src/libpwmd.h.in

   1 /* vim:tw=78:ts=8:sw=4:set ft=c:  */
   2 /*
   3     Copyright (C) 2006-2009 Ben Kibbey <bjk@luxsci.net>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02110-1301  USA
  18 */
  19 /*! \headerfile libpwmd.h
  20  *
  21  * libpwmd is a library making it easy for applications to use the pwmd
  22  * server.
  23  */
  24
  25 /*! \section ssh SSH Details
  26  *
  27  * A remote connection to a pwmd server is possible by using an SSH channel
  28  * which spawns a shell and executes a proxy server that connects to the pwmd
  29  * local unix domain socket. Authenication is done by using SSH public key
  30  * (see \ref ssh-keygen(1)) authentication and verifying the host key against
  31  * a local file containing SHA1 hashes of known hosts. It's alot like how the
  32  * standard OpenSSH does things only the known_hosts file is in a different
  33  * format.
  34  *
  35  * The server hash can be had by using \ref pwmd_get_hostkey() and storing the
  36  * result in a file. This file is then used as the \a known_hosts argument to
  37  * the SSH connection functions.
  38  *
  39  * Here's an example \ref authorized_keys(5) entry. The hash portion should be
  40  * the same as the contents of the \a identity.pub file which is passed as a
  41  * parameter to the SSH connection functions:
  42  *
  43  * \code
  44  * command="socat gopen:$HOME/.pwmd/socket -" <hash> ...
  45  * \endcode
  46  *
  47  * \x11
  48  */
  49
  50 /*! \section pinentry Pinentry Details
  51  *
  52  * \ref pinentry(1) is a program that prompts the user for input which is
  53  * normally a passphrase or a confirmation. libpwmd can use this program
  54  * either locally (the connection is to a remote server not on this host) or
  55  * have the pwmd server use it's pinentry to retrieve a passphrase when
  56  * needed.
  57  *
  58  * There are a few options that tell pinentry how and where to prompt for a
  59  * passphrase. See the \ref pwmd_option_t section for details. These options
  60  * are not sent (when using pwmd's pinentry) until the pinentry is needed.
  61  *
  62  * If using a local pinentry by calling \ref pwmd_open2(), \ref pwmd_save2(),
  63  * \ref pwmd_open_async2() or pwmd_save_async2(), libpwmd will send the
  64  * command "OPTION PINENTRY=0" to the server. This is needed for pinentry
  65  * retries (passphrase or confirmation failure). So if you need to change
  66  * pinentry methods, then set this option as needed.
  67  *
  68  * Some pinentry options can also be specified in a local configuration file
  69  * \a "~/.pwmd/pinentry.conf". These options are initial values for each
  70  * invokation and may be changed by setting the appropriate \ref
  71  * pwmd_option_t. Each option and value is separated with a '=' on a single
  72  * line. Unrecognized options are ignored. Here are the recognized options:
  73  *
  74  * \param PATH The full path to the location of the pinentry binary.
  75  * \param DISPLAY The X11 display to use.
  76  * \param TTYNAME The full path to the tty that pinentry should prompt on.
  77  * \param TTYTYPE The terminal type of the tty which is required if DISPLAY is
  78  * not set.
  79  *
  80  * \note After establishing an SSH connection, the pwmd pinentry is disabled
  81  * because it doesn't currently have a way to use the local display. You must
  82  * be careful to either use a local pinentry or set a passphrase manually with
  83  * \ref pwmd_setopt().
  84  *
  85  * \x11
  86  *
  87  * \see \ref ssh
  88  */
  89
  90 /*! \section example Example Client
  91  *
  92  * The following example will list the element tree of the data file specified
  93  * in the first command line argument.
  94  *
  95  * \code
  96  * #include <stdio.h>
  97  * #include <libpwmd.h>
  98  *
  99  * int main()
 100  * {
 101  *     pwm_t *pwm = pwmd_new(NULL);
 102  *     gpg_error_t rc = pwmd_connect(pwm, NULL);
 103  *     char *result;
 104  *
 105  *     if (!rc) {
 106  *         rc = pwmd_open(pwm, argv[1]);
 107  *
 108  *         if (!rc) {
 109  *             rc = pwmd_command(pwm, &result, "%s", "LIST");
 110  *
 111  *             if (!rc) {
 112  *                 printf("%s", result);
 113  *                 pwmd_free(result);
 114  *             }
 115  *         }
 116  *     }
 117  *
 118  *     pwmd_close(pwm);
 119  *
 120  *     if (rc)
 121  *         fprintf(stderr, "ERR: %s\n", pwmd_strerror(rc));
 122  *
 123  *     exit(rc ? 1 : 0);
 124  * }
 125  * \endcode
 126  */
 127
 128 /*! \file */
 129 #ifndef LIBPWMD_H
 130 #define LIBPWMD_H
 131
 132 #include <gpg-error.h>
 133 #include <stdarg.h>
 134
 135 #ifdef __cplusplus
 136 extern "C" {
 137 #endif
 138
 139 /*! \def LIBPWMD_VERSION
 140  *  \hideinitializer
 141  *
 142  * The version of this library.
