Add the force_command option to the pipe transport

Normally when a router redirects an address directly to a pipe command
the command option on the transport is ignored.  If force_command
is set, the command option will expanded and used. This is especially
useful for forcing a wrapper or additional argument to be added to the
command.

4 files changed, 140 insertions, 8 deletions

diff --git a/src/src/structs.h b/src/src/structs.h
index d11e91adb..1105bb718 100644
--- a/src/src/structs.h
+++ b/src/src/structs.h
@@ -482,6 +482,7 @@ typedef struct address_item_propagated {
 #define af_cert_verified       0x01000000 /* delivered with verified TLS cert */
 #define af_pass_message        0x02000000 /* pass message in bounces */
 #define af_bad_reply           0x04000000 /* filter could not generate autoreply */
+#define af_force_command       0x08000000 /* force command */
 
 #ifdef EXPERIMENTAL_PRDR
 # define af_prdr_used          0x08000000 /* delivery used SMTP PRDR */
diff --git a/src/src/transport.c b/src/src/transport.c
index 160d080b9..a112820fd 100644
--- a/src/src/transport.c
+++ b/src/src/transport.c
@@ -1997,8 +1997,124 @@ if (expand_arguments)
         memmove(argv + i + 1 + additional, argv + i + 1,
           (argcount - i)*sizeof(uschar *));
 
-      for (ad = addr; ad != NULL; ad = ad->next) argv[i++] = ad->address;
-      i--;
+      for (ad = addr; ad != NULL; ad = ad->next) {
+          argv[i++] = ad->address;
+          argcount++;
+      }
+
+        /* Subtract one since we replace $pipe_addresses */
+        argcount--;
+        i--;
+
+      }
+
+      /* Handle special case of $address_pipe when af_force_command is set */
+
+    else if (addr != NULL && testflag(addr,af_force_command) &&
+        (Ustrcmp(argv[i], "$address_pipe") == 0 ||
+         Ustrcmp(argv[i], "${address_pipe}") == 0))
+      {
+      int address_pipe_i;
+      int address_pipe_argcount = 0;
+      int address_pipe_max_args;
+      uschar **address_pipe_argv;
+
+      /* We can never have more then the argv we will be loading into */
+      address_pipe_max_args = max_args - argcount + 1;
+
+      DEBUG(D_transport)
+        debug_printf("address_pipe_max_args=%d\n",
+          address_pipe_max_args);
+
+      /* We allocate an additional for (uschar *)0 */
+      address_pipe_argv = store_get((address_pipe_max_args+1)*sizeof(uschar *));
+
+      /* +1 because addr->local_part[0] == '|' since af_force_command is set */
+      s = expand_string(addr->local_part + 1);
+
+      if (s == NULL || *s == '\0') {
+       addr->transport_return = FAIL;
+       addr->message = string_sprintf("Expansion of \"%s\" "
+          "from command \"%s\" in %s failed: %s",
+          (addr->local_part + 1), cmd, etext, expand_string_message);
+        return FALSE;
+      }
+
+      while (isspace(*s)) s++; /* strip leading space */
+
+      while (*s != 0 && address_pipe_argcount < address_pipe_max_args)
+        {
+        if (*s == '\'')
+          {
+          ss = s + 1;
+          while (*ss != 0 && *ss != '\'') ss++;
+          address_pipe_argv[address_pipe_argcount++] = ss = store_get(ss - s++);
+          while (*s != 0 && *s != '\'') *ss++ = *s++;
+          if (*s != 0) s++;
+          *ss++ = 0;
+          }
+        else address_pipe_argv[address_pipe_argcount++] = string_dequote(&s);
+        while (isspace(*s)) s++; /* strip space after arg */
+        }
+
+      address_pipe_argv[address_pipe_argcount] = (uschar *)0;
+
+      /* If *s != 0 we have run out of argument slots. */
+      if (*s != 0)
+        {
+        uschar *msg = string_sprintf("Too many arguments in $address_pipe "
+          "\"%s\" in %s", addr->local_part + 1, etext);
+        if (addr != NULL)
+          {
+          addr->transport_return = FAIL;
+          addr->message = msg;
+          }
+        else *errptr = msg;
+        return FALSE;
+        }
+
+        /* address_pipe_argcount - 1
+         * because we are replacing $address_pipe in the argument list
+         * with the first thing it expands to */
+      if (argcount + address_pipe_argcount - 1 > max_args)
+        {
+        addr->transport_return = FAIL;
+        addr->message = string_sprintf("Too many arguments to command "
+          "\"%s\" after expanding $address_pipe in %s", cmd, etext);
+        return FALSE;
+        }
+
+      /* If we are not just able to replace the slot that contained
+       * $address_pipe (address_pipe_argcount == 1)
+       * We have to move the existing argv by address_pipe_argcount
+       * Visually if address_pipe_argcount == 2:
+       * [argv 0][argv 1][argv 2($address_pipe)][argv 3][0]
+       * [argv 0][argv 1][XXXXXX][XXXXXX][old argv 3][0]
+       */
+      if (address_pipe_argcount > 1)
+        memmove(
+          /* current position + additonal args */
+          argv + i + address_pipe_argcount,
+          /* current position + 1 (for the (uschar *)0 at the end) */
+          argv + i + 1,
+          /* -1 for the (uschar *)0 at the end)*/
+          (argcount - i)*sizeof(uschar *)
+        );
+
+      /* Now we fill in the slots we just moved argv out of
+       * [argv 0][argv 1][argv 2=pipeargv[0]][argv 3=pipeargv[1]][old argv 3][0]
+       */
+       for (address_pipe_i = 0;
+            address_pipe_argv[address_pipe_i] != (uschar *)0;
+            address_pipe_i++) {
+         argv[i++] = address_pipe_argv[address_pipe_i];
+         argcount++;
+        }
+
+        /* Subtract one since we replace $address_pipe */
+        argcount--;
+        i--;
+
       }
 
