@kloenk @navi Back when 128 kB was the limit for argv+envp, Google was hitting it too because they passed all the configuration for their whole software stack on the command line as --long-option=value switches.

Their solution? Compress the command line. So every binary started by ungzipping argv[1] and parsing it to get the configuration.

The person explaining this to me saw my horrified face, and said with the perfect Hide The Pain Harold smile: "a series of individually completely rational and reasonable decisions led to this." and I have been thinking a lot about it since.

@lanodan @navi I don't think that's necessarily a problem. argv[1] doesn't have to be a string, it's a character array. Null is used as a separator when the kernel puts the whole argv on the stack, yes, but argv[1] is still just a pointer and if you know you're expecting a blob and have a way to know where the blob ends, it should work, I think.

Or they could have been base64-encoding the gzip for all I know, it's probably still smaller than the uncompressed argv.

(Edit: typo)

@ska @lanodan @navi Nope, it's a string. execve will stop processing it at the first null byte.

execve syscall essentially acts as a scatter-gather (in this case gather) operation running over the argv and environ pointer arrays in user memory and performing a string-copy-from-user operation for each one to built the object that will be prepopulated into the new process-image.