/*

 * env.c -- small service routines

 *

 * Copyright 1998 by Eric S. Raymond

 * For license terms, see the file COPYING in this directory.

 */

#include "config.h"

#include <stdio.h>

#include <ctype.h>

#if defined(STDC_HEADERS)

#include <stdlib.h>

#endif

#if defined(HAVE_UNISTD_H)

#include <unistd.h>

#endif

#include <pwd.h>

#include <string.h>

#ifdef HAVE_NET_SOCKET_H

#include <net/socket.h>

#endif

#include <netdb.h>

#include <sys/types.h>

#include <sys/socket.h>

#include "fetchmail.h"

#include "getaddrinfo.h"

#include "i18n.h"

#if defined(HAVE_SETLOCALE) && defined(ENABLE_NLS) && defined(HAVE_STRFTIME)

#include <locale.h>

#endif

#ifndef HAVE_DECL_GETENV

extern char *getenv(const char *);	/* needed on sysV68 R3V7.1. */

#endif

void envquery(int argc, char **argv)

/* set up basic stuff from the environment (including the rc file name) */

{

    struct passwd by_name, by_uid, *pwp;

    (void)argc;

    (void)argc;

    if (!(user = getenv("FETCHMAILUSER")))

    {

	if (!(user = getenv("LOGNAME")))

	{

	    user = getenv("USER");

	}

    }

    if ((program_name = strrchr(argv[0], '/')) != NULL)

	++program_name;

    else

	program_name = argv[0];

    if (getenv("QMAILINJECT") && strcmp(getenv("QMAILINJECT"), ""))

    {

	fprintf(stderr,

		GT_("%s: The QMAILINJECT environment variable is set.\n"

		    "This is dangerous as it can make qmail-inject or qmail's sendmail wrapper\n"  

		    "tamper with your From: or Message-ID: headers.\n"

		    "Try \"env QMAILINJECT= %s YOUR ARGUMENTS HERE\"\n"

		    "%s: Abort.\n"), 

		program_name, program_name, program_name);

	exit(PS_UNDEFINED);

    }

    if (getenv("NULLMAILER_FLAGS") && strcmp(getenv("NULLMAILER_FLAGS"), ""))

    {

	fprintf(stderr,

		GT_("%s: The NULLMAILER_FLAGS environment variable is set.\n"

		    "This is dangerous as it can make nullmailer-inject or nullmailer's\n" 

		    "sendmail wrapper tamper with your From:, Message-ID: or Return-Path: headers.\n"

		    "Try \"env NULLMAILER_FLAGS= %s YOUR ARGUMENTS HERE\"\n"

		    "%s: Abort.\n"), 

		program_name, program_name, program_name);

	exit(PS_UNDEFINED);

    }

    if (!(pwp = getpwuid(getuid())))

    {

	fprintf(stderr,

		GT_("%s: You don't exist.  Go away.\n"),

		program_name);

	exit(PS_UNDEFINED);

    }

    else

    {

	memcpy(&by_uid, pwp, sizeof(struct passwd));

	if (!user || !(pwp = getpwnam(user)))

	    pwp = &by_uid;

	else

	{

	    /*

	     * This logic is needed to handle gracefully the possibility

	     * that multiple names might be mapped to one UID.

	     */

	    memcpy(&by_name, pwp, sizeof(struct passwd));

	    if (by_name.pw_uid == by_uid.pw_uid)

		pwp = &by_name;

	    else

		pwp = &by_uid;

	}

	user = xstrdup(pwp->pw_name);

    }

    endpwent();

    /* compute user's home directory */

    home = getenv("HOME_ETC");

    if (!home && !(home = getenv("HOME")))

	home = xstrdup(pwp->pw_dir);

    /* compute fetchmail's home directory */

    if (!(fmhome = getenv("FETCHMAILHOME")))

	fmhome = home;

#define RCFILE_NAME	"fetchmailrc"

    /*

     * The (fmhome==home) leaves an extra character for a . at the

     * beginning of the rc file's name, iff fetchmail is using $HOME

     * for its files. We don't want to do that if fetchmail has its

     * own home ($FETCHMAILHOME), however.

