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#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <linux/kernel.h>
#include "vdso.h"
#include "util.h"
#include "symbol.h"
#include "linux/string.h"
#include "debug.h"
static bool vdso_found;
static char vdso_file[] = "/tmp/perf-vdso.so-XXXXXX";
static int find_vdso_map(void **start, void **end)
{
FILE *maps;
char line[128];
int found = 0;
maps = fopen("/proc/self/maps", "r");
if (!maps) {
pr_err("vdso: cannot open maps\n");
return -1;
}
while (!found && fgets(line, sizeof(line), maps)) {
int m = -1;
/* We care only about private r-x mappings. */
if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
start, end, &m))
continue;
if (m < 0)
continue;
if (!strncmp(&line[m], VDSO__MAP_NAME,
sizeof(VDSO__MAP_NAME) - 1))
found = 1;
}
fclose(maps);
return !found;
}
static char *get_file(void)
{
char *vdso = NULL;
char *buf = NULL;
void *start, *end;
size_t size;
int fd;
if (vdso_found)
return vdso_file;
if (find_vdso_map(&start, &end))
return NULL;
size = end - start;
buf = memdup(start, size);
if (!buf)
return NULL;
fd = mkstemp(vdso_file);
if (fd < 0)
goto out;
if (size == (size_t) write(fd, buf, size))
vdso = vdso_file;
close(fd);
out:
free(buf);
vdso_found = (vdso != NULL);
return vdso;
}
void vdso__exit(void)
{
if (vdso_found)
unlink(vdso_file);
}
struct dso *vdso__dso_findnew(struct list_head *head)
{
struct dso *dso = dsos__find(head, VDSO__MAP_NAME, true);
if (!dso) {
char *file;
file = get_file();
if (!file)
return NULL;
dso = dso__new(VDSO__MAP_NAME);
if (dso != NULL) {
dsos__add(head, dso);
dso__set_long_name(dso, file, false);
}
}
return dso;
}
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