 143  */
 144 #define LIBPWMD_VERSION 0x@VER_MAJOR@@VER_COMPAT@@VER_PATCH@
 145
 146
 147 struct pwm_s;
 148 /*! \typedef pwm_t
 149  *
 150  * When a handle is mentioned in this documentation it is a pointer of this
 151  * type. A new handle is created with \ref pwmd_new().
 152  */
 153 typedef struct pwm_s pwm_t;
 154
 155
 156 /*! \typedef pwmd_async_t
 157  *
 158  * The return code of \ref pwmd_process() which is used for all asynchronous
 159  * commands.
 160  */
 161 typedef enum {
 162     /*! \internal */
 163     ASYNC_INIT,
 164
 165     /*! \ref pwmd_process() should be called again. */
 166     ASYNC_PROCESS,
 167
 168     /*! The command has completed. The result code should be checked for an
 169      * error. */
 170     ASYNC_DONE,
 171 } pwmd_async_t;
 172
 173
 174 /*! \typedef pwmd_ip_version_t
 175  *
 176  * The value of the option \ref PWMD_OPTION_IP_VERSION which is set with \ref
 177  * pwmd_setopt().
 178  */
 179 typedef enum {
 180     /*! Try both IPv6 and IPv4 addresses. Note that IPv6 is tried first. */
 181     PWMD_IP_ANY,
 182
 183     /*! Only try IPv4. */
 184     PWMD_IPV4,
 185
 186     /*! Only try IPv6. */
 187     PWMD_IPV6
 188 } pwmd_ip_version_t;
 189
 190
 191 /*! \def PWMD_FD_READABLE
 192  * \hideinitializer
 193  *
 194  * Set when the file descriptor is readable.
 195  */
 196 #define PWMD_FD_READABLE        0x01
 197
 198
 199 /*! \def PWMD_FD_WRITABLE
 200  * \hideinitializer
 201  *
 202  * Set when the file descriptor is writable.
 203  */
 204 #define PWMD_FD_WRITABLE        0x02
 205
 206
 207 /*! \typedef pwmd_fd_t
 208  *
 209  * For use with \ref pwmd_get_fds().
 210  */
 211 typedef struct {
 212     /*! The file descriptor. */
 213     int fd;
 214
 215     /*! A bitmask of \ref PWMD_FD_READABLE and \ref PWMD_FD_WRITABLE. */
 216     unsigned flags;
 217 } pwmd_fd_t;
 218
 219
 220 /*! \typedef pwmd_passphrase_cb_t
 221  *
 222  * The value of the option \ref PWMD_OPTION_PASSPHRASE_CB which is set with
 223  * \ref pwmd_setopt().
 224  *
 225  * \param user A user data pointer which is set with \ref
 226  * PWMD_OPTION_PASSPHRASE_DATA.
 227  * \param[out] passphrase The passphrase which may be an empty string or NULL.
 228  * \return 0 on success or an error code which will cause a command to fail.
 229  */
 230 typedef gpg_error_t (*pwmd_passphrase_cb_t)(void *user, char **passphrase);
 231
 232
 233 /*! \typedef pwmd_status_cb_t
 234  *
 235  * The value of the option \ref PWMD_OPTION_STATUS_CB which is set with \ref
 236  * pwmd_setopt().
 237  *
 238  * \param user A user data pointer which is set with \ref
 239  * PWMD_OPTION_STATUS_DATA.
 240  * \param line The status message line.
 241  * \return 0 on success or an error code which will cause a command to fail.
 242  */
 243 typedef int (*pwmd_status_cb_t)(void *user, const char *line);
 244
 245
 246 /*! \typedef pwmd_inquire_cb_t
 247  *
 248  * This is a callback function that gets passed to \ref pwmd_inquire(). It is
 249  * used for sending data to the server for commands that return an INQUIRE
 250  * response (STORE and IMPORT). The reason for this callback is to let the
 251  * client send as many bytes as it wants rather than the entire chunk at once.
 252  * It gets called during \ref assuan_transact() from an internal inquire
 253  * callback function which in turn calls this function by looping over its
 254  * return value.
 255  *
 256  * \param user The user data pointer passed to \ref pwmd_inquire().
 257  * \param cmd The same as the \a cmd argument to \ref pwmd_inquire().
 258  * \param rc The result of the last internal call to \ref assuan_send_data()
 259  * which did the sending of the data to the pwmd server. On the first call to
 260  * this callback it will always be 0 because no data has been sent yet.
