expando_msgid.c

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#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include "mutt/lib.h"
#include "address/lib.h"
#include "email/lib.h"
#include "expando_msgid.h"
#include "expando/lib.h"
#include "globals.h"
#include "sendlib.h"

static void msgid_counter(const struct ExpandoNode *node, void *data,
                          MuttFormatFlags flags, struct Buffer *buf)
{
  static char Counter = 'A';
 
  buf_addch(buf, Counter);
  Counter = (Counter == 'Z') ? 'A' : Counter + 1;
}

static long msgid_day_num(const struct ExpandoNode *node, void *data, MuttFormatFlags flags)
{
  struct MsgIdData *mid = data;
 
  return mid->tm.tm_mday;
}

static void msgid_hostname(const struct ExpandoNode *node, void *data,
                           MuttFormatFlags flags, struct Buffer *buf)
{
  struct MsgIdData *mid = data;
 
  buf_strcpy(buf, mid->fqdn);
}

static long msgid_hour_num(const struct ExpandoNode *node, void *data, MuttFormatFlags flags)
{
  struct MsgIdData *mid = data;
 
  return mid->tm.tm_hour;
}

static long msgid_minute_num(const struct ExpandoNode *node, void *data, MuttFormatFlags flags)
{
  struct MsgIdData *mid = data;
 
  return mid->tm.tm_min;
}

static long msgid_month_num(const struct ExpandoNode *node, void *data, MuttFormatFlags flags)
{
  struct MsgIdData *mid = data;
 
  return mid->tm.tm_mon + 1;
}

static long msgid_pid_num(const struct ExpandoNode *node, void *data, MuttFormatFlags flags)
{
  return getpid();
}

static void msgid_random_1(const struct ExpandoNode *node, void *data,
                           MuttFormatFlags flags, struct Buffer *buf)
{
  char raw[2] = { 0 };
 
  // hex encoded random byte
  mutt_randbuf(raw, 1);
  buf_printf(buf, "%02x", (unsigned char) raw[0]);
}

static void msgid_random_3(const struct ExpandoNode *node, void *data,
                           MuttFormatFlags flags, struct Buffer *buf)
{
  char raw[3] = { 0 };
  char enc[6] = { 0 };
 
  mutt_randbuf(raw, sizeof(raw));
  mutt_b64_encode_urlsafe(raw, sizeof(raw), enc, sizeof(enc));
 
  buf_strcpy(buf, enc);
}

static void msgid_random_12(const struct ExpandoNode *node, void *data,
                            MuttFormatFlags flags, struct Buffer *buf)
{
  char raw[12] = { 0 };
  char enc[20] = { 0 };
 
  struct MsgIdData *mid = data;
 
  // Convert the four least significant bytes of our timestamp and put it in
  // raw, with proper endianness (for humans) taken into account
  for (int i = 0; i < 4; i++)
    raw[i] = (uint8_t) (mid->now >> (3 - i) * 8u);
 
  mutt_randbuf(raw + 4, sizeof(raw) - 4);
  mutt_b64_encode_urlsafe(raw, sizeof(raw), enc, sizeof(enc));
 
  buf_strcpy(buf, enc);
}

static long msgid_second_num(const struct ExpandoNode *node, void *data, MuttFormatFlags flags)
{
  struct MsgIdData *mid = data;
 
  return mid->tm.tm_sec;
}

static long msgid_year_num(const struct ExpandoNode *node, void *data, MuttFormatFlags flags)
{
  struct MsgIdData *mid = data;
 
  return mid->tm.tm_year + 1900;
}

const struct ExpandoRenderCallback MsgIdRenderCallbacks[] = {
  // clang-format off
  { ED_MSG_ID, ED_MSG_COUNTER,   msgid_counter,   NULL             },
  { ED_MSG_ID, ED_MSG_DAY,       NULL,            msgid_day_num    },
  { ED_MSG_ID, ED_MSG_HOSTNAME,  msgid_hostname,  NULL             },
  { ED_MSG_ID, ED_MSG_HOUR,      NULL,            msgid_hour_num   },
  { ED_MSG_ID, ED_MSG_MINUTE,    NULL,            msgid_minute_num },
  { ED_MSG_ID, ED_MSG_MONTH,     NULL,            msgid_month_num  },
  { ED_MSG_ID, ED_MSG_PID,       NULL,            msgid_pid_num    },
  { ED_MSG_ID, ED_MSG_RANDOM_1,  msgid_random_1,  NULL             },
  { ED_MSG_ID, ED_MSG_RANDOM_3,  msgid_random_3,  NULL             },
  { ED_MSG_ID, ED_MSG_RANDOM_12, msgid_random_12, NULL             },
  { ED_MSG_ID, ED_MSG_SECOND,    NULL,            msgid_second_num },
  { ED_MSG_ID, ED_MSG_YEAR,      NULL,            msgid_year_num   },
  { -1, -1, NULL, NULL },
  // clang-format on
};

static char *msgid_gen_random(void)
{
  const int ID_LEFT_LEN = 50;
  const int ID_RIGHT_LEN = 12;
  char rnd_id_left[ID_LEFT_LEN + 1];
  char rnd_id_right[ID_RIGHT_LEN + 1];
  char buf[128] = { 0 };
 
  mutt_rand_base32(rnd_id_left, sizeof(rnd_id_left) - 1);
  mutt_rand_base32(rnd_id_right, sizeof(rnd_id_right) - 1);
  rnd_id_left[ID_LEFT_LEN] = 0;
  rnd_id_right[ID_RIGHT_LEN] = 0;
 
  snprintf(buf, sizeof(buf), "<%s@%s>", rnd_id_left, rnd_id_right);
  return mutt_str_dup(buf);
}

char *msgid_generate(void)
{
  const struct Expando *c_message_id_format = cs_subset_expando(NeoMutt->sub, "message_id_format");
  if (!c_message_id_format)
    return msgid_gen_random();
 
  struct MsgIdData mid = { 0 };
 
  mid.now = time(NULL);
  mid.tm = mutt_date_gmtime(mid.now);
 
  mid.fqdn = mutt_fqdn(false, NeoMutt->sub);
  if (!mid.fqdn)
    mid.fqdn = NONULL(ShortHostname);
 
  struct Buffer *buf = buf_pool_get();
 
  expando_filter(c_message_id_format, MsgIdRenderCallbacks, &mid,
                 MUTT_FORMAT_NO_FLAGS, buf->dsize, NeoMutt->env, buf);
  if (buf_is_empty(buf))
  {
    buf_pool_release(&buf);
    return msgid_gen_random();
  }
 
  if (buf_at(buf, 0) != '<')
    buf_insert(buf, 0, "<");
 
  const int last = buf_len(buf) - 1;
  if (buf_at(buf, last) != '>')
    buf_addch(buf, '>');
 
  char *msgid = buf_strdup(buf);
  buf_pool_release(&buf);
 
  return msgid;
}