Add signal sets and sigprocmask

3 files changed, 317 insertions, 1 deletions

diff --git a/luxio.c b/luxio.c
index f3e298d..0db4979 100644
--- a/luxio.c
+++ b/luxio.c
@@ -480,7 +480,144 @@ luxio_kill(lua_State *L) /* 3.3.2 */
 
 /* Signals are going to be almost impossible to do nicely and safely. */
 
-/* TODO: Manipulate Signal Sets 3.3.3 */
+#define LUXIO_SIGNALSET_METATABLE "luxio.signalset"
+
+typedef struct {
+	sigset_t set;
+} luxio_signalset;
+
+static int
+luxio_signalset_tostring(lua_State *L)
+{
+	luxio_signalset *s = luaL_checkudata(L, 1, LUXIO_SIGNALSET_METATABLE);
+	char buf[1024];
+
+	snprintf(buf, sizeof(buf), "sigset: %p", &s->set);
+	lua_pushstring(L, buf);
+
+	return 1;
+}
+
+static void
+luxio__bless_signalset(lua_State *L)
+{
+	int create = luaL_newmetatable(L, LUXIO_SIGNALSET_METATABLE);
+
+	if (create != 0) {
+		lua_pushcfunction(L, luxio_signalset_tostring);
+		lua_setfield(L, -2, "__tostring");
+	}
+
+	lua_setmetatable(L, -2);
+}
+
+/*** Create a new signal set
+@treturn A new signal set
+*/
+static int
+luxio_newsigset(lua_State *L)
+{
+	luxio_signalset *s = lua_newuserdata(L, sizeof(*s));
+
+	luxio__bless_signalset(L);
+
+	return 1;
+}
+
+/*** Initialise a signal set to be empty.
+
+Return 0 on success, or -1 on error with errno set appropriately.
+
+@tparam sigset sigset signal set
+@tparam number signo signal
+@treturn number return value
+@treturn errno errno
+@function sigemptyset
+*/
+static int
+luxio_sigemptyset(lua_State *L)
+{
+	luxio_signalset *s = luaL_checkudata(L, 1, LUXIO_SIGNALSET_METATABLE);
+	lua_pushinteger(L, sigemptyset(&s->set));
+	lua_pushinteger(L, errno);
+
+	return 2;
+}
+
+/*** Initialise a signal set to contain all signals.
+
+Return 0 on success, or -1 on error with errno set appropriately.
+
+@tparam sigset sigset signal set
+@tparam number signo signal
+@treturn number return value
+@treturn errno errno
+@function sigfillset
+*/
+static int
+luxio_sigfillset(lua_State *L)
+{
+	luxio_signalset *s = luaL_checkudata(L, 1, LUXIO_SIGNALSET_METATABLE);
+	lua_pushinteger(L, sigfillset(&s->set));
+	lua_pushinteger(L, errno);
+
+	return 2;
+}
+
+#define LUXIO__SIGSET_OPERATION(L, op) do { \
+	luxio_signalset *s = luaL_checkudata(L, 1, LUXIO_SIGNALSET_METATABLE); \
+	int signo = luaL_checkinteger(L, 2); \
+	lua_pushinteger(L, op(&s->set, signo)); \
+	lua_pushinteger(L, errno); \
+	return 2; \
+} while (0)
+
+/*** Add a signal to a signal set.
+
+Return 0 on success, or -1 on error with errno set appropriately.
+
+@tparam sigset sigset signal set
+@tparam number signo signal
+@treturn number return value
+@treturn errno errno
+@function sigaddset
+*/
+static int
+luxio_sigaddset(lua_State *L)
+{
+	LUXIO__SIGSET_OPERATION(L, sigaddset);
+}
+
+/*** Remove a signal from a signal set.
+
+Return 0 on success, or -1 on error with errno set appropriately.
+
+@tparam sigset sigset signal set
+@tparam number signo signal
+@treturn number return value
+@treturn errno errno
+@function sigdelset
+*/
+static int
+luxio_sigdelset(lua_State *L)
+{
+	LUXIO__SIGSET_OPERATION(L, sigdelset);
+}
+
+/*** Check whether a signal set contains a given signal.
+
+Return 0 on success, or -1 on error with errno set appropriately.
+
+@tparam sigset signal set
+@tparam number signo signal
+@treturn number return value
+@treturn errno errno
+@function sigismember
+*/
+static int luxio_sigismember(lua_State *L)
+{
+	LUXIO__SIGSET_OPERATION(L, sigismember);
+}
 
