telnet: auto-completion of "registered" commands
authorTarek BOCHKATI <tarek.bouchkati@gmail.com>
Thu, 11 Mar 2021 02:38:54 +0000 (03:38 +0100)
committerAntonio Borneo <borneo.antonio@gmail.com>
Sat, 1 May 2021 12:53:57 +0000 (13:53 +0100)
auto-completion behavior:
- if there is only one matched command complete the user-command
- else if multiple matches add the common part then in second step
  list all matched commands
- sub-commands are handled in the same way
- auto-completion restarts after these characters ';', '[', '{'

Change-Id: I1b81dd19191a5785e68d0bb5cd244e01a4dd0587
Signed-off-by: Tarek BOCHKATI <tarek.bouchkati@gmail.com>
Reviewed-on: http://openocd.zylin.com/6095
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
src/server/telnet_server.c

index e9de4f033b30d93354089d55a19d0d9bf58be40b..d5e0353c884b754e119bb0e71aecac40becde25a 100644 (file)
@@ -29,6 +29,7 @@
 #include "telnet_server.h"
 #include <target/target_request.h>
 #include <helper/configuration.h>
+#include <helper/list.h>
 
 static char *telnet_port;
 
@@ -58,6 +59,13 @@ static int telnet_write(struct connection *connection, const void *data,
        return ERROR_SERVER_REMOTE_CLOSED;
 }
 
+/* output an audible bell */
+static int telnet_bell(struct connection *connection)
+{
+       /* ("\a" does not work, at least on windows) */
+       return telnet_write(connection, "\x07", 1);
+}
+
 static int telnet_prompt(struct connection *connection)
 {
        struct telnet_connection *t_con = connection->priv;
@@ -366,6 +374,217 @@ static void telnet_move_cursor(struct connection *connection, size_t pos)
        tc->line_cursor = pos;
 }
 
