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-rw-r--r--linuxthreads/tst-context.c116
1 files changed, 116 insertions, 0 deletions
diff --git a/linuxthreads/tst-context.c b/linuxthreads/tst-context.c
new file mode 100644
index 0000000000..2938a9f7fa
--- /dev/null
+++ b/linuxthreads/tst-context.c
@@ -0,0 +1,116 @@
+/* Ack, a hack! We need to get the proper definition, or lack thereof,
+ for FLOATING_STACKS. But when !IS_IN_libpthread, this can get defined
+ incidentally by <tls.h>. So kludge around it. */
+
+#define IS_IN_libpthread
+#include <tls.h>
+#undef IS_IN_libpthread
+#undef USE___THREAD
+
+#include <errno.h>
+#include <error.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ucontext.h>
+
+
+#define N 4
+
+#ifdef FLOATING_STACKS
+static char stacks[N][8192];
+static ucontext_t ctx[N][2];
+static volatile int failures;
+
+static void
+fct (long int n)
+{
+ /* Just to use the thread local descriptor. */
+ printf ("%ld: in %s now\n", n, __FUNCTION__);
+ errno = 0;
+}
+
+static void *
+threadfct (void *arg)
+{
+ int n = (int) (long int) arg;
+
+ if (getcontext (&ctx[n][1]) != 0)
+ {
+ printf ("%d: cannot get context: %m\n", n);
+ exit (1);
+ }
+
+ printf ("%d: %s: before makecontext\n", n, __FUNCTION__);
+
+ ctx[n][1].uc_stack.ss_sp = stacks[n];
+ ctx[n][1].uc_stack.ss_size = 8192;
+ ctx[n][1].uc_link = &ctx[n][0];
+ makecontext (&ctx[n][1], (void (*) (void)) fct, 1, (long int) n);
+
+ printf ("%d: %s: before swapcontext\n", n, __FUNCTION__);
+
+ if (swapcontext (&ctx[n][0], &ctx[n][1]) != 0)
+ {
+ ++failures;
+ printf ("%d: %s: swapcontext failed\n", n, __FUNCTION__);
+ }
+ else
+ printf ("%d: back in %s\n", n, __FUNCTION__);
+
+ return NULL;
+}
+#endif
+
+
+#ifdef FLOATING_STACKS
+static volatile int global;
+#endif
+
+int
+main (void)
+{
+#ifndef FLOATING_STACKS
+ puts ("not supported");
+ return 0;
+#else
+ int n;
+ pthread_t th[N];
+ ucontext_t mctx;
+
+ puts ("making contexts");
+ if (getcontext (&mctx) != 0)
+ {
+ if (errno == ENOSYS)
+ {
+ puts ("context handling not supported");
+ exit (0);
+ }
+
+ printf ("%s: getcontext: %m\n", __FUNCTION__);
+ exit (1);
+ }
+
+ /* Play some tricks with this context. */
+ if (++global == 1)
+ if (setcontext (&mctx) != 0)
+ {
+ printf ("%s: setcontext: %m\n", __FUNCTION__);
+ exit (1);
+ }
+ if (global != 2)
+ {
+ printf ("%s: 'global' not incremented twice\n", __FUNCTION__);
+ exit (1);
+ }
+
+ for (n = 0; n < N; ++n)
+ if (pthread_create (&th[n], NULL, threadfct, (void *) (long int) n) != 0)
+ error (EXIT_FAILURE, errno, "cannot create all threads");
+
+ for (n = 0; n < N; ++n)
+ pthread_join (th[n], NULL);
+
+ return failures;
+#endif
+}