libposix: complete POSIX_signal_execute

sys/src/lib/posix/build.json

@@ -16,7 +16,8 @@
 			"initlib.c",
 			"memory.c",
 			"others.c",
-			"processes.c"
+			"processes.c",
+			"signals.c"
 		]
 	}
 }

sys/src/lib/posix/initlib.c

@@ -30,6 +30,7 @@ libposix_check_configuration(void)
 	__libposix_errors_check_conf();
 	__libposix_files_check_conf();
 	__libposix_processes_check_conf();
+	__libposix_signal_check_conf();
 }
 
 void

sys/src/lib/posix/internal.h

@@ -26,6 +26,7 @@ struct WaitList
 extern void __libposix_files_check_conf(void);
 extern void __libposix_errors_check_conf(void);
 extern void __libposix_processes_check_conf(void);
+extern void __libposix_signal_check_conf(void);
 extern int __libposix_initialized(void);
 
 extern int __libposix_get_errno(PosixError e);
@@ -35,3 +36,5 @@ extern void __libposix_setup_exec_environment(char * const *env);
 extern int __libposix_translate_errstr(uintptr_t caller);
 
 extern int __libposix_note_handler(void *ureg, char *note);
+
+extern void __libposix_free_wait_list(void);

sys/src/lib/posix/processes.c

@@ -23,14 +23,13 @@
 extern char **environ;
 
 WaitList **__libposix_wait_list;
-static PosixSignalTrampoline __libposix_signal_trampoline;
 static PosixExitStatusTranslator __libposix_exit_status_translator;
 static int __libposix_wnohang;
 
 #define __POSIX_SIGNAL_PREFIX_LEN (sizeof(__POSIX_SIGNAL_PREFIX)-1)
 
-static void
+void
-free_wait_list(void)
+__libposix_free_wait_list(void)
 {
 	WaitList *wl, *c;
 
@@ -53,7 +52,7 @@ POSIX_exit(int code)
 {
 	char buf[64], *s;
 
-	free_wait_list();
+	__libposix_free_wait_list();
 
 	if(__libposix_exit_status_translator != nil
 	&&(s = __libposix_exit_status_translator(code)) != nil){
@@ -80,7 +79,7 @@ POSIX_execve(int *errnop, const char *name, char * const*argv, char * const*env)
 		__libposix_setup_exec_environment(env);
 	}
 
-	free_wait_list();
+	__libposix_free_wait_list();
 
 	ret = sys_exec(name, argv);
 	switch(ret){
@@ -96,6 +95,30 @@ POSIX_execve(int *errnop, const char *name, char * const*argv, char * const*env)
 	return -1;
 }
 
+int
+POSIX_getpid(int *errnop)
+{
+	return getpid();
+}
+
+int
+POSIX_getppid(int *errnop)
+{
+	return getppid();
+}
+
+int
+POSIX_fork(int *errnop)
+{
+	int pid = fork();
+
+	if(pid == 0){
+		/* reset wait list for the child */
+		*__libposix_wait_list = nil;
+	}
+	return pid;
+}
+
 int
 POSIX_wait(int *errnop, int *status)
 {
@@ -244,131 +267,6 @@ WaitAgain:
 	return -1;
 }
 