     */

    rcfile = (char *)xmalloc(strlen(fmhome)+sizeof(RCFILE_NAME)+(fmhome==home)+2);

    /* avoid //.fetchmailrc */

    if (strcmp(fmhome, "/") != 0)

	strcpy(rcfile, fmhome);

    else

	*rcfile = '\0';

    if (rcfile[strlen(rcfile) - 1] != '/')

	strcat(rcfile, "/");

    if (fmhome==home)

	strcat(rcfile, ".");

    strcat(rcfile, RCFILE_NAME);

}

char *host_fqdn(int required)

{

    char tmpbuf[HOSTLEN+1];

    char *result;

    if (gethostname(tmpbuf, sizeof(tmpbuf)))

    {

	fprintf(stderr, GT_("%s: can't determine your host!"),

		program_name);

	exit(PS_DNS);

    }

    /* if we got no . in the hostname, try to canonicalize it,

     * else assume it is a FQDN */

    if (strchr(tmpbuf, '.') == NULL)

    {

	/* if we got a basename without dots, as we often do in Linux,

	 * look up canonical name (make a FQDN of it) */

	struct addrinfo hints, *res;

	int e;

	memset(&hints, 0, sizeof hints);

	hints.ai_family = AF_UNSPEC;

	hints.ai_socktype = SOCK_STREAM;

	hints.ai_flags = AI_CANONNAME;

	e = fm_getaddrinfo(tmpbuf, NULL, &hints, &res);

	if (e) {

	    /* exit with error message */

	    fprintf(stderr,

		    GT_("gethostbyname failed for %s\n"), tmpbuf);

	    fprintf(stderr, "%s", gai_strerror(e));

	    fprintf(stderr, GT_("Cannot find my own host in hosts database to qualify it!\n"));

	    if (required)

		exit(PS_DNS);

	    else {

		fprintf(stderr, GT_("Trying to continue with unqualified hostname.\nDO NOT report broken Received: headers, HELO/EHLO lines or similar problems!\nDO repair your /etc/hosts, DNS, NIS or LDAP instead.\n"));

		return xstrdup(tmpbuf);

	    }

	}

	result = xstrdup(res->ai_canonname ? res->ai_canonname : tmpbuf);

	fm_freeaddrinfo(res);

    }

    else

	result = xstrdup(tmpbuf);

    return result;

}

static char *tzoffset(time_t *now)

/* calculate timezone offset */

{

    static char offset_string[6];

    struct tm gmt, *lt;

    int off;

    char sign = '+';

    gmt = *gmtime(now);

    lt = localtime(now);

    off = (lt->tm_hour - gmt.tm_hour) * 60 + lt->tm_min - gmt.tm_min;

    if (lt->tm_year < gmt.tm_year)

	off -= 24 * 60;

    else if (lt->tm_year > gmt.tm_year)

	off += 24 * 60;

    else if (lt->tm_yday < gmt.tm_yday)

	off -= 24 * 60;

    else if (lt->tm_yday > gmt.tm_yday)

	off += 24 * 60;

    if (off < 0) {

	sign = '-';

	off = -off;

    }

    if (off >= 24 * 60)			/* should be impossible */

	off = 23 * 60 + 59;		/* if not, insert silly value */

    snprintf(offset_string, sizeof(offset_string),

	    "%c%02d%02d", sign, off / 60, off % 60);

    return (offset_string);

}

char *rfc822timestamp(void)

/* return a timestamp in RFC822 form */

{

    time_t	now;

    static char buf[50];

    time(&now);

#ifdef HAVE_STRFTIME

    /*

     * Conform to RFC822.  We generate a 4-digit year here, avoiding

     * Y2K hassles.  Max length of this timestamp in an English locale

     * should be 29 chars.  The only things that should vary by locale

     * are the day and month abbreviations.  The set_locale calls prevent

     * weird multibyte i18n characters (such as kanji) from showing up

     * in your Received headers.

