From 6bc1984355334968ed8930b2efcc9e05d2d58396 Mon Sep 17 00:00:00 2001
From: Rob Landley <rob@landley.net>
Date: Wed, 1 Oct 2025 15:58:40 -0500
Subject: [PATCH] Cleanup prompt logic.

---
 toys/pending/sh.c | 101 ++++++++++++++++------------------------------
 1 file changed, 35 insertions(+), 66 deletions(-)

diff --git a/toys/pending/sh.c b/toys/pending/sh.c
index 7563294c..137edd7c 100644
--- a/toys/pending/sh.c
+++ b/toys/pending/sh.c
@@ -3758,9 +3758,8 @@ static int wait_pipeline(struct sh_process *pp)
 // Truncated to 4k at the moment, waiting for somebody to complain.
 static void do_prompt(char *prompt)
 {
-  char *s, *ss, c, cc, *pp = toybuf;
+  char *s, *ss, *sss, c, cc, *pp = toybuf;
   int len, ll;
-  time_t t;
 
   if (!prompt) return;
   while ((len = sizeof(toybuf)-(pp-toybuf))>0 && *prompt) {
@@ -3783,76 +3782,46 @@ static void do_prompt(char *prompt)
       // Ignore bash's "nonprintable" hack; query our cursor position instead.
       if (cc=='[' || cc==']') continue;
       else if (cc=='$') *pp++ = getuid() ? '$' : '#';
-      else if (cc=='d'||cc=='D'||cc=='t'||cc=='T'||cc=='@'||cc=='A') {
-        t = time(NULL);
-        char *fmt = "%a %b %d";
-        if (cc=='D') {
-          char *end;
-          if (*prompt!='{') {
-            *pp++ = '\\';
-            *pp++ = 'D';
-            continue;
-          }
-          prompt++;
-          if (!(end = strchr(prompt, '}'))) {
-            *pp++ = '\\';
-            *pp++ = 'D';
-            continue;
-          }
-          if (prompt==end) {
-            const char ascfmt[] = "%X";
-            fmt = strncpy(xmalloc(sizeof(ascfmt)), ascfmt, sizeof(ascfmt));
-            prompt++;
-          } else {
-            fmt = strncpy(xmalloc(end-prompt), prompt, end-prompt);
-            fmt[end-prompt] = '\0';
+      else if (strchr("DdtT@A", cc)) {
+        char *end, *fmt = (char *[]){0, "%a %b %d", "%H:%M:%S", "%I:%M:%S",
+          "%I:%M %p", "%R"}[stridx("dtT@A", cc)];
+        time_t tt = time(0);
+
+        if (!fmt) {
+          // todo: slashcopy? Would allow escaped \} but can't handle missing }
+          if (*prompt!='{' || !(end = strchr(prompt+1, '}'))) *pp++ = cc;
+          else {
+            if (end==prompt+1) fmt = "%X";
+            else fmt = xstrndup(prompt, end-prompt);
             prompt = end+1;
           }
-        } else if (cc=='t') {
-          const char tfmt[] = "%H:%M:%S";
-          fmt = strncpy(xmalloc(sizeof(tfmt)), tfmt, sizeof(tfmt));
-        } else if (cc=='T') {
-          const char Tfmt[] = "%I:%M:%S";
-          fmt = strncpy(xmalloc(sizeof(Tfmt)), Tfmt, sizeof(Tfmt));
-        } else if (cc=='@') {
-          const char atfmt[] = "%I:%M %p";
-          fmt = strncpy(xmalloc(sizeof(atfmt)), atfmt, sizeof(atfmt));
-        } else if (cc=='A') {
-          const char Afmt[] = "%R";
-          fmt = strncpy(xmalloc(sizeof(Afmt)), Afmt, sizeof(Afmt));
         }
-        strftime(pp, len, fmt, localtime(&t));
-        pp += strlen(pp);
-        if (cc!='d') free(fmt);
+        pp += strftime(pp, len, fmt, localtime(&tt));
+        if (cc=='D') free(fmt);
       } else if (cc=='h' || cc=='H') {
-        *pp = 0;
-        gethostname(pp, len);
-        pp[len-1] = 0;
-        if (cc=='h' && (s = strchr(pp, '.'))) *s = 0;
-        pp += strlen(pp);
-      } else if (cc=='s') {
-        s = getbasename(*toys.argv);
-        while (*s && len--) *pp++ = *s++;
-      } else if (cc=='u') {
-        struct passwd *pw;
-        if ((pw = xgetpwuid(getuid()))) {
-          ll = strlen(pw->pw_name);
-          pp = stpncpy(pp, pw->pw_name, ll>len ? len : ll);
-        }
-      } else if (cc=='v'||cc=='V') {
-        ll = strlen(TOYBOX_VERSION);
-        pp = stpncpy(pp, TOYBOX_VERSION, ll>len ? len : ll);
-      } else if (cc=='w'||cc=='W') {
-        if ((s = getvar("PWD"))) {
+        if ((len = gethostname(pp, len)) && cc=='h' && (s = strchr(pp, '.')))
+          len = s-pp;
+      } else if (cc=='s')
+        for (s = getbasename(TT.argv0); *s && len--; *pp++ = *s++);
+      else if (cc=='u') {
+        struct passwd *pw = bufgetpwuid(ll = getuid());
+        char buf[16];
+
+        sprintf(buf, "%d", ll);
+        s = pw ? pw->pw_name : buf;
+        if (pw) pp += sprintf(pp, "%.*s", len-1, s);
+      } else if (cc=='v'||cc=='V')
+        pp += sprintf(pp, "%.*s", len-1, TOYBOX_VERSION);
+      else if (cc=='w'||cc=='W') {
+        if ((s = sss = getvar("PWD"))) {
           if ((ss = getvar("HOME")) && strstart(&s, ss)) {
-            *pp++ = '~';
-            if (--len && *s!='/') *pp++ = '/';
-            len--;
-          }
-          if (len>0) {
-            ll = strlen(s);
-            pp = stpncpy(pp, s, ll>len ? len : ll);
+            if (*s && *s!='/') s = sss;
+            else if (cc!='W' || !*s) {
+              *pp++ = '~';
+              if (--len && *s && *s!='/') *pp++ = '/', len--;
+            }
           }
+          if (len>0) pp += sprintf(pp, "%.*s", len-1, s);
         }
       } else if (!(c = unescape(cc))) {
         *pp++ = '\\';
-- 
2.39.5