Bug#844038: ocamlnet: FTBFS on hurd-i386: PATH_MAX

[Samuel Thibault <sthibault@debian.org>]

Hello,

Agreed, here is a fixed patch.

Samuel

--- ./src/netsys/netsys_c.c.original	2016-11-20 18:55:38.789583992 +0100
+++ ./src/netsys/netsys_c.c	2016-11-20 19:00:46.708028548 +0100
@@ -607,12 +607,34 @@
 CAMLprim value netsys_readlinkat(value dirfd, value path)
 {
 #ifdef HAVE_AT
-  char buffer[PATH_MAX];
-  int len;
-  len = readlinkat(Int_val(dirfd), String_val(path), buffer, sizeof(buffer)-1);
-  if (len == -1) uerror("readlinkat", path);
+  char *buffer;
+  int buflen, len;
+  struct stat sb;
+  value ret;
+  if (fstatat(Int_val(dirfd), String_val(path), &sb, AT_SYMLINK_NOFOLLOW) != -1) {
+    if (!S_ISLNK(sb.st_mode))
+      unix_error(EINVAL, "readlinkat", path);
+    buflen = sb.st_size + 1;
+  }
+  else {
+    buflen = 64;
+  }
+  while (1) {
+    buffer = malloc(buflen);
+    len = readlinkat(Int_val(dirfd), String_val(path), buffer, buflen);
+    if (len == -1) {
+      free(buffer);
+      uerror("readlinkat", path);
+    }
+    if (len < buflen)
+      break;
+    free(buffer);
+    buflen *= 2;
+  }
   buffer[len] = '\0';
-  return copy_string(buffer);
+  ret = copy_string(buffer);
+  free(buffer);
+  return ret;
 #else
     invalid_argument("Netsys_posix.readlinkat not available");
 #endif