From aefa2697d705e316aa5255004e4b6a129e9afe2a Mon Sep 17 00:00:00 2001
From: Robert Morris <rtm@csail.mit.edu>
Date: Wed, 19 Aug 2020 12:35:14 -0400
Subject: usertest for exec() out of memory recovery and fix a few exec() bugs
---
user/usertests.c | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
(limited to 'user/usertests.c')
diff --git a/user/usertests.c b/user/usertests.c
index cc88555..acdba0f 100644
--- a/user/usertests.c
+++ b/user/usertests.c
@@ -2452,6 +2452,42 @@ badarg(char *s)
exit(0);
}
+// test the exec() code that cleans up if it runs out
+// of memory. it's really a test that such a condition
+// doesn't cause a panic.
+void
+execout(char *s)
+{
+ for(int avail = 0; avail < 15; avail++){
+ int pid = fork();
+ if(pid < 0){
+ printf("fork failed\n");
+ exit(1);
+ } else if(pid == 0){
+ // allocate all of memory.
+ while(1){
+ uint64 a = (uint64) sbrk(4096);
+ if(a == 0xffffffffffffffffLL)
+ break;
+ }
+
+ // free a few pages, in order to let exec() make some
+ // progress.
+ for(int i = 0; i < avail; i++)
+ sbrk(-4096);
+
+ close(1);
+ char *args[] = { "echo", "x", 0 };
+ exec("echo", args);
+ exit(0);
+ } else {
+ wait((int*)0);
+ }
+ }
+
+ exit(0);
+}
+
//
// use sbrk() to count how many free physical memory pages there are.
//
@@ -2520,6 +2556,7 @@ main(int argc, char *argv[])
void (*f)(char *);
char *s;
} tests[] = {
+ {execout, "execout"},
{copyin, "copyin"},
{copyout, "copyout"},
{copyinstr1, "copyinstr1"},
--
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