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sendmail: handle a case when the whole mail comes from stdin (and no separate sender/subj is provided) both by dronnikov AT gmail.com function old new delta sendgetmail_main 1509 1674 +165 SynchronizeFile 671 767 +96 packed_usage 24054 24088 +34 crond_main 1404 1420 +16 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 4/0 up/down: 311/0) Total: 311 bytes
612 lines
14 KiB
C
612 lines
14 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* bare bones sendmail/fetchmail
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*
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* Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
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*
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* Licensed under GPLv2, see file LICENSE in this tarball for details.
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*/
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#include "libbb.h"
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#define INITIAL_STDIN_FILENO 3
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static void uuencode(char *fname, const char *text)
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{
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enum {
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SRC_BUF_SIZE = 45, /* This *MUST* be a multiple of 3 */
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DST_BUF_SIZE = 4 * ((SRC_BUF_SIZE + 2) / 3),
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};
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#define src_buf text
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int fd;
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#define len fd
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char dst_buf[DST_BUF_SIZE + 1];
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if (fname) {
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fd = INITIAL_STDIN_FILENO;
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if (NOT_LONE_DASH(fname))
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fd = xopen(fname, O_RDONLY);
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src_buf = bb_common_bufsiz1;
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// N.B. strlen(NULL) segfaults!
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} else if (text) {
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// though we do not call uuencode(NULL, NULL) explicitly
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// still we do not want to break things suddenly
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len = strlen(text);
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} else
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return;
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fflush(stdout); // sync stdio and unistd output
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while (1) {
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size_t size;
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if (fname) {
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size = full_read(fd, (char *)src_buf, SRC_BUF_SIZE);
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if ((ssize_t)size < 0)
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bb_perror_msg_and_die(bb_msg_read_error);
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} else {
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size = len;
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if (len > SRC_BUF_SIZE)
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size = SRC_BUF_SIZE;
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}
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if (!size)
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break;
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// encode the buffer we just read in
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bb_uuencode(dst_buf, src_buf, size, bb_uuenc_tbl_base64);
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if (fname) {
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xwrite(STDOUT_FILENO, "\r\n", 2);
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} else {
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src_buf += size;
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len -= size;
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}
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xwrite(STDOUT_FILENO, dst_buf, 4 * ((size + 2) / 3));
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}
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if (fname)
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close(fd);
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}
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struct globals {
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pid_t helper_pid;
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unsigned timeout;
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// arguments for SSL connection helper
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const char *xargs[9];
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// arguments for postprocess helper
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const char *fargs[3];
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};
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#define G (*ptr_to_globals)
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#define helper_pid (G.helper_pid)
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#define timeout (G.timeout )
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#define xargs (G.xargs )
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#define fargs (G.fargs )
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#define INIT_G() do { \
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SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
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xargs[0] = "openssl"; \
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xargs[1] = "s_client"; \
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xargs[2] = "-quiet"; \
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xargs[3] = "-connect"; \
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/*xargs[4] = "server[:port]";*/ \
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xargs[5] = "-tls1"; \
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xargs[6] = "-starttls"; \
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xargs[7] = "smtp"; \
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fargs[0] = "utf-8"; \
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} while (0)
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#define opt_connect (xargs[4])
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#define opt_after_connect (xargs[5])
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#define opt_charset (fargs[0])
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#define opt_subject (fargs[1])
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static void kill_helper(void)
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{
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// TODO!!!: is there more elegant way to terminate child on program failure?