 /* NSIG is not in POSIX, it's 64 on Linux and 33 on OpenBSD
  * we define a value much larger than either to be on the safe side */
@@ -703,6 +840,10 @@ luxio_sigaction(lua_State *L)
 			} else {
 				goto einval;
 			}
+		} else if (strcmp(key, "sa_mask") == 0) {
+			luxio_signalset *s = luaL_checkudata(L, -1, LUXIO_SIGNALSET_METATABLE);
+			sa.sa_mask = s->set;
+			lua_pop(L, 1);
 		} else if (strcmp(key, "sa_flags") == 0) {
 			sa.sa_flags = luaL_checkint(L, -1);
 			lua_pop(L, 1);
@@ -738,6 +879,61 @@ enospc:
 }
 
 /* TODO: pthread_sigmask(), sigprocmask() 3.3.5 */
+
+/*** Manipulate the current signal mask.
+
+sigprocmask examines and/or changes the current process signal mask.
+Signals are blocked if they are members of the current signal mask set.
+
+The action performed by sigprocmask depends on the value of `how`,
+which can be one of:
+
+- `luxio.SIG_BLOCK` - The new mask is the existing mask plus all of the
+signals in the specified set.
+
+- `luxio.SIG_UNBLOCK` - The new mask is the existing mask minus the signals
+contained within the specified set.
+
+- `luxio.SIG_SETMASK` - The current mask is replaced with the specified set.
+
+On success the previous signal mask will be returned, otherwise on error
+nil will be returned and errno will be set appropriately.
+
+If the `set` parameter is set to nil then the current signal mask will
+be returned without performing any modification to the current signal mask,
+and the `how` parameter will be ignored.
+
+@tparam number how Action to perform on signal mask
+@tparam sigset set signal set
+@treturn return number return value
+@treturn errno
+@function sigprocmask
+*/
+static int
+luxio_sigprocmask(lua_State *L)
+{
+	int how = luaL_checkinteger(L, 1);
+	void *p = lua_touserdata(L, 2);
+	sigset_t orig, *set = NULL;
+
+	if (p != NULL) {
+		luxio_signalset *s = luaL_checkudata(L, 2, LUXIO_SIGNALSET_METATABLE);
+		set = &s->set;
+	}
+
+	if (sigprocmask(how, set, &orig) == -1) {
+		lua_pushnil(L);
+	} else {
+		luxio_signalset *o = lua_newuserdata(L, sizeof(*o));
+		o->set = orig;
+		luxio__bless_signalset(L);
+	}
+
+	lua_pushinteger(L, errno);
+
+	return 2;
+}
+
 /* TODO: sigpending() 3.3.6 */
 /* TODO: sigsuspend() 3.3.7 */
 /* TODO: sigwait(), sigwaitinfo(), sigtimedwait() 3.3.8 */
@@ -4818,7 +5014,15 @@ luxio_functions[] = {
 	{ "chdir", luxio_chdir },
 	{ "getcwd", luxio_getcwd },
 
+	{ "newsigset", luxio_newsigset },
+	{ "sigemptyset", luxio_sigemptyset },
+	{ "sigfillset", luxio_sigfillset },
+	{ "sigaddset", luxio_sigaddset },
+	{ "sigdelset", luxio_sigdelset },
+	{ "sigismember", luxio_sigismember },
+
 	{ "sigaction", luxio_sigaction },
+	{ "sigprocmask", luxio_sigprocmask },
 
