9os

commit e1773e8bd9716a04d941981e555c7612e099a3d9
parent 8410cbe6340a2fd39da4866ce239b95f81569bda
Author: Roberto E. Vargas Caballero <roberto.vargas@midokura.com>
Date:   Thu, 17 Nov 2022 07:42:16 +0100

os9: Add savectx() to rfork()

Savectx() saves the current content to the task pointer
passed. It means that the original task (proc) returns
from this function with a value of 1 and the child
returns with 0.

Diffstat:
M
include/os9/os9.h
 | 
1
+
M
src/os9/hosted/Makefile
 | 
1
+
M
src/os9/hosted/arch.c
 | 
9
---------
A
src/os9/hosted/ctx.c
 | 
19
+++++++++++++++++++
M
src/os9/proc.c
 | 
32
++++++++++++++++++--------------

5 files changed, 39 insertions(+), 23 deletions(-)
diff --git a/include/os9/os9.h b/include/os9/os9.h
@@ -274,6 +274,7 @@ extern noreturn void swtch(Context *ctx);
 extern noreturn void trap(Context *ctx);
 extern Ptable *initptable(Task *);
 extern int ictx(Task *, void *);
+extern int savectx(Task *);
 extern char *getconf(char *);
 extern void idle(void);
 
diff --git a/src/os9/hosted/Makefile b/src/os9/hosted/Makefile
@@ -4,6 +4,7 @@ include $(PROJECTDIR)/scripts/rules.mk
 
 OBJS =\
 	arch.o\
+	ctx.o\
 	mmu.o\
 	lock.o\
 	main.o\
diff --git a/src/os9/hosted/arch.c b/src/os9/hosted/arch.c
@@ -70,12 +70,3 @@ void
 idle(void)
 {
 }
-
-int
-ictx(Task *tp, void *fn)
-{
-	tp->ctx.stack = (void *) tp->stack.va;
-	tp->ctx.entry = fn;
-
-	return 0;
-}
diff --git a/src/os9/hosted/ctx.c b/src/os9/hosted/ctx.c
@@ -0,0 +1,19 @@
+#include <os9/os9.h>
+
+int
+savectx(Task *tp)
+{
+	tp->m = 0;
+	tp->ctx.entry = proc->ctx.entry;
+
+	return 1;
+}
+
+int
+ictx(Task *tp, void *fn)
+{
+	tp->ctx.stack = (void *) tp->stack.va;
+	tp->ctx.entry = fn;
+
+	return 0;
+}
diff --git a/src/os9/proc.c b/src/os9/proc.c
@@ -248,7 +248,7 @@ newtask(void)
 
 	last = pid;
 	tp->pid = pid;
-	tp->ppid = (proc) ? proc->pid : 0;
+	tp->ppid = 0;
 	tp->state = TINIT;
 
 	unlock(&m);
@@ -346,12 +346,11 @@ clone(Task *parent)
 	if ((tp = newtask()) == NULL)
 		return NULL;
 
-	tp->ppid = parent->pid;
-
 	if (!initptable(tp) || !newstack(tp))
 		goto err;
 
-	lock(&parent->m);
+	tp->ppid = parent->pid;
+
 	tp->text = parent->text;
 	if (tp->text)
 		incref(&parent->text->ref);
@@ -367,7 +366,6 @@ clone(Task *parent)
 	tp->fds = parent->fds;
 	if (tp->fds)
 		incref(&parent->fds->ref);
-	unlock(&parent->m);
 
 	return tp;
 
@@ -380,7 +378,7 @@ err:
 int
 rfork(int flags)
 {
-	Task *tp, *parent;
+	Task *tp;
 	Nspace *ns;
 	Fdset *fds;
 	Map *data;
@@ -392,21 +390,28 @@ rfork(int flags)
 		return -1;
 	}
 
-	tp = parent = proc;
+	tp = proc;
 	ns = NULL;
 	fds = NULL;
 	data = NULL;
 
+	lock(&proc->m);
 	if ((flags & RFPROC) != 0) {
-		if ((tp = clone(parent)) == NULL)
+		if ((tp = clone(proc)) == NULL)
 			return -1;
+		/*
+		 * if savectx() returns 0 then we are the child and
+		 * the mutex was already released by the parent
+		 */
+		if (savectx(tp) == 0)
+			return 0;
 	}
 	if ((flags & RFCNAMEG) != 0) {
 		if ((ns = newspace(NULL)) == NULL)
 			goto err;
 	}
 	if ((flags & RFNAMEG) != 0) {
-		if ((ns = newspace(parent->ns)) == NULL)
+		if ((ns = newspace(proc->ns)) == NULL)
 			goto err;
 	}
 	if ((flags & RFCFDG) != 0) {
@@ -414,11 +419,11 @@ rfork(int flags)
 			goto err;
 	}
 	if ((flags & RFFDG) != 0) {
-		if ((fds = newfds(parent->fds)) == NULL)
+		if ((fds = newfds(proc->fds)) == NULL)
 			goto err;
 	}
 	if ((flags & RFMEM) == 0) {
-		if ((data = dupmap(parent->data)) == NULL)
+		if ((data = dupmap(proc->data)) == NULL)
 			goto err;
 	}
 
@@ -438,10 +443,9 @@ rfork(int flags)
 		tp->data = data;
 	}
 
-	if (flags & RFPROC) {
+	unlock(&proc->m);
+	if (flags & RFPROC)
 		unlock(&tp->m);
-		return tp->pid;
-	}
 
 	return 0;