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 
12 static int autocorrect;
13 
14 static 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 
23 static 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 
32 static 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 
55 const 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 	}
116 end:
117 	exit(1);
118 }
119