Clarify Fcntl PPROCADDDR and PLOADINFO modes

Thanks to Jo Even Skarstein for reporting.

Fixes #171.

gemdos/file/fcntl.ui

@@ -409,11 +409,13 @@ In the parameter (!I)arg(!i) a pointer to the address of the
 (!nolink [GEMDOS]) (!link [basepage] [BASEPAGE]) of the process opened as a file is returned. The
 command is supported in MagiC from Version 3.0 onwards.
 
-!label PPROCADDDR
-(!B)PPROCADDDR (0x5001):(!b)
+!label PPROCADDR
+(!B)PPROCADDR (0x5001):(!b)
 (!nl)
 In the parameter (!I)arg(!i) a pointer to the address of the PCB
-((!B)P(!b)rocess (!B)C(!b)ontrol (!B)B(!b)lock) is returned.
+((!B)P(!b)rocess (!B)C(!b)ontrol (!B)B(!b)lock) is returned. If memory protection is enabled, this
+memory cannot be read directly, use Fseek/Fread on the open process file. This is to prevent manipulation
+of process' rgid/ruid/egid/euid fields to e.g. become the root.
 
 !label PCTXTSIZE
 (!B)PCTXTSIZE (0x5003):(!b)
@@ -474,8 +476,12 @@ present.
 !label PLOADINFO
 (!B)PLOADINFO (0x500c):(!b)
 (!nl)
-This command returns in (!I)arg(!i) a pointer to the ploadinfo structure, in
-which the program name and command line are stored.
+(!I)arg(!i) is a pointer to the ploadinfo structure. (!I)fnamelen(!i) must contain
+the length of (!I)fname(!i) buffer in bytes and both (!I)cmdlin(!i) and (!I)fname(!i)
+must be preallocated (the former to at least 128 bytes and the latter to at least
+(!I)fnamelen(!i) bytes). Processes' command line will be copied into (!I)cmdlin(!i).
+The complete path and filename of the process' parent will be copied into (!I)fname(!i).
+If the buffer is too short the call will return EBADARG.
 
 !label PFSTAT
 (!B)PFSTAT (0x500d):(!b)
@@ -1128,8 +1134,8 @@ Im Parameter (!I)arg(!i) wird ein Zeiger auf die Adresse der (!link [Basepage] [
 als Datei ge”ffneten Prozesses zurckgegeben. Das Kommando wird in MagiC ab
 Version 3.0 untersttzt.
 
-!label PPROCADDDR
-(!B)PPROCADDDR (0x5001):(!b)
+!label PPROCADDR
+(!B)PPROCADDR (0x5001):(!b)
 (!nl)
 Im Parameter (!I)arg(!i) wird ein Zeiger auf die Adresse des PCB
 (Prozess-Control-Blocks) zurckgegeben.