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// SPDX-License-Identifier: GPL-2.0-only
/*
* Manage printing of source lines
* Copyright (c) 2017, Intel Corporation.
* Author: Andi Kleen
*/
#include <linux/list.h>
#include <linux/zalloc.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <string.h>
#include "srccode.h"
#include "debug.h"
#include <internal/lib.h> // page_size
#define MAXSRCCACHE (32*1024*1024)
#define MAXSRCFILES 64
#define SRC_HTAB_SZ 64
struct srcfile {
struct hlist_node hash_nd;
struct list_head nd;
char *fn;
char **lines;
char *map;
unsigned numlines;
size_t maplen;
};
static struct hlist_head srcfile_htab[SRC_HTAB_SZ];
static LIST_HEAD(srcfile_list);
static long map_total_sz;
static int num_srcfiles;
static unsigned shash(unsigned char *s)
{
unsigned h = 0;
while (*s)
h = 65599 * h + *s++;
return h ^ (h >> 16);
}
static int countlines(char *map, int maplen)
{
int numl;
char *end = map + maplen;
char *p = map;
if (maplen == 0)
return 0;
numl = 0;
while (p < end && (p = memchr(p, '\n', end - p)) != NULL) {
numl++;
p++;
}
if (p < end)
numl++;
return numl;
}
static void fill_lines(char **lines, int maxline, char *map, int maplen)
{
int l;
char *end = map + maplen;
char *p = map;
if (maplen == 0 || maxline == 0)
return;
l = 0;
lines[l++] = map;
while (p < end && (p = memchr(p, '\n', end - p)) != NULL) {
if (l >= maxline)
return;
lines[l++] = ++p;
}
if (p < end)
lines[l] = p;
}
static void free_srcfile(struct srcfile *sf)
{
list_del_init(&sf->nd);
hlist_del(&sf->hash_nd);
map_total_sz -= sf->maplen;
munmap(sf->map, sf->maplen);
zfree(&sf->lines);
zfree(&sf->fn);
free(sf);
num_srcfiles--;
}
static struct srcfile *find_srcfile(char *fn)
{
struct stat st;
struct srcfile *h;
int fd;
unsigned long sz;
unsigned hval = shash((unsigned char *)fn) % SRC_HTAB_SZ;
hlist_for_each_entry (h, &srcfile_htab[hval], hash_nd) {
if (!strcmp(fn, h->fn)) {
/* Move to front */
list_del(&h->nd);
list_add(&h->nd, &srcfile_list);
return h;
}
}
/* Only prune if there is more than one entry */
while ((num_srcfiles > MAXSRCFILES || map_total_sz > MAXSRCCACHE) &&
srcfile_list.next != &srcfile_list) {
assert(!list_empty(&srcfile_list));
h = list_entry(srcfile_list.prev, struct srcfile, nd);
free_srcfile(h);
}
fd = open(fn, O_RDONLY);
if (fd < 0 || fstat(fd, &st) < 0) {
pr_debug("cannot open source file %s\n", fn);
return NULL;
}
h = malloc(sizeof(struct srcfile));
if (!h)
return NULL;
h->fn = strdup(fn);
if (!h->fn)
goto out_h;
h->maplen = st.st_size;
sz = (h->maplen + page_size - 1) & ~(page_size - 1);
h->map = mmap(NULL, sz, PROT_READ, MAP_SHARED, fd, 0);
close(fd);
if (h->map == (char *)-1) {
pr_debug("cannot mmap source file %s\n", fn);
goto out_fn;
}
h->numlines = countlines(h->map, h->maplen);
h->lines = calloc(h->numlines, sizeof(char *));
if (!h->lines)
goto out_map;
fill_lines(h->lines, h->numlines, h->map, h->maplen);
list_add(&h->nd, &srcfile_list);
hlist_add_head(&h->hash_nd, &srcfile_htab[hval]);
map_total_sz += h->maplen;
num_srcfiles++;
return h;
out_map:
munmap(h->map, sz);
out_fn:
zfree(&h->fn);
out_h:
free(h);
return NULL;
}
/* Result is not 0 terminated */
char *find_sourceline(char *fn, unsigned line, int *lenp)
{
char *l, *p;
struct srcfile *sf = find_srcfile(fn);
if (!sf)
return NULL;
line--;
if (line >= sf->numlines)
return NULL;
l = sf->lines[line];
if (!l)
return NULL;
p = memchr(l, '\n', sf->map + sf->maplen - l);
*lenp = p - l;
return l;
}
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