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if (helper_pid > 0)
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kill(helper_pid, SIGTERM);
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}
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// generic signal handler
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static void signal_handler(int signo)
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{
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#define err signo
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if (SIGALRM == signo) {
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kill_helper();
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bb_error_msg_and_die("timed out");
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}
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// SIGCHLD. reap zombies
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if (wait_any_nohang(&err) > 0)
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if (WIFEXITED(err) && WEXITSTATUS(err))
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bb_error_msg_and_die("child exited (%d)", WEXITSTATUS(err));
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}
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static void launch_helper(const char **argv)
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{
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// setup vanilla unidirectional pipes interchange
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int idx;
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int pipes[4];
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xpipe(pipes);
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xpipe(pipes+2);
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helper_pid = vfork();
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if (helper_pid < 0)
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bb_perror_msg_and_die("vfork");
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idx = (!helper_pid)*2;
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xdup2(pipes[idx], STDIN_FILENO);
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xdup2(pipes[3-idx], STDOUT_FILENO);
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if (ENABLE_FEATURE_CLEAN_UP)
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for (int i = 4; --i >= 0; )
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if (pipes[i] > STDOUT_FILENO)
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close(pipes[i]);
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if (!helper_pid) {
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// child: try to execute connection helper
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BB_EXECVP(*argv, (char **)argv);
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_exit(127);
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}
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// parent: check whether child is alive
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bb_signals(0
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+ (1 << SIGCHLD)
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+ (1 << SIGALRM)
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, signal_handler);
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signal_handler(SIGCHLD);
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// child seems OK -> parent goes on
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}
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static const char *command(const char *fmt, const char *param)
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{
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const char *msg = fmt;
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alarm(timeout);
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if (msg) {
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msg = xasprintf(fmt, param);
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printf("%s\r\n", msg);
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}
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fflush(stdout);
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return msg;
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}
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static int smtp_checkp(const char *fmt, const char *param, int code)
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{
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char *answer;
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const char *msg = command(fmt, param);
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// read stdin
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// if the string has a form \d\d\d- -- read next string. E.g. EHLO response
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// parse first bytes to a number
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// if code = -1 then just return this number
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// if code != -1 then checks whether the number equals the code
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// if not equal -> die saying msg
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while ((answer = xmalloc_fgetline(stdin)) != NULL)
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if (strlen(answer) <= 3 || '-' != answer[3])
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break;
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if (answer) {
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int n = atoi(answer);
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alarm(0);
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if (ENABLE_FEATURE_CLEAN_UP) {
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free(answer);
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}
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if (-1 == code || n == code) {
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return n;
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}
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}
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kill_helper();
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bb_error_msg_and_die("%s failed", msg);
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}
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static int inline smtp_check(const char *fmt, int code)
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{
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return smtp_checkp(fmt, NULL, code);
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}
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// strip argument of bad chars
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static char *sane(char *str)
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{
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char *s = str;
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char *p = s;
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while (*s) {
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if (isalnum(*s) || '_' == *s || '-' == *s || '.' == *s || '@' == *s) {
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*p++ = *s;
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}
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s++;
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}
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*p = '\0';
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return str;
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}
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#if ENABLE_FETCHMAIL
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static void pop3_checkr(const char *fmt, const char *param, char **ret)
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{
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const char *msg = command(fmt, param);
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char *answer = xmalloc_fgetline(stdin);
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if (answer && '+' == *answer) {
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alarm(0);
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if (ret)
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*ret = answer+4; // skip "+OK "
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else if (ENABLE_FEATURE_CLEAN_UP)
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free(answer);
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return;
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}
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kill_helper();
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bb_error_msg_and_die("%s failed", msg);
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}
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static void inline pop3_check(const char *fmt, const char *param)
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{
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pop3_checkr(fmt, param, NULL);
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}
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static void pop3_message(const char *filename)
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{
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int fd;
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char *answer;
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// create and open file filename
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// read stdin, copy to created file
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fd = xopen(filename, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL);
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while ((answer = xmalloc_fgets_str(stdin, "\r\n")) != NULL) {
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char *s = answer;
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if ('.' == *answer) {
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if ('.' == answer[1])
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s++;
