Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1/*
2 * Manage printing of source lines
3 * Copyright (c) 2017, Intel Corporation.
4 * Author: Andi Kleen
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 */
15#include "linux/list.h"
16#include <stdlib.h>
17#include <sys/mman.h>
18#include <sys/stat.h>
19#include <fcntl.h>
20#include <unistd.h>
21#include <assert.h>
22#include <string.h>
23#include "srccode.h"
24#include "debug.h"
25#include "util.h"
26
27#define MAXSRCCACHE (32*1024*1024)
28#define MAXSRCFILES 64
29#define SRC_HTAB_SZ 64
30
31struct srcfile {
32 struct hlist_node hash_nd;
33 struct list_head nd;
34 char *fn;
35 char **lines;
36 char *map;
37 unsigned numlines;
38 size_t maplen;
39};
40
41static struct hlist_head srcfile_htab[SRC_HTAB_SZ];
42static LIST_HEAD(srcfile_list);
43static long map_total_sz;
44static int num_srcfiles;
45
46static unsigned shash(unsigned char *s)
47{
48 unsigned h = 0;
49 while (*s)
50 h = 65599 * h + *s++;
51 return h ^ (h >> 16);
52}
53
54static int countlines(char *map, int maplen)
55{
56 int numl;
57 char *end = map + maplen;
58 char *p = map;
59
60 if (maplen == 0)
61 return 0;
62 numl = 0;
63 while (p < end && (p = memchr(p, '\n', end - p)) != NULL) {
64 numl++;
65 p++;
66 }
67 if (p < end)
68 numl++;
69 return numl;
70}
71
72static void fill_lines(char **lines, int maxline, char *map, int maplen)
73{
74 int l;
75 char *end = map + maplen;
76 char *p = map;
77
78 if (maplen == 0 || maxline == 0)
79 return;
80 l = 0;
81 lines[l++] = map;
82 while (p < end && (p = memchr(p, '\n', end - p)) != NULL) {
83 if (l >= maxline)
84 return;
85 lines[l++] = ++p;
86 }
87 if (p < end)
88 lines[l] = p;
89}
90
91static void free_srcfile(struct srcfile *sf)
92{
93 list_del(&sf->nd);
94 hlist_del(&sf->hash_nd);
95 map_total_sz -= sf->maplen;
96 munmap(sf->map, sf->maplen);
97 free(sf->lines);
98 free(sf->fn);
99 free(sf);
100 num_srcfiles--;
101}
102
103static struct srcfile *find_srcfile(char *fn)
104{
105 struct stat st;
106 struct srcfile *h;
107 int fd;
108 unsigned long sz;
109 unsigned hval = shash((unsigned char *)fn) % SRC_HTAB_SZ;
110
111 hlist_for_each_entry (h, &srcfile_htab[hval], hash_nd) {
112 if (!strcmp(fn, h->fn)) {
113 /* Move to front */
114 list_del(&h->nd);
115 list_add(&h->nd, &srcfile_list);
116 return h;
117 }
118 }
119
120 /* Only prune if there is more than one entry */
121 while ((num_srcfiles > MAXSRCFILES || map_total_sz > MAXSRCCACHE) &&
122 srcfile_list.next != &srcfile_list) {
123 assert(!list_empty(&srcfile_list));
124 h = list_entry(srcfile_list.prev, struct srcfile, nd);
125 free_srcfile(h);
126 }
127
128 fd = open(fn, O_RDONLY);
129 if (fd < 0 || fstat(fd, &st) < 0) {
130 pr_debug("cannot open source file %s\n", fn);
131 return NULL;
132 }
133
134 h = malloc(sizeof(struct srcfile));
135 if (!h)
136 return NULL;
137
138 h->fn = strdup(fn);
139 if (!h->fn)
140 goto out_h;
141
142 h->maplen = st.st_size;
143 sz = (h->maplen + page_size - 1) & ~(page_size - 1);
144 h->map = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
145 close(fd);
146 if (h->map == (char *)-1) {
147 pr_debug("cannot mmap source file %s\n", fn);
148 goto out_fn;
149 }
150 h->numlines = countlines(h->map, h->maplen);
151 h->lines = calloc(h->numlines, sizeof(char *));
152 if (!h->lines)
153 goto out_map;
154 fill_lines(h->lines, h->numlines, h->map, h->maplen);
155 list_add(&h->nd, &srcfile_list);
156 hlist_add_head(&h->hash_nd, &srcfile_htab[hval]);
157 map_total_sz += h->maplen;
158 num_srcfiles++;
159 return h;
160
161out_map:
162 munmap(h->map, sz);
163out_fn:
164 free(h->fn);
165out_h:
166 free(h);
167 return NULL;
168}
169
170/* Result is not 0 terminated */
171char *find_sourceline(char *fn, unsigned line, int *lenp)
172{
173 char *l, *p;
174 struct srcfile *sf = find_srcfile(fn);
175 if (!sf)
176 return NULL;
177 line--;
178 if (line >= sf->numlines)
179 return NULL;
180 l = sf->lines[line];
181 if (!l)
182 return NULL;
183 p = memchr(l, '\n', sf->map + sf->maplen - l);
184 *lenp = p - l;
185 return l;
186}