+/* check buffer size leaving one spare character for string null termination */
+static inline bool telnet_can_insert(struct connection *connection, size_t len)
+{
+       struct telnet_connection *t_con = connection->priv;
+
+       return t_con->line_size + len < TELNET_LINE_MAX_SIZE;
+}
+
+/* write to telnet console, and update the telnet_connection members
+ * this function is capable of inserting in the middle of a line
+ * please ensure that data does not contain special characters (\n, \r, \t, \b ...)
+ *
+ * returns false when it fails to insert the requested data
+ */
+static bool telnet_insert(struct connection *connection, const void *data, size_t len)
+{
+       struct telnet_connection *t_con = connection->priv;
+
+       if (!telnet_can_insert(connection, len)) {
+               telnet_bell(connection);
+               return false;
+       }
+
+       if (t_con->line_cursor < t_con->line_size) {
+               /* we have some content after the cursor */
+               memmove(t_con->line + t_con->line_cursor + len,
+                               t_con->line + t_con->line_cursor,
+                               t_con->line_size - t_con->line_cursor);
+       }
+
+       strncpy(t_con->line + t_con->line_cursor, data, len);
+
+       telnet_write(connection,
+                       t_con->line + t_con->line_cursor,
+                       t_con->line_size + len - t_con->line_cursor);
+
+       t_con->line_size += len;
+       t_con->line_cursor += len;
+
+       for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+               telnet_write(connection, "\b", 1);
+
+       return true;
+}
+
+static void telnet_auto_complete(struct connection *connection)
+{
+       struct telnet_connection *t_con = connection->priv;
+       struct command_context *command_context = connection->cmd_ctx;
+
+       struct cmd_match {
+               char *cmd;
+               struct list_head lh;
+       };
+
+       LIST_HEAD(matches);
+
+       /* user command sequence, either at line beginning
+        * or we start over after these characters ';', '[', '{' */
+       size_t seq_start = (t_con->line_cursor == 0) ? 0 : (t_con->line_cursor - 1);
+       while (seq_start > 0) {
+               char c = t_con->line[seq_start];
+               if (c == ';' || c == '[' || c == '{') {
+                       seq_start++;
+                       break;
+               }
+
+               seq_start--;
+       }
+
+       /* user command position in the line, ignore leading spaces */
+       size_t usr_cmd_pos = seq_start;
+       while ((usr_cmd_pos < t_con->line_cursor) && isspace(t_con->line[usr_cmd_pos]))
+               usr_cmd_pos++;
+
+       /* user command length */
+       size_t usr_cmd_len = t_con->line_cursor - usr_cmd_pos;
+
+       /* optimize multiple spaces in the user command,
+        * because info commands does not tolerate multiple spaces */
+       size_t optimized_spaces = 0;
+       char query[usr_cmd_len + 1];
+       for (size_t i = 0; i < usr_cmd_len; i++) {
+               if ((i < usr_cmd_len - 1) && isspace(t_con->line[usr_cmd_pos + i])
+                               && isspace(t_con->line[usr_cmd_pos + i + 1])) {
+                       optimized_spaces++;
+                       continue;
+               }
+
+               query[i - optimized_spaces] = t_con->line[usr_cmd_pos + i];
+       }
+
+       usr_cmd_len -= optimized_spaces;
+       query[usr_cmd_len] = '\0';
+
+       /* filter commands */
+       char *query_cmd = alloc_printf("lsort [info commands {%s*}]", query);
+
+       if (!query_cmd) {
+               LOG_ERROR("Out of memory");
+               return;
+       }
+
+       int retval = Jim_EvalSource(command_context->interp, __FILE__, __LINE__, query_cmd);
+       free(query_cmd);
+       if (retval != JIM_OK)
+               return;
+
+       Jim_Obj *list = Jim_GetResult(command_context->interp);
+       Jim_IncrRefCount(list);
+
+       /* common prefix length of the matched commands */
+       size_t common_len = 0;
+       char *first_match = NULL; /* used to compute the common prefix length */
+
+       int len = Jim_ListLength(command_context->interp, list);
+       for (int i = 0; i < len; i++) {
+               Jim_Obj *elem = Jim_ListGetIndex(command_context->interp, list, i);
+               Jim_IncrRefCount(elem);
+
+               char *name = (char *)Jim_GetString(elem, NULL);
+
+               /* validate the command */
+               bool ignore_cmd = false;
+               Jim_Cmd *jim_cmd = Jim_GetCommand(command_context->interp, elem, JIM_NONE);
+
+               if (!jim_cmd)
+                       ignore_cmd = true;
+               else {
+                       if (!jim_cmd->isproc) {
+                               /* ignore commands without handler
+                                * and those with COMMAND_CONFIG mode */
+                               /* FIXME it's better to use jimcmd_is_ocd_command(jim_cmd)
+                                * or command_find_from_name(command_context->interp, name) */
+                               struct command *cmd = jim_cmd->u.native.privData;
+                               if (!cmd)
+                                       ignore_cmd = true;
+                               /* make Valgrind happy by checking that cmd is not NULL  */
+                               else if (cmd != NULL && !cmd->handler && !cmd->jim_handler)
+                                       ignore_cmd = true;
+                               else if (cmd != NULL && cmd->mode == COMMAND_CONFIG)
+                                       ignore_cmd = true;
+                       }
+               }
+
+               /* save the command in the prediction list */
+               if (!ignore_cmd) {
+                       struct cmd_match *match = calloc(1, sizeof(struct cmd_match));
+                       if (!match) {
+                               LOG_ERROR("Out of memory");
+                               Jim_DecrRefCount(command_context->interp, elem);
+                               break; /* break the for loop */
+                       }
+
+                       if (list_empty(&matches)) {
