compress.c

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#include "config.h"
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include "mutt/lib.h"
#include "config/lib.h"
#include "core/lib.h"
#include "gui/lib.h"
#include "mutt.h"
#include "lib.h"
#include "expando/lib.h"
#include "hooks/lib.h"
#include "expando.h"
#include "mx.h"
 
struct Email;

const struct Command CompCommands[] = {
  // clang-format off
  { "append-hook", CMD_APPEND_HOOK, parse_compress_hook,
        N_("Define command to append to a compressed mailbox"),
        N_("append-hook <regex> <shell-command>"),
        "optionalfeatures.html#append-hook" },
  { "close-hook", CMD_CLOSE_HOOK, parse_compress_hook,
        N_("Define command to close a compressed mailbox"),
        N_("close-hook <regex> <shell-command>"),
        "optionalfeatures.html#close-hook" },
  { "open-hook", CMD_OPEN_HOOK, parse_compress_hook,
        N_("Define command to open a compressed mailbox"),
        N_("open-hook <regex> <shell-command>"),
        "optionalfeatures.html#open-hook" },
 
  { NULL, CMD_NONE, NULL, NULL, NULL, NULL, CF_NONE },
  // clang-format on
};

const struct ExpandoDefinition CompressFormatDef[] = {
  // clang-format off
  { "f", "from", ED_COMPRESS, ED_CMP_FROM, NULL },
  { "t", "to",   ED_COMPRESS, ED_CMP_TO,   NULL },
  { NULL, NULL, 0, -1, NULL }
  // clang-format on
};

static bool lock_realpath(struct Mailbox *m, bool excl)
{
  if (!m || !m->compress_info)
    return false;
 
  struct CompressInfo *ci = m->compress_info;
 
  if (ci->locked)
    return true;
 
  if (excl)
    ci->fp_lock = mutt_file_fopen(m->realpath, "a");
  else
    ci->fp_lock = mutt_file_fopen(m->realpath, "r");
  if (!ci->fp_lock)
  {
    mutt_perror("%s", m->realpath);
    return false;
  }
 
  int r = mutt_file_lock(fileno(ci->fp_lock), excl, true);
  if (r == 0)
  {
    ci->locked = true;
  }
  else if (excl)
  {
    mutt_file_fclose(&ci->fp_lock);
    m->readonly = true;
    return true;
  }
  else
  {
    mutt_file_fclose(&ci->fp_lock);
  }
 
  return r == 0;
}

static void unlock_realpath(struct Mailbox *m)
{
  if (!m || !m->compress_info)
    return;
 
  struct CompressInfo *ci = m->compress_info;
 
  if (!ci->locked)
    return;
 
  mutt_file_unlock(fileno(ci->fp_lock));
 
  ci->locked = false;
  mutt_file_fclose(&ci->fp_lock);
}

static int setup_paths(struct Mailbox *m)
{
  if (!m)
    return -1;
 
  /* Setup the right paths */
  mutt_str_replace(&m->realpath, mailbox_path(m));
 
  /* We will uncompress to TMPDIR */
  struct Buffer *buf = buf_pool_get();
  buf_mktemp(buf);
  buf_copy(&m->pathbuf, buf);
  buf_pool_release(&buf);
 
  return mutt_file_touch(mailbox_path(m)) ? 0 : -1;
}

static void store_size(const struct Mailbox *m)
{
  if (!m || !m->compress_info)
    return;
 
  struct CompressInfo *ci = m->compress_info;
 
  ci->size = mutt_file_get_size(m->realpath);
}

static struct Expando *validate_compress_expando(const char *s)
{
  struct Buffer *err = buf_pool_get();
 
  struct Expando *exp = expando_parse(s, CompressFormatDef, err);
  if (!exp)
  {
    mutt_error(_("Expando parse error: %s"), buf_string(err));
  }
 
  buf_pool_release(&err);
  return exp;
}

static struct CompressInfo *set_compress_info(struct Mailbox *m)
{
  if (!m)
    return NULL;
 
  if (m->compress_info)
    return m->compress_info;
 
  /* Open is compulsory */
  const char *o = mutt_find_hook(CMD_OPEN_HOOK, mailbox_path(m));
  if (!o)
    return NULL;
 
  const char *c = mutt_find_hook(CMD_CLOSE_HOOK, mailbox_path(m));
  const char *a = mutt_find_hook(CMD_APPEND_HOOK, mailbox_path(m));
 
  struct CompressInfo *ci = MUTT_MEM_CALLOC(1, struct CompressInfo);
  m->compress_info = ci;
 
  ci->cmd_open = validate_compress_expando(o);
  ci->cmd_close = c ? validate_compress_expando(c) : NULL;
  ci->cmd_append = a ? validate_compress_expando(a) : NULL;
 
  return ci;
}

static void compress_info_free(struct Mailbox *m)
{
  if (!m || !m->compress_info)
    return;
 
  struct CompressInfo *ci = m->compress_info;
  expando_free(&ci->cmd_open);
  expando_free(&ci->cmd_close);
  expando_free(&ci->cmd_append);
 
  unlock_realpath(m);
 