 261  * \param[out] data The next chunk of data to send or NULL.
 262  * \param[out] len The length of \a data or 0.
 263  *
 264  * \retval 0 There is more data to be sent.
 265  * \retval GPG_ERR_EOF No need to call this function again, the current
 266  * \a line is the last to send.
 267  * \retval code Any other error code which will terminate the INQUIRE.
 268  *
 269  * \note The sent data is processed line-per-line. The line is either newline
 270  * terminated or is buffered until ASSUAN_LINELENGTH bytes have been
 271  * allocated. Any remaining bytes are sent after the INQUIRE has finished.
 272  */
 273 typedef gpg_error_t (*pwmd_inquire_cb_t)(void *user, const char *cmd,
 274         gpg_error_t rc, char **data, size_t *len);
 275
 276
 277 /*! \enum pwmd_option_t
 278  *
 279  * libpwmd options which are set with \ref pwmd_setopt().
 280  */
 281 typedef enum {
 282     /*! A custom passphrase retrieval function which, when set, will be used
 283      * instead of \ref pinentry(1). This function will not be used when the
 284      * passphrase is cached on the server or the file is a new one. The value
 285      * of this option should be a \ref pwmd_passphrase_cb_t function pointer.
 286      */
 287     PWMD_OPTION_PASSPHRASE_CB,
 288
 289     /*! User supplied data which is passed to the custom password function. */
 290     PWMD_OPTION_PASSPHRASE_DATA,
 291
 292     /*! A string to use as the passphrase when doing an open or save. When not
 293      * NULL, this option has precedence over \ref PWMD_OPTION_PASSPHRASE_CB.
 294      */
 295     PWMD_OPTION_PASSPHRASE,
 296
 297     /*! An integer value that specifies the specified the number of tries
 298      * before \ref pinentry(1) will give up when opening a file with the wrong
 299      * supplied passphrase. The default is 3.
 300      *
 301      * \note This option has no effect when trying to save a file. The user
 302      * must either cancel the pinentry causing the save to fail or enter the
 303      * correct passphrase during passphrase confirmation.
 304      */
 305     PWMD_OPTION_PINENTRY_TRIES,
 306
 307     /*! A character string value which specifies the full path of the \ref
 308      * pinentry(1) binary. For the local \ref pinentry(1) method, the default
 309      * is specified at compile time.
 310      *
 311      * \see \ref pinentry
 312      */
 313     PWMD_OPTION_PINENTRY_PATH,
 314
 315     /*! A value which specifies the full path to the tty that \ref pinentry(1)
 316      * will use. When set and no DISPLAY is available, \ref
 317      * PWMD_OPTION_PINENTRY_TERM must also be set.
 318      *
 319      * \see \ref pinentry
 320      */
 321     PWMD_OPTION_PINENTRY_TTY,
 322
 323     /*! A value which specifies the terminal type (e.g., vt100) that \ref
 324      * pinentry(1) will use when no X11 display is available.
 325      *
 326      * \see \ref pinentry
 327      */
 328     PWMD_OPTION_PINENTRY_TERM,
 329
 330     /*! A value which specifies the X11 display that \ref pinentry(1) will
 331      * use.
 332      *
 333      * \see \ref pinentry
 334      */
 335     PWMD_OPTION_PINENTRY_DISPLAY,
 336
 337     /*! A character string that \ref pinentry(1) will use in it's dialog
 338      * window.
 339      */
 340     PWMD_OPTION_PINENTRY_TITLE,
 341
 342     /*! \copydoc PWMD_OPTION_PINENTRY_TITLE */
 343     PWMD_OPTION_PINENTRY_PROMPT,
 344
 345     /*! \copydoc PWMD_OPTION_PINENTRY_TITLE */
 346     PWMD_OPTION_PINENTRY_DESC,
 347
 348     /*! For \ref pinentry(1) localization. */
 349     PWMD_OPTION_PINENTRY_LC_CTYPE,
 350
 351     /*! \copydoc PWMD_OPTION_PINENTRY_LC_CTYPE */
 352     PWMD_OPTION_PINENTRY_LC_MESSAGES,
 353
 354     /*! An integer value that specifies the number of seconds \ref pinentry(1)
 355      * will wait for input before timing out and aborting the current command.
 356      * If 0, then no timeout will be used. The default is 30.
 357      */
 358     PWMD_OPTION_PINENTRY_TIMEOUT,
 359
 360     /*! A function pointer of type \ref pwmd_status_cb_t that will process
 361      * status messages received from the pwmd server.
 362      */
 363     PWMD_OPTION_STATUS_CB,
 364
 365     /*! A user data pointer which is passed to the status message function. */
 366     PWMD_OPTION_STATUS_DATA,
 367
 368     /*! The IP version of type \ref pwmd_ip_version_t that \ref
 369      * pwmd_ssh_connect() and \ref pwmd_ssh_connect_async() will use when
 370      * connecting to the remote pwmd server.
