/*** updatehosts - accept /etc/host file section updates via mail.****  Accepts mail on stdin, then looks at body of message for:**      # begin: foo****  whereupon it writes this and all lines up to and including:**      # end: foo****  to the file HOSTDIR/foo... If a line of the format:**      # adminmail: goober**  is encountered an acknowledgment is sent to goober. ****  If it sees: **      send**  it will send the sender a copy of the current hosts file. If it**  sees:**      help**  it will send the sender a copy of the help file******  to make the program receive mail addressed to updatehosts,**  add the following line to your /usr/lib/aliases file **	updatehosts: "|/usr/local/adm/hosts/updatehosts"****  Written by Bob Coggeshall (coggs@boulder.Colorado.EDU)***/#define JTY "Just thought you'd like to know.\n"#include <stdio.h>#include <ctype.h>#include <sys/param.h>#define HOSTDIR         "/usr/local/adm/hosts/hostsrc/"#define HOSTS           "/usr/local/adm/hosts/hostsrc/hosts"#define HELPFILE        "/usr/local/adm/hosts/doc/updatehosts.catme"/** NEDITOR should be the name of the person allowed to edit  **/#define NEDITOR         "coggs"#define TEMPFILEPREF    "/tmp/updatehosts."#define STDERR      	"/tmp/updatehosts.stderr"#define UMASK		002/** domainame contains your domain name **/char *domainame = "colorado.edu";char hostname[MAXHOSTNAMELEN];/* values used by upexit() */#define FAIL 1#define FAKEFAIL 0		/* avoid generating mail bounces */#define SUCCESS 0/* values returned by parsline() */#define BEGIN       1#define END         2#define ADMINMAIL   3#define MAILHEAD    4#define DATA        5#define SEND        6#define HELP        7#define SUBJECT     8	/* values used by mail() */#define INDENT   1#define NOINDENT 0char *gets();char *rindex();char *index();char *getcuradmin();FILE *fopen();FILE *freopen();char *progname;char wrkline[256];          /* yet another */char wrkline1[256];         /* yet another 1 */char realsender[256];       /* sender from the 'From ' line */char curadminmail[256];     /* current value of 'Adminmail:' arg from file */FILE *fd = NULL;            /* file descriptor for writing section file */FILE *tfd = NULL;           /* file descriptor for temp file */FILE *efd = NULL;           /* file descriptor for stderr */char *cp;                   /* general purpose character pointer */char tempfile[256];         /* name of temporary file */main(ac,av)int ac;char **av;{    char arg[256];              /* rhs of arguments from input file */    char line[256];             /* general purpose line buffer */    char secfile[256];          /* name of section file */    char secname[256];          /* name of section */    char adminmail[256];        /* administrator mail arg */    int pid;                    /* process id */    int freadcount;             /* count returned from fread() */    int systatus;               /* returned by system() */	umask(UMASK);    /*    ** get the hostname and the program name.    */    gethostname(hostname,sizeof(hostname));    if ((progname = rindex(*av,'/')) == 0)        progname = *av;    else        progname++;    /*    ** redirect stderr to a file    */    if ( (efd = freopen(STDERR,"w+",stderr)) == NULL) {        sprintf(wrkline, "%s: couldn't freopen() %s", progname,STDERR);        mail(NEDITOR,wrkline, JTY,0,0);    }    /*     ** process input, parseline figures out what kind of line it is    ** and this case statement decides what to do.    */    while (gets(line) != NULL)    {        switch (parseline(line,arg)) {                case ADMINMAIL:         /* snarf adminmail arg */                    if (tfd) {                        fputs(line,tfd);                        fputc('\n',tfd);                    }                    strcpy(adminmail,arg);                    /*                    ** check that old adminmail and new adminmail args match                    */                    strcpy(wrkline,adminmail);                    if ((cp = index(wrkline,'@')) != 0)                             *cp = '\0';                    strcpy(wrkline1,curadminmail);                    if ((cp = index(wrkline1,'@')) != 0)                             *cp = '\0';                    if ( (strncmp(wrkline,wrkline1,sizeof(wrkline)) != 0) ) {                        sprintf(wrkline,			"%s: new adminmail:%s and current adminmail: %s  don't match",                        progname,adminmail,curadminmail);                        mail(NEDITOR,wrkline, JTY,0,0);                        upexit(FAKEFAIL);                    }                    break;                case MAILHEAD:          /* its the mail header, skip it */                    strcpy(realsender,arg); /* snarf sender */					fprintf(stderr,"realsender: %s\n",realsender);                    break;                case SUBJECT:                     break;                case SEND:          /* they want a copy of the whole thing */                    sprintf(wrkline,"%s: copy of current hosts file:",progname);                    mail(realsender,wrkline,"",HOSTS,NOINDENT);                    sprintf(wrkline,"%s: sent %s copy of current hosts file",                            progname,realsender);                    mail(NEDITOR,wrkline,JTY,0,0);                    upexit(SUCCESS);                    break;                case HELP:          /* send them the help file */                    sprintf(wrkline,"%s: help file",progname);                    mail(realsender,wrkline,"",HELPFILE,NOINDENT);                    sprintf(wrkline,"%s: sent %s the help file",                            progname,realsender);                    mail(NEDITOR,wrkline,JTY,0,0);                    upexit(SUCCESS);                    break;                case DATA:              /* its data, snarf it. */                    if (tfd) {                        fputs(line,tfd);                        fputc('\n',tfd);                    }                    break;                case BEGIN:                                 /*                    ** if begin, then see if section file exists                    ** if it doesn't send mail and die. if it does                    ** open it tempfile for write.                    */                    strcpy(secfile,HOSTDIR);                    strcpy(secname,arg);                    strcat(secfile,secname);                    if (access(secfile,0) != 0) {                        sprintf(wrkline,"%s: Can't access() %s",                        progname,secfile);                        mail(NEDITOR,wrkline,                        "File needs to exist before i'll overwrite it",0,0);                        upexit(FAKEFAIL);                    }                                    /*                     ** read secfile and get the current adminmail: arg                    ** and authenticate by comparing it with sender                    */                    strcpy(curadminmail,getcuradmin(secfile));                    strcpy(wrkline,curadminmail);                    if ((cp = index(wrkline,'@')) != 0)                             *cp = '\0';                    strcpy(wrkline1,realsender);                    if ((cp = index(wrkline1,'@')) != 0)                             *cp = '\0';                    if ( (strncmp(wrkline,wrkline1,sizeof(wrkline)) != 0) ) {                    /*                    ** some exceptions....                    */                    strcpy(wrkline,NEDITOR);                    if ((cp  = index(wrkline,'@')) != 0)                        *cp = '\0';                    if ( (strncmp(wrkline,wrkline1,sizeof(wrkline)) == 0)||                         strncmp(wrkline,"root",sizeof("root")) == 0)                        goto except;                    sprintf(wrkline,                    "%s: sender: %s and current adminmail: %s don't match",                    progname,realsender,curadminmail);                    mail(NEDITOR,wrkline, JTY,0,0);                    upexit(FAKEFAIL);                }            except:                    /*                    ** open temporary file.                    */                    pid = getpid();                     sprintf(tempfile,"%s%d",TEMPFILEPREF,pid);                    if ( (tfd = fopen(tempfile,"w+")) == 0) {                        sprintf(wrkline,"%s: Can't fopen() %s",                        progname,tempfile);                        mail(NEDITOR,wrkline,JTY,0,0);                        upexit(FAKEFAIL);                    }                    if ( (fputs("##\n",tfd)) == EOF) {                        sprintf(wrkline,"%s: %s: Write failed",                         progname, tempfile);                        mail(NEDITOR,wrkline,JTY,0,0);                        upexit(FAKEFAIL);                    }                    fputs(line,tfd);                    fputc('\n',tfd);                    break;                case END:                    /*                    **   if end then close file, make sure begin and                    **  end agree. complain and die if not. otherwise                    **  send mail that things are ok                    */                    strcpy(wrkline,HOSTDIR);                    strcat(wrkline,arg);                    if (strncmp(wrkline,secfile,strlen(tempfile)) != 0) {                        sprintf(wrkline,"%s %s",NEDITOR,adminmail);                        sprintf(wrkline1,                        "%s: 'End:' arg disagreed with 'Begin:' arg",progname);                        mail(wrkline,wrkline1,JTY,0,0);                        upexit(FAKEFAIL);                    }                    fputs(line,tfd);                    fputc('\n',tfd);                    fputs("##\n",tfd);                    (void)fseek(tfd,0L,0);                    if ( (fd = fopen(secfile,"w")) == 0) {                        sprintf(wrkline,"%s: Can't fopen() %s",                        progname,secfile);                        mail(NEDITOR,wrkline,JTY,0,0);                        upexit(FAKEFAIL);                    }                    while( (freadcount = fread(wrkline,                                         sizeof(*wrkline),                                        sizeof(wrkline),tfd))  > 0)                        if ((fwrite(wrkline,