xref: /linux/tools/perf/util/help-unknown-cmd.c (revision fd01d06ae33be63cff7d133e650cd1eb32f1d548)
1 #include "cache.h"
2 #include "config.h"
3 #include <subcmd/help.h>
4 #include "../builtin.h"
5 #include "levenshtein.h"
6 
7 static int autocorrect;
8 static struct cmdnames aliases;
9 
10 static int perf_unknown_cmd_config(const char *var, const char *value,
11 				   void *cb __maybe_unused)
12 {
13 	if (!strcmp(var, "help.autocorrect"))
14 		autocorrect = perf_config_int(var,value);
15 	/* Also use aliases for command lookup */
16 	if (!prefixcmp(var, "alias."))
17 		add_cmdname(&aliases, var + 6, strlen(var + 6));
18 
19 	return 0;
20 }
21 
22 static int levenshtein_compare(const void *p1, const void *p2)
23 {
24 	const struct cmdname *const *c1 = p1, *const *c2 = p2;
25 	const char *s1 = (*c1)->name, *s2 = (*c2)->name;
26 	int l1 = (*c1)->len;
27 	int l2 = (*c2)->len;
28 	return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
29 }
30 
31 static int add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
32 {
33 	unsigned int i, nr = cmds->cnt + old->cnt;
34 	void *tmp;
35 
36 	if (nr > cmds->alloc) {
37 		/* Choose bigger one to alloc */
38 		if (alloc_nr(cmds->alloc) < nr)
39 			cmds->alloc = nr;
40 		else
41 			cmds->alloc = alloc_nr(cmds->alloc);
42 		tmp = realloc(cmds->names, cmds->alloc * sizeof(*cmds->names));
43 		if (!tmp)
44 			return -1;
45 		cmds->names = tmp;
46 	}
47 	for (i = 0; i < old->cnt; i++)
48 		cmds->names[cmds->cnt++] = old->names[i];
49 	zfree(&old->names);
50 	old->cnt = 0;
51 	return 0;
52 }
53 
54 const char *help_unknown_cmd(const char *cmd)
55 {
56 	unsigned int i, n = 0, best_similarity = 0;
57 	struct cmdnames main_cmds, other_cmds;
58 
59 	memset(&main_cmds, 0, sizeof(main_cmds));
60 	memset(&other_cmds, 0, sizeof(main_cmds));
61 	memset(&aliases, 0, sizeof(aliases));
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, &aliases) < 0 ||
68 	    add_cmd_list(&main_cmds, &other_cmds) < 0) {
69 		fprintf(stderr, "ERROR: Failed to allocate command list for unknown command.\n");
70 		goto end;
71 	}
72 	qsort(main_cmds.names, main_cmds.cnt,
73 	      sizeof(main_cmds.names), cmdname_compare);
74 	uniq(&main_cmds);
75 
76 	if (main_cmds.cnt) {
77 		/* This reuses cmdname->len for similarity index */
78 		for (i = 0; i < main_cmds.cnt; ++i)
79 			main_cmds.names[i]->len =
80 				levenshtein(cmd, main_cmds.names[i]->name, 0, 2, 1, 4);
81 
82 		qsort(main_cmds.names, main_cmds.cnt,
83 		      sizeof(*main_cmds.names), levenshtein_compare);
84 
85 		best_similarity = main_cmds.names[0]->len;
86 		n = 1;
87 		while (n < main_cmds.cnt && best_similarity == main_cmds.names[n]->len)
88 			++n;
89 	}
90 
91 	if (autocorrect && n == 1) {
92 		const char *assumed = main_cmds.names[0]->name;
93 
94 		main_cmds.names[0] = NULL;
95 		clean_cmdnames(&main_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 	}
117 end:
118 	exit(1);
119 }
120