 371      *
 372      * \pre_conn_req
 373      */
 374     PWMD_OPTION_IP_VERSION,
 375 } pwmd_option_t;
 376
 377
 378 /*! \brief Initialize the library.
 379  *
 380  * This function must be the first function called in the library before any
 381  * others. It sets up internationalization among other things.
 382  *
 383  * \return 0 Success.
 384  */
 385 gpg_error_t pwmd_init(void);
 386
 387
 388 /*! \brief Creates a new handle.
 389  *
 390  * Creates a new handle for use with the other functions.
 391  *
 392  * \param name If not NULL, the name of the application. The application name
 393  * is sent to the pwmd server after successfully connecting.
 394  *
 395  * \param name The application name or NULL.
 396  * \return a new handle or NULL if there was not enough memory.
 397  */
 398 pwm_t *pwmd_new(const char *name)
 399     __attribute__ ((warn_unused_result));
 400
 401
 402 /*! \brief Connect to a local pwmd server.
 403  *
 404  * Connects to a local unix domain socket.
 405  *
 406  * \param pwm A handle.
 407  * \param path The socket path to connect to. If NULL, then a default of
 408  * \a "~/.pwmd/socket" will be used.
 409  * \return 0 on success or an error code.
 410  * \see pwmd_ssh_connect(), pwmd_ssh_connect_async()
 411  */
 412 gpg_error_t pwmd_connect(pwm_t *pwm, const char *path)
 413     __attribute__ ((warn_unused_result));
 414
 415
 416 /*! \brief Establish a remote connection to a pwmd server.
 417  *
 418  * Connects to a pwmd server over an SSH channel.
 419  *
 420  * \param pwm A handle.
 421  * \param host The hostname to connect to.
 422  * \param port The port or -1 for the default.
 423  * \param identity The SSH identity file to use for authentication. This
 424  * should specify the private key. The public key is assumed to be \a
 425  * identity.pub.
 426  * \param user The username on the SSH server to login as. If NULL then
 427  * invoking user will be used.
 428  * \param known_hosts A file containing the public SSH server key hash in SHA1
 429  * format.
 430  * \return 0 on success or an error code.
 431  * \see pwmd_ssh_connect_async(), pwmd_process(), \ref ssh
 432  */
 433 gpg_error_t pwmd_ssh_connect(pwm_t *pwm, const char *host, int port,
 434         const char *identity, const char *user, const char *known_hosts)
 435     __attribute__ ((warn_unused_result));
 436
 437
 438 /*! \brief Establish a remote connection to a pwmd server asynchronously.
 439  *
 440  * This is a variant of \ref pwmd_ssh_connect() that will not block while doing
 441  * DNS lookups or while connecting.
 442  *
 443  * \process
 444  *
 445  * \param pwm A handle.
 446  * \param host The hostname to connect to.
 447  * \param port The port or -1 for the default.
 448  * \param identity The SSH identity file to use for authentication. This
 449  * should specify the private key. The public key is assumed to be \a
 450  * identity.pub.
 451  * \param user The username on the SSH server to login as. If NULL, the
 452  * invoking username will be used.
 453  * \param known_hosts A file containing the public SSH server key hash in SHA1
 454  * format.
 455  * \return 0 on success or an error code.
 456  * \see pwmd_process(), \ref ssh
 457  */
 458 gpg_error_t pwmd_ssh_connect_async(pwm_t *pwm, const char *host, int port,
 459         const char *identity, const char *user, const char *known_hosts)
 460     __attribute__ ((warn_unused_result));
 461
 462
 463 /*! \brief Establish a connection by parsing a URL.
 464  *
 465  * This allows for connecting to a pwmd server by parsing the given URL
 466  * string. Whether the connection is to a remote or local server depends on
 467  * the contents:
 468  * \code
 469  *
 470  * socket://[path/to/local/socket]
 471  *
 472  * or
 473  *
 474  * ssh[46]://[username@]hostname[:port],identity,known_hosts
 475  * \endcode
 476  *
 477  * The parameters in square brackets are optional and if not specified the
 478  * defaults will be used.
 479  *
 480  * \param pwm A handle.
 481  * \param url The string to parse.
 482  * \return 0 on success or an error code.
 483  */
 484 gpg_error_t pwmd_connect_url(pwm_t *pwm, const char *url)
 485     __attribute__ ((warn_unused_result));
 486
 487
 488 /*! \brief Establish a connection asynchronously by parsing a URL.
