+/* guestfish - the filesystem interactive shell
+ * Copyright (C) 2011 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <assert.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+#include <guestfs.h>
+
+#include "hash.h"
+#include "hash-pjw.h"
+
+#include "fish.h"
+
+/* The hash table maps names to multiple (linked list of) event handlers. */
+static Hash_table *event_handlers;
+
+struct entry {
+ struct entry *next; /* Next entry in linked list. */
+ char *name; /* Event name. */
+ char *command; /* Shell script / command that runs. */
+ uint64_t event_bitmask; /* Events this is registered for. */
+ int eh; /* Event handle (from guestfs_set_event_callback). */
+};
+
+static void
+entry_free (void *x)
+{
+ if (x) {
+ struct entry *p = x;
+ entry_free (p->next);
+ free (p->name);
+ free (p->command);
+ free (p);
+ }
+}
+
+static size_t
+entry_hash (void const *x, size_t table_size)
+{
+ struct entry const *p = x;
+ return hash_pjw (p->name, table_size);
+}
+
+static bool
+entry_compare (void const *x, void const *y)
+{
+ struct entry const *p = x;
+ struct entry const *q = y;
+ return STREQ (p->name, q->name);
+}
+
+void
+init_event_handlers (void)
+{
+ assert (event_handlers == NULL);
+ event_handlers =
+ hash_initialize (64, NULL, entry_hash, entry_compare, entry_free);
+}
+
+void
+free_event_handlers (void)
+{
+ assert (event_handlers != NULL);
+ hash_free (event_handlers);
+ event_handlers = NULL;
+}
+
+static void
+do_event_handler (guestfs_h *g,
+ void *opaque,
+ uint64_t event,
+ int event_handle,
+ int flags,
+ const char *buf, size_t buf_len,
+ const uint64_t *array, size_t array_len)
+{
+ pid_t pid;
+ const char *argv[8 + array_len];
+ const char *shell;
+ struct entry *entry = opaque;
+ size_t i, j;
+ char *s;
+
+ pid = fork ();
+ if (pid == -1) {
+ perror ("event handler: fork");
+ return;
+ }
+
+ if (pid == 0) { /* Child process. */
+ shell = getenv ("SHELL");
+ if (!shell)
+ shell = "/bin/sh";
+
+ setenv ("EVENT", event_name_of_event_bitmask (event), 1);
+
+ /* Construct the command and arguments. */
+ i = 0;
+ argv[i++] = shell;
+ argv[i++] = "-c";
+ argv[i++] = entry->command;
+ argv[i++] = ""; /* $0 */
+
+ if (buf != NULL)
+ /* XXX: So far, buf is always ASCII NUL-terminated. There is no
+ * way to pass arbitrary 8 bit buffers.
+ */
+ argv[i++] = buf;
+
+ for (j = 0; j < array_len; ++j) {
+ if (asprintf (&s, "%" PRIu64, array[j]) == -1) {
+ perror ("event handler: asprintf");
+ _exit (EXIT_FAILURE);
+ }
+ argv[i++] = s;
+ }
+
+ argv[i++] = NULL;
+
+ execvp (argv[0], (void *) argv);
+ perror (argv[0]);
+
+ _exit (EXIT_FAILURE);
+ }
+
+ if (waitpid (pid, NULL, 0) == -1)
+ perror ("event handler: waitpid");
+}
+
+int
+run_event (const char *cmd, size_t argc, char *argv[])
+{
+ int r;
+ struct entry *entry = NULL, *old_entry;
+
+ if (argc != 3) {
+ fprintf (stderr,
+ _("use 'event <name> <eventset> <script>' to register an event handler\n"));
+ goto error;
+ }
+
+ entry = calloc (1, sizeof *entry);
+ if (entry == NULL) {
+ perror ("calloc");
+ goto error;
+ }
+ entry->eh = -1;
+
+ r = event_bitmask_of_event_set (argv[1], &entry->event_bitmask);
+ if (r == -1)
+ goto error;
+
+ entry->name = strdup (argv[0]);
+ if (entry->name == NULL) {
+ perror ("strdup");
+ goto error;
+ }
+ entry->command = strdup (argv[2]);
+ if (entry->command == NULL) {
+ perror ("strdup");
+ goto error;
+ }
+
+ entry->eh =
+ guestfs_set_event_callback (g, do_event_handler,
+ entry->event_bitmask, 0, entry);
+ if (entry->eh == -1)
+ goto error;
+
+ r = hash_insert_if_absent (event_handlers, entry, (const void **) &old_entry);
+ if (r == -1)
+ goto error;
+ if (r == 0) { /* old_entry set to existing entry */
+ entry->next = old_entry->next;
+ /* XXX are we allowed to update the old entry? */
+ old_entry->next = entry;
+ }
+
+ return 0;
+
+ error:
+ if (entry) {
+ if (entry->eh >= 0)
+ guestfs_delete_event_callback (g, entry->eh);
+ free (entry->name);
+ free (entry->command);
+ free (entry);
+ }
+ return -1;
+}
+
+int
+run_delete_event (const char *cmd, size_t argc, char *argv[])
+{
+ if (argc != 1) {
+ fprintf (stderr,
+ _("use 'delete-event <name>' to delete an event handler\n"));
+ return -1;
+ }
+
+ const struct entry key = { .name = bad_cast (argv[0]) };
+ struct entry *entry, *p;
+
+ entry = hash_delete (event_handlers, &key);
+ if (!entry) {
+ fprintf (stderr, _("delete-event: %s: no such event handler\n"), argv[0]);
+ return -1;
+ }
+
+ /* Delete them from the handle. */
+ p = entry;
+ while (p) {
+ guestfs_delete_event_callback (g, p->eh);
+ p = p->next;
+ }
+
+ /* Free the structures. */
+ entry_free (entry);
+
+ return 0;
+}
+
+static bool
+list_event (void *x, void *data)
+{
+ struct entry *entry = x;
+
+ while (entry) {
+ printf ("\"%s\" (%d): ", entry->name, entry->eh);
+ print_event_set (entry->event_bitmask, stdout);
+ printf (": %s\n", entry->command);
+ entry = entry->next;
+ }
+
+ return 1;
+}
+
+int
+run_list_events (const char *cmd, size_t argc, char *argv[])
+{
+ if (argc != 0) {
+ fprintf (stderr,
+ _("use 'list-events' to list event handlers\n"));
+ return -1;
+ }
+
+ hash_do_for_each (event_handlers, list_event, NULL);
+ return 0;
+}
git.annexia.org / libguestfs.git / commitdiff