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/* Copyright (C) 2019 C. McEnroe <june@causal.agency>
*
* 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 <https://www.gnu.org/licenses/>.
*/
#include "compat.h"
#include <ctype.h>
#include <err.h>
#include <regex.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/wait.h>
#include <sysexits.h>
#include <tls.h>
#include <unistd.h>
#ifndef NO_READPASSPHRASE_H
#include <readpassphrase.h>
#endif
#if !defined(DIG_PATH) && !defined(DRILL_PATH)
# ifdef __FreeBSD__
# define DRILL_PATH "/usr/bin/drill"
# else
# define DIG_PATH "dig"
# endif
#endif
static void compile(regex_t *regex, const char *pattern) {
if (regex->re_nsub) return;
int error = regcomp(regex, pattern, REG_EXTENDED | REG_NEWLINE);
if (!error) return;
char buf[256];
regerror(error, regex, buf, sizeof(buf));
errx(EX_SOFTWARE, "regcomp: %s: %s", buf, pattern);
}
static void printLines(const char *lines) {
static regex_t fromRegex;
compile(&fromRegex, "^>*From ");
while (*lines) {
size_t len = strcspn(lines, "\r\n");
regmatch_t match;
if (!regexec(&fromRegex, lines, 1, &match, 0) && !match.rm_so) {
printf(">%.*s\n", (int)len, lines);
} else {
printf("%.*s\n", (int)len, lines);
}
lines += len;
if (*lines == '\r') lines++;
if (*lines == '\n') lines++;
}
}
static void mboxrd(const char *headers, const char *body) {
#define MATCH(str, match) \
(int)((match).rm_eo - (match).rm_so), &(str)[(match).rm_so]
static regex_t fromRegex, dateRegex;
compile(&fromRegex, "^From: ([^\r]|\r\n[ \t])*<([^>]+)>");
regmatch_t from[3];
int error = regexec(&fromRegex, headers, 3, from, 0);
if (error) errx(EX_DATAERR, "missing From header");
printf("From %.*s ", MATCH(headers, from[2]));
// Day, Date Month Year Time -> Day Month Date Time Year
compile(&dateRegex, "^Date: (...), (..) (...) (....) (.{8})");
regmatch_t date[6];
error = regexec(&dateRegex, headers, 6, date, 0);
if (error) errx(EX_DATAERR, "missing Date header");
printf(
"%.*s %.*s %.*s %.*s %.*s\n",
MATCH(headers, date[1]),
MATCH(headers, date[3]),
MATCH(headers, date[2]),
MATCH(headers, date[5]),
MATCH(headers, date[4])
);
printLines(headers);
printLines(body);
printf("\n");
#undef MATCH
}
static void lookup(const char **host, const char **port, const char *domain) {
static char buf[1024];
snprintf(buf, sizeof(buf), "_imaps._tcp.%s", domain);
int rw[2];
int error = pipe(rw);
if (error) err(EX_OSERR, "pipe");
pid_t pid = fork();
if (pid < 0) err(EX_OSERR, "fork");
if (!pid) {
close(rw[0]);
dup2(rw[1], STDOUT_FILENO);
dup2(rw[1], STDERR_FILENO);
close(rw[1]);
#ifdef DRILL_PATH
execlp(DRILL_PATH, DRILL_PATH, buf, "SRV", NULL);
err(EX_CONFIG, "%s", DRILL_PATH);
#else
execlp(DIG_PATH, DIG_PATH, "-t", "SRV", "-q", buf, "+short", NULL);
err(EX_CONFIG, "%s", DIG_PATH);
#endif
}
int status;
pid = wait(&status);
if (pid < 0) err(EX_OSERR, "wait");
close(rw[1]);
FILE *pipe = fdopen(rw[0], "r");
if (!pipe) err(EX_IOERR, "fdopen");
fgets(buf, sizeof(buf), pipe);
if (ferror(pipe)) err(EX_IOERR, "fgets");
if (!WIFEXITED(status) || WEXITSTATUS(status)) {
fprintf(stderr, "%s", buf);
