From 913ff471b4a46dc7e41d7c3e5db55165c02e2b2e Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 21 Aug 2022 16:08:23 +0100
Subject: [PATCH 1/1] prefork-interp: ident, options

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 cprogs/prefork-interp.c | 20 ++++++++++++++++++--
 cprogs/prefork.c        | 21 +++++++++++++++------
 cprogs/prefork.h        |  5 +++--
 3 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/cprogs/prefork-interp.c b/cprogs/prefork-interp.c
index 8fcb5dc..61dcca9 100644
--- a/cprogs/prefork-interp.c
+++ b/cprogs/prefork-interp.c
@@ -7,11 +7,27 @@
  *   prefork-interp  [<option>,..],<interpreter>   <script> [<args> ...]
  *   prefork-interp '[<option> ..] <interpreter>'  <script> [<args> ...]
  *
- * Options must specify argument laundering mode.
- * Currently the only mode supported is:
+ * Options must specify argument mediation approach.
+ * Currently the only argument mediation supported is:
+ *
  *   -U    unlaundered: setup and executor both get all arguments and env vars
  *         ident covers only env vars specified  with -E
  *         ident covers only arguments interpreter and (if present) script
+ *
+ * Options for setting the operation mode:
+ *
+ *   (none)     Default: start new server if needed, then run service
+ *   -f         Force a fresh service (old one is terminated)
+ *   --kill     Kill any existing service; do not actually run anything
+ *
+ * Options for controlling whether different invocations share a server:
+ *
+ *   -E VAR      ident includes env var VAR (or its absence)
+ *   -G STRING   ident includes string STRING
+ *   -g IDENT    use IDENT rather than hex(SHA256(... identity things ...))
+ *
+ * (Ordering of -E and -G options is relevant; invocations with different
+ * -E -G options are different even if the env var settings are the same)
  */
 
 /*
diff --git a/cprogs/prefork.c b/cprogs/prefork.c
index e25aadf..eca03c8 100644
--- a/cprogs/prefork.c
+++ b/cprogs/prefork.c
@@ -55,19 +55,28 @@ void of_iassign(const struct cmdinfo *ci, const char *val) {
   *ci->iassignto = v;
 }
 
-void ident_addstring(const struct cmdinfo *ci, const char *string) {
-  /* ci may be 0 and is provided so this can be .call */
+static void ident_addbyte(char c) {
+  IDENT_ADD_OBJ(c);
+}
+
+void ident_addstring(const char *string) {
   sha256_update(&identsc,strlen(string)+1,string);
 }
 
+void off_ident_addstring(const struct cmdinfo *ci, const char *string) {
+  ident_addbyte('S');
+  ident_addstring(string);
+}
+
 void off_ident_addenv(const struct cmdinfo *ci, const char *name) {
   const char *val = getenv(name);
+  ident_addbyte('E');
   if (val) {
     sha256_update(&identsc,strlen(name),name); /* no nul */
     sha256_update(&identsc,1,"=");
-    ident_addstring(0,val);
+    ident_addstring(val);
   } else {
-    ident_addstring(0,name);
+    ident_addstring(name);
   }
 }
 
@@ -152,9 +161,9 @@ void find_socket_path(void) {
     unsigned char bbuf[32];
     int i;
 
-    ident_addstring(0,interp);
+    ident_addstring(interp);
     if (script)
-      ident_addstring(0,script);
+      ident_addstring(script);
     sha256_digest(&identsc,sizeof(bbuf),bbuf);
 
     for (i=0; i<identlen; i += 2)
diff --git a/cprogs/prefork.h b/cprogs/prefork.h
index cfbd715..eef6b2c 100644
--- a/cprogs/prefork.h
+++ b/cprogs/prefork.h
@@ -51,7 +51,7 @@ extern const struct cmdinfo cmdinfos[];
 #define PREFORK_CMDINFOS \
   { "help",   0, .call=of_help                                         }, \
   { 0, 'g',   1,                    .sassignto= &ident                 }, \
-  { 0, 'G',   1, .call= ident_addstring                                }, \
+  { 0, 'G',   1, .call= off_ident_addstring                            }, \
   { 0, 'E',   1, .call= off_ident_addenv                               },
 
 void process_opts(const char *const **argv_io);
@@ -83,7 +83,8 @@ void fusagemessage(FILE *f);
 void usagemessage(void);
 void of_help(const struct cmdinfo *ci, const char *val);
 void of_iassign(const struct cmdinfo *ci, const char *val);
-void ident_addstring(const struct cmdinfo *ci, const char *string);
+void ident_addstring(const char *string);
+void off_ident_addstring(const struct cmdinfo *ci, const char *name);
 void off_ident_addenv(const struct cmdinfo *ci, const char *name);
 void ident_addinit(void);
 bool stabs_same_inode(struct stat *a, struct stat *b);
-- 
2.30.2