     */

#if defined(HAVE_SETLOCALE) && defined(ENABLE_NLS)

    setlocale (LC_TIME, "C");

#endif

    strftime(buf, sizeof(buf)-1, 

	     "%a, %d %b %Y %H:%M:%S XXXXX (%Z)", localtime(&now));

#if defined(HAVE_SETLOCALE) && defined(ENABLE_NLS)

    setlocale (LC_TIME, "");

#endif

    strncpy(strstr(buf, "XXXXX"), tzoffset(&now), 5);

#else

    /*

     * This is really just a portability fallback, as the

     * date format ctime(3) emits is not RFC822

     * conformant.

     */

    strlcpy(buf, ctime(&now), sizeof(buf));

    buf[strlen(buf)-1] = '\0';	/* remove trailing \n */

#endif /* HAVE_STRFTIME */

    return(buf);

}

const char *showproto(int proto)

/* protocol index to protocol name mapping */

{

    switch (proto)

    {

    case P_AUTO: return("auto");

#ifdef POP2_ENABLE

    case P_POP2: return("POP2");

#endif /* POP2_ENABLE */

#ifdef POP3_ENABLE

    case P_POP3: return("POP3");

    case P_APOP: return("APOP");

    case P_RPOP: return("RPOP");

#endif /* POP3_ENABLE */

#ifdef IMAP_ENABLE

    case P_IMAP: return("IMAP");

#endif /* IMAP_ENABLE */

#ifdef ETRN_ENABLE

    case P_ETRN: return("ETRN");

#endif /* ETRN_ENABLE */

#ifdef ODMR_ENABLE

    case P_ODMR: return("ODMR");

#endif /* ODMR_ENABLE */

    default: return("unknown?!?");

    }

}

char *visbuf(const char *buf)

/* visibilize a given string */

{

    static char *vbuf;

    static size_t vbufs;

    char *tp;

    size_t needed;

    needed = strlen(buf) * 5 + 1; /* worst case: HEX, plus NUL byte */

    if (!vbuf || needed > vbufs) {

	vbufs = needed;

	vbuf = (char *)xrealloc(vbuf, vbufs);

    }

    tp = vbuf;

    while (*buf)

    {

	     if (*buf == '"')  { *tp++ = '\\'; *tp++ = '"'; buf++; }

	else if (*buf == '\\') { *tp++ = '\\'; *tp++ = '\\'; buf++; }

	else if (isprint((unsigned char)*buf) || *buf == ' ') *tp++ = *buf++;

	else if (*buf == '\a') { *tp++ = '\\'; *tp++ = 'a'; buf++; }

	else if (*buf == '\b') { *tp++ = '\\'; *tp++ = 'b'; buf++; }

	else if (*buf == '\f') { *tp++ = '\\'; *tp++ = 'f'; buf++; }

	else if (*buf == '\n') { *tp++ = '\\'; *tp++ = 'n'; buf++; }

	else if (*buf == '\r') { *tp++ = '\\'; *tp++ = 'r'; buf++; }

	else if (*buf == '\t') { *tp++ = '\\'; *tp++ = 't'; buf++; }

	else if (*buf == '\v') { *tp++ = '\\'; *tp++ = 'v'; buf++; }

	else

	{

	    const char hex[] = "0123456789abcdef";

	    *tp++ = '\\'; *tp++ = '0'; *tp++ = 'x';

	    *tp++ = hex[*buf >> 4];

	    *tp++ = hex[*buf & 0xf];

	    buf++;

	}

    }

    *tp = '\0';

    return(vbuf);

}

/* env.c ends here */