 489  *
 490  * This allows for connecting to a pwmd server by parsing the given URL
 491  * string. Whether the connection is to a remote or local server depends on
 492  * the contents:
 493  * \code
 494  *
 495  * socket://[path/to/local/socket]
 496  *
 497  * or
 498  *
 499  * ssh[46]://[username@]hostname[:port],identity,known_hosts
 500  * \endcode
 501  *
 502  * The parameters in square brackets are optional and if not specified the
 503  * defaults will be used.
 504  *
 505  * \process
 506  *
 507  * \param pwm A handle.
 508  * \param url The string to parse.
 509  * \return 0 on success or an error code.
 510  */
 511 gpg_error_t pwmd_connect_url_async(pwm_t *pwm, const char *url)
 512     __attribute__ ((warn_unused_result));
 513
 514
 515 /*! \brief Retrieve a remote SSH host key.
 516  *
 517  * This key is needed for host verification of the remote pwmd server.
 518  *
 519  * \param pwm A handle.
 520  * \param host The hostname to connect to.
 521  * \param port The port.
 522  * \param[out] result The server host key which must be freed with \ref
 523  * pwmd_free().
 524  * \return 0 on success or an error code.
 525  * \see pwmd_get_hostkey_async(), \ref ssh
 526  */
 527 gpg_error_t pwmd_get_hostkey(pwm_t *pwm, const char *host, int port,
 528         char **result)
 529     __attribute__ ((warn_unused_result));
 530
 531
 532 /*! \brief Retrieve a remote SSH host key asynchronously.
 533  *
 534  * This key is needed for host verification of the remote pwmd server.
 535  *
 536  * \process
 537  *
 538  * \param pwm A handle.
 539  * \param host The hostname to connect to.
 540  * \param port The port or a default if set to -1.
 541  * \return 0 on success or an error code.
 542  * \see pwmd_get_hostkey(), \ref pwmd_process(), \ref ssh
 543  */
 544 gpg_error_t pwmd_get_hostkey_async(pwm_t *pwm, const char *host, int port)
 545     __attribute__ ((warn_unused_result));
 546
 547
 548 /*! \brief Get the associated file descriptor(s) for a handle.
 549  *
 550  * This function lets the application poll the available file descriptors for
 551  * the specified handle. It should be called after each asynchronous function
 552  * and after each call to \ref pwmd_process() since the polled file
 553  * descriptors may have been closed since the last call. It should also be
 554  * called periodically to determine when to call \ref pwmd_process() to parse
 555  * any pending status messages.
 556  *
 557  * After returning, \a n_fds is set to the number of available file
 558  * descriptors which are stored in \a fds. The .flags member of \ref pwmd_fd_t
 559  * specifies what can be monitored and is a bitmask of \ref PWMD_FD_READABLE
 560  * and \ref PWMD_FD_WRITABLE. When ready, \ref pwmd_process() should be
 561  * called.
 562  *
 563  * \param pwm A handle.
 564  * \param[out] fds Set to the file descriptor(s) of the associated handle.
 565  * \param[out] n_fds Initially the size of \a fds then updated to the number
 566  * of available file descriptors which are stored in \a fds.
 567  * \retval 0 on success or an error code.
 568  * \retval GPG_ERR_ERANGE There are more file descriptors than the amount
 569  * specified in \a n_fds. \a fds and \a n_fds are still usable though.
 570  * \see pwmd_process()
 571  */
 572 gpg_error_t pwmd_get_fds(pwm_t *pwm, pwmd_fd_t *fds, int *n_fds)
 573     __attribute__ ((warn_unused_result));
 574
 575
 576 /*! \brief Check for a unparsed buffered line.
 577  *
 578  * A buffered line is a line that was read from the server but was not
 579  * processed. This function determines if there is such a line.
 580  *
 581  * \param pwm A handle.
 582  * \retval 0 if there is pending data.
 583  * \retval GPG_ERR_NO_DATA if there is no pending data.
 584  * \see pwmd_process()
 585  */
 586 gpg_error_t pwmd_pending_line(pwm_t *pwm)
 587     __attribute__ ((warn_unused_result));
 588
 589
 590 /*! \brief Set library options.
 591  *
 592  * See \ref pwmd_option_t for option specific details.
 593  *
 594  * \param pwm A handle.
 595  * \param opt The option.
 596  * \param ... The option value.
 597  * \return 0 on success or an error code.
 598  */
 599 gpg_error_t pwmd_setopt(pwm_t *pwm, pwmd_option_t opt, ...)
 600     __attribute__ ((warn_unused_result));
 601
 602
 603 /*! \brief Open a file on the pwmd server.
 604  *
 605  * This will send the OPEN command to the server.
 606  *
 607  * \param pwm A handle.
 608  * \param filename The filename to open.
 609  * \return 0 on success or an error code.
 610  * \see \ref pinentry
 611  */
 612 gpg_error_t pwmd_open(pwm_t *pwm, const char *filename)
 613     __attribute__ ((warn_unused_result));
 614
 615 /*! \brief Open a file on the pwmd server using a local pinentry.
