make sure realloc preserves data

1 files changed, 45 insertions, 17 deletions

diff --git a/src/regress/lib/libc/malloc/malloc_general/malloc_general.c b/src/regress/lib/libc/malloc/malloc_general/malloc_general.c
index 336326bc57..3458b64c2a 100644
--- a/src/regress/lib/libc/malloc/malloc_general/malloc_general.c
+++ b/src/regress/lib/libc/malloc/malloc_general/malloc_general.c
@@ -23,16 +23,36 @@
 
 #define N 1000
 
-size_t size(void)
+size_t
+size(void)
 {
         int p = arc4random_uniform(13) + 3;
         return arc4random_uniform(1 << p);
 }
 
-void *a[N];
+struct { void *p; size_t sz; } a[N];
 
 extern char *malloc_options;
 
+void
+fill(u_char *p, size_t sz)
+{
+        size_t i;
+
+        for (i = 0; i < sz; i++)
+                p[i] = i % 256;
+}
+
+void
+check(u_char *p, size_t sz)
+{
+        size_t i;
+
+        for (i = 0; i < sz; i++)
+                if (p[i] != i % 256)
+                        errx(1, "check");
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -54,43 +74,51 @@ main(int argc, char *argv[])
                 i = arc4random_uniform(N);
                 switch (p) {
                 case 0:
-                        if (a[i]) {
+                        if (a[i].p) {
 #ifdef VERBOSE
-                                printf("F %p\n", a[i]);
+                                printf("F %p\n", a[i].p);
 #endif
-                                free(a[i]);
-                                a[i] = NULL;
+                                if (a[i].p)
+                                        check(a[i].p, a[i].sz);
+                                free(a[i].p);
+                                a[i].p = NULL;
                         }
                         sz = size();
 #ifdef VERBOSE
                         printf("M %zu=", sz);
 #endif
-                        a[i] = malloc(sz);
+                        a[i].p = malloc(sz);
+                        a[i].sz = sz;
 #ifdef VERBOSE
-                        printf("%p\n", a[i]);
+                        printf("%p\n", a[i].p);
 #endif
-                        if (a[i])
-                                memset(a[i], 0xff, sz);
+                        if (a[i].p)
+                                fill(a[i].p, sz);
                         break;
                 case 1:
                         sz = size();
 #ifdef VERBOSE
-                        printf("R %p %zu=", a[i], sz);
+                        printf("R %p %zu=", a[i].p, sz);
 #endif
-                        q = realloc(a[i], sz);
+                        q = realloc(a[i].p, sz);
 #ifdef VERBOSE
                         printf("%p\n", q);
 #endif
+                        if (a[i].p && q)
+                                check(q, a[i].sz < sz ? a[i].sz : sz);
                         if (q) {
-                                a[i]= q;
-                                if (a[i])
-                                        memset(a[i], 0xff, sz);
+                                a[i].p = q;
+                                a[i].sz = sz;
+                                fill(a[i].p, sz);
                         }
                         break;
                 }
         }
-        for (i = 0; i < N; i++)
-                free(a[i]);
+        for (i = 0; i < N; i++) {
+                if (a[i].p)
+                        check(a[i].p, a[i].sz);
+                free(a[i].p);
+        }
         printf("\n");
         return 0;
 }