w3mail

dirpop3d.c (5428B)

---

 /*
 
   dirpop3d -- pop3 server for w3mail
 
   Copyright (C) 2011 Tomas Hlavaty
 
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.
 
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see
   <http://www.gnu.org/licenses/>.
 
 */
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
 #include <unistd.h>
 
 #include "utils.h"
 
 struct msg {
   int deleted;
   int nbytes;
   char *fname;
 };
 
 struct flist {
   int len;
   int n;
   int nbytes;
   struct msg msg[];
 };
 
 static int sizeof_flist(int len) {
   return 3 * sizeof(int) + sizeof(struct msg) * len;
 }
 
 static struct flist *flist_new(int len) {
   struct flist *x = malloc(sizeof_flist(len));
   x->len = len;
   x->n = 0;
   x->nbytes = 0;
   return x;
 }
 
 static void flist_free(struct flist *x) {
   for(int i = 0; i < x->n; i++)
     free(x->msg[i].fname);
   free(x);
 }
 
 static struct flist *flist_realloc(struct flist *x, int len) {
   if(x->len < len) {
     struct flist *y = realloc(x, sizeof_flist(len));
     y->len = len;
     return y;
   }
   return x;
 }
 
 static struct flist *flist_add(struct flist *x, char *fname, int nbytes) {
   if(x->len <= x->n)
     x = flist_realloc(x, x->len + 100);
   x->nbytes += nbytes;
   struct msg *y = &x->msg[x->n++];
   y->deleted = 0;
   y->nbytes = nbytes;
   y->fname = malloc(strlen(fname) + 1);
   strcpy(y->fname, fname);
   return x;
 }
 
 struct xlist {
   struct flist *flist;
 };
 
 static int list_cb(void *udata, char *path, char *fname, struct dirent *e, struct stat *s) {
   struct xlist *x = udata;
   if(S_ISREG(s->st_mode))
     x->flist = flist_add(x->flist, fname, s->st_size);
   return 1;
 }
 
 static int line(int fd, char *buf, char *end) {
   int n = 0;
   while(buf < end) {
     char c;
     int m = read(fd, &c, sizeof(char));
     if(m <= 0) break;
     if(m != sizeof(char)) exit(-1);
     *buf++ = c;
     n++;
     if('\n' == c) break;
   }
   return n;
 }
 
 static inline void crlf() {
   printf("\r\n");
   fflush(stdout);
 }
 
 static void pr(char *fmt, ...) {
   va_list v;
   va_start(v, fmt);
   vprintf(fmt, v);
   crlf();
   va_end(v);
 }
 
 int main(int argc, char *argv[]) {
   if(argc != 2) quit(1, "Usage: %s rootdir", argv[0]);
   char *rootdir = argv[1];
   pr("+OK dirpop3d ready");
   enum {START, USER, PASS, STAT, LIST} state = START;
   char cmd[BLEN], usr[BLEN], pwd[BLEN];
   struct flist *flist = NULL;
   char buf[BLEN];
   for(int n; 0 < (n = line(0, buf, buf + BLEN));) {
     rtrim(buf);
     sscanf(buf, "%s", cmd);
     if(0 == strcmp("QUIT", cmd)) {
       if(flist) {
         for(int i = 0; i < flist->n; i++) {
           struct msg *x = &flist->msg[i];
           if(x->deleted) unlink(x->fname);
         }
         flist_free(flist);
         flist = NULL;
       }
       pr("+OK dirpop3d bye");
       break;
     }
     else if(0 == strcmp("USER", cmd)) {
       if(state != START) pr("-ERR");
       else {
         sscanf(buf, "%s %s", cmd, usr);
         pr("+OK hi %s", usr);
         state = USER;
       }
     }
     else if(0 == strcmp("PASS", cmd)) {
       if(state != USER) pr("-ERR");
       else {
         sscanf(buf, "%s %s", cmd, pwd);
         pr("+OK welcome %s", usr);
         state = PASS;
       }
     }
     else if(0 == strcmp("STAT", cmd)) {
       if(state != PASS) pr("-ERR");
       else {
         if(!flist) {
           flist = flist_new(100);
           struct xlist x = {flist};
           dir(&x, list_cb, "%s/%s", rootdir, usr);
           flist = x.flist;
         }
         pr("+OK %d %d", flist->n, flist->nbytes);
         state = STAT;
       }
     }
     else if(0 == strcmp("LIST", cmd)) {
       if(state != STAT) pr("-ERR");
       else {
         pr("+OK %d messages (%d octets)", flist->n, flist->nbytes);
         for(int i = 0; i < flist->n; i++)
           pr("%d %d", i + 1, flist->msg[i].nbytes);
         pr(".");
         state = LIST;
       }
     }
     else if(0 == strcmp("RETR", cmd)) {
       if(state != STAT) pr("-ERR");
       else {
         int n = 0;
         sscanf(buf, "%s %d", cmd, &n);
         if(0 < n && n <= flist->n) {
           struct msg *x = &flist->msg[n - 1];
           pr("+OK %d octets", x->nbytes);
           FILE *in = fopen(x->fname, "r");
           if(!in) die(1, "echo(): cannot open input file '%s'", x->fname);
           /* Note that the served files must have lines shorter than
              BLEN and no single dot char on its own line.  Therefore
              use base64 for the message body. */
           char buf[BLEN];
           while(fgets(buf, BLEN, in)) {
             rtrim(buf);
             pr("%s", buf);
           }
           fclose(in);
           pr(".");
         }
         else pr("-ERR");
       }
     }
     else if(0 == strcmp("DELE", cmd)) {
       if(state != STAT) pr("-ERR");
       else {
         int n = 0;
         sscanf(buf, "%s %d", cmd, &n);
         if(0 < n && n <= flist->n) {
           struct msg *x = &flist->msg[n - 1];
           x->deleted = 1;
           pr("+OK message %d deleted", n);
         }
         else pr("-ERR");
       }
     }
     else pr("-ERR wrong command");
   }
 }