     /* Handle normal expansion string */
diff --git a/src/src/transports/pipe.c b/src/src/transports/pipe.c
index fe94e8575..39a9d8b47 100644
--- a/src/src/transports/pipe.c
+++ b/src/src/transports/pipe.c
@@ -37,6 +37,8 @@ optionlist pipe_transport_options[] = {
       (void *)offsetof(pipe_transport_options_block, environment) },
   { "escape_string",     opt_stringptr,
       (void *)offsetof(pipe_transport_options_block, escape_string) },
+  { "force_command",         opt_bool,
+      (void *)offsetof(pipe_transport_options_block, force_command) },
   { "freeze_exec_fail",  opt_bool,
       (void *)offsetof(pipe_transport_options_block, freeze_exec_fail) },
   { "freeze_signal",     opt_bool,
@@ -110,6 +112,7 @@ pipe_transport_options_block pipe_transport_option_defaults = {
   20480,          /* max_output */
   60*60,          /* timeout */
   0,              /* options */
+  FALSE,          /* force_command */
   FALSE,          /* freeze_exec_fail */
   FALSE,          /* freeze_signal */
   FALSE,          /* ignore_status */
@@ -569,10 +572,18 @@ options. */
 
 if (testflag(addr, af_pfr) && addr->local_part[0] == '|')
   {
-  cmd = addr->local_part + 1;
-  while (isspace(*cmd)) cmd++;
-  expand_arguments = testflag(addr, af_expand_pipe);
-  expand_fail = FAIL;
+    if (ob->force_command) {
+     /* Enables expansion of $address_pipe into seperate arguments */
+     setflag(addr,af_force_command);
+     cmd = ob->cmd;
+     expand_arguments = TRUE;
+     expand_fail = PANIC;
+    } else {
+     cmd = addr->local_part + 1;
+     while (isspace(*cmd)) cmd++;
+     expand_arguments = testflag(addr, af_expand_pipe);
+     expand_fail = FAIL;
+    }
   }
 else
   {
@@ -581,9 +592,12 @@ else
   expand_fail = PANIC;
   }
 
-/* If no command has been supplied, we are in trouble. */
+/* If no command has been supplied, we are in trouble.
+ * We also check for an empty string since it may be
+ * coming from addr->local_part[0] == '|'
+ */
 
-if (cmd == NULL)
+if (cmd == NULL || *cmd == '\0')
   {
   addr->transport_return = DEFER;
   addr->message = string_sprintf("no command specified for %s transport",
diff --git a/src/src/transports/pipe.h b/src/src/transports/pipe.h
index 343628e20..e10117458 100644
--- a/src/src/transports/pipe.h
+++ b/src/src/transports/pipe.h
@@ -21,6 +21,7 @@ typedef struct {
   int   max_output;
   int   timeout;
   int   options;
+  BOOL  force_command;
   BOOL  freeze_exec_fail;
   BOOL  freeze_signal;
   BOOL  ignore_status;