exit(WEXITSTATUS(status));
}
char *ptr = buf;
#ifdef DRILL_PATH
for (;;) {
char *line = fgets(buf, sizeof(buf), pipe);
if (!line || !strcmp(line, ";; ANSWER SECTION:\n")) break;
}
fgets(buf, sizeof(buf), pipe);
if (ferror(pipe)) err(EX_IOERR, "fgets");
ptr = strrchr(buf, '\t');
ptr = (ptr ? ptr + 1 : buf);
#endif
fclose(pipe);
char *dot = strrchr(ptr, '.');
if (dot) *dot = '\0';
strsep(&ptr, " \n"); // priority
strsep(&ptr, " \n"); // weight
*port = strsep(&ptr, " \n");
*host = strsep(&ptr, " \n");
if (!*host) {
*host = domain;
*port = "imaps";
}
}
static bool verbose;
int tlsRead(void *_tls, char *ptr, int len) {
struct tls *tls = _tls;
ssize_t ret;
do {
ret = tls_read(tls, ptr, len);
} while (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT);
if (ret < 0) errx(EX_IOERR, "tls_read: %s", tls_error(tls));
if (verbose) fprintf(stderr, "%.*s", (int)ret, ptr);
return ret;
}
int tlsWrite(void *_tls, const char *ptr, int len) {
struct tls *tls = _tls;
ssize_t ret;
do {
ret = tls_write(tls, ptr, len);
} while (ret == TLS_WANT_POLLIN || ret == TLS_WANT_POLLOUT);
if (ret < 0) errx(EX_IOERR, "tls_write: %s", tls_error(tls));
if (verbose) fprintf(stderr, "%.*s", (int)ret, ptr);
return ret;
}
int tlsClose(void *_tls) {
struct tls *tls = _tls;
int error = tls_close(tls);
if (error) errx(EX_IOERR, "tls_close: %s", tls_error(tls));
return error;
}
#define ENUM_ATOM \
X(Unknown, "") \
X(Untagged, "*") \
X(Ok, "OK") \
X(No, "NO") \
X(Bad, "BAD") \
X(Bye, "BYE") \
X(Login, "LOGIN") \
X(Examine, "EXAMINE") \
X(Search, "SEARCH") \
X(Fetch, "FETCH")
enum Atom {
#define X(id, _) id,
ENUM_ATOM
#undef X
AtomsLen,
};
static const char *Atoms[AtomsLen] = {
#define X(id, str) [id] = str,
ENUM_ATOM
#undef X
};
static enum Atom atom(const char *str) {
if (!str) return Unknown;
for (enum Atom i = 0; i < AtomsLen; ++i) {
if (!strcmp(str, Atoms[i])) return i;
}
return Unknown;
}
static char *readLiteral(FILE *imap, const char *line) {
char *prefix = strrchr(line, '{');
if (!prefix) errx(EX_PROTOCOL, "no literal prefix");
size_t size = strtoul(prefix + 1, NULL, 10);
if (!size) errx(EX_PROTOCOL, "invalid literal size");
char *literal = malloc(size + 1);
if (!literal) err(EX_OSERR, "malloc");
size_t count = fread(literal, size, 1, imap);
if (!count) errx(EX_PROTOCOL, "could not read literal");
literal[size] = '\0';
return literal;
}
int main(int argc, char *argv[]) {
const char *host = NULL;
const char *port = "imaps";
const char *mailbox = "INBOX";
const char *subject = "[PATCH";
const char *from = NULL;
const char *to = NULL;
const char *cc = NULL;
int rppFlags = 0;
int opt;
while (0 < (opt = getopt(argc, argv, "C:F:S:T:h:m:p:vw"))) {
switch (opt) {
break; case 'C': cc = optarg;
break; case 'F': from = optarg;
break; case 'S': subject = optarg;
break; case 'T': to = optarg;
break; case 'h': host = optarg;
break; case 'm': mailbox = optarg;
break; case 'p': port = optarg;
break; case 'v': verbose = true;
break; case 'w': rppFlags |= RPP_STDIN;
break; default: return EX_USAGE;
}
}
const char *user = argv[optind];
if (!user) errx(EX_USAGE, "username required");
