random_get()

Fill a buffer with high-quality random data. This function may be slow and block.

Description

The random_get() function is used to fill a buffer with high-quality random data. It takes a pointer to a buffer and the number of bytes to be written as input. The function will generate random bytes and write them to the specified buffer.

Generating high-quality random data may be a slow operation and may block in certain cases, especially when the system's entropy pool is depleted. Therefore, this function should be used with caution in performance-sensitive scenarios.

Syntax

  ;;; number generator, rather than to provide the random data directly.
  ;;; required, it's advisable to use this function to seed a pseudo-random
  ;;; This function may execute slowly, so when large mounts of random data are
  ;;; provide sufficient high-quality random data.
  ;;; This function blocks when the implementation is unable to immediately
  ;;; Write high-quality random data into a buffer.
  (@interface func (export "random_get")
    ;;; The buffer to fill with random data.
    (param $buf (@witx pointer u8))
    (param $buf_len $size)
    (result $error (expected (error $errno)))
  )

Parameters

• ctx: The function environment.
• buf: A pointer to the buffer where the random bytes will be written.
• buf_len: The number of bytes to be written.

Return Value

The function returns an Errno value indicating the result of the operation. If the operation is successful and the random data is generated and written to the buffer, it returns Errno::Success. If there is an error generating the random data, it returns Errno::Io.

Logging

This function is instrumented with trace level logging. It includes the following field for debugging purposes:

• buf_len: The length of the buffer in bytes.

Note

• The random_get() function fills a buffer with high-quality random data.
• It uses the getrandom crate to generate the random data.
• The function creates a u8 buffer with the specified length and calls getrandom::getrandom() to generate random bytes.
• If the random data is generated successfully, it writes the data to the buffer specified by buf.
• The function returns Errno::Success if the operation is successful.
• If there is an error generating the random data, such as when the system's entropy pool is depleted, it returns Errno::Io.