pop3.c

   1 /*
   2  * A NEAT POP3 MAIL CLIENT
   3  *
   4  * Copyright (C) 2010-2021 Ali Gholami Rudi
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18 #include <ctype.h>
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <netdb.h>
  22 #include <signal.h>
  23 #include <stdarg.h>
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <string.h>
  27 #include <time.h>
  28 #include <unistd.h>
  29 #include "conf.h"
  30 #include "uidl.h"
  31 #include "conn.h"
  32
  33 #define BUFFSIZE                (1 << 12)
  34 #define ARRAY_SIZE(a)           (sizeof(a) / sizeof((a)[0]))
  35 #define MIN(a, b)               ((a) < (b) ? (a) : (b))
  36
  37 static struct mailinfo {
  38         char name[1 << 4];
  39         char id[1 << 6];
  40         int size;
  41 } *mails;                       /* pop3 message list */
  42 static int mails_n;
  43 static int mails_sz;
  44 static struct uidl *uidl;
  45
  46 static char buf[BUFFSIZE];      /* pop3 input buffer */
  47 static int buf_len;
  48 static int buf_pos;
  49 static struct conn *conn;       /* pop3 connection */
  50 static char *mailbuf;           /* message content */
  51 static int mailbuf_sz;
  52 static int mailbuf_maxsz;       /* the maximum message length */
  53
  54 static int pop3_read(void)
  55 {
  56         if (buf_pos == buf_len) {
  57                 buf_len = conn_read(conn, buf, sizeof(buf));
  58                 buf_pos = 0;
  59         }
  60         return buf_pos < buf_len ? (unsigned char) buf[buf_pos++] : -1;
  61 }
  62
  63 /* read a line from the server */
  64 static int pop3_get(char *dst, int len)
  65 {
  66         int i = 0;
  67         int c;
  68         while (i < len - 1) {
  69                 c = pop3_read();
  70                 if (c < 0)
  71                         return -1;
  72                 dst[i++] = c;
  73                 if (c == '\n')
  74                         break;
  75         }
  76         dst[i] = '\0';
  77         LOG(dst);
  78         return i;
  79 }
  80
  81 /* read a pop3 response line */
  82 static int pop3_res(char *dst, int len)
  83 {
  84         pop3_get(dst, len);
  85         if (dst[0] != '+')
  86                 printf("%s", dst);
  87         return dst[0] != '+';
  88 }
  89
  90 /* send a pop3 command */
  91 static void pop3_cmd(char *cmd, ...)
  92 {
  93         static char buf[512];
  94         va_list ap;
  95         va_start(ap, cmd);
  96         vsnprintf(buf, sizeof(buf), cmd, ap);
  97         va_end(ap);
  98         conn_write(conn, buf, strlen(buf));
  99         LOG(buf);
 100 }
 101
 102 static int pop3_iseoc(char *line, int len)
 103 {
 104         return len >= 2 && len <= 3 && line[0] == '.' &&
 105                 (line[1] == '\r' || line[1] == '\n');
 106 }
 107
 108 static int pop3_login(char *user, char *pass)
 109 {
 110         char line[BUFFSIZE];
 111         pop3_cmd("USER %s\r\n", user);
 112         if (pop3_res(line, sizeof(line)))
 113                 return 1;
 114         pop3_cmd("PASS %s\r\n", pass);
 115         if (pop3_res(line, sizeof(line)))
 116                 return 1;
 117         return 0;
 118 }
 119
 120 static int pop3_stat(void)
 121 {
 122         char line[BUFFSIZE];
 123         int len;
 124         pop3_cmd("STAT\r\n");
 125         if (pop3_res(line, sizeof(line)))
 126                 return 1;
 127         printf("%s", line);
 128         pop3_cmd("LIST\r\n");
 129         if (pop3_res(line, sizeof(line)))
 130                 return 1;
 131         while ((len = pop3_get(line, sizeof(line))) >= 0) {
 132                 struct mailinfo *mail;
 133                 if (pop3_iseoc(line, len))
 134                         break;
 135                 if (mails_n == mails_sz) {
 136                         struct mailinfo *mails_old = mails;
 137                         mails_sz = mails_sz + (mails_sz ? mails_sz : 256);
 138                         mails = malloc(mails_sz * sizeof(mails[0]));