if (!host) {
const char *domain = strchr(user, '@');
if (!domain) errx(EX_USAGE, "no domain in username");
lookup(&host, &port, &domain[1]);
}
char buf[1024];
char *pass = readpassphrase(
(rppFlags & RPP_STDIN ? "" : "Password: "),
buf, sizeof(buf), rppFlags
);
if (!pass) err(EX_UNAVAILABLE, "readpassphrase");
struct tls *client = tls_client();
if (!client) errx(EX_SOFTWARE, "tls_client");
struct tls_config *config = tls_config_new();
if (!config) errx(EX_SOFTWARE, "tls_config_new");
int error = tls_configure(client, config);
if (error) errx(EX_SOFTWARE, "tls_configure: %s", tls_error(client));
tls_config_free(config);
error = tls_connect(client, host, port);
if (error) errx(EX_NOHOST, "tls_connect: %s", tls_error(client));
FILE *imap = funopen(client, tlsRead, tlsWrite, NULL, tlsClose);
if (!imap) err(EX_SOFTWARE, "funopen");
setlinebuf(imap);
bool login = false;
char *nums = NULL;
char *line = NULL;
size_t cap = 0;
while (0 < getline(&line, &cap, imap)) {
char *cr = strchr(line, '\r');
if (cr) *cr = '\0';
char *rest = line;
enum Atom tag = atom(strsep(&rest, " "));
if (rest && isdigit(rest[0])) {
strsep(&rest, " ");
}
enum Atom resp = atom(strsep(&rest, " "));
if (resp == No || resp == Bad || resp == Bye) {
errx(
EX_CONFIG, "%s: %s %s",
Atoms[tag], Atoms[resp], (rest ? rest : "")
);
}
switch (tag) {
break; case Untagged: {
if (login) break;
fprintf(
imap, "%s LOGIN \"%s\" \"%s\"\r\n",
Atoms[Login], user, pass
);
login = true;
}
break; case Login: {
fprintf(imap, "%s EXAMINE \"%s\"\r\n", Atoms[Examine], mailbox);
}
break; case Examine: {
fprintf(
imap,
"%s SEARCH CHARSET UTF-8 OR "
"NOT HEADER Content-Type \"\" "
"HEADER Content-Type \"text/plain\"",
Atoms[Search]
);
if (subject) fprintf(imap, " SUBJECT \"%s\"", subject);
if (from) fprintf(imap, " FROM \"%s\"", from);
if (to) fprintf(imap, " TO \"%s\"", to);
if (cc) fprintf(imap, " CC \"%s\"", cc);
fprintf(imap, "\r\n");
}
break; case Search: {
if (!nums) errx(EX_PROTOCOL, "no search response");
for (char *ch = nums; *ch; ++ch) {
if (*ch == ' ') *ch = ',';
}
fprintf(
imap,
"%s FETCH %s (BODY[HEADER.FIELDS ("
"Date From To Cc Subject Message-Id In-Reply-To References "
"Content-Transfer-Encoding"
")] BODY[TEXT])\r\n",
Atoms[Fetch], nums
);
free(nums);
nums = NULL;
}
break; case Fetch: {
fprintf(imap, "ayy LOGOUT\r\n");
fclose(imap);
return EX_OK;
}
break; default:;
}
switch (resp) {
break; case Search: {
if (!rest) errx(EX_TEMPFAIL, "no matching messages");
nums = strdup(rest);
if (!nums) err(EX_OSERR, "strdup");
}
break; case Fetch: {
char *headers = readLiteral(imap, rest);
ssize_t len = getline(&line, &cap, imap);
if (len <= 0) errx(EX_PROTOCOL, "unexpected eof after headers");
char *body = readLiteral(imap, line);
len = getline(&line, &cap, imap);
if (len <= 0) errx(EX_PROTOCOL, "unexpected eof after body");
if (strcmp(line, ")\r\n")) {
errx(EX_PROTOCOL, "trailing data after headers and body");
}
mboxrd(headers, body);
free(headers);
free(body);
}
break; default:;
}
}
errx(EX_PROTOCOL, "unexpected eof");
}
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