Get rid of strcpy

On OpenBSD:

```
ld: warning: namespace.c:731(namespace.o:(rb_namespace_local_extension)): warning: strcpy() is almost always misused, please use strlcpy()
```

Author: nobu

addr2line.c

@@ -637,12 +637,13 @@ follow_debuglink_build_id(const char *build_id, size_t build_id_size, int num_tr
                           obj_info_t **objp, line_info_t *lines, int offset, FILE *errout)
 {
     static const char global_debug_dir[] = "/usr/lib/debug/.build-id/";
+    static const char debug_suffix[] = ".debug";
     const size_t global_debug_dir_len = sizeof(global_debug_dir) - 1;
     char *p;
     obj_info_t *o1 = *objp, *o2;
     size_t i;
 
-    if (PATH_MAX < global_debug_dir_len + 1 + build_id_size * 2 + 6) return;
+    if (PATH_MAX < global_debug_dir_len + build_id_size * 2 + sizeof(debug_suffix)) return;
 
     memcpy(binary_filename, global_debug_dir, global_debug_dir_len);
     p = binary_filename + global_debug_dir_len;
@@ -653,7 +654,7 @@ follow_debuglink_build_id(const char *build_id, size_t build_id_size, int num_tr
         *p++ = tbl[n % 16];
         if (i == 0) *p++ = '/';
     }
-    strcpy(p, ".debug");
+    memcpy(p, debug_suffix, sizeof(debug_suffix));
 
     append_obj(objp);
     o2 = *objp;

ext/socket/getaddrinfo.c

@@ -171,9 +171,7 @@ static const char *const ai_errlist[] = {
 
 #define GET_CANONNAME(ai, str) \
 if (pai->ai_flags & AI_CANONNAME) {\
-        if (((ai)->ai_canonname = (char *)malloc(strlen(str) + 1)) != NULL) {\
-                strcpy((ai)->ai_canonname, (str));\
-        } else {\
+        if (((ai)->ai_canonname = strdup(str)) == NULL) {\
                 error = EAI_MEMORY;\
                 goto free;\
         }\

ext/socket/getnameinfo.c

@@ -118,6 +118,16 @@ static struct afd {
 #define ENI_FAMILY	5
 #define ENI_SALEN	6
 
+static ssize_t
+strappend(char *dest, const char *src, size_t size)
+{
+        size_t len = strlen(src);
+        if (len + 1 > size || len >= SSIZE_MAX - 1)
+                return (ssize_t)-1;
+        memcpy(dest, src, len + 1);
+        return (ssize_t)(len + 1);
+}
+
 int
 getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, socklen_t hostlen, char *serv, socklen_t servlen, int flags)
 {
@@ -158,16 +168,14 @@ getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, socklen_t ho
                 /* what we should do? */
         } else if (flags & NI_NUMERICSERV) {
                 snprintf(numserv, sizeof(numserv), "%d", ntohs(port));
-                if (strlen(numserv) + 1 > servlen)
+                if (strappend(serv, numserv, servlen) < 0)
                         return ENI_MEMORY;
-                strcpy(serv, numserv);
         } else {
 #if defined(HAVE_GETSERVBYPORT)
                 struct servent *sp = getservbyport(port, (flags & NI_DGRAM) ? "udp" : "tcp");
                 if (sp) {
-                        if (strlen(sp->s_name) + 1 > servlen)
+                        if (strappend(serv, sp->s_name, servlen) < 0)
                                 return ENI_MEMORY;
-                        strcpy(serv, sp->s_name);
                 } else
                         return ENI_NOSERVNAME;
 #else
@@ -202,9 +210,8 @@ getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, socklen_t ho
                 if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
                     == NULL)
                         return ENI_SYSTEM;
-                if (strlen(numaddr) > hostlen)
+                if (strappend(host, numaddr, hostlen) < 0)
                         return ENI_MEMORY;
-                strcpy(host, numaddr);
         } else {
 #ifdef INET6
                 hp = getipnodebyaddr(addr, afd->a_addrlen, afd->a_af, &h_error);
@@ -218,13 +225,12 @@ getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, socklen_t ho
                                 p = strchr(hp->h_name, '.');
                                 if (p) *p = '\0';
                         }
-                        if (strlen(hp->h_name) + 1 > hostlen) {
+                        if (strappend(host, hp->h_name, hostlen) < 0) {
 #ifdef INET6
                                 freehostent(hp);
 #endif
                                 return ENI_MEMORY;
                         }
-                        strcpy(host, hp->h_name);
 #ifdef INET6
                         freehostent(hp);
 #endif
@@ -234,9 +240,8 @@ getnameinfo(const struct sockaddr *sa, socklen_t salen, char *host, socklen_t ho
                         if (inet_ntop(afd->a_af, addr, numaddr, sizeof(numaddr))
                             == NULL)
                                 return ENI_NOHOSTNAME;
-                        if (strlen(numaddr) > hostlen)
+                        if (strappend(host, numaddr, hostlen) < 0)
                                 return ENI_MEMORY;
-                        strcpy(host, numaddr);
                 }
         }
         return SUCCESS;