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else if ('\r' == answer[1] && '\n' == answer[2] && '\0' == answer[3])
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break;
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}
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xwrite(fd, s, strlen(s));
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free(answer);
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}
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close(fd);
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}
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#endif
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int sendgetmail_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int sendgetmail_main(int argc ATTRIBUTE_UNUSED, char **argv)
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{
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llist_t *opt_recipients = NULL;
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const char *opt_user;
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const char *opt_pass;
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enum {
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OPT_w = 1 << 0, // network timeout
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OPT_U = 1 << 1, // user
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OPT_P = 1 << 2, // password
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OPT_X = 1 << 3, // connect using openssl s_client helper
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OPTS_n = 1 << 4, // sendmail: request notification
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OPTF_t = 1 << 4, // fetchmail: use "TOP" not "RETR"
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OPTS_s = 1 << 5, // sendmail: subject
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OPTF_z = 1 << 5, // fetchmail: delete from server
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OPTS_c = 1 << 6, // sendmail: assumed charset
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OPTS_t = 1 << 7, // sendmail: recipient(s)
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OPTS_i = 1 << 8, // sendmail: ignore lone dots in message body (implied)
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};
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const char *options;
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unsigned opts;
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// init global variables
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INIT_G();
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// parse options, different option sets for sendmail and fetchmail
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// N.B. opt_after_connect hereafter is NULL if we are called as fetchmail
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// and is NOT NULL if we are called as sendmail
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if (!ENABLE_FETCHMAIL || 's' == applet_name[0]) {
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// SENDMAIL
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// save initial stdin (body or attachements can be piped!)
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xdup2(STDIN_FILENO, INITIAL_STDIN_FILENO);
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opt_complementary = "-2:w+:t::";
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options = "w:U:P:X" "ns:c:t:i";
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} else {
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// FETCHMAIL
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opt_after_connect = NULL;
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opt_complementary = "-2:w+:P";
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options = "w:U:P:X" "tz";
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}
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opts = getopt32(argv, options,
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&timeout, &opt_user, &opt_pass,
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&opt_subject, &opt_charset, &opt_recipients
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);
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//argc -= optind;
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argv += optind;
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// first argument is remote server[:port]
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opt_connect = *argv++;
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// connect to server
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// SSL ordered? ->
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if (opts & OPT_X) {
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// ... use openssl helper
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launch_helper(xargs);
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// no SSL ordered? ->
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} else {
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// ... make plain connect
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int fd = create_and_connect_stream_or_die(opt_connect, 25);
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// make ourselves a simple IO filter
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// from now we know nothing about network :)
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xmove_fd(fd, STDIN_FILENO);
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xdup2(STDIN_FILENO, STDOUT_FILENO);
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}
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#if ENABLE_FETCHMAIL
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// we are sendmail?
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if (opt_after_connect)
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#endif
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{
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/***************************************************
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* SENDMAIL
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***************************************************/
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char *opt_from;
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int code;
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char *boundary;
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const char *fmt;
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const char *p;
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char *q;
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// we didn't use SSL helper? ->
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if (!(opts & OPT_X)) {
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// ... wait for initial server OK
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smtp_check(NULL, 220);
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}
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// get the sender
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opt_from = sane(*argv++);
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// if no recipients _and_ no body files specified -> enter all-included mode
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// i.e. scan stdin for To: and Subject: lines ...
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// ... and then use the rest of stdin as message body
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if (!opt_recipients && !*argv) {
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// fetch recipients and (optionally) subject
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char *s;
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while ((s = xmalloc_reads(INITIAL_STDIN_FILENO, NULL, NULL)) != NULL) {
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if (0 == strncmp("To: ", s, 4)) {
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llist_add_to_end(&opt_recipients, s+4);
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} else if (0 == strncmp("Subject: ", s, 9)) {
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opt_subject = s+9;
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opts |= OPTS_s;
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} else {
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char first = s[0];
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free(s);
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if (!first)
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break; // empty line
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}
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}
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// order to read body from stdin
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*--argv = (char *)"-";
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}
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// introduce to server
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// we should start with modern EHLO
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if (250 != smtp_checkp("EHLO %s", opt_from, -1)) {
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smtp_checkp("HELO %s", opt_from, 250);
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}
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// set sender
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// NOTE: if password has not been specified
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// then no authentication is possible
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code = (opts & OPT_P) ? -1 : 250;
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// first try softly without authentication
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while (250 != smtp_checkp("MAIL FROM:<%s>", opt_from, code)) {
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// MAIL FROM failed -> authentication needed
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// have we got username?