 139                         memcpy(mails, mails_old, mails_n * sizeof(mails[0]));
 140                         free(mails_old);
 141                 }
 142                 mail = &mails[mails_n++];
 143                 sscanf(line, "%s %d", mail->name, &mail->size);
 144         }
 145         return 0;
 146 }
 147
 148 static int pop3_uidl(void)
 149 {
 150         char line[BUFFSIZE];
 151         char name[128];
 152         int len;
 153         int i = 0;
 154         pop3_cmd("UIDL\r\n");
 155         if (pop3_res(line, sizeof(line)))
 156                 return 1;
 157         while ((len = pop3_get(line, sizeof(line))) > 0 && !pop3_iseoc(line, len))
 158                 sscanf(line, "%s %s", name, mails[i++].id);
 159         return 0;
 160 }
 161
 162 static void pop3_retr(int i)
 163 {
 164         pop3_cmd("RETR %s\r\n", mails[i].name);
 165 }
 166
 167 static char *mail_dst(char *hdr, int len)
 168 {
 169         int i;
 170         hdr[len] = '\0';
 171         for (i = 0; i < ARRAY_SIZE(filters); i++)
 172                 if (!strncmp(filters[i].hdr, hdr, strlen(filters[i].hdr)) &&
 173                                 strstr(hdr, filters[i].val))
 174                         return filters[i].dst;
 175         return NULL;
 176 }
 177
 178 static int xwrite(int fd, char *buf, int len)
 179 {
 180         int nw = 0;
 181         while (nw < len) {
 182                 int ret = write(fd, buf + nw, len - nw);
 183                 if (ret == -1 && (errno == EAGAIN || errno == EINTR))
 184                         continue;
 185                 if (ret < 0)
 186                         break;
 187                 nw += ret;
 188         }
 189         return nw;
 190 }
 191
 192 static int mail_write(char *dst, char *mail, int len)
 193 {
 194         int fd = open(dst, O_WRONLY | O_APPEND | O_CREAT, 0600);
 195         if (fd < 0)
 196                 return 1;
 197         if (xwrite(fd, mail, len) != len)
 198                 return 1;
 199         close(fd);
 200         return 0;
 201 }
 202
 203 static int mail_from_(char *s)
 204 {
 205         char date[128];
 206         time_t t;
 207         time(&t);
 208         strftime(date, sizeof(date), "%a %b %d %H:%M:%S %Y", localtime(&t));
 209         return sprintf(s, "From %s %s\n", getenv("USER") ? getenv("USER") : "root", date);
 210 }
 211
 212 static int pop3_lonefrom_(char *s)
 213 {
 214         while (*s == '>')
 215                 s++;
 216         return !strncmp("From ", s, 5);
 217 }
 218
 219 static int fetch_one(int i)
 220 {
 221         char line[BUFFSIZE];
 222         char *dst = NULL;
 223         int pos = 0;
 224         int hdr = 1;
 225         int ret;
 226         if (pop3_res(line, sizeof(line)))
 227                 return 1;
 228         printf("%s", mails[i].name);
 229         fflush(stdout);
 230         pos = mail_from_(mailbuf);
 231         while (1) {
 232                 int len = pop3_get(line, sizeof(line));
 233                 if (len <= 0)           /* end of stream or error */
 234                         return 1;
 235                 if (pop3_iseoc(line, len))
 236                         break;
 237                 if (len > 1 && line[len - 2] == '\r')
 238                         line[len-- - 2] = '\n';
 239                 if (line[0] == '\n')
 240                         hdr = 0;
 241                 if (hdr && !dst)
 242                         dst = mail_dst(line, len);
 243                 while (pos + len + 2 >= mailbuf_sz) {
 244                         mailbuf_sz += mailbuf_sz ? mailbuf_sz : 512;
 245                         mailbuf = realloc(mailbuf, mailbuf_sz);
 246                 }
 247                 if (pop3_lonefrom_(line))
 248                         mailbuf[pos++] = '>';
 249                 memcpy(mailbuf + pos, line, len);
 250                 pos += len;
 251         }
 252         mailbuf[pos++] = '\n';
 253         if (!dst)
 254                 dst = SPOOL;
