nodejs: file io

README.adoc

@@ -13188,8 +13188,10 @@ ERROR: package host-nodejs installs executables without proper RPATH
 
 Examples:
 
-* process
+* `process`
 ** link:rootfs_overlay/lkmc/nodejs/command_line_arguments.js[]
+* `fs`
+** link:rootfs_overlay/lkmc/nodejs/file_write_read.js[]
 
 === Userland content bibliography
 

rootfs_overlay/lkmc/nodejs/command_line_arguments.js

@@ -1,5 +1,7 @@
 #!/usr/bin/env node
 
+// https://cirosantilli.com/linux-kernel-module-cheat#node-js
+
 for (const arg of process.argv) {
   console.log(arg);
 }

rootfs_overlay/lkmc/nodejs/file_write_read.js

@@ -0,0 +1,20 @@
+#!/usr/bin/env node
+
+// https://cirosantilli.com/linux-kernel-module-cheat#node-js
+
+const assert = require('assert');
+const fs = require('fs');
+const path = require('path');
+
+const file_path = path.basename(__filename) + '.tmp';
+const data = 'asdf\nqwer\n';
+const encoding = 'utf8';
+
+// Write to file.
+//
+// Error handling through exceptions:
+// https://stackoverflow.com/questions/15543235/checking-if-writefilesync-successfully-wrote-the-file
+fs.writeFileSync(file_path, data, encoding);
+
+// Read from file.
+assert.strictEqual(fs.readFileSync(file_path, encoding), data);

userland/c/file_write_read.c

@@ -108,10 +108,10 @@ int file_write(char *path, char *write_string) {
 
 int main(void) {
     char *path = LKMC_TMP_FILE;
-    char *input = "asdf\nqwer\n";
+    char *data = "asdf\nqwer\n";
 
     /* Write entire string to file at once. */
-    if (file_write(path, input) == -1) {
+    if (file_write(path, data) == -1) {
         LKMC_IO_ERROR("file_write", path);
     }
 
@@ -121,7 +121,7 @@ int main(void) {
         if (output == NULL) {
             LKMC_IO_ERROR("file_read", path);
         }
-        assert(strcmp(input, output) == 0);
+        assert(strcmp(data, output) == 0);
         free(output);
     }
 
@@ -131,7 +131,7 @@ int main(void) {
         if (size == -1) {
             LKMC_IO_ERROR("file_size", path);
         }
-        assert((size_t)size == strlen(input));
+        assert((size_t)size == strlen(data));
     }
 
     return EXIT_SUCCESS;