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if (!(opts & OPT_U)) {
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// no! fetch it from "from" option
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//opts |= OPT_U;
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opt_user = xstrdup(opt_from);
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*strchrnul(opt_user, '@') = '\0';
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}
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// now we've got username
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// so try to authenticate
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if (334 == smtp_check("AUTH LOGIN", -1)) {
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uuencode(NULL, opt_user);
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smtp_check("", 334);
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uuencode(NULL, opt_pass);
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smtp_check("", 235);
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}
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// authenticated OK? -> retry to set sender
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// but this time die on failure!
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code = 250;
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}
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// set recipients
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for (llist_t *to = opt_recipients; to; to = to->link) {
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smtp_checkp("RCPT TO:<%s>", sane(to->data), 250);
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}
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// enter "put message" mode
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smtp_check("DATA", 354);
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// put address headers
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printf("From: %s\r\n", opt_from);
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for (llist_t *to = opt_recipients; to; to = to->link) {
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printf("To: %s\r\n", to->data);
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}
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// put encoded subject
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if (opts & OPTS_c)
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sane((char *)opt_charset);
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if (opts & OPTS_s) {
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printf("Subject: =?%s?B?", opt_charset);
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uuencode(NULL, opt_subject);
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printf("?=\r\n");
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}
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// put notification
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if (opts & OPTS_n)
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printf("Disposition-Notification-To: %s\r\n", opt_from);
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// make a random string -- it will delimit message parts
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srand(monotonic_us());
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boundary = xasprintf("%d-%d-%d", rand(), rand(), rand());
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// put common headers and body start
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printf(
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"Message-ID: <%s>\r\n"
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"Mime-Version: 1.0\r\n"
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"%smultipart/mixed; boundary=\"%s\"\r\n"
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, boundary
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, "Content-Type: "
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, boundary
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);
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// put body + attachment(s)
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// N.B. all these weird things just to be tiny
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// by reusing string patterns!
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fmt =
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"\r\n--%s\r\n"
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"%stext/plain; charset=%s\r\n"
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"%s%s\r\n"
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"%s"
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;
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p = opt_charset;
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q = (char *)"";
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while (*argv) {
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printf(
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fmt
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, boundary
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, "Content-Type: "
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, p
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, "Content-Disposition: inline"
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, q
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, "Content-Transfer-Encoding: base64\r\n"
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);
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p = "";
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fmt =
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"\r\n--%s\r\n"
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"%sapplication/octet-stream%s\r\n"
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"%s; filename=\"%s\"\r\n"
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"%s"
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;
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uuencode(*argv, NULL);
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if (*(++argv))
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q = bb_get_last_path_component_strip(*argv);
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}
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// put message terminator
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printf("\r\n--%s--\r\n" "\r\n", boundary);
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// leave "put message" mode
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smtp_check(".", 250);
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// ... and say goodbye
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smtp_check("QUIT", 221);
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#if ENABLE_FETCHMAIL
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} else {
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/***************************************************
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* FETCHMAIL
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***************************************************/
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char *buf;
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unsigned nmsg;
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char *hostname;
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pid_t pid;
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// cache fetch command:
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// TOP will return only the headers
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// RETR will dump the whole message
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const char *retr = (opts & OPTF_t) ? "TOP %u 0" : "RETR %u";
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// goto maildir
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xchdir(*argv++);
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// cache postprocess program
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*fargs = *argv;
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// authenticate
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if (!(opts & OPT_U)) {
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//opts |= OPT_U;
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// N.B. IMHO getenv("USER") can be way easily spoofed!