+                               common_len = strlen(name);
+                               first_match = name;
+                       } else {
+                               size_t new_common_len = usr_cmd_len; /* save some loops */
+
+                               while (new_common_len < common_len && first_match[new_common_len] == name[new_common_len])
+                                       new_common_len++;
+
+                               common_len = new_common_len;
+                       }
+
+                       match->cmd = name;
+                       list_add_tail(&match->lh, &matches);
+               }
+
+               Jim_DecrRefCount(command_context->interp, elem);
+       }
+       /* end of command filtering */
+
+       /* proceed with auto-completion */
+       if (list_empty(&matches))
+               telnet_bell(connection);
+       else if (common_len == usr_cmd_len && list_is_singular(&matches) && t_con->line_cursor == t_con->line_size)
+               telnet_insert(connection, " ", 1);
+       else if (common_len > usr_cmd_len) {
+               int completion_size = common_len - usr_cmd_len;
+               if (telnet_insert(connection, first_match + usr_cmd_len, completion_size)) {
+                       /* in bash this extra space is only added when the cursor in at the end of line */
+                       if (list_is_singular(&matches) && t_con->line_cursor == t_con->line_size)
+                               telnet_insert(connection, " ", 1);
+               }
+       } else if (!list_is_singular(&matches)) {
+               telnet_write(connection, "\n\r", 2);
+
+               struct cmd_match *match;
+               list_for_each_entry(match, &matches, lh) {
+                       telnet_write(connection, match->cmd, strlen(match->cmd));
+                       telnet_write(connection, "\n\r", 2);
+               }
+
+               telnet_prompt(connection);
+               telnet_write(connection, t_con->line, t_con->line_size);
+
+               /* restore the terminal visible cursor location */
+               for (size_t i = t_con->line_cursor; i < t_con->line_size; i++)
+                       telnet_write(connection, "\b", 1);
+       }
+
+       /* destroy the command_list */
+       struct cmd_match *tmp, *match;
+       list_for_each_entry_safe(match, tmp, &matches, lh)
+               free(match);
+
+       Jim_DecrRefCount(command_context->interp, list);
+}
+
 static int telnet_input(struct connection *connection)
 {
        int bytes_read;
@@ -391,30 +610,7 @@ static int telnet_input(struct connection *connection)
                                        t_con->state = TELNET_STATE_IAC;
                                else {
                                        if (isprint(*buf_p)) {  /* printable character */
-                                               /* watch buffer size leaving one spare character for
-                                                * string null termination */
-                                               if (t_con->line_size == TELNET_LINE_MAX_SIZE-1) {
-                                                       /* output audible bell if buffer is full
-                                                        * "\a" does not work, at least on windows */
-                                                       telnet_write(connection, "\x07", 1);
-                                               } else if (t_con->line_cursor == t_con->line_size) {
-                                                       telnet_write(connection, buf_p, 1);
-                                                       t_con->line[t_con->line_size++] = *buf_p;
-                                                       t_con->line_cursor++;
-                                               } else {
-                                                       size_t i;
-                                                       memmove(t_con->line + t_con->line_cursor + 1,
-                                                                       t_con->line + t_con->line_cursor,
-                                                                       t_con->line_size - t_con->line_cursor);
-                                                       t_con->line[t_con->line_cursor] = *buf_p;
-                                                       t_con->line_size++;
-                                                       telnet_write(connection,
-                                                                       t_con->line + t_con->line_cursor,
-                                                                       t_con->line_size - t_con->line_cursor);
-                                                       t_con->line_cursor++;
-                                                       for (i = t_con->line_cursor; i < t_con->line_size; i++)
-                                                               telnet_write(connection, "\b", 1);
-                                               }
+                                               telnet_insert(connection, buf_p, 1);
                                        } else {        /* non-printable */
                                                if (*buf_p == 0x1b) {   /* escape */
                                                        t_con->state = TELNET_STATE_ESCAPE;
@@ -548,7 +744,9 @@ static int telnet_input(struct connection *connection)
                                                                t_con->line[t_con->line_cursor] = '\0';
                                                                t_con->line_size = t_con->line_cursor;
                                                        }
-                                               } else
+                                               } else if (*buf_p == '\t')
+                                                       telnet_auto_complete(connection);
+                                               else
                                                        LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
                                        }
                                }