g13: New command --find-device.

* common/status.h (STATUS_BLOCKDEV: New.
* g13/call-syshelp.c: Include "call-syshelp.h".
(finddevice_status_cb, call_syshelp_find_device): New.
* g13/g13.c (aFindDevice): New.
(opts): Add "--find-device".
(main): Implement --find-device.
* g13/sh-cmd.c (cmd_finddevice): New.
(register_commands): Register new command.
--

This might be useful for scripting.

Signed-off-by: Werner Koch <wk@gnupg.org>

common/status.h

@@ -142,6 +142,7 @@ enum
 
     STATUS_TRUNCATED,
     STATUS_MOUNTPOINT,
+    STATUS_BLOCKDEV,
 
     STATUS_PINENTRY_LAUNCHED,
 

g13/call-syshelp.c

@@ -33,6 +33,7 @@
 #include "keyblob.h"
 #include "membuf.h"
 #include "create.h"
+#include "call-syshelp.h"
 
 
 /* Local data for this module.  A pointer to this is stored in the
@@ -172,6 +173,68 @@ call_syshelp_release (ctrl_t ctrl)
 }
 
 
+
+/* Staus callback for call_syshelp_find_device.  */
+static gpg_error_t
+finddevice_status_cb (void *opaque, const char *line)
+{
+  char **r_blockdev = opaque;
+  char *p;
+
+  if ((p = has_leading_keyword (line, "BLOCKDEV")) && *p && !*r_blockdev)
+    {
+      *r_blockdev = xtrystrdup (p);
+      if (!*r_blockdev)
+        return gpg_error_from_syserror ();
+    }
+
+  return 0;
+}
+
+
+/* Send the FINDDEVICE command to the syshelper.  On success the name
+ * of the block device is stored at R_BLOCKDEV. */
+gpg_error_t
+call_syshelp_find_device (ctrl_t ctrl, const char *name, char **r_blockdev)
+{
+  gpg_error_t err;
+  assuan_context_t ctx;
+  char *line = NULL;
+  char *blockdev = NULL;  /* The result.  */
+
+  *r_blockdev = NULL;
+
+  err = start_syshelp (ctrl, &ctx);
+  if (err)
+    goto leave;
+
+  line = xtryasprintf ("FINDDEVICE %s", name);
+  if (!line)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+  err = assuan_transact (ctx, line, NULL, NULL, NULL, NULL,
+                         finddevice_status_cb, &blockdev);
+  if (err)
+    goto leave;
+  if (!blockdev)
+    {
+      log_error ("status line for successful FINDDEVICE missing\n");
+      err = gpg_error (GPG_ERR_UNEXPECTED);
+      goto leave;
+    }
+  *r_blockdev = blockdev;
+  blockdev = NULL;
+
+ leave:
+  xfree (blockdev);
+  xfree (line);
+  return err;
+}
+
+
+
 /* Send the DEVICE command to the syshelper.  FNAME is the name of the
    device.  */
 gpg_error_t

g13/call-syshelp.h

@@ -23,6 +23,8 @@
 #include "g13tuple.h"
 
 void call_syshelp_release (ctrl_t ctrl);
+gpg_error_t call_syshelp_find_device (ctrl_t ctrl,
+                                      const char *name, char **r_blockdev);
 gpg_error_t call_syshelp_set_device (ctrl_t ctrl, const char *fname);
 gpg_error_t call_syshelp_run_create (ctrl_t ctrl, int conttype);
 gpg_error_t call_syshelp_run_mount (ctrl_t ctrl, int conttype,

g13/g13.c

@@ -62,6 +62,7 @@ enum cmd_and_opt_values {
   aSuspend,
   aResume,
   aServer,
+  aFindDevice,
 
   oOptions,
   oDebug,
@@ -115,6 +116,7 @@ static ARGPARSE_OPTS opts[] = {
   ARGPARSE_c (aSuspend, "suspend", N_("Suspend a file system container") ),
   ARGPARSE_c (aResume,  "resume",  N_("Resume a file system container") ),
   ARGPARSE_c (aServer, "server", N_("Run in server mode")),
+  ARGPARSE_c (aFindDevice, "find-device", "@"),
 
