of the local host. The returned value points to static space that is reused on subsequent calls, or NULL on error.

GetModeratorAddress returns the mailing address of the moderator for specified group or NULL on error. 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.

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. It gets the values by doing a getrusage(2) system call. It returns -1 on failure, or zero on success.

GetTimeInfo fills in the now parameter with information about the current time and tzone. The ``time'' and ``usec'' fields will be filled in by a call to gettimeofday(2). The ``tzone'' field will be filled in with the current offset from GMT. This is done by calling localtime(3) and comparing the value with that returned by a call to gmtime(3). For efficiency, the ``tzone'' field is only recalculated if more than an hour pass passed since the last time GetTimeInfo has been called. This routine returns -1 on failure, or zero on success.

NNTPlocalopen opens a connection to the private port of an InterNetNews server running on the local host. It returns -1 on failure, or zero 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. This routine is not for general use.

NNTPremoteopen does the same except that it calls GetConfigValue to find the name of the local server, and opens a connection to the standard NNTP port. Any client program can use this routine. It returns -1 on failure, or zero on success.

NNTPconnect is the same as NNTPremoteopen except that the desired host is given as the host parameter.

NNTPcheckarticle verifies that the text meets the NNTP limitations on line length. It returns -1 on failure, or zero if the text is valid.

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 non-zero, then the routine will also write the NNTP data-termination marker on the stream. It returns -1 on failure, or zero on success.

NNTPsendpassword sends authentication information to an NNTP server by finding the appropriate entry in the passwd.nntp(5) file. Server contains the name of the host; GetConfigValue 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.

Radix32 converts the number in value into a radix-32 string into the buffer pointed to by p. The number is split into five-bit pieces and each pieces 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 p need only point 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.

INNVersion returns a pointer to a string identifying the INN version, suitable for printing in logon banners.

EXAMPLES
    char	*p;
    char	*Article;
    char	buff[256];
    FILE	*F;
    FILE	*ToServer;
    FILE	*FromServer;
    if ((p = HeaderFind(Article, "From", 4)) == NULL)
        Fatal("Can't find From line");
    (void)strcpy(buff, p);
    HeaderCleanFrom(buff);
    if ((F = CAopen(FromServer, ToServer)) == NULL)
        Fatal("Can't open active file");
    /* Don't pass the file on to our children. */
    CloseOnExec(fileno(F), 1);
    /* Make a local copy. */
    p = ReadInDescriptor(fileno(F), (struct stat *)NULL);
    /* Close the file. */
    CAclose();
    if (NNTPremoteopen(&FromServer, &ToServer) < 0)
        Fatal("Can't connect to server");
    if ((p = GetModeratorAddress("comp.sources.unix")) == NULL)
        Fatal("Can't find moderator's address");

HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews.

SEE ALSO
active(5), dbz(3z), parsedate(3), inn.conf(5), inndcomm(3), moderators(5), passwd.nntp(5).