[PATCH] vmsplice2: add switch for stack allocation

diff --git a/vmsplice2.c b/vmsplice2.c
index f4182ed160d330184931e5488716847392bd5b6c..a905b83ae31b8597d6c5ecd2eedb836c6269e4e3 100644 (file)
--- a/vmsplice2.c
+++ b/vmsplice2.c
@@ -13,6 +13,8 @@
 
 #include "splice.h"
 
+static int alloc_stack;
+
 int do_vmsplice(int fd, struct iovec *iov, unsigned long nr_vecs)
 {
        struct pollfd pfd = { .fd = fd, .events = POLLOUT, };
@@ -53,10 +55,28 @@ int do_vmsplice(int fd, struct iovec *iov, unsigned long nr_vecs)
 
 static int usage(char *name)
 {
-       fprintf(stderr, "%s | ...\n", name);
+       fprintf(stderr, "%s [-s(tack)] | ...\n", name);
        return 1;
 }
 
+static int parse_options(int argc, char *argv[])
+{
+       int c, index = 1;
+
+       while ((c = getopt(argc, argv, "s")) != -1) {
+               switch (c) {
+               case 's':
+                       alloc_stack = 1;
+                       index++;
+                       break;
+               default:
+                       return -1;
+               }
+       }
+
+       return index;
+}
+
 #define S1     "header header header header header header header header"
 #define S2     "body body body body body body body body body body body"
 #define S3     "footer footer footer footer footer footer footer footer"
@@ -64,24 +84,28 @@ static int usage(char *name)
 int main(int argc, char *argv[])
 {
        struct iovec vecs[3];
-#if 0
-       /* Dangerous on-stack usage! */
-       char h[] = S1;
-       char b[] = S2;
-       char f[] = S3;
+       char *h, *b, *f;
+
+       if (parse_options(argc, argv) < 0)
+               return usage(argv[0]);
+
+       if (alloc_stack) {
+               /* Dangerous on-stack usage! */
+               h = S1;
+               b = S2;
+               f = S3;
+       } else {
+               h = strdup(S1);
+               b = strdup(S2);
+               f = strdup(S3);
+       }
 
        vecs[0].iov_base = h;
        vecs[1].iov_base = b;
        vecs[2].iov_base = f;
-#else
-       vecs[0].iov_base = strdup(S1);
-       vecs[1].iov_base = strdup(S2);
-       vecs[2].iov_base = strdup(S3);
-
        vecs[0].iov_len = strlen(vecs[0].iov_base);
        vecs[1].iov_len = strlen(vecs[1].iov_base);
        vecs[2].iov_len = strlen(vecs[2].iov_base);
-#endif
                
        if (check_output_pipe())
                return usage(argv[0]);