examples: Add simple way to generate key files from libssh

Signed-off-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>

examples/CMakeLists.txt

@@ -70,6 +70,10 @@ add_executable(senddata senddata.c ${examples_SRCS})
 target_compile_options(senddata PRIVATE ${DEFAULT_C_COMPILE_FLAGS})
 target_link_libraries(senddata ${LIBSSH_SHARED_LIBRARY})
 
+add_executable(keygen keygen.c)
+target_compile_options(keygen PRIVATE ${DEFAULT_C_COMPILE_FLAGS})
+target_link_libraries(keygen ${LIBSSH_SHARED_LIBRARY})
+
 add_executable(libsshpp libsshpp.cpp)
 target_link_libraries(libsshpp ${LIBSSH_SHARED_LIBRARY})
 

examples/keygen.c

@@ -0,0 +1,41 @@
+/* keygen.c
+ * Sample implementation of ssh-keygen using libssh
+ */
+
+/*
+Copyright 2019 Red Hat, Inc.
+
+Author: Jakub Jelen <jjelen@redhat.com>
+
+This file is part of the SSH Library
+
+You are free to copy this file, modify it in any way, consider it being public
+domain. This does not apply to the rest of the library though, but it is
+allowed to cut-and-paste working code from this file to any license of
+program.
+ */
+
+#include <libssh/libssh.h>
+#include <stdio.h>
+
+int main(void)
+{
+    ssh_key key = NULL;
+    int rv;
+
+    /* Generate a new ED25519 private key file */
+    rv = ssh_pki_generate(SSH_KEYTYPE_ED25519, 0, &key);
+    if (rv != SSH_OK) {
+        fprintf(stderr, "Failed to generate private key");
+	return -1;
+    }
+
+    /* Write it to a file testkey in the current dirrectory */
+    rv = ssh_pki_export_privkey_file(key, NULL, NULL, NULL, "testkey");
+    if (rv != SSH_OK) {
+        fprintf(stderr, "Failed to write private key file");
+	return -1;
+    }
+
+    return 0;
+}