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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 "machine.h"
#include "linux/string.h"
#include "debug.h"
#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"
struct vdso_file {
bool found;
bool error;
char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
const char *dso_name;
};
struct vdso_info {
struct vdso_file vdso;
};
static struct vdso_info vdso_info_ = {
.vdso = {
.temp_file_name = VDSO__TEMP_FILE_NAME,
.dso_name = VDSO__MAP_NAME,
},
};
static struct vdso_info *vdso_info = &vdso_info_;
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(struct vdso_file *vdso_file)
{
char *vdso = NULL;
char *buf = NULL;
void *start, *end;
size_t size;
int fd;
if (vdso_file->found)
return vdso_file->temp_file_name;
if (vdso_file->error || find_vdso_map(&start, &end))
return NULL;
size = end - start;
buf = memdup(start, size);
if (!buf)
return NULL;
fd = mkstemp(vdso_file->temp_file_name);
if (fd < 0)
goto out;
if (size == (size_t) write(fd, buf, size))
vdso = vdso_file->temp_file_name;
close(fd);
out:
free(buf);
vdso_file->found = (vdso != NULL);
vdso_file->error = !vdso_file->found;
return vdso;
}
void vdso__exit(void)
{
if (vdso_info->vdso.found)
unlink(vdso_info->vdso.temp_file_name);
}
struct dso *vdso__dso_findnew(struct machine *machine)
{
struct dso *dso = dsos__find(&machine->user_dsos, VDSO__MAP_NAME, true);
if (!dso) {
char *file;
file = get_file(&vdso_info->vdso);
if (!file)
return NULL;
dso = dso__new(VDSO__MAP_NAME);
if (dso != NULL) {
dsos__add(&machine->user_dsos, dso);
dso__set_long_name(dso, file, false);
}
}
return dso;
}
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