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)
 56{
 57	unsigned int i, n = 0, best_similarity = 0;
 58	struct cmdnames main_cmds, other_cmds;
 59
 60	memset(&main_cmds, 0, sizeof(main_cmds));
 61	memset(&other_cmds, 0, sizeof(main_cmds));
 62
 63	perf_config(perf_unknown_cmd_config, NULL);
 64
 65	load_command_list("perf-", &main_cmds, &other_cmds);
 66
 67	if (add_cmd_list(&main_cmds, &other_cmds) < 0) {
 68		fprintf(stderr, "ERROR: Failed to allocate command list for unknown command.\n");
 69		goto end;
 70	}
 71	qsort(main_cmds.names, main_cmds.cnt,
 72	      sizeof(main_cmds.names), cmdname_compare);
 73	uniq(&main_cmds);
 74
 75	if (main_cmds.cnt) {
 76		/* This reuses cmdname->len for similarity index */
 77		for (i = 0; i < main_cmds.cnt; ++i)
 78			main_cmds.names[i]->len =
 79				levenshtein(cmd, main_cmds.names[i]->name, 0, 2, 1, 4);
 80
 81		qsort(main_cmds.names, main_cmds.cnt,
 82		      sizeof(*main_cmds.names), levenshtein_compare);
 83
 84		best_similarity = main_cmds.names[0]->len;
 85		n = 1;
 86		while (n < main_cmds.cnt && best_similarity == main_cmds.names[n]->len)
 87			++n;
 88	}
 89
 90	if (autocorrect && n == 1) {
 91		const char *assumed = main_cmds.names[0]->name;
 92
 93		main_cmds.names[0] = NULL;
 94		clean_cmdnames(&main_cmds);
 95		fprintf(stderr, "WARNING: You called a perf program named '%s', "
 96			"which does not exist.\n"
 97			"Continuing under the assumption that you meant '%s'\n",
 98			cmd, assumed);
 99		if (autocorrect > 0) {
100			fprintf(stderr, "in %0.1f seconds automatically...\n",
101				(float)autocorrect/10.0);
102			poll(NULL, 0, autocorrect * 100);
103		}
104		return assumed;
105	}
106
107	fprintf(stderr, "perf: '%s' is not a perf-command. See 'perf --help'.\n", cmd);
108
109	if (main_cmds.cnt && best_similarity < 6) {
110		fprintf(stderr, "\nDid you mean %s?\n",
111			n < 2 ? "this": "one of these");
112
113		for (i = 0; i < n; i++)
114			fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
115	}
116end:
117	exit(1);
118}