  FREE(&m->compress_info);
}

static bool execute_command(struct Mailbox *m, const struct Expando *exp, const char *progress)
{
  if (!m || !exp || !progress)
    return false;
 
  if (m->verbose)
    mutt_message(progress, m->realpath);
 
  bool rc = true;
  struct Buffer *sys_cmd = buf_pool_get();
  buf_alloc(sys_cmd, STR_COMMAND);
 
  mutt_sig_block();
  mutt_endwin();
  fflush(stdout);
 
  expando_render(exp, CompressRenderCallbacks, m, MUTT_FORMAT_NONE, sys_cmd->dsize, sys_cmd);
 
  if (mutt_system(buf_string(sys_cmd)) != 0)
  {
    rc = false;
    mutt_any_key_to_continue(NULL);
    mutt_error(_("Error running \"%s\""), buf_string(sys_cmd));
  }
 
  mutt_sig_unblock();
 
  buf_pool_release(&sys_cmd);
  return rc;
}

bool mutt_comp_can_append(struct Mailbox *m)
{
  if (!m)
    return false;
 
  /* If this succeeds, we know there's an open-hook */
  struct CompressInfo *ci = set_compress_info(m);
  if (!ci)
    return false;
 
  /* We have an open-hook, so to append we need an append-hook,
   * or a close-hook. */
  if (ci->cmd_append || ci->cmd_close)
    return true;
 
  mutt_error(_("Can't append without an append-hook or close-hook : %s"), mailbox_path(m));
  return false;
}

bool mutt_comp_can_read(const char *path)
{
  if (!path)
    return false;
 
  if (mutt_find_hook(CMD_OPEN_HOOK, path))
    return true;
 
  return false;
}

int mutt_comp_valid_command(const char *cmd)
{
  if (!cmd)
    return 0;
 
  return strstr(cmd, "%f") && strstr(cmd, "%t");
}

static bool comp_ac_owns_path(struct Account *a, const char *path)
{
  return false;
}

static bool comp_ac_add(struct Account *a, struct Mailbox *m)
{
  return true;
}

static enum MxOpenReturns comp_mbox_open(struct Mailbox *m)
{
  struct CompressInfo *ci = set_compress_info(m);
  if (!ci)
    return MX_OPEN_ERROR;
 
  /* If there's no close-hook, or the file isn't writable */
  if (!ci->cmd_close || (access(mailbox_path(m), W_OK) != 0))
    m->readonly = true;
 
  if (setup_paths(m) != 0)
    goto cmo_fail;
  store_size(m);
 
  if (!lock_realpath(m, false))
  {
    mutt_error(_("Unable to lock mailbox"));
    goto cmo_fail;
  }
 
  if (!execute_command(m, ci->cmd_open, _("Decompressing %s")))
    goto cmo_fail;
 
  unlock_realpath(m);
 
  m->type = mx_path_probe(mailbox_path(m));
  if (m->type == MUTT_UNKNOWN)
  {
    mutt_error(_("Can't identify the contents of the compressed file"));
    goto cmo_fail;
  }
 
  ci->child_ops = mx_get_ops(m->type);
  if (!ci->child_ops)
  {
    mutt_error(_("Can't find mailbox ops for mailbox type %d"), m->type);
    goto cmo_fail;
  }
 
  m->account->type = m->type;
  return ci->child_ops->mbox_open(m);
 
cmo_fail:
  /* remove the partial uncompressed file */
  (void) remove(mailbox_path(m));
  compress_info_free(m);
  return MX_OPEN_ERROR;
}

static bool comp_mbox_open_append(struct Mailbox *m, OpenMailboxFlags flags)
{
  /* If this succeeds, we know there's an open-hook */
  struct CompressInfo *ci = set_compress_info(m);
  if (!ci)
    return false;
 
  /* To append we need an append-hook or a close-hook */
  if (!ci->cmd_append && !ci->cmd_close)
  {
    mutt_error(_("Can't append without an append-hook or close-hook : %s"),
               mailbox_path(m));
    goto cmoa_fail1;
  }
 
  if (setup_paths(m) != 0)
    goto cmoa_fail2;
 
