Re: [PATCH qemu-server v2 3/3] agent: file-read: Allow specifying byte offset to start reading at

[Fiona Ebner <f.ebner@proxmox.com>]

Am 25.02.26 um 1:06 PM schrieb Markus Ebner:
> The previous implementation only allowed reads of fixed size starting
> at byte offset 0. This made the Proxmox's agent/file-read unsuitable
> for reading large files.
> The new offset parameter allows specifying a byte offset position
> relative to the start of the file (offset 0) from which the following
> read should be performed. The implementation's behavior follows the
> lseek semantics - directly following qemu-guest-agent's behavior:
> 
> - fseek() does not perform validation against the file size
> - Seeking beyond the end of the file is not an error but explicitly
>   allowed and specified behavior
> - Subsequent fread() calls at positions beyond the file size return
>   zero bytes
> 
> Additionally, this is equivalent to the behavior of POSIX pread().
> Reading a large file block-by-block thus becomes (pseudo-code):
> let content = [];
> while(response.truncated) {
>     response = proxmox.agent_file_read(offset = content.length);
>     content .= response.content;
> }
> 
> To be backwards compatible, offset defaults to 0.
> 
> Signed-off-by: Markus Ebner <info@ebner-markus.de>

Reviewed-by: Fiona Ebner <f.ebner@proxmox.com>