 616  *
 617  * This will send the OPEN command to the server like \ref pwmd_open() but
 618  * will use the local pinentry and not pwmd's pinentry.
 619  *
 620  * \sigalrm
 621  *
 622  * \param pwm A handle.
 623  * \param filename The filename to open.
 624  * \return 0 on success or an error code.
 625  * \see \ref pinentry
 626  */
 627 gpg_error_t pwmd_open2(pwm_t *pwm, const char *filename)
 628     __attribute__ ((warn_unused_result));
 629
 630
 631 /*! \brief Open a file on the pwmd server asynchronously (fork method).
 632  *
 633  * This will send the OPEN command to the pwmd server. The difference from
 634  * \ref pwmd_open() is that it will not block if a pinentry is needed for
 635  * passphrase input.
 636  *
 637  * The difference from \ref pwmd_open_async() is that libpwmd will \ref fork()
 638  * a pinentry process rather than have pwmd use it's pinentry method. This may
 639  * be useful if the passphrase isn't cached on a remote pwmd server and a
 640  * remote \ref pinentry(1) is not possible.
 641  *
 642  * \process
 643  *
 644  * \sigalrm
 645  *
 646  * \param pwm A handle.
 647  * \param filename The filename to open.
 648  * \return 0 on success or an error code.
 649  * \see pwmd_process(), \ref pinentry
 650  */
 651 gpg_error_t pwmd_open_async2(pwm_t *pwm, const char *filename)
 652     __attribute__ ((warn_unused_result));
 653
 654
 655 /*! \brief Open a file on the pwmd server asynchronously.
 656  *
 657  * This will send the OPEN command to the pwmd server. The difference from
 658  * \ref pwmd_open() is that it will not block if a pinentry is needed for
 659  * passphrase input.
 660  *
 661  * \process
 662  *
 663  * \param pwm A handle.
 664  * \param filename The filename to open.
 665  * \return 0 on success or an error code.
 666  * \see pwmd_process(), \ref pinentry
 667  */
 668 gpg_error_t pwmd_open_async(pwm_t *pwm, const char *filename)
 669     __attribute__ ((warn_unused_result));
 670
 671
 672 /*! \brief Process an asynchronous function.
 673  *
 674  * After an asynchronous function has been called and has returned
 675  * successfully, this function must be called to process the command to
 676  * retrieve the result or return value.
 677  *
 678  * This function may also be called when not in a command to check for pending
 679  * status messages sent from the server or to process a pending line.
 680  *
 681  * \param pwm A handle.
 682  * \param rc Set to the return code of the command after ASYNC_DONE is
 683  * returned. This value must be checked to determine if the command succeeded.
 684  * \param[out] result Set to the result of the command when \a rc is 0. Note
 685  * that not all commands return a result.
 686  * \retval ASYNC_DONE The command has completed. \a rc should be checked to
 687  * determine if the command was successful or not.
 688  * \retval ASYNC_PROCESS The command is still running and this function should
 689  * be called again.
 690  * \see pwmd_get_fds(), pwmd_pending_line()
 691  */
 692 pwmd_async_t pwmd_process(pwm_t *pwm, gpg_error_t *rc, char **result)
 693     __attribute__ ((warn_unused_result));
 694
 695
 696 /*! \brief Save a file on the pwmd server.
 697  *
 698  * This will send the SAVE command.
 699  *
 700  * \param pwm A handle.
 701  * \return 0 on success or an error code.
 702  * \see \ref pinentry
 703  */
 704 gpg_error_t pwmd_save(pwm_t *pwm)
 705     __attribute__ ((warn_unused_result));
 706
 707
 708 /*! \brief Save a file on the pwmd server using the local pinentry.
 709  *
 710  * This will send the SAVE command like \ref pwmd_save() but will use a local
 711  * pinentry and not pwmd's pinentry.
 712  *
 713  * \param pwm A handle.
 714  * \return 0 on success or an error code.
 715  * \see \ref pinentry
 716  */
 717 gpg_error_t pwmd_save2(pwm_t *pwm)
 718     __attribute__ ((warn_unused_result));
 719
 720
 721 /*! \brief Save a file on the pwmd server asynchronously (fork method).
 722  *
 723  * This will send the SAVE command to the pwmd server. The difference from
 724  * \ref pwmd_save() is that it will not block if a pinentry is needed for
 725  * passphrase input.
 726  *
 727  * The difference from \ref pwmd_save_async() is that libpwmd will \ref fork()
 728  * a pinentry process rather than have pwmd use it's pinentry method. This may
 729  * be useful if the passphrase isn't cached on a remote pwmd server and a
 730  * remote \ref pinentry(1) is not possible.
 731  *
 732  * \process
 733  *
 734  * \param pwm A handle.
