diff options
Diffstat (limited to 'libtdenetwork/libgpgme-copy/gpgme/wait-global.c')
-rw-r--r-- | libtdenetwork/libgpgme-copy/gpgme/wait-global.c | 384 |
1 files changed, 384 insertions, 0 deletions
diff --git a/libtdenetwork/libgpgme-copy/gpgme/wait-global.c b/libtdenetwork/libgpgme-copy/gpgme/wait-global.c new file mode 100644 index 00000000..bfa618dd --- /dev/null +++ b/libtdenetwork/libgpgme-copy/gpgme/wait-global.c @@ -0,0 +1,384 @@ +/* wait-global.c + Copyright (C) 2000 Werner Koch (dd9jn) + Copyright (C) 2001, 2002, 2003, 2004, 2005 g10 Code GmbH + + This file is part of GPGME. + + GPGME is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of + the License, or (at your option) any later version. + + GPGME is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + 02110-1301, USA. */ + +#if HAVE_CONFIG_H +#include <config.h> +#endif +#include <stdlib.h> +#include <assert.h> +#include <string.h> +#include <errno.h> + +#include "gpgme.h" +#include "sema.h" +#include "util.h" +#include "context.h" +#include "wait.h" +#include "priv-io.h" + +/* The global event loop is used for all asynchronous operations + (except key listing) for which no user I/O callbacks are specified. + + A context sets up its initial I/O callbacks and then sends the + GPGME_EVENT_START event. After that, it is added to the global + list of active contexts. + + The gpgme_wait function contains a select() loop over all file + descriptors in all active contexts. If an error occurs, it closes + all fds in that context and moves the context to the global done + list. Likewise, if a context has removed all I/O callbacks, it is + moved to the global done list. + + All contexts in the global done list are eligible for being + returned by gpgme_wait if requested by the caller. */ + +/* The ctx_list_lock protects the list of active and done contexts. + Insertion into any of these lists is only allowed when the lock is + held. This allows a muli-threaded program to loop over gpgme_wait + and in parallel start asynchronous gpgme operations. + + However, the fd tables in the contexts are not protected by this + lock. They are only allowed to change either before the context is + added to the active list (ie, before the start event is signalled) + or in a callback handler. */ +DEFINE_STATIC_LOCK (ctx_list_lock); + +/* A ctx_list_item is an item in the global list of active or done + contexts. */ +struct ctx_list_item +{ + /* Every ctx_list_item is an element in a doubly linked list. The + list pointers are protected by the ctx_list_lock. */ + struct ctx_list_item *next; + struct ctx_list_item *prev; + + gpgme_ctx_t ctx; + /* The status is set when the ctx is moved to the done list. */ + gpgme_error_t status; +}; + +/* The active list contains all contexts that are in the global event + loop, have active I/O callbacks, and have already seen the start + event. */ +static struct ctx_list_item *ctx_active_list; + +/* The done list contains all contexts that have previously been + active but now are not active any longer, either because they + finished successfully or an I/O callback returned an error. The + status field in the list item contains the error value (or 0 if + successful). */ +static struct ctx_list_item *ctx_done_list; + + +/* Enter the context CTX into the active list. */ +static gpgme_error_t +ctx_active (gpgme_ctx_t ctx) +{ + struct ctx_list_item *li = malloc (sizeof (struct ctx_list_item)); + if (!li) + return gpg_error_from_errno (errno); + li->ctx = ctx; + + LOCK (ctx_list_lock); + /* Add LI to active list. */ + li->next = ctx_active_list; + li->prev = NULL; + if (ctx_active_list) + ctx_active_list->prev = li; + ctx_active_list = li; + UNLOCK (ctx_list_lock); + return 0; +} + + +/* Enter the context CTX into the done list with status STATUS. */ +static void +ctx_done (gpgme_ctx_t ctx, gpgme_error_t status) +{ + struct ctx_list_item *li; + + LOCK (ctx_list_lock); + li = ctx_active_list; + while (li && li->ctx != ctx) + li = li->next; + assert (li); + + /* Remove LI from active list. */ + if (li->next) + li->next->prev = li->prev; + if (li->prev) + li->prev->next = li->next; + else + ctx_active_list = li->next; + + li->status = status; + + /* Add LI to done list. */ + li->next = ctx_done_list; + li->prev = NULL; + if (ctx_done_list) + ctx_done_list->prev = li; + ctx_done_list = li; + UNLOCK (ctx_list_lock); +} + + +/* Find finished context CTX (or any context if CTX is NULL) and + return its status in STATUS after removing it from the done list. + If a matching context could be found, return it. Return NULL if no + context could be found. */ +static gpgme_ctx_t +ctx_wait (gpgme_ctx_t ctx, gpgme_error_t *status) +{ + struct ctx_list_item *li; + + LOCK (ctx_list_lock); + li = ctx_done_list; + if (ctx) + { + /* A specific context is requested. */ + while (li && li->ctx != ctx) + li = li->next; + } + if (li) + { + ctx = li->ctx; + if (status) + *status = li->status; + + /* Remove