 255         ret = mail_write(dst, mailbuf, pos);
 256         printf(" -> %s%s\n", dst, ret ? " [failed]" : "");
 257         return ret;
 258 }
 259
 260 static void pop3_del(int i)
 261 {
 262         pop3_cmd("DELE %s\r\n", mails[i].name);
 263 }
 264
 265 static int size_ok(int i)
 266 {
 267         return mailbuf_maxsz <= 0 || mails[i].size < mailbuf_maxsz;
 268 }
 269
 270 static int uidl_new(int i)
 271 {
 272         return !uidl || !uidl_find(uidl, mails[i].id);
 273 }
 274
 275 static int fetch_mails(int beg, int end, int del)
 276 {
 277         char line[BUFFSIZE];
 278         int i;
 279         for (i = beg; i < end; i++)
 280                 if (size_ok(i) && uidl_new(i))
 281                         pop3_retr(i);
 282         for (i = beg; i < end; i++) {
 283                 if (size_ok(i) && uidl_new(i)) {
 284                         if (fetch_one(i))
 285                                 return 1;
 286                         if (uidl)
 287                                 uidl_add(uidl, mails[i].id);
 288                 }
 289         }
 290         if (del) {
 291                 for (i = beg; i < end; i++)
 292                         if ((!uidl && size_ok(i)) || (uidl && !uidl_new(i)))
 293                                 pop3_del(i);
 294                 for (i = beg; i < end; i++)
 295                         if ((!uidl && size_ok(i)) || (uidl && !uidl_new(i)))
 296                                 pop3_get(line, sizeof(line));
 297         }
 298         return 0;
 299 }
 300
 301 static int fetch(struct account *account)
 302 {
 303         char line[BUFFSIZE];
 304         int batch;
 305         int failed = 0;
 306         int i;
 307         mails_n = 0;
 308         conn = conn_connect(account->server, account->port);
 309         if (!conn)
 310                 return 1;
 311         if (account->stls) {
 312                 if (pop3_res(line, sizeof(line)))
 313                         return 1;
 314                 pop3_cmd("STLS\r\n");
 315                 if (pop3_res(line, sizeof(line)))
 316                         return 1;
 317         }
 318         if (conn_tls(conn, account->cert)) {
 319                 conn_close(conn);
 320                 return 1;
 321         }
 322         buf_pos = 0;
 323         buf_len = 0;
 324         if (account->uidl)
 325                 uidl = uidl_read(account->uidl);
 326         printf("fetching %s@%s\n", account->user, account->server);
 327         if (!account->stls)
 328                 if (pop3_res(line, sizeof(line)))
 329                         return 1;
 330         if (pop3_login(account->user, account->pass))
 331                 return 1;
 332         if (pop3_stat())
 333                 return 1;
 334         if (account->uidl)
 335                 if (pop3_uidl())
 336                         return 1;
 337         batch = account->nopipe ? 1 : mails_n;
 338         for (i = 0; i < mails_n; i += batch)
 339                 if ((failed = fetch_mails(i, MIN(mails_n, i + batch), account->del)))
 340                         break;
 341         if (!failed) {
 342                 pop3_cmd("QUIT\r\n");
 343                 pop3_get(line, sizeof(line));
 344         }
 345         conn_close(conn);
 346         if (uidl)
 347                 uidl_save(uidl);
 348         uidl = NULL;
 349         return failed;
 350 }
 351
 352 static void sigint(int sig)
 353 {
 354         if (uidl)
 355                 uidl_save(uidl);
 356         exit(1);
 357 }
 358
 359 int main(int argc, char *argv[])
 360 {
 361         int i;
 362         signal(SIGINT, sigint);
 363         mailbuf_sz = 1 << 21;
 364         mailbuf = malloc(mailbuf_sz);
 365         for (i = 0; i < ARRAY_SIZE(accounts); i++) {
 366                 mailbuf_maxsz = accounts[i].maxsize;
 367                 fetch(&accounts[i]);
 368         }
 369         free(mailbuf);
 370         free(mails);
 371         return 0;
 372 }