 735  * \return 0 on success or an error code.
 736  * \see pwmd_process(), \ref pinentry
 737  */
 738 gpg_error_t pwmd_save_async2(pwm_t *pwm)
 739     __attribute__ ((warn_unused_result));
 740
 741
 742 /*! \brief Save changes to a file on the pwmd server asynchronously.
 743  *
 744  * This will send the SAVE command to the pwmd server. The difference from
 745  * \ref pwmd_save() is that it will not block if a pinentry is needed for
 746  * passphrase input.
 747  *
 748  * \process
 749  *
 750  * \param pwm A handle.
 751  * \return 0 on success or an error code.
 752  * \see pwmd_process(), \ref pinentry
 753  */
 754 gpg_error_t pwmd_save_async(pwm_t *pwm)
 755     __attribute__ ((warn_unused_result));
 756
 757
 758 /*! \brief Send a command to the pwmd server.
 759  *
 760  * Sends a command to the pwmd server. You should avoid sending the BYE
 761  * command here because the assuan context will be freed and bad things will
 762  * happen. Use \ref pwmd_close() instead. For commands that use an INQUIRE to
 763  * send data to the server (STORE and IMPORT), \ref pwmd_inquire() should be
 764  * used and not this function.
 765  *
 766  * \param pwm A handle.
 767  * \param[out] result The result of the command when successful and which must
 768  * be freed with \ref pwmd_free(). Note that not all commands return a result.
 769  * \param cmd The command to send.
 770  * \param ... The arguments to \a cmd.
 771  * \return 0 on success or an error code.
 772  */
 773 gpg_error_t pwmd_command(pwm_t *pwm, char **result, const char *cmd, ...)
 774     __attribute__ ((warn_unused_result));
 775
 776
 777 /*! \brief Send a command to the pwmd server.
 778  *
 779  * Like \ref pwmd_command() but uses an argument pointer instead.
 780  *
 781  * \param pwm A handle.
 782  * \param[out] result The result of the command when successful which must be
 783  * freed with \ref pwmd_free(). Note that not all commands return a result.
 784  * \param cmd The command to send.
 785  * \param ap The arguments to \a cmd.
 786  * \return 0 on success or an error code.
 787  */
 788 gpg_error_t pwmd_command_ap(pwm_t *pwm, char **result, const char *cmd,
 789         va_list ap)
 790     __attribute__ ((warn_unused_result));
 791
 792
 793 /*! \brief Send data to a pwmd server.
 794  *
 795  * This lets commands that use an INQUIRE (STORE and IMPORT) send the data
 796  * to the server. Use this function rather than \ref pwmd_command() for these
 797  * commands.
 798  *
 799  * \param pwm A handle.
 800  * \param cmd The command to send that uses an INQUIRE.
 801  * \param func A callback function which sets the data to be sent.
 802  * \param user A user data pointer passed to the callback function \a func.
 803  * \return 0 on success or an error code.
 804  *
 805  * \see pwmd_inquire_cb_t
 806  */
 807 gpg_error_t pwmd_inquire(pwm_t *pwm, const char *cmd, pwmd_inquire_cb_t func,
 808         void *user)
 809     __attribute__ ((warn_unused_result));
 810
 811
 812 /*! \brief Close a handle.
 813  *
 814  * This will close the connection to a pwmd server and free any resources
 815  * associated with it.
 816  *
 817  * \param pwm A handle.
 818  * \return Nothing.
 819  */
 820 void pwmd_close(pwm_t *pwm);
 821
 822
 823 /*! \brief Free a previously allocated pointer.
 824  *
 825  * Use this function to free resources allocated by the other libpwmd memory
 826  * functions. Do not use it to free your own allocations.
 827  *
 828  * The difference between the standard free() and this function is that
 829  * this one will zero out the contents of the pointer before freeing it.
 830  *
 831  * \param ptr The pointer to deallocate.
 832  * \return Nothing.
 833  * \see pwmd_malloc(), pwmd_calloc(), pwmd_realloc(), pwmd_strdup(),
 834  * pwmd_process(), pwmd_command()
 835  */
 836 void pwmd_free(void *ptr);
 837
 838
 839 /*! \brief A wrapper around malloc.
 840  *
 841  * Like malloc(), but lets libpwmd keep track of the pointer.
 842  *
 843  * \param size The number of bytes to allocate.
 844  * \return A newly allocated pointer or NULL if there wasn't enough memory.
 845  * \see malloc(3), pwmd_free()
 846  */
 847 void *pwmd_malloc(size_t size)
 848     __attribute__ ((warn_unused_result));
 849
 850
 851 /*! \brief A wrapper around calloc().
 852  *
 853  * Like calloc(), but lets libpwmd keep track of the pointer.
 854  *
 855  * \param nmemb The number of bytes to allocate.