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opt_user = bb_getpwuid(NULL, -1, getuid());
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}
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// get server greeting
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pop3_checkr(NULL, NULL, &buf);
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// server supports APOP?
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if ('<' == *buf) {
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md5_ctx_t md5;
|
|
// yes! compose <stamp><password>
|
|
char *s = strchr(buf, '>');
|
|
if (s)
|
|
strcpy(s+1, opt_pass);
|
|
s = buf;
|
|
// get md5 sum of <stamp><password>
|
|
md5_begin(&md5);
|
|
md5_hash(s, strlen(s), &md5);
|
|
md5_end(s, &md5);
|
|
// NOTE: md5 struct contains enough space
|
|
// so we reuse md5 space instead of xzalloc(16*2+1)
|
|
#define md5_hex ((uint8_t *)&md5)
|
|
// uint8_t *md5_hex = (uint8_t *)&md5;
|
|
*bin2hex(md5_hex, s, 16) = '\0';
|
|
// APOP
|
|
s = xasprintf("%s %s", opt_user, md5_hex);
|
|
#undef md5_hex
|
|
pop3_check("APOP %s", s);
|
|
if (ENABLE_FEATURE_CLEAN_UP) {
|
|
free(s);
|
|
free(buf-4); // buf is "+OK " away from malloc'ed string
|
|
}
|
|
// server ignores APOP -> use simple text authentication
|
|
} else {
|
|
// USER
|
|
pop3_check("USER %s", opt_user);
|
|
// PASS
|
|
pop3_check("PASS %s", opt_pass);
|
|
}
|
|
|
|
// get mailbox statistics
|
|
pop3_checkr("STAT", NULL, &buf);
|
|
|
|
// prepare message filename suffix
|
|
hostname = safe_gethostname();
|
|
pid = getpid();
|
|
|
|
// get messages counter
|
|
// NOTE: we don't use xatou(buf) since buf is "nmsg nbytes"
|
|
// we only need nmsg and atoi is just exactly what we need
|
|
// if atoi fails to convert buf into number it returns 0
|
|
// in this case the following loop simply will not be executed
|
|
nmsg = atoi(buf);
|
|
if (ENABLE_FEATURE_CLEAN_UP)
|
|
free(buf-4); // buf is "+OK " away from malloc'ed string
|
|
|
|
// loop through messages
|
|
for (; nmsg; nmsg--) {
|
|
|
|
// generate unique filename
|
|
char *filename = xasprintf("tmp/%llu.%u.%s", monotonic_us(), pid, hostname);
|
|
char *target;
|
|
int rc;
|
|
|
|
// retrieve message in ./tmp/
|
|
pop3_check(retr, (const char *)(ptrdiff_t)nmsg);
|
|
pop3_message(filename);
|
|
// delete message from server
|
|
if (opts & OPTF_z)
|
|
pop3_check("DELE %u", (const char*)(ptrdiff_t)nmsg);
|
|
|
|
// run postprocessing program
|
|
if (*fargs) {
|
|
fargs[1] = filename;
|
|
rc = wait4pid(spawn((char **)fargs));
|
|
if (99 == rc)
|
|
break;
|
|
if (1 == rc)
|
|
goto skip;
|
|
}
|
|
|
|
// atomically move message to ./new/
|
|
target = xstrdup(filename);
|
|
strncpy(target, "new", 3);
|
|
// ... or just stop receiving on error
|
|
if (rename_or_warn(filename, target))
|
|
break;
|
|
free(target);
|
|
skip:
|
|
free(filename);
|
|
}
|
|
|
|
// Bye
|
|
pop3_check("QUIT", NULL);
|
|
#endif // ENABLE_FETCHMAIL
|
|
}
|
|
|
|
return 0;
|
|
}
|