   ARGPARSE_c (aGPGConfList, "gpgconf-list", "@"),
   ARGPARSE_c (aGPGConfTest, "gpgconf-test", "@"),
@@ -491,6 +493,7 @@ main ( int argc, char **argv)
         case aSuspend:
         case aResume:
         case aCreate:
+        case aFindDevice:
           set_cmd (&cmd, pargs.r_opt);
           break;
 
@@ -744,6 +747,22 @@ main ( int argc, char **argv)
       }
       break;
 
+    case aFindDevice:
+      {
+        char *blockdev;
+
+        if (argc != 1)
+          wrong_args ("--find-device name");
+
+        err = call_syshelp_find_device (&ctrl, argv[0], &blockdev);
+        if (err)
+          log_error ("error finding device '%s': %s <%s>\n",
+                     argv[0], gpg_strerror (err), gpg_strsource (err));
+        else
+          puts (blockdev);
+      }
+      break;
+
     case aCreate: /* Create a new container. */
       {
         if (argc != 1)

g13/sh-cmd.c

@@ -157,6 +157,82 @@ reset_notify (assuan_context_t ctx, char *line)
 }
 
 
+static const char hlp_finddevice[] =
+  "FINDDEVICE <name>\n"
+  "\n"
+  "Find the device matching NAME.  NAME be any identifier from\n"
+  "g13tab permissable for the user.  The corresponding block\n"
+  "device is retruned using a status line.";
+static gpg_error_t
+cmd_finddevice (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  gpg_error_t err = 0;
+  tab_item_t ti;
+  const char *s;
+  const char *name;
+
+  name = skip_options (line);
+
+  /* Are we allowed to use the given device?  We check several names:
+   *  1. The full block device
+   *  2. The label
+   *  3. The final part of the block device if NAME does not have a slash.
+   *  4. The mountpoint
+   */
+  for (ti=ctrl->client.tab; ti; ti = ti->next)
+    if (!strcmp (name, ti->blockdev))
+      break;
+  if (!ti)
+    {
+      for (ti=ctrl->client.tab; ti; ti = ti->next)
+        if (ti->label && !strcmp (name, ti->label))
+          break;
+    }
+  if (!ti && !strchr (name, '/'))
+    {
+      for (ti=ctrl->client.tab; ti; ti = ti->next)
+        {
+          s = strrchr (ti->blockdev, '/');
+          if (s && s[1] && !strcmp (name, s+1))
+            break;
+        }
+    }
+  if (!ti)
+    {
+      for (ti=ctrl->client.tab; ti; ti = ti->next)
+        if (ti->mountpoint && !strcmp (name, ti->mountpoint))
+          break;
+    }
+
+  if (!ti)
+    {
+      err = set_error (GPG_ERR_NOT_FOUND, "device not configured for user");
+      goto leave;
+    }
+
+  /* Check whether we have permissions to open the device.  */
+  {
+    estream_t fp = es_fopen (ti->blockdev, "rb");
+    if (!fp)
+      {
+        err = gpg_error_from_syserror ();
+        log_error ("error opening '%s': %s\n",
+                   ti->blockdev, gpg_strerror (err));
+        goto leave;
+      }
+    es_fclose (fp);
+  }
+
+  err = g13_status (ctrl, STATUS_BLOCKDEV, ti->blockdev, NULL);
+  if (err)
+    return err;
+
+ leave:
+  return leave_cmd (ctx, err);
+}
+
+
 static const char hlp_device[] =
   "DEVICE <name>\n"
   "\n"
@@ -588,6 +664,7 @@ register_commands (assuan_context_t ctx, int fail_all)
     assuan_handler_t handler;
     const char * const help;
   } table[] =  {
+    { "FINDDEVICE",    cmd_finddevice, hlp_finddevice },
     { "DEVICE",        cmd_device, hlp_device },
     { "CREATE",        cmd_create, hlp_create },
     { "MOUNT",         cmd_mount,  hlp_mount  },