From 8c33c921b485f4c07d2f5943a7dd64b9375ecafc Mon Sep 17 00:00:00 2001
From: Giacomo Tesio <giacomo@tesio.it>
Date: Mon, 1 May 2017 23:57:05 +0200
Subject: [PATCH] libposix: draft waitpid (still broken)

---
 sys/include/posix.h           |  1 +
 sys/src/lib/posix/initlib.c   |  9 +++-
 sys/src/lib/posix/processes.c | 80 ++++++++++++++++++++++++++++++++++-
 3 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/sys/include/posix.h b/sys/include/posix.h
index 589932d..e5a2a7a 100644
--- a/sys/include/posix.h
+++ b/sys/include/posix.h
@@ -51,6 +51,7 @@ extern int POSIX_stat(int *errnop, const char *file, void *stat);
 extern clock_t POSIX_times(int *errnop, void *tms);
 extern int POSIX_unlink(int *errnop, const char *name);
 extern int POSIX_wait(int *errnop, int *status);
+extern int POSIX_waitpid(int *errnop, int pid, int *status, int options);
 extern long POSIX_write(int *errnop, int fd, const void *buf, size_t len);
 extern int POSIX_gettimeofday(int *errnop, void *timeval, void *timezone);
 extern char* POSIX_getenv(int *errnop, const char *name);
diff --git a/sys/src/lib/posix/initlib.c b/sys/src/lib/posix/initlib.c
index f720b70..817858f 100644
--- a/sys/src/lib/posix/initlib.c
+++ b/sys/src/lib/posix/initlib.c
@@ -21,6 +21,7 @@
 #include "internal.h"
 
 extern int *__libposix_errors_codes;
+extern WaitList **__libposix_wait_list;
 static int __initialized;
 
 static void
@@ -35,14 +36,20 @@ void
 libposix_init(int argc, char *argv[], PosixInit init)
 {
 	extern int main(int, char**);
-	int error_codes[ERRNO_LAST-ERRNO_FIRST];
+	WaitList *wait_list;
 	int status;
+	int error_codes[ERRNO_LAST-ERRNO_FIRST];
+	
 
 	assert(__initialized == 0);
 
 	/* initialize PosixErrors map */
 	memset(error_codes, 0, sizeof(error_codes));
 	__libposix_errors_codes=error_codes;
+	
+	/* initialize wait_list; see also POSIX_fork and POSIX_exit */
+	wait_list = nil;
+	__libposix_wait_list = &wait_list;
 
 	if(!atnotify(__libposix_note_handler, 1))
 		sysfatal("libposix: atnotify");
diff --git a/sys/src/lib/posix/processes.c b/sys/src/lib/posix/processes.c
index c68e3ce..2d84602 100644
--- a/sys/src/lib/posix/processes.c
+++ b/sys/src/lib/posix/processes.c
@@ -22,6 +22,15 @@
 
 extern char **environ;
 
+typedef struct WaitList WaitList;
+struct WaitList
+{
+	int pid;
+	int status;
+	WaitList *next;
+};
+
+WaitList **__libposix_wait_list;
 static PosixSignalTrampoline __libposix_signal_trampoline;
 static PosixExitStatusTranslator __libposix_exit_status_translator;
 
@@ -31,6 +40,20 @@ void
 POSIX_exit(int code)
 {
 	char buf[64], *s;
+	WaitList *wl, c;
+
+	/* free the wait list as the memory is shared */
+	wl = *__libposix_wait_list;
+	if(wl != nil){
+		*__libposix_wait_list = nil;
+		do
+		{
+			c = wl;
+			wl = c->next;
+			free(c);
+		}
+		while (wl != nil)
+	}
 
 	if(__libposix_exit_status_translator != nil
 	&&(s = __libposix_exit_status_translator(code)) != nil){
@@ -75,9 +98,19 @@ int
 POSIX_wait(int *errnop, int *status)
 {
 	Waitmsg *w;
+	WaitList *l;
 	char *s;
 	int ret = 0, pid;
 	
+	l = *__libposix_wait_list; 
+	if(l != nil){
+		*__libposix_wait_list = l->next;
+		*status = l->status;
+		pid = l->pid;
+		free(l);
+		return pid;
+	}
+	
 	w = wait();
 	if(w == nil){
 		*errnop = __libposix_get_errno(PosixECHILD);
@@ -100,6 +133,45 @@ POSIX_wait(int *errnop, int *status)
 	return pid;
 }
 
+int
+POSIX_waitpid(int *errnop, int pid, int *status, int options)
+{
+	Waitmsg *w;
+	WaitList *c, **nl;
+	char *s;
+	int ret = 0, pid;
+
+	nl = __libposix_wait_list;
+	l = *nl'
+	while(l != nil){
+	}
+	if(l != nil){
+		
+	}
+
+	w = wait();
+	if(w == nil){
+		*errnop = __libposix_get_errno(PosixECHILD);
+		return -1;
+	}
+	pid = w->pid;
+	if(w->msg[0] != 0){
+		s = strstr(w->msg, __POSIX_EXIT_PREFIX);
+		if(s){
+			s += (sizeof(__POSIX_EXIT_PREFIX)/sizeof(char) - 1);
+			ret = atoi(s);
+		} else {
+			/* TODO: setup configurable interpretations */
+			ret = 127;
+		}
+	}
+	if(status != nil)
+		*status = ret;
+	free(w);
+	return pid;
+
+}
+
 static int
 note_all_writable_processes(int *errnop, char *note)
 {
@@ -162,7 +234,13 @@ POSIX_getppid(int *errnop)
 int
 POSIX_fork(int *errnop)
 {
-	return fork();
+	int pid = fork();
+
+	if(pid == 0){
+		/* reset wait list for the child */
+		*__libposix_wait_list = nil;
+	}
+	return pid;
 }
 
 static int