/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Mail -- a mail program
 *
 * Handle name lists.
 */

#include "rcv.h"
#include <fcntl.h>
#include "extern.h"

/*
 * Allocate a single element of a name list,
 * initialize its name field to the passed
 * name and return it.
 */
struct name *
nalloc(char str[], int ntype)
{
        struct name *np;

        np = (struct name *)salloc(sizeof(*np));
        np->n_flink = NULL;
        np->n_blink = NULL;
        np->n_type = ntype;
        np->n_name = savestr(str);
        return (np);
}

/*
 * Find the tail of a list and return it.
 */
struct name *
tailof(struct name *name)
{
        struct name *np;

        np = name;
        if (np == NULL)
                return (NULL);
        while (np->n_flink != NULL)
                np = np->n_flink;
        return (np);
}

/*
 * Extract a list of names from a line,
 * and make a list of names from it.
 * Return the list or NULL if none found.
 */
struct name *
extract(char *line, int ntype)
{
        char *cp, *nbuf;
        struct name *top, *np, *t;

        if (line == NULL || *line == '\0')
                return (NULL);
        if ((nbuf = malloc(strlen(line) + 1)) == NULL)
                err(1, "Out of memory");
        top = NULL;
        np = NULL;
        cp = line;
        while ((cp = yankword(cp, nbuf)) != NULL) {
                t = nalloc(nbuf, ntype);
                if (top == NULL)
                        top = t;
                else
                        np->n_flink = t;
                t->n_blink = np;
                np = t;
        }
        (void)free(nbuf);
        return (top);
}

/*
 * Turn a list of names into a string of the same names.
 */
char *
detract(struct name *np, int ntype)
{
        int s, comma;
        char *cp, *top;
        struct name *p;

        comma = ntype & GCOMMA;
        if (np == NULL)
                return (NULL);
        ntype &= ~GCOMMA;
        s = 0;
        if (debug && comma)
                fprintf(stderr, "detract asked to insert commas\n");
        for (p = np; p != NULL; p = p->n_flink) {
                if (ntype && (p->n_type & GMASK) != ntype)
                        continue;
                s += strlen(p->n_name) + 1;
                if (comma)
                        s++;
        }
        if (s == 0)
                return (NULL);
        s += 2;
        top = salloc(s);
        cp = top;
        for (p = np; p != NULL; p = p->n_flink) {
                if (ntype && (p->n_type & GMASK) != ntype)
                        continue;
                cp += strlcpy(cp, p->n_name, strlen(p->n_name) + 1);
                if (comma && p->n_flink != NULL)
                        *cp++ = ',';
                *cp++ = ' ';
        }
        *--cp = '\0';
        if (comma && *--cp == ',')
                *cp = '\0';
        return (top);
}

/*
 * Grab a single word (liberal word)
 * Throw away things between ()'s, and take anything between <>.
 */
char *
yankword(char *ap, char *wbuf)
{
        char *cp, *cp2;

        cp = ap;
        for (;;) {
                if (*cp == '\0')
                        return (NULL);
                if (*cp == '(') {
                        int nesting = 0;

                        while (*cp != '\0') {
                                switch (*cp++) {
                                case '(':
                                        nesting++;
                                        break;
                                case ')':
                                        --nesting;
                                        break;
                                }
                                if (nesting <= 0)
                                        break;
                        }
                } else if (*cp == ' ' || *cp == '\t' || *cp == ',')
                        cp++;
                else
                        break;
        }
        if (*cp ==  '<')
                for (cp2 = wbuf; *cp && (*cp2++ = *cp++) != '>';)
                        ;
        else
                for (cp2 = wbuf; *cp != '\0' && strchr(" \t,(", *cp) == NULL;
                    *cp2++ = *cp++)
                        ;
        *cp2 = '\0';
        return (cp);
}

/*
 * Grab a single login name (liberal word)
 * Throw away things between ()'s, take anything between <>,
 * and look for words before metacharacters %, @, !.
 */
char *
yanklogin(char *ap, char *wbuf)
{
        char *cp, *cp2, *cp_temp;
        int n;

        cp = ap;
        for (;;) {
                if (*cp == '\0')
                        return (NULL);
                if (*cp == '(') {
                        int nesting = 0;

                        while (*cp != '\0') {
                                switch (*cp++) {
                                case '(':
                                        nesting++;
                                        break;
                                case ')':
                                        --nesting;
                                        break;
                                }
                                if (nesting <= 0)
                                        break;
                        }
                } else if (*cp == ' ' || *cp == '\t' || *cp == ',')
                        cp++;
                else
                        break;
        }