  /* Lock the realpath for the duration of the append.
   * It will be unlocked in the close */
  if (!lock_realpath(m, true))
  {
    mutt_error(_("Unable to lock mailbox"));
    goto cmoa_fail2;
  }
 
  /* Open the existing mailbox, unless we are appending */
  if (!ci->cmd_append && (mutt_file_get_size(m->realpath) > 0))
  {
    if (!execute_command(m, ci->cmd_open, _("Decompressing %s")))
    {
      mutt_error(_("Compress command failed: %s"), ci->cmd_open->string);
      goto cmoa_fail2;
    }
    m->type = mx_path_probe(mailbox_path(m));
  }
  else
  {
    m->type = cs_subset_enum(NeoMutt->sub, "mbox_type");
  }
 
  /* We can only deal with mbox and mmdf mailboxes */
  if ((m->type != MUTT_MBOX) && (m->type != MUTT_MMDF))
  {
    mutt_error(_("Unsupported mailbox type for appending"));
    goto cmoa_fail2;
  }
 
  ci->child_ops = mx_get_ops(m->type);
  if (!ci->child_ops)
  {
    mutt_error(_("Can't find mailbox ops for mailbox type %d"), m->type);
    goto cmoa_fail2;
  }
 
  if (!ci->child_ops->mbox_open_append(m, flags))
    goto cmoa_fail2;
 
  return true;
 
cmoa_fail2:
  /* remove the partial uncompressed file */
  (void) remove(mailbox_path(m));
cmoa_fail1:
  /* Free the compress_info to prevent close from trying to recompress */
  compress_info_free(m);
 
  return false;
}

static enum MxStatus comp_mbox_check(struct Mailbox *m)
{
  if (!m->compress_info)
    return MX_STATUS_ERROR;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops)
    return MX_STATUS_ERROR;
 
  long size = mutt_file_get_size(m->realpath);
  if (size == ci->size)
    return MX_STATUS_OK;
 
  if (!lock_realpath(m, false))
  {
    mutt_error(_("Unable to lock mailbox"));
    return MX_STATUS_ERROR;
  }
 
  bool rc = execute_command(m, ci->cmd_open, _("Decompressing %s"));
  store_size(m);
  unlock_realpath(m);
  if (!rc)
    return MX_STATUS_ERROR;
 
  return ops->mbox_check(m);
}

static enum MxStatus comp_mbox_sync(struct Mailbox *m)
{
  if (!m->compress_info)
    return MX_STATUS_ERROR;
 
  struct CompressInfo *ci = m->compress_info;
 
  if (!ci->cmd_close)
  {
    mutt_error(_("Can't sync a compressed file without a close-hook"));
    return MX_STATUS_ERROR;
  }
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops)
    return MX_STATUS_ERROR;
 
  if (!lock_realpath(m, true))
  {
    mutt_error(_("Unable to lock mailbox"));
    return MX_STATUS_ERROR;
  }
 
  enum MxStatus check = comp_mbox_check(m);
  if (check != MX_STATUS_OK)
    goto sync_cleanup;
 
  check = ops->mbox_sync(m);
  if (check != MX_STATUS_OK)
    goto sync_cleanup;
 
  if (!execute_command(m, ci->cmd_close, _("Compressing %s")))
  {
    check = MX_STATUS_ERROR;
    goto sync_cleanup;
  }
 
  check = MX_STATUS_OK;
 
sync_cleanup:
  store_size(m);
  unlock_realpath(m);
  return check;
}

static enum MxStatus comp_mbox_close(struct Mailbox *m)
{
  if (!m->compress_info)
    return MX_STATUS_ERROR;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops)
  {
    compress_info_free(m);
    return MX_STATUS_ERROR;
  }
 
  ops->mbox_close(m);
 
  /* sync has already been called, so we only need to delete some files */
  if (m->append)
  {
    const struct Expando *append = NULL;
    const char *msg = NULL;
 
