Shuffle arguments around (TNAME->NAME->COMM->CMD), working around posix

constraints while still trying to get sane behavior. Discard the old CMD,
move COMM to CMD, move the old NAME to COMM, and move TNAME to NAME.

Posix assumes argv[] is the only source of process name data, but Linux has
three sources (/proc/$PID/cmdline, /proc/$PID/exe, /proc/$PID/stat field 2)
and android uses multiple sources simultaneously to identify its processes
and threads.

Toybox ps also assumes that the field names displayed in the headers
can be fed to -o to get that output, which is an assumption posix's
ps spec clearly does not have. Before we were erring on the side of posix,
now we're erring on the side of sanity.

CMD now shows stat[2], all the time. The posix -f behavior change is now
just an ARGS=CMD alias in the -f default command line, which -o overrides.
(Before -f changed the behavior of -o CMD, which is closer to what
posix says but is _insane_ and we've stopped doing it.)

COMM now shows /proc/$PID/exe minus the path. (I'm aware posix says argv[0]
here, but it says argv everywhere.)

NAME is now argv[0] of $PID.

TNAME went away.

Both $COMM and $NAME show the data for $PID, which is a thread's parent
process when $TID != $PID.

1 files changed, 13 insertions, 15 deletions

diff --git a/toys/posix/ps.c b/toys/posix/ps.c
index 74f8954a..8ac6eef7 100644
--- a/toys/posix/ps.c
+++ b/toys/posix/ps.c
@@ -83,7 +83,7 @@ config PS
 
     Which FIELDs to show. (Default = -o PID,TTY,TIME,CMD)
 
-    -f	Full listing (-o USER:8=UID,PID,PPID,C,STIME,TTY,TIME,CMD)
+    -f	Full listing (-o USER:8=UID,PID,PPID,C,STIME,TTY,TIME,ARGS=CMD)
     -l	Long listing (-o F,S,UID,PID,PPID,C,PRI,NI,ADDR,SZ,WCHAN,TTY,TIME,CMD)
     -o	Output FIELDs instead of defaults, each with optional :size and =title
     -O	Add FIELDS to defaults
@@ -91,10 +91,9 @@ config PS
 
     Command line -o fields:
 
-      ARGS     Command line (argv[] -path)    CMD    COMM, or ARGS with -f
-      CMDLINE  Command line (argv[])          COMM   Original command name (stat[2])
-      COMMAND  Command name (/proc/$PID/exe)  NAME   Command name (COMMAND -path)
-      TNAME    Thread name (argv[0] of $PID)
+      ARGS     CMDLINE minus initial path     CMD  Command name (stat2)
+      CMDLINE  Command line (argv[])          COMM Command filename (/proc/$PID/exe)
+      COMMAND  Command file (/proc/$PID/exe)  NAME Process name (argv[0] of $PID)
 
     Process attribute -o FIELDs:
 
@@ -346,9 +345,9 @@ struct typography {
   {"TID", 5, SLOT_tid}, {"TCNT", 4, SLOT_tcount}, {"BIT", 3, SLOT_bits},
 
   // String fields
-  {"TTY", -8, -2}, {"WCHAN", -6, -3}, {"LABEL", -30, -4}, {"COMM", -15, -1},
-  {"NAME", -15, -5}, {"TNAME", -27, -7}, {"COMMAND", -27, -5},
-  {"CMDLINE", -27, -6}, {"ARGS", -27, -6}, {"CMD", -27, -1},
+  {"TTY", -8, -2}, {"WCHAN", -6, -3}, {"LABEL", -30, -4}, {"COMM", -27, -5},
+  {"NAME", -27, -7}, {"COMMAND", -27, -5}, {"CMDLINE", -27, -6},
+  {"ARGS", -27, -6}, {"CMD", -15, -1},
 
   // user/group
   {"UID", 5, SLOT_uid}, {"USER", -8, 64|SLOT_uid}, {"RUID", 4, SLOT_ruid},
@@ -443,7 +442,7 @@ static char *string_field(struct carveup *tb, struct strawberry *field)
     sl *= -1;
     // First string slot has offset 0, others are offset[-slot-2]
     if (--sl) out += tb->offset[--sl];
-    if (which==PS_ARGS || which==PS_NAME) {
+    if (which==PS_ARGS || which==PS_COMM) {
       int i;
 
       s = out;
@@ -605,8 +604,8 @@ static int get_ps(struct dirtree *new)
   } fetch[] = {
     // sources for carveup->offset[] data
     {"fd/", _PS_TTY}, {"wchan", _PS_WCHAN}, {"attr/current", _PS_LABEL},
-    {"exe", _PS_COMMAND|_PS_NAME}, {"cmdline", _PS_CMDLINE|_PS_ARGS|_PS_TNAME},
-    {"", _PS_TNAME}
+    {"exe", _PS_COMMAND|_PS_COMM}, {"cmdline", _PS_CMDLINE|_PS_ARGS|_PS_NAME},
+    {"", _PS_NAME}
   };
   struct carveup *tb = (void *)toybuf;
   long long *slot = tb->slot;
@@ -1178,12 +1177,12 @@ void ps_main(void)
   // Figure out which fields to display
   not_o = "%sTTY,TIME,CMD";
   if (toys.optflags&FLAG_f)
-    sprintf(not_o = toybuf+128, "USER:8=UID,%%sPPID,%s,STIME,TTY,TIME,CMD",
+    sprintf(not_o = toybuf+128, "USER:8=UID,%%sPPID,%s,STIME,TTY,TIME,ARGS=CMD",
       (toys.optflags&FLAG_T) ? "TCNT" : "C");
   else if (toys.optflags&FLAG_l)
     not_o = "F,S,UID,%sPPID,C,PRI,NI,ADDR,SZ,WCHAN,TTY,TIME,CMD";
   else if (CFG_TOYBOX_ON_ANDROID)
-    not_o = "USER,%sPPID,VSIZE,RSS,WCHAN:10,ADDR:10=PC,S,TNAME";
+    not_o = "USER,%sPPID,VSIZE,RSS,WCHAN:10,ADDR:10=PC,S,NAME";
   sprintf(toybuf, not_o, (toys.optflags & FLAG_T) ? "PID,TID," : "PID,");
 
   // Init TT.fields. This only uses toybuf if TT.ps.o is NULL
@@ -1202,7 +1201,6 @@ void ps_main(void)
     struct strawberry *ever;
 
     for (ever = TT.fields; ever; ever = ever->next) {
-      if ((toys.optflags&FLAG_f) && ever->which==PS_CMD) ever->which = PS_ARGS;
       if ((toys.optflags&FLAG_n) && ever->which>=PS_UID
         && ever->which<=PS_RGROUP && (typos[ever->which].slot&64))
           ever->which--;
@@ -1216,7 +1214,7 @@ void ps_main(void)
   if (!(toys.optflags&(FLAG_k|FLAG_M))) TT.show_process = (void *)show_ps;
   TT.match_process = ps_match_process;
   dt = dirtree_read("/proc",
-    ((toys.optflags&FLAG_T) || (TT.bits&(_PS_TID|_PS_TCNT/*|_PS_TNAME*/)))
+    ((toys.optflags&FLAG_T) || (TT.bits&(_PS_TID|_PS_TCNT)))
       ? get_threads : get_ps);
 
   if (toys.optflags&(FLAG_k|FLAG_M)) {