 856  * \param size The number of bytes to allocate.
 857  * \return A newly allocated pointer or NULL if there wasn't enough memory.
 858  * \see calloc(3), pwmd_free()
 859  */
 860 void *pwmd_calloc(size_t nmemb, size_t size)
 861     __attribute__ ((warn_unused_result));
 862
 863
 864 /*! \brief A wrapper around realloc().
 865  *
 866  * Like realloc(), but lets libpwmd keep track of the pointer. Note that this
 867  * function will try and allocate the entire \a size before freeing the
 868  * original pointer and returning the new one.
 869  *
 870  * \param ptr The pointer to reallocate.
 871  * \param size The new number of bytes to allocate.
 872  * \return A newly allocated pointer or NULL if there wasn't enough memory.
 873  * \see realloc(3), pwmd_free()
 874  */
 875 void *pwmd_realloc(void *ptr, size_t size)
 876     __attribute__ ((warn_unused_result));
 877
 878
 879 /*! \brief A wrapper around strdup().
 880  *
 881  * Like strdup(), but lets libpwmd keep track of the pointer.
 882  *
 883  * \param str The string to duplicate.
 884  * \return A newly allocated character pointer or NULL if there wasn't
 885  * enough memory.
 886  * \see strdup(3), pwmd_free()
 887  */
 888 char *pwmd_strdup(const char *str)
 889     __attribute__ ((warn_unused_result));
 890
 891 /*! \brief Duplicate a formatted string.
 892  *
 893  * Like sprintf() but returns an allocated string.
 894  *
 895  * \param fmt The formatted string.
 896  * \param ... Any format arguments to the string.
 897  * \return A newly allocated character pointer or NULL if there wasn't
 898  * enough memory.
 899  * \see pwmd_free()
 900  */
 901 char *pwmd_strdup_printf(const char *fmt, ...)
 902     __attribute__ ((warn_unused_result));
 903
 904 /*! \def EPWMD_ERROR
 905  *  \hideinitializer
 906  *
 907  * A general pwmd error with no suitable description.
 908  */
 909 #define EPWMD_ERROR             GPG_ERR_USER_1
 910
 911
 912 /*! \def EPWMD_MAX_SLOTS
 913  *  \hideinitializer
 914  *
 915  * The maximum number of cache slots has been reached. There is no available
 916  * slot for a new file.
 917  */
 918 #define EPWMD_MAX_SLOTS         GPG_ERR_USER_2
 919
 920
 921 /*! \def EPWMD_LOOP
 922  *  \hideinitializer
 923  *
 924  * A recursion loop was detected while processing a "target" attribute.
 925  */
 926 #define EPWMD_LOOP              GPG_ERR_USER_3
 927
 928
 929 /*! \def EPWMD_NO_FILE
 930  *  \hideinitializer
 931  *
 932  * A command required an open file, but no file has yet been opened.
 933  */
 934 #define EPWMD_NO_FILE           GPG_ERR_USER_4
 935
 936
 937 /*! \def EPWMD_LIBXML_ERROR
 938  *  \hideinitializer
 939  *
 940  * An XML parse or other libxml2 error occurred.
 941  */
 942 #define EPWMD_LIBXML_ERROR      GPG_ERR_USER_5
 943
 944
 945 /*! \def EPWMD_FILE_MODIFIED
 946  *  \hideinitializer
 947  *
 948  * The data file was modified either externally or by another another client
 949  * while trying to process a command.
 950  */
 951 #define EPWMD_FILE_MODIFIED     GPG_ERR_USER_6
 952
 953
 954 /*! \def EPWMD_MAX
 955  *  \hideinitializer
 956  * \if cond1
 957  * \endif
 958  */
 959 #define EPWMD_MAX               GPG_ERR_USER_7
 960
 961
 962 /*! \brief Return a description of an error code.
 963  *
 964  * \param code The error code to describe.
 965  * \return A character description of the error code.
 966  * \see pwmd_strerror_r()
 967  */
 968 const char *pwmd_strerror(gpg_error_t code)
 969     __attribute__ ((warn_unused_result));
 970
 971
 972 /*! \brief Return a description of an error code (thread-safe).
 973  *
 974  * This is a thread-safe version of \ref pwmd_strerror().
 975  *
 976  * \param code The error code to describe.
 977  * \param[out] buf An allocated buffer to hold the error description.
 978  * \param size The size of the allocated buffer \a buf.
 979  *
 980  * \retval 0 Success.
 981  * \retval ERANGE \a size was not large enough to hold the entire description
 982  * and \a buf is set to the truncated error string.
 983  */
 984 int pwmd_strerror_r(gpg_error_t code, char *buf, size_t size);
 985
 986 #ifdef __cplusplus
 987 }
 988 #endif
 989
 990 #endif