ext/socket/raddrinfo.c

@@ -387,15 +387,15 @@ allocate_getaddrinfo_arg(const char *hostp, const char *portp, const struct addr
 
     if (hostp) {
         arg->node = buf + hostp_offset;
-        strcpy(arg->node, hostp);
+        memcpy(arg->node, hostp, portp_offset - hostp_offset);
     }
     else {
         arg->node = NULL;
     }
 
     if (portp) {
         arg->service = buf + portp_offset;
-        strcpy(arg->service, portp);
+        memcpy(arg->service, portp, bufsize - portp_offset);
     }
     else {
         arg->service = NULL;

namespace.c

@@ -725,28 +725,31 @@ copy_ext_file(char *src_path, char *dst_path)
 #define IS_DLEXT(e) (strcmp((e), DLEXT) == 0)
 
 static void
-fname_without_suffix(char *fname, char *rvalue)
+fname_without_suffix(const char *fname, char *rvalue, size_t rsize)
 {
-    char *pos;
-    strcpy(rvalue, fname);
-    for (pos = rvalue + strlen(fname); pos > rvalue; pos--) {
+    size_t len = strlen(fname);
+    const char *pos;
+    for (pos = fname + len; pos > fname; pos--) {
         if (IS_SOEXT(pos) || IS_DLEXT(pos)) {
-            *pos = '\0';
-            return;
+            len = pos - fname;
+            break;
         }
     }
+    if (len > rsize - 1) len = rsize - 1;
+    memcpy(rvalue, fname, len);
+    rvalue[len] = '\0';
 }
 
 static void
-escaped_basename(char *path, char *fname, char *rvalue)
+escaped_basename(const char *path, const char *fname, char *rvalue, size_t rsize)
 {
-    char *pos, *leaf, *found;
-    leaf = path;
+    char *pos;
+    const char *leaf = path, *found;
     // `leaf + 1` looks uncomfortable (when leaf == path), but fname must not be the top-dir itself
     while ((found = strstr(leaf + 1, fname)) != NULL) {
         leaf = found; // find the last occurrence for the path like /etc/my-crazy-lib-dir/etc.so
     }
-    strcpy(rvalue, leaf);
+    strlcpy(rvalue, leaf, rsize);
     for (pos = rvalue; *pos; pos++) {
         if (isdirsep(*pos)) {
             *pos = '+';
@@ -762,8 +765,8 @@ rb_namespace_local_extension(VALUE namespace, VALUE fname, VALUE path)
     char *src_path = RSTRING_PTR(path), *fname_ptr = RSTRING_PTR(fname);
     rb_namespace_t *ns = rb_get_namespace_t(namespace);
 
-    fname_without_suffix(fname_ptr, fname2);
-    escaped_basename(src_path, fname2, basename);
+    fname_without_suffix(fname_ptr, fname2, sizeof(fname2));
+    escaped_basename(src_path, fname2, basename, sizeof(basename));
 
     wrote = sprint_ext_filename(ext_path, sizeof(ext_path), ns->ns_id, NAMESPACE_TMP_PREFIX, basename);
     if (wrote >= (int)sizeof(ext_path)) {