LU-16392 utils: use --list-commands for bash completion

[fs/lustre-release.git] / libcfs / libcfs / util / parser.c

diff --git a/libcfs/libcfs/util/parser.c b/libcfs/libcfs/util/parser.c
index be97809..504cead 100644 (file)
--- a/libcfs/libcfs/util/parser.c
+++ b/libcfs/libcfs/util/parser.c
@@ -123,6 +123,17 @@ int Parser_execarg(int argc, char **argv, command_t cmds[])
                }
                return rc;
        }
+       /*
+        * handle --help here as a synonym of --list-commands so that it can be
+        * applied to all commands without needing to individually add a --help
+        * option to each command.
+        * This does not apply to lctl which has its own --help option because
+        * `lctl --list-commands` uses a unique format.
+        */
+       if (strcmp(argv[0], "--help") == 0) {
+               Parser_list_commands(cmds, 80, 4);
+               return 0;
+       }
        fprintf(stderr,
                "%s: '%s' is not a valid command. See '%s --list-commands'.\n",
                program_invocation_short_name, argv[0],
@@ -543,72 +554,49 @@ void Parser_printhelp(char *cmd)
 /**
  * Parser_list_commands() - Output a list of the supported commands.
  * @cmdlist:     Array of structures describing the commands.
- * @buffer:      String buffer used to temporarily store the output text.
- * @buf_size:    Length of the string buffer.
- * @parent_cmd:          When called recursively, contains the name of the parent cmd.
- * @col_start:   Column where printing should begin.
+ * @line_len:    Length of output line.
  * @col_num:     The number of commands printed in a single row.
  *
  * The commands and subcommands supported by the utility are printed, arranged
- * into several columns for readability.  If a command supports subcommands, the
- * function is called recursively, and the name of the parent command is
- * supplied so that it can be prepended to the names of the subcommands.
+ * into several columns for readability.
  *
  * Return: The number of items that were printed.
  */
-int Parser_list_commands(const command_t *cmdlist, char *buffer,
-                        size_t buf_size, const char *parent_cmd,
-                        int col_start, int col_num)
+int Parser_list_commands(const command_t *cmdlist, int line_len,
+                        int col_num)
 {
-       int col = col_start;
        int char_max;
-       int len;
        int count = 0;
-       int rc;
+       int col = 0;
 
-       if (col_start >= col_num)
-               return 0;
+       int nprinted = 0;
+       int offset = 0;
 
-       char_max = (buf_size - 1) / col_num; /* Reserve 1 char for NUL */
+       char_max = line_len / col_num;
 
        for (; cmdlist->pc_name; cmdlist++) {
                if (!cmdlist->pc_func && !cmdlist->pc_sub_cmd)
                        break;
                count++;
-               if (parent_cmd)
-                       len = snprintf(&buffer[col * char_max],
-                                      char_max + 1, "%s %s", parent_cmd,
-                                      cmdlist->pc_name);
-               else
-                       len = snprintf(&buffer[col * char_max],
-                                      char_max + 1, "%s", cmdlist->pc_name);
-
-               /* Add trailing spaces to pad the entry to the column size */
-               if (len < char_max) {
-                       snprintf(&buffer[col * char_max] + len,
-                                char_max - len + 1, "%*s", char_max - len,
-                                " ");
-               } else {
-                       buffer[(col + 1) * char_max - 1] = ' ';
-               }
+
+               nprinted = fprintf(stdout, "%-*s ", char_max - offset - 1,
+                                  cmdlist->pc_name);
+               /*
+                * when a column is too wide, save offset so subsequent columns
+                * can be aligned properly
+                */
+               offset = offset + nprinted - char_max;
+               offset = offset > 0 ? offset : 0;
 
                col++;
                if (col >= col_num) {
-                       fprintf(stdout, "%s\n", buffer);
+                       fprintf(stdout, "\n");
                        col = 0;
-                       buffer[0] = '\0';
-               }
-
-               if (cmdlist->pc_sub_cmd) {
-                       rc = Parser_list_commands(cmdlist->pc_sub_cmd, buffer,
-                                                 buf_size, cmdlist->pc_name,
-                                                 col, col_num);
-                       col = (col + rc) % col_num;
-                       count += rc;
+                       offset = 0;
                }
        }
-       if (!parent_cmd && col != 0)
-               fprintf(stdout, "%s\n", buffer);
+       if (col != 0)
+               fprintf(stdout, "\n");
        return count;
 }