pop3.c

   1 /*
   2  * A NEAT POP3 MAIL CLIENT
   3  *
   4  * Copyright (C) 2010-2017 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 <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <time.h>
  27 #include <unistd.h>
  28 #include "conf.h"
  29 #include "uidl.h"
  30 #include "conn.h"
  31
  32 #define BUFFSIZE                (1 << 12)
  33 #define ARRAY_SIZE(a)           (sizeof(a) / sizeof((a)[0]))
  34 #define MIN(a, b)               ((a) < (b) ? (a) : (b))
  35 #define PRINT(s, l)             (write(1, (s), (l)))
  36
  37 static struct mailinfo {
  38         char name[1 << 4];
  39         char id[1 << 6];
  40         int size;
  41 } mails[MAXMAILS];
  42 static int nmails;
  43 static struct uidl *uidl;
  44
  45 static char buf[BUFFSIZE];
  46 static int buf_len;
  47 static int buf_pos;
  48 static struct conn *conn;
  49 static char *mailbuf;
  50
  51 static int pop3_read(void)
  52 {
  53         if (buf_pos == buf_len) {
  54                 buf_len = conn_read(conn, buf, sizeof(buf));
  55                 buf_pos = 0;
  56         }
  57         return buf_pos < buf_len ? (unsigned char) buf[buf_pos++] : -1;
  58 }
  59
  60 static int pop3_get(char *dst, int len)
  61 {
  62         int i = 0;
  63         int c;
  64         while (i < len - 1) {
  65                 c = pop3_read();
  66                 if (c < 0)
  67                         return -1;
  68                 dst[i++] = c;
  69                 if (c == '\n')
  70                         break;
  71         }
  72         dst[i] = '\0';
  73         DPRINT(dst, i);
  74         return i;
  75 }
  76
  77 static void pop3_cmd(char *cmd)
  78 {
  79         conn_write(conn, cmd, strlen(cmd));
  80         DPRINT(cmd, strlen(cmd));
  81 }
  82
  83 static int pop3_iseoc(char *line, int len)
  84 {
  85         return len >= 2 && len <= 3 && line[0] == '.' &&
  86                 (line[1] == '\r' || line[1] == '\n');
  87 }
  88
  89 static void pop3_login(char *user, char *pass)
  90 {
  91         char line[BUFFSIZE];
  92         sprintf(line, "USER %s\r\n", user);
  93         pop3_cmd(line);
  94         pop3_get(line, sizeof(line));
  95         sprintf(line, "PASS %s\r\n", pass);
  96         pop3_cmd(line);
  97         pop3_get(line, sizeof(line));
  98 }
  99
 100 static void pop3_stat(void)
 101 {
 102         char line[BUFFSIZE];
 103         int len;
 104         pop3_cmd("STAT\r\n");
 105         len = pop3_get(line, sizeof(line));
 106         PRINT(line, len);
 107         pop3_cmd("LIST\r\n");
 108         len = pop3_get(line, sizeof(line));
 109         while ((len = pop3_get(line, sizeof(line))) >= 0) {
 110                 struct mailinfo *mail;
 111                 if (pop3_iseoc(line, len))
 112                         break;
 113                 mail = &mails[nmails++];
 114                 sscanf(line, "%s %d", mail->name, &mail->size);
 115         }
 116 }
 117
 118 static void pop3_uidl(void)
 119 {
 120         char line[BUFFSIZE];
 121         char name[128];
 122         int len;
 123         int i = 0;
 124         pop3_cmd("UIDL\r\n");
 125         len = pop3_get(line, sizeof(line));
 126         while ((len = pop3_get(line, sizeof(line))) > 0 && !pop3_iseoc(line, len))
 127                 sscanf(line, "%s %s", name, mails[i++].id);
 128 }
 129
 130 static void pop3_retr(int i)
 131 {
 132         char cmd[100];
 133         sprintf(cmd, "RETR %s\r\n", mails[i].name);
 134         pop3_cmd(cmd);
 135 }
 136
 137 static char *mail_dst(char *hdr, int len)
 138 {
 139         int i;
 140         hdr[len] = '\0';
 141         for (i = 0; i < ARRAY_SIZE(filters); i++)
 142                 if (!strncmp(filters[i].hdr, hdr, strlen(filters[i].hdr)) &&
 143                                 strstr(hdr, filters[i].val))
 144                         return filters[i].dst;
 145         return NULL;
 146 }
 147
 148 static int xwrite(int fd, char *buf, int len)
 149 {
 150         int nw = 0;
 151         while (nw < len) {
 152                 int ret = write(fd, buf + nw, len - nw);
 153                 if (ret == -1 && (errno == EAGAIN || errno == EINTR))
 154                         continue;
 155                 if (ret < 0)
 156                         break;
 157                 nw += ret;
 158         }
 159         return nw;
 160 }
 161
 162 static int mail_write(char *dst, char *mail, int len)
 163 {
 164         int fd = open(dst, O_WRONLY | O_APPEND | O_CREAT, 0600);
 165         if (fd < 0)
 166                 return 1;
 167         if (xwrite(fd, mail, len) != len)
 168                 return 1;
 169         close(fd);
 170         return 0;
 171 }
 172
 173 static int mail_from_(char *s)
 174 {
 175         char date[128];
 176         time_t t;
 177         time(&t);
 178         strftime(date, sizeof(date), "%a %b %d %H:%M:%S %Y", localtime(&t));
 179         return sprintf(s, "From %s %s\n", getenv("USER") ? getenv("USER") : "root", date);
 180 }
 181
 182 static int pop3_lonefrom_(char *s)
