ash: add support for command_not_found_handle hook function (bashism)

This implements support for the command_not_found_handle hook function, which is
useful for allowing package managers to suggest packages which could provide the
command.

Unlike bash, however, we ignore exit codes from the hook function and always return
the correct POSIX error code (EX_NOTFOUND).

function                                             old     new   delta
find_command                                         911     990     +79

Signed-off-by: William Pitcock <nenolod@dereferenced.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 23 insertions, 1 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 8211c766f..865159d20 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -51,6 +51,15 @@
 //config:       default y
 //config:       depends on ASH || SH_IS_ASH || BASH_IS_ASH
 //config:
+//config:config ASH_BASH_NOT_FOUND_HOOK
+//config:       bool "command_not_found_handle hook support"
+//config:       default y
+//config:       depends ASH_BASH_COMPAT
+//config:       help
+//config:       Enable support for the 'command_not_found_handle' hook function,
+//config:       from GNU bash, which allows for alternative command not found
+//config:       handling.
+//config:
 //config:config ASH_JOB_CONTROL
 //config:       bool "Job control"
 //config:       default y
@@ -13227,8 +13236,21 @@ find_command(char *name, struct cmdentry *entry, int act, const char *path)
         /* We failed.  If there was an entry for this command, delete it */
         if (cmdp && updatetbl)
                 delete_cmd_entry();
-        if (act & DO_ERR)
+        if (act & DO_ERR) {
+#if ENABLE_ASH_BASH_NOT_FOUND_HOOK
+                struct tblentry *hookp = cmdlookup("command_not_found_handle", 0);
+                if (hookp && hookp->cmdtype == CMDFUNCTION) {
+                        char *argv[3];
+                        argv[0] = (char*) "command_not_found_handle";
+                        argv[1] = name;
+                        argv[2] = NULL;
+                        evalfun(hookp->param.func, 2, argv, 0);
+                        entry->cmdtype = CMDUNKNOWN;
+                        return;
+                }
+#endif
                 ash_msg("%s: %s", name, errmsg(e, "not found"));
+        }
         entry->cmdtype = CMDUNKNOWN;
         return;