 	{ "alarm", luxio_alarm },
 	{ "pause", luxio_pause },
diff --git a/luxio_constants.inc.in b/luxio_constants.inc.in
index ef3cadb..22a1f13 100644
--- a/luxio_constants.inc.in
+++ b/luxio_constants.inc.in
@@ -216,6 +216,9 @@ static const struct {
 	/* signals */
 	{"SIG_DFL", (int) SIG_DFL},
 	{"SIG_IGN", (int) SIG_IGN},
+	E(SIG_BLOCK),
+	E(SIG_UNBLOCK),
+	E(SIG_SETMASK),
 	E(SIGHUP),
 	E(SIGINT),
 	E(SIGQUIT),
diff --git a/tests/test-sigprocmask.lua b/tests/test-sigprocmask.lua
new file mode 100644
index 0000000..490672b
--- /dev/null
+++ b/tests/test-sigprocmask.lua
@@ -0,0 +1,109 @@
+local l = require "luxio"
+
+set = l.newsigset()
+
+r, errno = l.sigemptyset(set)
+if r == -1 then
+   io.stderr:write(("sigemptyset: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+
+print("Empty set", set)
+
+r, errno = l.sigfillset(set)
+if r == -1 then
+   io.stderr:write(("sigfillset: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+
+print("Full set", set)
+
+r, errno = l.sigismember(set, l.SIGINT)
+if r == -1 then
+   io.stderr:write(("sigismember: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+
+print("SIGINT is member of set?", r == 1 and "yes" or "no")
+
+print("sigdelset(set, SIGINT)...")
+r, errno = l.sigdelset(set, l.SIGINT)
+if r == -1 then
+   io.stderr:write(("sigdelset: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+
+r, errno = l.sigismember(set, l.SIGINT)
+if r == -1 then
+   io.stderr:write(("sigismember: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+
+print("SIGINT is member of set?", r == 1 and "yes" or "no")
+
+print("l.sigemptyset(set)...")
+r, errno = l.sigemptyset(set)
+if r == -1 then
+   io.stderr:write(("sigemptyset: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+
+print("Empty set", set)
+
+
+to_block = {["SIGINT"] = l.SIGINT, ["SIGUSR1"] = l.SIGUSR1}
+
+for signame, signo in pairs(to_block) do
+   print(("sigaddset(set, %s)..."):format(signame))
+   r, errno = l.sigaddset(set, signo)
+   if r == -1 then
+      io.stderr:write(("sigaddset: %s\n"):format(l.strerror(errno)))
+      os.exit(os.EXIT_FAILURE)
+   end
+
+   r, errno = l.sigismember(set, signo)
+   if r == -1 then
+      io.stderr:write(("sigismember: %s\n"):format(l.strerror(errno)))
+      os.exit(os.EXIT_FAILURE)
+   end
+
+   print(("%s is member of set?"):format(signame), r == 1 and "yes" or "no")
+end
+
+origset, errno = l.sigprocmask(0, nil)
+if origset == nil then
+   io.stderr:write(("sigprocmask: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+print("Got the current signal set", origset)
+
+print("set", set)
+origset, errno = l.sigprocmask(l.SIG_BLOCK, set)
+if origset == nil then
+   io.stderr:write(("sigprocmask: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+print("origset", origset)
+
+i = 1
+while (i <= 5) do
+   print(i)
+   l.sleep(2)
+   i = i + 1
+end
+
+print("restoring original signal mask...")
+
+origset, errno = l.sigprocmask(l.SIG_SETMASK, origset)
+if origset == nil then
+   io.stderr:write(("sigprocmask: %s\n"):format(l.strerror(errno)))
+   os.exit(os.EXIT_FAILURE)
+end
+
+print("done")
+print("origset", origset)
+
+while (true) do
+   l.sleep(2)
+   print("sleep")
+end