        /*
         * Now, let's go forward till we meet the needed character,
         * and step one word back.
         */

        /* First, remember current point. */
        cp_temp = cp;
        n = 0;

        /*
         * Note that we look ahead in a cycle. This is safe, since
         * non-end of string is checked first.
         */
        while(*cp != '\0' && strchr("@%!", *(cp + 1)) == NULL)
                cp++;

        /*
         * Now, start stepping back to the first non-word character,
         * while counting the number of symbols in a word.
         */
        while(cp != cp_temp && strchr(" \t,<>", *(cp - 1)) == NULL) {
                n++;
                cp--;
        }

        /* Finally, grab the word forward. */
        cp2 = wbuf;
        while(n >= 0) {
                *cp2++=*cp++;
                n--;
        }

        *cp2 = '\0';
        return (cp);
}

/*
 * For each recipient in the passed name list with a /
 * in the name, append the message to the end of the named file
 * and remove him from the recipient list.
 *
 * Recipients whose name begins with | are piped through the given
 * program and removed.
 */
struct name *
outof(struct name *names, FILE *fo, struct header *hp)
{
        int c, ispipe;
        struct name *np, *top;
        time_t now;
        char *date, *fname;
        FILE *fout, *fin;

        top = names;
        np = names;
        (void)time(&now);
        date = ctime(&now);
        while (np != NULL) {
                if (!isfileaddr(np->n_name) && np->n_name[0] != '|') {
                        np = np->n_flink;
                        continue;
                }
                ispipe = np->n_name[0] == '|';
                if (ispipe)
                        fname = np->n_name+1;
                else
                        fname = expand(np->n_name);

                /*
                 * See if we have copied the complete message out yet.
                 * If not, do so.
                 */

                if (image < 0) {
                        int fd;
                        char tempname[PATHSIZE];

                        (void)snprintf(tempname, sizeof(tempname),
                            "%s/mail.ReXXXXXXXXXX", tmpdir);
                        if ((fd = mkstemp(tempname)) == -1 ||
                            (fout = Fdopen(fd, "a")) == NULL) {
                                warn("%s", tempname);
                                senderr++;
                                goto cant;
                        }
                        image = open(tempname, O_RDWR);
                        (void)rm(tempname);
                        if (image < 0) {
                                warn("%s", tempname);
                                senderr++;
                                (void)Fclose(fout);
                                goto cant;
                        }
                        (void)fcntl(image, F_SETFD, 1);
                        fprintf(fout, "From %s %s", myname, date);
                        puthead(hp, fout,
                            GTO|GSUBJECT|GCC|GREPLYTO|GINREPLYTO|GNL);
                        while ((c = getc(fo)) != EOF)
                                (void)putc(c, fout);
                        rewind(fo);
                        fprintf(fout, "\n");
                        (void)fflush(fout);
                        if (ferror(fout)) {
                                warn("%s", tempname);
                                senderr++;
                                (void)Fclose(fout);
                                goto cant;
                        }
                        (void)Fclose(fout);
                }

                /*
                 * Now either copy "image" to the desired file
                 * or give it as the standard input to the desired
                 * program as appropriate.
                 */

                if (ispipe) {
                        int pid;
                        char *sh;
                        sigset_t nset;

                        /*
                         * XXX
                         * We can't really reuse the same image file,
                         * because multiple piped recipients will
                         * share the same lseek location and trample
                         * on one another.
                         */
                        if ((sh = value("SHELL")) == NULL)
                                sh = _PATH_CSHELL;
                        (void)sigemptyset(&nset);
                        (void)sigaddset(&nset, SIGHUP);
                        (void)sigaddset(&nset, SIGINT);
                        (void)sigaddset(&nset, SIGQUIT);
                        pid = start_command(sh, &nset, image, -1, "-c", fname,
                            NULL);
                        if (pid < 0) {
                                senderr++;
                                goto cant;
                        }
                        free_child(pid);
                } else {
                        int f;
                        if ((fout = Fopen(fname, "a")) == NULL) {
                                warn("%s", fname);
                                senderr++;
                                goto cant;
                        }
                        if ((f = dup(image)) < 0) {
                                warn("dup");
                                fin = NULL;
                        } else
                                fin = Fdopen(f, "r");
                        if (fin == NULL) {
                                fprintf(stderr, "Can't reopen image\n");
                                (void)Fclose(fout);
                                senderr++;
                                goto cant;
                        }
                        rewind(fin);
                        while ((c = getc(fin)) != EOF)
                                (void)putc(c, fout);
                        if (ferror(fout)) {
                                warnx("%s", fname);
                                senderr++;
                                (void)Fclose(fout);
                                (void)Fclose(fin);
                                goto cant;
                        }
                        (void)Fclose(fout);
                        (void)Fclose(fin);
                }
cant:
                /*
                 * In days of old we removed the entry from the
                 * the list; now for sake of header expansion
                 * we leave it in and mark it as deleted.
                 */
                np->n_type |= GDEL;
                np = np->n_flink;
        }
        if (image >= 0) {
                (void)close(image);
                image = -1;
        }
        return (top);
}

