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