chunk: Use dynamically allocated buffer in chunk_from_fd()

When acting on files, we can use fstat() to estimate the buffer size. On
non-file FDs, we dynamically increase an allocated buffer.

Additionally we slightly change the function signature to properly handle
zero-length files and add appropriate unit tests.

1 files changed, 6 insertions, 1 deletions

diff --git a/src/pki/commands/req.c b/src/pki/commands/req.c
index 628463e7b..64609597d 100644
--- a/src/pki/commands/req.c
+++ b/src/pki/commands/req.c
@@ -16,6 +16,7 @@
  */
 
 #include <time.h>
+#include <errno.h>
 
 #include "pki.h"
 
@@ -118,7 +119,11 @@ static int req()
 	{
 		chunk_t chunk;
 
-		chunk = chunk_from_fd(0);
+		if (!chunk_from_fd(0, &chunk))
+		{
+			fprintf(stderr, "reading private key failed: %s\n", strerror(errno));
+			return 1;
+		}
 		private = lib->creds->create(lib->creds, CRED_PRIVATE_KEY, type,
 									 BUILD_BLOB, chunk, BUILD_END);
 		free(chunk.ptr);