Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Manage printing of source lines
4 * Copyright (c) 2017, Intel Corporation.
5 * Author: Andi Kleen
6 */
7#include "linux/list.h"
8#include <stdlib.h>
9#include <sys/mman.h>
10#include <sys/stat.h>
11#include <fcntl.h>
12#include <unistd.h>
13#include <assert.h>
14#include <string.h>
15#include "srccode.h"
16#include "debug.h"
17#include "util.h"
18
19#define MAXSRCCACHE (32*1024*1024)
20#define MAXSRCFILES 64
21#define SRC_HTAB_SZ 64
22
23struct srcfile {
24 struct hlist_node hash_nd;
25 struct list_head nd;
26 char *fn;
27 char **lines;
28 char *map;
29 unsigned numlines;
30 size_t maplen;
31};
32
33static struct hlist_head srcfile_htab[SRC_HTAB_SZ];
34static LIST_HEAD(srcfile_list);
35static long map_total_sz;
36static int num_srcfiles;
37
38static unsigned shash(unsigned char *s)
39{
40 unsigned h = 0;
41 while (*s)
42 h = 65599 * h + *s++;
43 return h ^ (h >> 16);
44}
45
46static int countlines(char *map, int maplen)
47{
48 int numl;
49 char *end = map + maplen;
50 char *p = map;
51
52 if (maplen == 0)
53 return 0;
54 numl = 0;
55 while (p < end && (p = memchr(p, '\n', end - p)) != NULL) {
56 numl++;
57 p++;
58 }
59 if (p < end)
60 numl++;
61 return numl;
62}
63
64static void fill_lines(char **lines, int maxline, char *map, int maplen)
65{
66 int l;
67 char *end = map + maplen;
68 char *p = map;
69
70 if (maplen == 0 || maxline == 0)
71 return;
72 l = 0;
73 lines[l++] = map;
74 while (p < end && (p = memchr(p, '\n', end - p)) != NULL) {
75 if (l >= maxline)
76 return;
77 lines[l++] = ++p;
78 }
79 if (p < end)
80 lines[l] = p;
81}
82
83static void free_srcfile(struct srcfile *sf)
84{
85 list_del(&sf->nd);
86 hlist_del(&sf->hash_nd);
87 map_total_sz -= sf->maplen;
88 munmap(sf->map, sf->maplen);
89 free(sf->lines);
90 free(sf->fn);
91 free(sf);
92 num_srcfiles--;
93}
94
95static struct srcfile *find_srcfile(char *fn)
96{
97 struct stat st;
98 struct srcfile *h;
99 int fd;
100 unsigned long sz;
101 unsigned hval = shash((unsigned char *)fn) % SRC_HTAB_SZ;
102
103 hlist_for_each_entry (h, &srcfile_htab[hval], hash_nd) {
104 if (!strcmp(fn, h->fn)) {
105 /* Move to front */
106 list_del(&h->nd);
107 list_add(&h->nd, &srcfile_list);
108 return h;
109 }
110 }
111
112 /* Only prune if there is more than one entry */
113 while ((num_srcfiles > MAXSRCFILES || map_total_sz > MAXSRCCACHE) &&
114 srcfile_list.next != &srcfile_list) {
115 assert(!list_empty(&srcfile_list));
116 h = list_entry(srcfile_list.prev, struct srcfile, nd);
117 free_srcfile(h);
118 }
119
120 fd = open(fn, O_RDONLY);
121 if (fd < 0 || fstat(fd, &st) < 0) {
122 pr_debug("cannot open source file %s\n", fn);
123 return NULL;
124 }
125
126 h = malloc(sizeof(struct srcfile));
127 if (!h)
128 return NULL;
129
130 h->fn = strdup(fn);
131 if (!h->fn)
132 goto out_h;
133
134 h->maplen = st.st_size;
135 sz = (h->maplen + page_size - 1) & ~(page_size - 1);
136 h->map = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
137 close(fd);
138 if (h->map == (char *)-1) {
139 pr_debug("cannot mmap source file %s\n", fn);
140 goto out_fn;
141 }
142 h->numlines = countlines(h->map, h->maplen);
143 h->lines = calloc(h->numlines, sizeof(char *));
144 if (!h->lines)
145 goto out_map;
146 fill_lines(h->lines, h->numlines, h->map, h->maplen);
147 list_add(&h->nd, &srcfile_list);
148 hlist_add_head(&h->hash_nd, &srcfile_htab[hval]);
149 map_total_sz += h->maplen;
150 num_srcfiles++;
151 return h;
152
153out_map:
154 munmap(h->map, sz);
155out_fn:
156 free(h->fn);
157out_h:
158 free(h);
159 return NULL;
160}
161
162/* Result is not 0 terminated */
163char *find_sourceline(char *fn, unsigned line, int *lenp)
164{
165 char *l, *p;
166 struct srcfile *sf = find_srcfile(fn);
167 if (!sf)
168 return NULL;
169 line--;
170 if (line >= sf->numlines)
171 return NULL;
172 l = sf->lines[line];
173 if (!l)
174 return NULL;
175 p = memchr(l, '\n', sf->map + sf->maplen - l);
176 *lenp = p - l;
177 return l;
178}