/*
 * Determine if the passed address is a local "send to file" address.
 * If any of the network metacharacters precedes any slashes, it can't
 * be a filename.  We cheat with .'s to allow path names like ./...
 */
int
isfileaddr(char *name)
{
        char *cp;

        if (*name == '+')
                return (1);
        for (cp = name; *cp != '\0'; cp++) {
                if (*cp == '!' || *cp == '%' || *cp == '@')
                        return (0);
                if (*cp == '/')
                        return (1);
        }
        return (0);
}

/*
 * Map all of the aliased users in the invoker's mailrc
 * file and insert them into the list.
 * Changed after all these months of service to recursively
 * expand names (2/14/80).
 */

struct name *
usermap(struct name *names)
{
        struct name *new, *np, *cp;
        struct grouphead *gh;
        int metoo;

        new = NULL;
        np = names;
        metoo = (value("metoo") != NULL);
        while (np != NULL) {
                if (np->n_name[0] == '\\') {
                        cp = np->n_flink;
                        new = put(new, np);
                        np = cp;
                        continue;
                }
                gh = findgroup(np->n_name);
                cp = np->n_flink;
                if (gh != NULL)
                        new = gexpand(new, gh, metoo, np->n_type);
                else
                        new = put(new, np);
                np = cp;
        }
        return (new);
}

/*
 * Recursively expand a group name.  We limit the expansion to some
 * fixed level to keep things from going haywire.
 * Direct recursion is not expanded for convenience.
 */

struct name *
gexpand(struct name *nlist, struct grouphead *gh, int metoo, int ntype)
{
        struct group *gp;
        struct grouphead *ngh;
        struct name *np;
        static int depth;
        char *cp;

        if (depth > MAXEXP) {
                printf("Expanding alias to depth larger than %d\n", MAXEXP);
                return (nlist);
        }
        depth++;
        for (gp = gh->g_list; gp != NULL; gp = gp->ge_link) {
                cp = gp->ge_name;
                if (*cp == '\\')
                        goto quote;
                if (strcmp(cp, gh->g_name) == 0)
                        goto quote;
                if ((ngh = findgroup(cp)) != NULL) {
                        nlist = gexpand(nlist, ngh, metoo, ntype);
                        continue;
                }
quote:
                np = nalloc(cp, ntype);
                /*
                 * At this point should allow to expand
                 * to self if only person in group
                 */
                if (gp == gh->g_list && gp->ge_link == NULL)
                        goto skip;
                if (!metoo && strcmp(cp, myname) == 0)
                        np->n_type |= GDEL;
skip:
                nlist = put(nlist, np);
        }
        depth--;
        return (nlist);
}

/*
 * Concatenate the two passed name lists, return the result.
 */
struct name *
cat(struct name *n1, struct name *n2)
{
        struct name *tail;

        if (n1 == NULL)
                return (n2);
        if (n2 == NULL)
                return (n1);
        tail = tailof(n1);
        tail->n_flink = n2;
        n2->n_blink = tail;
        return (n1);
}

/*
 * Unpack the name list onto a vector of strings.
 * Return an error if the name list won't fit.
 */
char **
unpack(struct name *np)
{
        char **ap, **top;
        struct name *n;
        int t, extra, metoo, verbose;

        n = np;
        if ((t = count(n)) == 0)
                errx(1, "No names to unpack");
        /*
         * Compute the number of extra arguments we will need.
         * We need at least two extra -- one for "mail" and one for
         * the terminating 0 pointer.  Additional spots may be needed
         * to pass along -f to the host mailer.
         */
        extra = 2;
        extra++;
        metoo = value("metoo") != NULL;
        if (metoo)
                extra++;
        verbose = value("verbose") != NULL;
        if (verbose)
                extra++;
        top = (char **)salloc((t + extra) * sizeof(*top));
        ap = top;
        *ap++ = "sendmail";
        *ap++ = "-i";
        if (metoo)
                *ap++ = "-m";
        if (verbose)
                *ap++ = "-v";
        for (; n != NULL; n = n->n_flink)
                if ((n->n_type & GDEL) == 0)
                        *ap++ = n->n_name;
        *ap = NULL;
        return (top);
}