 183 {
 184         while (*s == '>')
 185                 s++;
 186         return !strncmp("From ", s, 5);
 187 }
 188
 189 static int fetch_one(int i)
 190 {
 191         char line[BUFFSIZE];
 192         char *s = mailbuf;
 193         int len = pop3_get(line, sizeof(line));
 194         char *dst = NULL;
 195         int hdr = 1;
 196         int ret;
 197         PRINT(mails[i].name, strlen(mails[i].name));
 198         s += mail_from_(s);
 199         while (1) {
 200                 len = pop3_get(line, sizeof(line));
 201                 if (len <= 0)           /* end of stream or error */
 202                         return 1;
 203                 if (pop3_iseoc(line, len))
 204                         break;
 205                 if (len > 1 && line[len - 2] == '\r')
 206                         line[len-- - 2] = '\n';
 207                 if (line[0] == '\n')
 208                         hdr = 0;
 209                 if (hdr && !dst)
 210                         dst = mail_dst(line, len);
 211                 if (pop3_lonefrom_(line))
 212                         *s++ = '>';
 213                 memcpy(s, line, len);
 214                 s += len;
 215         }
 216         *s++ = '\n';
 217         if (!dst)
 218                 dst = SPOOL;
 219         ret = mail_write(dst, mailbuf, s - mailbuf);
 220         sprintf(line, " -> %s%s\n", dst, ret ? " [failed]" : "");
 221         PRINT(line, strlen(line));
 222         return ret;
 223 }
 224
 225 static void pop3_del(int i)
 226 {
 227         char cmd[100];
 228         sprintf(cmd, "DELE %s\r\n", mails[i].name);
 229         pop3_cmd(cmd);
 230 }
 231
 232 static int size_ok(int i)
 233 {
 234         return mails[i].size + 100 < MAXSIZE;
 235 }
 236
 237 static int uidl_new(int i)
 238 {
 239         return !uidl || !uidl_find(uidl, mails[i].id);
 240 }
 241
 242 static int fetch_mails(int beg, int end, int del)
 243 {
 244         char line[BUFFSIZE];
 245         int i;
 246         for (i = beg; i < end; i++)
 247                 if (size_ok(i) && uidl_new(i))
 248                         pop3_retr(i);
 249         for (i = beg; i < end; i++) {
 250                 if (size_ok(i) && uidl_new(i)) {
 251                         if (fetch_one(i))
 252                                 return 1;
 253                         if (uidl)
 254                                 uidl_add(uidl, mails[i].id);
 255                 }
 256         }
 257         if (del) {
 258                 for (i = beg; i < end; i++)
 259                         if ((!uidl && size_ok(i)) || (uidl && !uidl_new(i)))
 260                                 pop3_del(i);
 261                 for (i = beg; i < end; i++)
 262                         if ((!uidl && size_ok(i)) || (uidl && !uidl_new(i)))
 263                                 pop3_get(line, sizeof(line));
 264         }
 265         return 0;
 266 }
 267
 268 static int fetch(struct account *account)
 269 {
 270         char line[BUFFSIZE];
 271         int batch;
 272         int failed = 0;
 273         int i;
 274         nmails = 0;
 275         conn = conn_connect(account->server, account->port);
 276         if (!conn)
 277                 return 1;
 278         if (account->stls) {
 279                 pop3_get(line, sizeof(line));
 280                 pop3_cmd("STLS\r\n");
 281                 pop3_get(line, sizeof(line));
 282         }
 283         if (conn_tls(conn, account->cert)) {
 284                 conn_close(conn);
 285                 return 1;
 286         }
 287         buf_pos = 0;
 288         buf_len = 0;
 289         if (account->uidl)
 290                 uidl = uidl_read(account->uidl);
 291         sprintf(line, "fetching %s@%s\n", account->user, account->server);
 292         PRINT(line, strlen(line));
 293         if (!account->stls)
 294                 pop3_get(line, sizeof(line));
 295         pop3_login(account->user, account->pass);
 296         pop3_stat();
 297         if (account->uidl)
 298                 pop3_uidl();
 299         batch = account->nopipe ? 1 : nmails;
 300         for (i = 0; i < nmails; i += batch)
 301                 if ((failed = fetch_mails(i, MIN(nmails, i + batch), account->del)))
 302                         break;
 303         if (!failed) {
 304                 pop3_cmd("QUIT\r\n");
 305                 pop3_get(line, sizeof(line));
 306         }
 307         conn_close(conn);
 308         if (uidl)
 309                 uidl_save(uidl);
 310         uidl = NULL;
 311         return failed;
 312 }
 313
 314 static void sigint(int sig)
 315 {
 316         if (uidl)
 317                 uidl_save(uidl);
 318         exit(1);
 319 }
 320
 321 int main(int argc, char *argv[])
 322 {
 323         int i;
 324         signal(SIGINT, sigint);
 325         mailbuf = malloc(MAXSIZE);
 326         for (i = 0; i < ARRAY_SIZE(accounts); i++)
 327                 if (fetch(&accounts[i]))
 328                         return 1;
 329         free(mailbuf);
 330         return 0;
 331 }