9os

commit 1f846556907895e491d5dfeea711b93dc4d38787
parent 11d57f50f23ea8fffe3bdabd37f9ecf8c9e1b3f4
Author: Roberto E. Vargas Caballero <k0ga@shike2.com>
Date:   Sun, 25 Oct 2020 22:47:38 +0100

os9/proc: Add rfork()

Change-Id: I627931dd9348c0d212ca046b87702c30b7f9564f

Diffstat:
M
include/os9/os9.h
 | 
20
+++++++++++++++-----
M
src/os9/proc.c
 | 
108
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 123 insertions(+), 5 deletions(-)
diff --git a/include/os9/os9.h b/include/os9/os9.h
@@ -48,6 +48,15 @@ typedef struct nspace Nspace;
 typedef struct fdset Fdset;
 typedef struct ref Ref;
 
+enum rforkflags {
+	RFPROC = 1 << 0,
+	RFNAMEG = 1 << 1,
+	RFCNAMEG = 1 << 2,
+	RFFDG = 1 <<  3,
+	RFCFDG = 1 << 4,
+	RFMEM = 1 << 5,
+};
+
 enum barrier_type {
 	CODE,
 	DATA,
@@ -98,7 +107,13 @@ enum map_attr {
 	MD = 1 << 3,
 };
 
+struct ref {
+	mutex_t m;
+	int cnt;
+};
+
 struct map {
+	Ref ref;
 	char *name;
 	unsigned perm;
 
@@ -144,11 +159,6 @@ struct chan {
 	mutex_t mutex;
 };
 
-struct ref {
-	mutex_t m;
-	int cnt;
-};
-
 struct mpoint {
 	Chan *new;
 	Chan *old;
diff --git a/src/os9/proc.c b/src/os9/proc.c
@@ -1,5 +1,6 @@
 #include <os9/os9.h>
 
+#include <errno.h>
 #include <limits.h>
 
 struct nspace {
@@ -8,6 +9,12 @@ struct nspace {
 	struct mpoint mpoints[NR_MPOINTS];
 };
 
+struct fdset {
+	Ref ref;
+	mutex_t m;
+	Chan fdset[NR_CHANS];
+};
+
 static Task tasktab[NR_TASKS];
 
 static void
@@ -108,3 +115,104 @@ newspace(Nspace *from)
 
 	return ns;
 }
+
+static Fdset *
+newfds(Fdset *from)
+{
+	Fdset *fds;
+
+	fds = alloc(sizeof(*fds));
+	if (from)
+		*fds = *from;
+	initref(&fds->ref);
+
+	return fds;
+}
+
+static Map *
+newmap(Map *from)
+{
+	Map *mp;
+
+	mp = alloc(sizeof(*mp));
+	if (from)
+		*mp = *from;
+	initref(&mp->ref);
+
+	return mp;
+}
+
+int
+rfork(int flags)
+{
+	Task *tp, *parent;
+	int tid;
+
+	tp = parent = task;
+
+	if ((flags & (RFPROC|RFMEM))  == RFPROC|RFMEM
+	||   (flags & (RFNAMEG|RFCNAMEG))  == RFNAMEG|RFCNAMEG
+	||   (flags & (RFFDG|RFCFDG))  == RFFDG|RFCFDG) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if ((flags & RFPROC) != 0) {
+		if ((tp = newslot()) == NULL)
+			return -1;
+
+		for (tp = tasktab; tp < &tasktab[NR_TASKS]; ++tp) {
+			if (tp->mode == PDISABLED)
+				break;
+		}
+
+		if (tp == &tasktab[NR_TASKS] || (tid = newtid()) < 0) {
+			errno = ENOMEM;
+			return -1;
+		}
+		tp->tid = tid;
+
+		incref(&parent->text->ref);
+		tp->text = parent->text;
+
+		incref(&parent->data->ref);
+		tp->data = parent->data;
+
+		incref(&parent->stack->ref);
+		tp->stack = parent->stack;
+
+		incref(&parent->ns->ref);
+		tp->ns = parent->ns;
+
+		incref(&parent->fds->ref);
+		tp->fds = parent->fds;
+	}
+
+	if ((flags & RFCNAMEG) != 0) {
+		decref(&tp->ns->ref);
+		tp->ns = newspace(NULL);
+		incref(&tp->ns->ref);
+	}
+	if ((flags & RFNAMEG) != 0) {
+		decref(&tp->ns->ref);
+		tp->ns = newspace(parent->ns);
+		incref(&tp->ns->ref);
+	}
+	if ((flags & RFCFDG) != 0) {
+		decref(&tp->fds->ref);
+		tp->fds = newfds(NULL);
+		incref(&tp->fds->ref);
+	}
+	if ((flags & RFFDG) != 0) {
+		decref(&tp->fds->ref);
+		tp->fds = newfds(parent->fds);
+		incref(&tp->fds->ref);
+	}
+	if ((flags & RFCFDG) != 0) {
+		decref(&tp->data->ref);
+		tp->data = newmap(parent->data);
+		incref(&tp->data->ref);
+	}
+
+	return (flags & RFPROC) ? tp->tid : 0;
+}