cli: introduce the concept of user defined hooks

Add mechanism for running user defined hooks. Hooks are executables or
symlinks to executables stored under the new notmuch hooks directory,
<database-path>/.notmuch/hooks.

No hooks are introduced here, but adding support for a hook is now a simple
matter of calling the new notmuch_run_hook() function at an appropriate
location with the hook name.

Signed-off-by: Jani Nikula <jani@nikula.org>

diff --git a/Makefile.local b/Makefile.local
index 28e371a86e805e25bd586785b1ed3f54d2957538..5108a0cc60393eda486088cd50620eeb34545a48 100644 (file)
--- a/Makefile.local
+++ b/Makefile.local
@@ -299,6 +299,7 @@ notmuch_client_srcs =               \
        debugger.c              \
        gmime-filter-reply.c    \
        gmime-filter-headers.c  \
+       hooks.c                 \
        notmuch.c               \
        notmuch-config.c        \
        notmuch-count.c         \

diff --git a/hooks.c b/hooks.c
new file mode 100644 (file)
index 0000000..44ee419
--- /dev/null
+++ b/hooks.c
@@ -0,0 +1,93 @@
+/* notmuch - Not much of an email program, (just index and search)
+ *
+ * This file is part of notmuch.
+ *
+ * Copyright © 2011 Jani Nikula
+ *
+ * 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 3 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, see http://www.gnu.org/licenses/ .
+ *
+ * Author: Jani Nikula <jani@nikula.org>
+ */
+
+#include "notmuch-client.h"
+#include <sys/wait.h>
+
+int
+notmuch_run_hook (const char *db_path, const char *hook)
+{
+    char *hook_path;
+    int status = 0;
+    pid_t pid;
+
+    hook_path = talloc_asprintf (NULL, "%s/%s/%s/%s", db_path, ".notmuch",
+                                "hooks", hook);
+    if (hook_path == NULL) {
+       fprintf (stderr, "Out of memory\n");
+       return 1;
+    }
+
+    /* Check access before fork() for speed and simplicity of error handling. */
+    if (access (hook_path, X_OK) == -1) {
+       /* Ignore ENOENT. It's okay not to have a hook, hook dir, or even
+        * notmuch dir. Dangling symbolic links also result in ENOENT, but
+        * we'll ignore that too for simplicity. */
+       if (errno != ENOENT) {
+           fprintf (stderr, "Error: %s hook access failed: %s\n", hook,
+                    strerror (errno));
+           status = 1;
+       }
+       goto DONE;
+    }
+
+    pid = fork();
+    if (pid == -1) {
+       fprintf (stderr, "Error: %s hook fork failed: %s\n", hook,
+                strerror (errno));
+       status = 1;
+       goto DONE;
+    } else if (pid == 0) {
+       execl (hook_path, hook_path, NULL);
+       /* Same as above for ENOENT, but unlikely now. Indicate all other errors
+        * to parent through non-zero exit status. */
+       if (errno != ENOENT) {
+           fprintf (stderr, "Error: %s hook execution failed: %s\n", hook,
+                    strerror (errno));
+           status = 1;
+       }
+       exit (status);
+    }
+
+    if (waitpid (pid, &status, 0) == -1) {
+       fprintf (stderr, "Error: %s hook wait failed: %s\n", hook,
+                strerror (errno));
+       status = 1;
+       goto DONE;
+    }
+
+    if (!WIFEXITED (status) || WEXITSTATUS (status)) {
+       if (WIFEXITED (status)) {
+           fprintf (stderr, "Error: %s hook failed with status %d\n",
+                    hook, WEXITSTATUS (status));
+       } else if (WIFSIGNALED (status)) {
+           fprintf (stderr, "Error: %s hook terminated with signal %d\n",
+                    hook, WTERMSIG (status));
+       }
+       status = 1;
+    }
+
+  DONE:
+    talloc_free (hook_path);
+
+    return status;
+}

diff --git a/notmuch-client.h b/notmuch-client.h
index 703f85618a56b362b682984ae130f4f0e48d7915..c602e2e08c28fd2d2d9011c2eacb3f7dac8f1d75 100644 (file)
--- a/notmuch-client.h
+++ b/notmuch-client.h
@@ -235,6 +235,9 @@ void
 notmuch_config_set_maildir_synchronize_flags (notmuch_config_t *config,
                                              notmuch_bool_t synchronize_flags);
 
+int
+notmuch_run_hook (const char *db_path, const char *hook);
+
 notmuch_bool_t
 debugger_is_active (void);