Como decía en mi anterior entrada, últimamente, he estado leyendo bastante documentación sobre el OS X proporcionada por Apple. Alguna me ha interesado especialmente. Así que, para no olvidarla, la incluiré aquí (una pura copia más… disculpas).
Execution Contexts
“If you’re familiar with traditional BSD programming, you will be familiar with the user IDs (UIDs) associated with a process (commonly referred to as the process’s owner). On a traditional BSD system, these UIDs control the capabilities of that process. You can, more or less, assume that two processes with matching UIDs have the same capabilities.
This is not true on Mac OS X. There are other elements of the process’s context that significantly alter its capabilities. So, for example, a daemon whose UIDs are set to that of the logged in console user is not equivalent to an application that has been launched by that user.
The following sections describe the elements of process’s context, and how they affect background programs.
UIDs
A process’s UIDs (its effective (EUID), real (RUID), and save (SUID) UIDs) are the most well known elements of the process’s context. These UIDs control various capabilities of the process, mostly centered on the BSD portions of the system (file system, networking, BSD process control). For example, a process’s ability to open a file is controlled by its EUID, and its ability to signal another process is controlled by its EUID and the EUID and RUID of the target.”
Más Información (Info de Apple salvo que se indique lo contrario)
security-overview-permissions-uids-acls.pdf