/*
 * Remove all of the duplicates from the passed name list by
 * insertion sorting them, then checking for dups.
 * Return the head of the new list.
 */
struct name *
elide(struct name *names)
{
        struct name *np, *t, *new;
        struct name *x;

        if (names == NULL)
                return (NULL);
        new = names;
        np = names;
        np = np->n_flink;
        if (np != NULL)
                np->n_blink = NULL;
        new->n_flink = NULL;
        while (np != NULL) {
                t = new;
                while (strcasecmp(t->n_name, np->n_name) < 0) {
                        if (t->n_flink == NULL)
                                break;
                        t = t->n_flink;
                }

                /*
                 * If we ran out of t's, put the new entry after
                 * the current value of t.
                 */

                if (strcasecmp(t->n_name, np->n_name) < 0) {
                        t->n_flink = np;
                        np->n_blink = t;
                        t = np;
                        np = np->n_flink;
                        t->n_flink = NULL;
                        continue;
                }

                /*
                 * Otherwise, put the new entry in front of the
                 * current t.  If at the front of the list,
                 * the new guy becomes the new head of the list.
                 */

                if (t == new) {
                        t = np;
                        np = np->n_flink;
                        t->n_flink = new;
                        new->n_blink = t;
                        t->n_blink = NULL;
                        new = t;
                        continue;
                }

                /*
                 * The normal case -- we are inserting into the
                 * middle of the list.
                 */

                x = np;
                np = np->n_flink;
                x->n_flink = t;
                x->n_blink = t->n_blink;
                t->n_blink->n_flink = x;
                t->n_blink = x;
        }

        /*
         * Now the list headed up by new is sorted.
         * Go through it and remove duplicates.
         */

        np = new;
        while (np != NULL) {
                t = np;
                while (t->n_flink != NULL &&
                    strcasecmp(np->n_name, t->n_flink->n_name) == 0)
                        t = t->n_flink;
                if (t == np || t == NULL) {
                        np = np->n_flink;
                        continue;
                }

                /*
                 * Now t points to the last entry with the same name
                 * as np.  Make np point beyond t.
                 */

                np->n_flink = t->n_flink;
                if (t->n_flink != NULL)
                        t->n_flink->n_blink = np;
                np = np->n_flink;
        }
        return (new);
}

/*
 * Put another node onto a list of names and return
 * the list.
 */
struct name *
put(struct name *list, struct name *node)
{
        node->n_flink = list;
        node->n_blink = NULL;
        if (list != NULL)
                list->n_blink = node;
        return (node);
}

/*
 * Determine the number of undeleted elements in
 * a name list and return it.
 */
int
count(struct name *np)
{
        int c;

        for (c = 0; np != NULL; np = np->n_flink)
                if ((np->n_type & GDEL) == 0)
                        c++;
        return (c);
}

/*
 * Delete the given name from a namelist.
 */
struct name *
delname(struct name *np, char name[])
{
        struct name *p;

        for (p = np; p != NULL; p = p->n_flink)
                if (strcasecmp(p->n_name, name) == 0) {
                        if (p->n_blink == NULL) {
                                if (p->n_flink != NULL)
                                        p->n_flink->n_blink = NULL;
                                np = p->n_flink;
                                continue;
                        }
                        if (p->n_flink == NULL) {
                                if (p->n_blink != NULL)
                                        p->n_blink->n_flink = NULL;
                                continue;
                        }
                        p->n_blink->n_flink = p->n_flink;
                        p->n_flink->n_blink = p->n_blink;
                }
        return (np);
}

/*
 * Pretty print a name list
 * Uncomment it if you need it.
 */

/*
void
prettyprint(struct name *name)
{
        struct name *np;

        np = name;
        while (np != NULL) {
                fprintf(stderr, "%s(%d) ", np->n_name, np->n_type);
                np = np->n_flink;
        }
        fprintf(stderr, "\n");
}
*/