-static int
-note_all_writable_processes(int *errnop, char *note)
-{
-	// TODO: loop over writable note files and post note.
-	*errnop = __libposix_get_errno(PosixEPERM);
-	return -1;
-}
-
-int
-POSIX_kill(int *errnop, int pid, int sig)
-{
-	char msg[64], file[128];
-	int mode;
-	int ret;
-
-	snprint(msg, sizeof(msg), __POSIX_SIGNAL_PREFIX "%d", sig);
-	switch(pid){
-	case 0:
-		mode = PNGROUP;
-		break;
-	case -1:
-		return note_all_writable_processes(errnop, msg);
-	default:
-		if(pid < 0){
-			mode = PNGROUP;
-			pid = -pid;
-		} else {
-			mode = PNPROC;
-		}
-	}
-
-	snprint(file, sizeof(file), "/proc/%d/note", pid);
-	if(access(file, AWRITE) != 0){
-		if(access(file, AEXIST) == 0)
-			*errnop = __libposix_get_errno(PosixEPERM);
-		else
-			*errnop = __libposix_get_errno(PosixESRCH);
-		return -1;
-	}
-	ret = postnote(mode, pid, msg);
-	if(ret != 0){
-		*errnop = __libposix_translate_errstr((uintptr_t)POSIX_kill);
-		return -1;
-	}
-	return 0;
-}
-
-int
-POSIX_getpid(int *errnop)
-{
-	return getpid();
-}
-
-int
-POSIX_getppid(int *errnop)
-{
-	return getppid();
-}
-
-int
-POSIX_fork(int *errnop)
-{
-	int pid = fork();
-
-	if(pid == 0){
-		/* reset wait list for the child */
-		*__libposix_wait_list = nil;
-	}
-	return pid;
-}
-
-static int
-translate_jehanne_note(char *note)
-{
-	// TODO: implement
-	return 0;
-}
-
-static void
-terminated_by_signal(int sig)
-{
-	char buf[64];
-
-	free_wait_list();
-
-	snprint(buf, sizeof(buf), __POSIX_EXIT_SIGNAL_PREFIX "%d", sig);
-	exits(buf);
-}
-
-int
-POSIX_signal_execute(int sig, PosixSignalDisposition action, int pid)
-{
-	switch(action){
-	case SignalHandled:
-		return 1;
-	case TerminateTheProcess:
-	case TerminateTheProcessAndCoreDump:
-		terminated_by_signal(sig);
-		break;
-	case StopTheProcess:
-		if(pid < 0)
-			sysfatal("libposix: stop signal reached the target process");
-		// TODO: write stop to ctl file
-		return 1;
-	case ResumeTheProcess:
-		if(pid < 0)
-			sysfatal("libposix: continue signal reached the target process");
-		// TODO: write start to ctl file
-		return 1;
-	}
-	return 0;
-}
-
-int
-__libposix_note_handler(void *ureg, char *note)
-{
-	int sig;
-	PosixSignalDisposition action;
-	if(strncmp(note, __POSIX_SIGNAL_PREFIX, __POSIX_SIGNAL_PREFIX_LEN) != 0)
-		return translate_jehanne_note(note); // TODO: should we translate common notes?
-	sig = atoi(note+__POSIX_SIGNAL_PREFIX_LEN);
-	action = __libposix_signal_trampoline(sig);
-	return POSIX_signal_execute(sig, action, -1);
-}
-
 int
 libposix_translate_exit_status(PosixExitStatusTranslator translator)
 {
@@ -380,17 +278,6 @@ libposix_translate_exit_status(PosixExitStatusTranslator translator)
 	return 1;
 }
 
-int
-libposix_set_signal_trampoline(PosixSignalTrampoline trampoline)
-{
-	if(__libposix_initialized())
-		return 0;
-	if(trampoline == nil)
-		return 0;
-	__libposix_signal_trampoline = trampoline;
-	return 1;
-}
-
 int
 libposix_set_wait_options(int wcontinued, int wnohang, int wuntraced)
 {
@@ -405,8 +292,6 @@ libposix_set_wait_options(int wcontinued, int wnohang, int wuntraced)
 void
 __libposix_processes_check_conf(void)
 {
-	if(__libposix_signal_trampoline == nil)
-		sysfatal("libposix: no signal trampoline");
 	if(__libposix_wnohang == 0)
 		sysfatal("libposix: WNOHANG is undefined");
 	/* __libposix_exit_status_translator is optional */

