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		clean_cmdnames(&other_cmds);
96		fprintf(stderr, "WARNING: You called a perf program named '%s', "
97			"which does not exist.\n"
98			"Continuing under the assumption that you meant '%s'\n",
99			cmd, assumed);
100		if (autocorrect > 0) {
101			fprintf(stderr, "in %0.1f seconds automatically...\n",
102				(float)autocorrect/10.0);
103			poll(NULL, 0, autocorrect * 100);
104		}
105		return assumed;
106	}
107
108	fprintf(stderr, "perf: '%s' is not a perf-command. See 'perf --help'.\n", cmd);
109
110	if (main_cmds.cnt && best_similarity < 6) {
111		fprintf(stderr, "\nDid you mean %s?\n",
112			n < 2 ? "this": "one of these");
113
114		for (i = 0; i < n; i++)
115			fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
116	}
117end:
118	clean_cmdnames(&main_cmds);
119	clean_cmdnames(&other_cmds);
120	exit(1);
121}
122