    /* The file exists and we can append */
    if ((access(m->realpath, F_OK) == 0) && ci->cmd_append)
    {
      append = ci->cmd_append;
      msg = _("Compressed-appending to %s...");
    }
    else
    {
      append = ci->cmd_close;
      msg = _("Compressing %s");
    }
 
    if (!execute_command(m, append, msg))
    {
      mutt_any_key_to_continue(NULL);
      mutt_error(_("Error. Preserving temporary file: %s"), mailbox_path(m));
    }
    else
    {
      if (remove(mailbox_path(m)) < 0)
      {
        mutt_debug(LL_DEBUG1, "remove failed: %s: %s (errno %d)\n",
                   mailbox_path(m), strerror(errno), errno);
      }
    }
 
    unlock_realpath(m);
  }
  else
  {
    /* If the file was removed, remove the compressed folder too */
    if (access(mailbox_path(m), F_OK) != 0)
    {
      const bool c_save_empty = cs_subset_bool(NeoMutt->sub, "save_empty");
      if (!c_save_empty)
      {
        if (remove(m->realpath) < 0)
        {
          mutt_debug(LL_DEBUG1, "remove failed: %s: %s (errno %d)\n",
                     m->realpath, strerror(errno), errno);
        }
      }
    }
    else
    {
      if (remove(mailbox_path(m)) < 0)
      {
        mutt_debug(LL_DEBUG1, "remove failed: %s: %s (errno %d)\n",
                   mailbox_path(m), strerror(errno), errno);
      }
    }
  }
 
  compress_info_free(m);
 
  return MX_STATUS_OK;
}

static bool comp_msg_open(struct Mailbox *m, struct Message *msg, struct Email *e)
{
  if (!m->compress_info)
    return false;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops)
    return false;
 
  /* Delegate */
  return ops->msg_open(m, msg, e);
}

static bool comp_msg_open_new(struct Mailbox *m, struct Message *msg, const struct Email *e)
{
  if (!m->compress_info)
    return false;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops)
    return false;
 
  /* Delegate */
  return ops->msg_open_new(m, msg, e);
}

static int comp_msg_commit(struct Mailbox *m, struct Message *msg)
{
  if (!m->compress_info)
    return -1;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops)
    return -1;
 
  /* Delegate */
  return ops->msg_commit(m, msg);
}

static int comp_msg_close(struct Mailbox *m, struct Message *msg)
{
  if (!m->compress_info)
    return -1;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops)
    return -1;
 
  /* Delegate */
  return ops->msg_close(m, msg);
}

static int comp_msg_padding_size(struct Mailbox *m)
{
  if (!m->compress_info)
    return 0;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops || !ops->msg_padding_size)
    return 0;
 
  return ops->msg_padding_size(m);
}

static int comp_msg_save_hcache(struct Mailbox *m, struct Email *e)
{
  if (!m->compress_info)
    return 0;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops || !ops->msg_save_hcache)
    return 0;
 
  return ops->msg_save_hcache(m, e);
}

static int comp_tags_edit(struct Mailbox *m, const char *tags, struct Buffer *buf)
{
  if (!m->compress_info)
    return 0;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops || !ops->tags_edit)
    return 0;
 
  return ops->tags_edit(m, tags, buf);
}

static int comp_tags_commit(struct Mailbox *m, struct Email *e, const char *buf)
{
  if (!m->compress_info)
    return 0;
 
  struct CompressInfo *ci = m->compress_info;
 
  const struct MxOps *ops = ci->child_ops;
  if (!ops || !ops->tags_commit)
    return 0;
 
  return ops->tags_commit(m, e, buf);
}

static enum MailboxType comp_path_probe(const char *path, const struct stat *st)
{
  if (!st || !S_ISREG(st->st_mode))
    return MUTT_UNKNOWN;
 
  if (mutt_comp_can_read(path))
    return MUTT_COMPRESSED;
 
  return MUTT_UNKNOWN;
}

static int comp_path_canon(struct Buffer *path)
{
  mutt_path_canon(path, NeoMutt->home_dir, false);
  return 0;
}

const struct MxOps MxCompOps = {
  // clang-format off
  .type            = MUTT_COMPRESSED,
  .name             = "compressed",
  .is_local         = true,
  .ac_owns_path     = comp_ac_owns_path,
  .ac_add           = comp_ac_add,
  .mbox_open        = comp_mbox_open,
  .mbox_open_append = comp_mbox_open_append,
  .mbox_check       = comp_mbox_check,
  .mbox_check_stats = NULL,
  .mbox_sync        = comp_mbox_sync,
  .mbox_close       = comp_mbox_close,
  .msg_open         = comp_msg_open,
  .msg_open_new     = comp_msg_open_new,
  .msg_commit       = comp_msg_commit,
  .msg_close        = comp_msg_close,
  .msg_padding_size = comp_msg_padding_size,
  .msg_save_hcache  = comp_msg_save_hcache,
  .tags_edit        = comp_tags_edit,
  .tags_commit      = comp_tags_commit,
  .path_probe       = comp_path_probe,
  .path_canon       = comp_path_canon,
  .path_is_empty    = NULL,
  // clang-format on
};