sys/src/lib/posix/signals.c

@@ -0,0 +1,168 @@
+/*
+ * This file is part of Jehanne.
+ *
+ * Copyright (C) 2017 Giacomo Tesio <giacomo@tesio.it>
+ *
+ * This is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, version 3 of the License.
+ *
+ * Jehanne 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 Affero General Public License
+ * along with Jehanne.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <u.h>
+#include <lib9.h>
+#include <posix.h>
+#include "internal.h"
+
+#define __POSIX_SIGNAL_PREFIX_LEN (sizeof(__POSIX_SIGNAL_PREFIX)-1)
+
+static PosixSignalTrampoline __libposix_signal_trampoline;
+
+static int
+note_all_writable_processes(int *errnop, char *note)
+{
+	// TODO: loop over writable note files and post note.
+	*errnop = __libposix_get_errno(PosixEPERM);
+	return -1;
+}
+
+int
+POSIX_kill(int *errnop, int pid, int sig)
+{
+	char msg[64], file[128];
+	int mode;
+	int ret;
+
+	snprint(msg, sizeof(msg), __POSIX_SIGNAL_PREFIX "%d", sig);
+	switch(pid){
+	case 0:
+		mode = PNGROUP;
+		break;
+	case -1:
+		return note_all_writable_processes(errnop, msg);
+	default:
+		if(pid < 0){
+			mode = PNGROUP;
+			pid = -pid;
+		} else {
+			mode = PNPROC;
+		}
+	}
+
+	snprint(file, sizeof(file), "/proc/%d/note", pid);
+	if(access(file, AWRITE) != 0){
+		if(access(file, AEXIST) == 0)
+			*errnop = __libposix_get_errno(PosixEPERM);
+		else
+			*errnop = __libposix_get_errno(PosixESRCH);
+		return -1;
+	}
+	ret = postnote(mode, pid, msg);
+	if(ret != 0){
+		*errnop = __libposix_translate_errstr((uintptr_t)POSIX_kill);
+		return -1;
+	}
+	return 0;
+}
+
+static int
+translate_jehanne_note(char *note)
+{
+	// TODO: implement
+	return 0;
+}
+
+static void
+terminated_by_signal(int sig)
+{
+	char buf[64];
+
+	__libposix_free_wait_list();
+
+	snprint(buf, sizeof(buf), __POSIX_EXIT_SIGNAL_PREFIX "%d", sig);
+	exits(buf);
+}
+
+static int
+send_control_msg(int pid, char *msg)
+{
+	int fd, n;
+	char buf[256];
+
+	n = snprint(buf, sizeof(buf), "/proc/%d/ctl", pid);
+	if(n < 0)
+		goto ErrorBeforeOpen;
+	fd = open(buf, OWRITE);
+	if(fd < 0)
+		goto ErrorBeforeOpen;
+	n = snprint(buf, sizeof(buf), "%s", msg);
+	if(n < 0)
+		goto ErrorAfterOpen;
+	if(write(fd, buf, n) < n)
+		goto ErrorAfterOpen;
+	close(fd);
+	return 1;
+
+ErrorAfterOpen:
+	close(fd);
+ErrorBeforeOpen:
+	return 0;
+}
+
+int
+POSIX_signal_execute(int sig, PosixSignalDisposition action, int pid)
+{
+	switch(action){
+	case SignalHandled:
+		return 1;
+	case TerminateTheProcess:
+	case TerminateTheProcessAndCoreDump:
+		terminated_by_signal(sig);
+		break;
+	case StopTheProcess:
+		if(pid < 0)
+			sysfatal("libposix: signal %d with stop disposition reached process %d", sig, pid);
+		return send_control_msg(pid, "stop");
+	case ResumeTheProcess:
+		if(pid < 0)
+			sysfatal("libposix: signal %d with continue disposition reached process %d", sig, pid);
+		return send_control_msg(pid, "start");
+	}
+	return 0;
+}
+
+int
+__libposix_note_handler(void *ureg, char *note)
+{
+	int sig;
+	PosixSignalDisposition action;
+	if(strncmp(note, __POSIX_SIGNAL_PREFIX, __POSIX_SIGNAL_PREFIX_LEN) != 0)
+		return translate_jehanne_note(note); // TODO: should we translate common notes?
+	sig = atoi(note+__POSIX_SIGNAL_PREFIX_LEN);
+	action = __libposix_signal_trampoline(sig);
+	return POSIX_signal_execute(sig, action, -1);
+}
+
+int
+libposix_set_signal_trampoline(PosixSignalTrampoline trampoline)
+{
+	if(__libposix_initialized())
+		return 0;
+	if(trampoline == nil)
+		return 0;
+	__libposix_signal_trampoline = trampoline;
+	return 1;
+}
+
+void
+__libposix_signal_check_conf(void)
+{
+	if(__libposix_signal_trampoline == nil)
+		sysfatal("libposix: no signal trampoline");
+}