1 files changed, 108 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/OR_USING_C/08.7.c b/reference/C/CONTRIB/OR_USING_C/08.7.c
new file mode 100644
index 0000000..5518c96
--- /dev/null
+++ b/reference/C/CONTRIB/OR_USING_C/08.7.c
@@ -0,0 +1,108 @@
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <signal.h>
+#include <stdio.h>
+
+char *stack;      /* pointer to signal stack base */
+int tooksig = 0;  /* 1 after we take the signal   */
+
+main()
+{
+    extern void x();
+    struct sigvec sv;
+    struct sigstack ss;
+    struct rlimit rlimit;
+
+    /*
+     * Set stack size limit to 50 kbytes.
+     */
+    getrlimit(RLIMIT_STACK, &rlimit);
+    rlimit.rlim_cur = 50 * 1024;
+
+    if (setrlimit(RLIMIT_STACK, &rlimit) < 0) {
+        perror("setrlimit");
+        exit(1);
+    }
+
+    /*
+     * Take illegal instruction and process it with x,
+     * on the interrupt stack.  For 4.2BSD, change
+     * sv_flags to sv_onstack and SV_ONSTACK to 1.
+     */
+    sv.sv_mask = 0;
+    sv.sv_handler = x;
+    sv.sv_flags = SV_ONSTACK;
+    sigvec(SIGILL, &sv, (struct sigvec *) 0);
+
+    /*
+     * Allocate memory for the signal stack.  The
+     * kernel assumes the addresses grow in the same
+     * direction as on the process stack (toward
+     * lower addresses, on a VAX).
+     */
+    if ((stack = (char *) malloc(10240)) == NULL) {
+        fprintf(stderr, "Out of memory.\n");
+        exit(1);
+    }
+
+    /*
+     * Issue the call to tell the system about the
+     * signal stack.  We pass the end of the signal
+     * stack, not the beginning, since the stack
+     * grows toward lower addresses.
+     */
+    ss.ss_onstack = 0;
+    ss.ss_sp = (caddr_t) stack + 10240;
+
+    if (sigstack(&ss, (struct sigstack *) 0) < 0) {
+        perror("sigstack");
+        exit(1);
+    }
+
+    /*
+     * Start using up stack space.
+     */
+    y();
+}
+
+y()
+{
+    /*
+     * Take up 5k of stack space.
+     */
+    char buf[5120];
+
+    printf("%s\n", tooksig ? "Now on extended stack." :
+        "On 50k stack.");
+
+    /*
+     * Recurse.
+     */
+    y();
+}
+
+/*
+ * Handle the signal.
+ */
+void x(sig, code, scp)
+int sig, code;
+struct sigcontext *scp;
+{
+    struct rlimit rlimit;
+
+    /*
+     * Increase the stack limit to the maximum.
+     */
+    getrlimit(RLIMIT_STACK, &rlimit);
+    rlimit.rlim_cur = rlimit.rlim_max;
+
+    if (setrlimit(RLIMIT_STACK, &rlimit) < 0) {
+        perror("setrlimit");
+        exit(1);
+    }
+
+    tooksig = 1;
+    return;
+}
+