1// SPDX-License-Identifier: GPL-2.0
  2#include "cache.h"
  3#include "config.h"
  4#include <poll.h>
  5#include <stdio.h>
  6#include <stdlib.h>
  7#include <subcmd/help.h>
  8#include "../builtin.h"
  9#include "levenshtein.h"
 10#include <linux/zalloc.h>
 11
 12static int autocorrect;
 13
 14static int perf_unknown_cmd_config(const char *var, const char *value,
 15				   void *cb __maybe_unused)
 16{
 17	if (!strcmp(var, "help.autocorrect"))
 18		return perf_config_int(&autocorrect, var,value);
 19
 20	return 0;
 21}
 22
 23static int levenshtein_compare(const void *p1, const void *p2)
 24{
 25	const struct cmdname *const *c1 = p1, *const *c2 = p2;
 26	const char *s1 = (*c1)->name, *s2 = (*c2)->name;
 27	int l1 = (*c1)->len;
 28	int l2 = (*c2)->len;
 29	return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
 30}
 31
 32static int add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
 33{
 34	unsigned int i, nr = cmds->cnt + old->cnt;
 35	void *tmp;
 36
 37	if (nr > cmds->alloc) {
 38		/* Choose bigger one to alloc */
 39		if (alloc_nr(cmds->alloc) < nr)
 40			cmds->alloc = nr;
 41		else
 42			cmds->alloc = alloc_nr(cmds->alloc);
 43		tmp = realloc(cmds->names, cmds->alloc * sizeof(*cmds->names));
 44		if (!tmp)
 45			return -1;
 46		cmds->names = tmp;
 47	}
 48	for (i = 0; i < old->cnt; i++)
 49		cmds->names[cmds->cnt++] = old->names[i];
 50	zfree(&old->names);
 51	old->cnt = 0;
 52	return 0;
 53}
 54
 55const char *help_unknown_cmd(const char *cmd, struct cmdnames *main_cmds)
 56{
 57	unsigned int i, n = 0, best_similarity = 0;
 58	struct cmdnames other_cmds;
 59
 60	memset(&other_cmds, 0, sizeof(other_cmds));
 61
 62	perf_config(perf_unknown_cmd_config, NULL);
 63
 64	load_command_list("perf-", main_cmds, &other_cmds);
 65
 66	if (add_cmd_list(main_cmds, &other_cmds) < 0) {
 67		fprintf(stderr, "ERROR: Failed to allocate command list for unknown command.\n");
 68		goto end;
 69	}
 70	qsort(main_cmds->names, main_cmds->cnt,
 71	      sizeof(main_cmds->names), cmdname_compare);
 72	uniq(main_cmds);
 73
 74	if (main_cmds->cnt) {
 75		/* This reuses cmdname->len for similarity index */
 76		for (i = 0; i < main_cmds->cnt; ++i) {
 77			main_cmds->names[i]->len =
 78				levenshtein(cmd, main_cmds->names[i]->name,
 79					/*swap_penalty=*/0,
 80					/*substition_penality=*/2,
 81					/*insertion_penality=*/1,
 82					/*deletion_penalty=*/1);
 83		}
 84		qsort(main_cmds->names, main_cmds->cnt,
 85		      sizeof(*main_cmds->names), levenshtein_compare);
 86
 87		best_similarity = main_cmds->names[0]->len;
 88		n = 1;
 89		while (n < main_cmds->cnt && best_similarity == main_cmds->names[n]->len)
 90			++n;
 91	}
 92
 93	if (autocorrect && n == 1) {
 94		const char *assumed = main_cmds->names[0]->name;
 95
 96		main_cmds->names[0] = NULL;
 97		clean_cmdnames(&other_cmds);
 98		fprintf(stderr, "WARNING: You called a perf program named '%s', "
 99			"which does not exist.\n"
100			"Continuing under the assumption that you meant '%s'\n",
101			cmd, assumed);
102		if (autocorrect > 0) {
103			fprintf(stderr, "in %0.1f seconds automatically...\n",
104				(float)autocorrect/10.0);
105			poll(NULL, 0, autocorrect * 100);
106		}
107		return assumed;
108	}
109
110	fprintf(stderr, "perf: '%s' is not a perf-command. See 'perf --help'.\n", cmd);
111
112	if (main_cmds->cnt && best_similarity < 6) {
113		fprintf(stderr, "\nDid you mean %s?\n",
114			n < 2 ? "this": "one of these");
115
116		for (i = 0; i < n; i++)
117			fprintf(stderr, "\t%s\n", main_cmds->names[i]->name);
118	}
119end:
120	clean_cmdnames(&other_cmds);
121	return NULL;
122}