LI from done list. */ + if (li->next) + li->next->prev = li->prev; + if (li->prev) + li->prev->next = li->next; + else + ctx_done_list = li->next; + free (li); + } + else + ctx = NULL; + UNLOCK (ctx_list_lock); + return ctx; +} + + +/* Internal I/O callback functions. */ + +/* The add_io_cb and remove_io_cb handlers are shared with the private + event loops. */ + +void +_gpgme_wait_global_event_cb (void *data, gpgme_event_io_t type, + void *type_data) +{ + gpgme_ctx_t ctx = (gpgme_ctx_t) data; + + assert (ctx); + + switch (type) + { + case GPGME_EVENT_START: + { + gpgme_error_t err = ctx_active (ctx); + + if (err) + { + /* An error occured. Close all fds in this context, and + send the error in a done event. */ + unsigned int idx; + + for (idx = 0; idx <= ctx->fdt.size; idx++) + if (ctx->fdt.fds[idx].fd != -1) + _gpgme_io_close (ctx->fdt.fds[idx].fd); + _gpgme_engine_io_event (ctx->engine, GPGME_EVENT_DONE, &err); + } + } + break; + + case GPGME_EVENT_DONE: + { + gpgme_error_t *errp = (gpgme_error_t *) type_data; + assert (errp); + ctx_done (ctx, *errp); + } + break; + + case GPGME_EVENT_NEXT_KEY: + assert (!"Unexpected event GPGME_EVENT_NEXT_KEY"); + break; + + case GPGME_EVENT_NEXT_TRUSTITEM: + assert (!"Unexpected event GPGME_EVENT_NEXT_TRUSTITEM"); + break; + + default: + assert (!"Unexpected event"); + break; + } +} + + + +/* Perform asynchronous operations in the global event loop (ie, any + asynchronous operation except key listing and trustitem listing + operations). If CTX is not a null pointer, the function will + return if the asynchronous operation in the context CTX finished. + Otherwise the function will return if any asynchronous operation + finished. If HANG is zero, the function will not block for a long + time. Otherwise the function does not return until an operation + matching CTX finished. + + If a matching context finished, it is returned, and *STATUS is set + to the error value of the operation in that context. Otherwise, if + the timeout expires, NULL is returned and *STATUS is 0. If an + error occurs, NULL is returned and *STATUS is set to the error + value. */ +gpgme_ctx_t +gpgme_wait (gpgme_ctx_t ctx, gpgme_error_t *status, int hang) +{ + do + { + unsigned int i = 0; + struct ctx_list_item *li; + struct fd_table fdt; + int nr; + + /* Collect the active file descriptors. */ + LOCK (ctx_list_lock); + for (li = ctx_active_list; li; li = li->next) + i += li->ctx->fdt.size; + fdt.fds = malloc (i * sizeof (struct io_select_fd_s)); + if (!fdt.fds) + { + int saved_errno = errno; + UNLOCK (ctx_list_lock); + if (status) + *status = gpg_error_from_errno (saved_errno); + return NULL; + } + fdt.size = i; + i = 0; + for (li = ctx_active_list; li; li = li->next) + { + memcpy (&fdt.fds[i], li->ctx->fdt.fds, + li->ctx->fdt.size * sizeof (struct io_select_fd_s)); + i += li->ctx->fdt.size; + } + UNLOCK (ctx_list_lock); + + nr = _gpgme_io_select (fdt.fds, fdt.size, 0); + if (nr < 0) + { + int saved_errno = errno; + free (fdt.fds); + if (status) + *status = gpg_error_from_errno (saved_errno); + return NULL; + } + + for (i = 0; i < fdt.size && nr; i++) + { + if (fdt.fds[i].fd != -1 && fdt.fds[i].signaled) + { + gpgme_ctx_t ictx; + gpgme_error_t err; + struct wait_item_s *item; + + assert (nr); + nr--; + + item = (struct wait_item_s *) fdt.fds[i].opaque; + assert (item); + ictx = item->ctx; + assert (ictx); + + err = _gpgme_run_io_cb (&fdt.fds[i], 0); + if (err) + { + /* An error occured. Close all fds in this context, + and signal it. */ + unsigned int idx; + + for (idx = 0; idx < ictx->fdt.size; idx++) + if (ictx->fdt.fds[idx].fd != -1) + _gpgme_io_close (ictx->fdt.fds[idx].fd); + _gpgme_engine_io_event (ictx->engine, GPGME_EVENT_DONE, + &err); + + /* Break out of the loop, and retry the select() + from scratch, because now all fds should be + gone. */ + break; + } + } + } + free (fdt.fds); + + /* Now some contexts might have finished successfully. */ + LOCK (ctx_list_lock); + retry: + for (li = ctx_active_list; li; li = li->next) + { + gpgme_ctx_t actx = li->ctx; + + for (i = 0; i < actx->fdt.size; i++) + if (actx->fdt.fds[i].fd != -1) + break; + if (i == actx->fdt.size) + { + gpgme_error_t err = 0; + + /* FIXME: This does not perform too well. We have to + release the lock because the I/O event handler + acquires it to remove the context from the active + list. Two alternative strategies are worth + considering: Either implement the DONE event handler + here in a lock-free manner, or save a list of all + contexts to be released and call the DONE events + afterwards. */ + UNLOCK (ctx_list_lock); + _gpgme_engine_io_event (actx->engine, GPGME_EVENT_DONE, &err); + LOCK (ctx_list_lock); + goto retry; + } + } + UNLOCK (ctx_list_lock); + + { + gpgme_ctx_t dctx = ctx_wait (ctx, status); + + if (dctx) + { + ctx = dctx; + hang = 0; + } + else if (!hang) + { + ctx = NULL; + if (status) + *status = 0; + } + } + } + while (hang); + + return ctx; +} |