MFC r269743:

Update the comments in exec.h with help from jilles.
This commit is contained in:
wblock 2014-08-26 19:58:48 +00:00
parent 05de13180a
commit a1bd433341

View File

@ -39,12 +39,17 @@
#define _SYS_EXEC_H_
/*
* The following structure is found at the top of the user stack of each
* user process. The ps program uses it to locate argv and environment
* strings. Programs that wish ps to display other information may modify
* it; normally ps_argvstr points to the argv vector, and ps_nargvstr
* is the same as the program's argc. The fields ps_envstr and ps_nenvstr
* are the equivalent for the environment.
* Before ps_args existed, the following structure, found at the top of
* the user stack of each user process, was used by ps(1) to locate
* environment and argv strings. Normally ps_argvstr points to the
* argv vector, and ps_nargvstr is the same as the program's argc. The
* fields ps_envstr and ps_nenvstr are the equivalent for the environment.
*
* Programs should now use setproctitle(3) to change ps output.
* setproctitle() always informs the kernel with sysctl and sets the
* pointers in ps_strings. The kern.proc.args sysctl first tries p_args.
* If p_args is NULL, it then falls back to reading ps_strings and following
* the pointers.
*/
struct ps_strings {
char **ps_argvstr; /* first of 0 or more argument strings */
@ -55,6 +60,7 @@ struct ps_strings {
/*
* Address of ps_strings structure (in user space).
* Prefer the kern.ps_strings or kern.proc.ps_strings sysctls to this constant.
*/
#define PS_STRINGS (USRSTACK - sizeof(struct ps_strings))
#define SPARE_USRSPACE 4096