#include <stdio.h>
-#define NMH_MESSAGE_ID_LOCALNAME 0
-#define NMH_MESSAGE_ID_RANDOM 1
-
-static int message_id_style = NMH_MESSAGE_ID_LOCALNAME;
+static enum {
+ NMH_MESSAGE_ID_LOCALNAME,
+ NMH_MESSAGE_ID_RANDOM
+} message_id_style = NMH_MESSAGE_ID_LOCALNAME;
static char message_id_[BUFSIZ];
char *
message_id (time_t tclock, int content_id) {
- if (message_id_style == NMH_MESSAGE_ID_LOCALNAME) {
- char *format = content_id ? "<%d.%ld.%%d@%s>" : "<%d.%ld@%s>";
-
- snprintf (message_id_, sizeof message_id_, format,
- (int) getpid (), (long) tclock, LocalName (1));
- } else if (message_id_style == NMH_MESSAGE_ID_RANDOM) {
- char *format = content_id
- ? "<%d-%ld.%06ld%%d@%.*s.%.*s.%.*s>"
- : "<%d-%ld.%06ld@%.*s.%.*s.%.*s>";
- /* Use a sequence of digits divisible by 3 because that will
- expand to base64 without any waste. Must be shorter than 58,
- see below. */
- unsigned char rnd[9];
- /* The part after the '@' is divided into thirds. The base64
- encoded string will be 4/3 the size of rnd. */
- size_t one_third = sizeof rnd * 4/3/3;
-
- if (m_rand (rnd, sizeof rnd) == 0) {
- struct timeval now;
- /* All we really need is 4 * [sizeof rnd/3] + 2, as long as the
- base64 encoding stays shorter than 76 bytes so embedded
- newlines aren't necessary. But use double the sizeof rnd
- just to be safe. */
- unsigned char rnd_base64[2 * sizeof rnd];
- int i;
-
- writeBase64 (rnd, sizeof rnd, rnd_base64);
-
- for (i = strlen ((const char *) rnd_base64) - 1;
- i > 0 && iscntrl (rnd_base64[i]);
- --i) {
- /* Remove trailing newline. rnd_base64 had better be shorter
- than 76 characters, so don't bother to look for embedded
- newlines. */
- rnd_base64[i] = '\0';
- }
+ switch (message_id_style) {
+ case NMH_MESSAGE_ID_LOCALNAME: {
+ char *format = content_id ? "<%d.%ld.%%d@%s>" : "<%d.%ld@%s>";
+
+ snprintf (message_id_, sizeof message_id_, format,
+ (int) getpid (), (long) tclock, LocalName (1));
+
+ break;
+ }
+
+ case NMH_MESSAGE_ID_RANDOM: {
+ char *format = content_id
+ ? "<%d-%ld.%06ld%%d@%.*s.%.*s.%.*s>"
+ : "<%d-%ld.%06ld@%.*s.%.*s.%.*s>";
+ /* Use a sequence of digits divisible by 3 because that will
+ expand to base64 without any waste. Must be shorter than 58,
+ see below. */
+ unsigned char rnd[9];
+ /* The part after the '@' is divided into thirds. The base64
+ encoded string will be 4/3 the size of rnd. */
+ size_t one_third = sizeof rnd * 4/3/3;
+
+ if (m_rand (rnd, sizeof rnd) == 0) {
+ struct timeval now;
+ /* All we really need is 4 * [sizeof rnd/3] + 2, as long as
+ the base64 encoding stays shorter than 76 bytes so embedded
+ newlines aren't necessary. But use double the sizeof rnd
+ just to be safe. */
+ unsigned char rnd_base64[2 * sizeof rnd];
+ unsigned char *cp;
+ int i;
+
+ writeBase64 (rnd, sizeof rnd, rnd_base64);
+
+ for (i = strlen ((const char *) rnd_base64) - 1;
+ i > 0 && iscntrl (rnd_base64[i]);
+ --i) {
+ /* Remove trailing newline. rnd_base64 had better be
+ shorter than 76 characters, so don't bother to look for
+ embedded newlines. */
+ rnd_base64[i] = '\0';
+ }
- {
- char *cp;
/* Try to make the base64 string look a little more like a
- hostname by replacing + with - and / with _. Also, the
- format string inserts a couple of dots. */
- for (cp = (char *) rnd_base64; *cp; ++cp) {
- char *plus, *slash;
- if ((plus = strchr (cp, '+'))) {
- *plus = '-';
- } else if ((slash = strchr (cp, '/'))) {
- *slash = '_';
- } else {
- break;
+ hostname by replacing + with - and / with _. */
+ for (cp = rnd_base64; *cp; ++cp) {
+ if (*cp == '+') {
+ *cp = '-';
+ } else if (*cp == '/') {
+ *cp = '_';
}
}
- }
- /* gettimeofday() and getpid() shouldn't fail on POSIX platforms. */
- gettimeofday (&now, 0);
+ /* gettimeofday() and getpid() shouldn't fail on POSIX platforms. */
+ gettimeofday (&now, 0);
+
+ /* The format string inserts a couple of dots, for the benefit
+ of spam filters that want to see a message id with a final
+ part that resembles a hostname. */
+ snprintf (message_id_, sizeof message_id_, format,
+ getpid (), (long) now.tv_sec, (long) now.tv_usec,
+ one_third, rnd_base64,
+ one_third, &rnd_base64[one_third],
+ one_third, &rnd_base64[2*one_third]);
+ }
- snprintf (message_id_, sizeof message_id_, format,
- getpid (), (long) now.tv_sec, (long) now.tv_usec,
- one_third, rnd_base64,
- one_third, &rnd_base64[one_third],
- one_third, &rnd_base64[2*one_third]);
+ break;
}
- } else {
- /* Should never get here. */
- adios (0, "invalid message id style \"%s\"", message_id_style);
}
-
return message_id_;
}