169 lines
3.0 KiB
C
169 lines
3.0 KiB
C
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <linux/kernel.h>
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#include "vdso.h"
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#include "util.h"
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#include "symbol.h"
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#include "machine.h"
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#include "linux/string.h"
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#include "debug.h"
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#define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX"
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struct vdso_file {
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bool found;
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bool error;
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char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
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const char *dso_name;
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};
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struct vdso_info {
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struct vdso_file vdso;
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};
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static struct vdso_info *vdso_info__new(void)
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{
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static const struct vdso_info vdso_info_init = {
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.vdso = {
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.temp_file_name = VDSO__TEMP_FILE_NAME,
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.dso_name = DSO__NAME_VDSO,
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},
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};
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return memdup(&vdso_info_init, sizeof(vdso_info_init));
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}
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static int find_vdso_map(void **start, void **end)
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{
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FILE *maps;
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char line[128];
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int found = 0;
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maps = fopen("/proc/self/maps", "r");
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if (!maps) {
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pr_err("vdso: cannot open maps\n");
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return -1;
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}
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while (!found && fgets(line, sizeof(line), maps)) {
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int m = -1;
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/* We care only about private r-x mappings. */
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if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
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start, end, &m))
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continue;
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if (m < 0)
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continue;
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if (!strncmp(&line[m], VDSO__MAP_NAME,
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sizeof(VDSO__MAP_NAME) - 1))
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found = 1;
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}
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fclose(maps);
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return !found;
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}
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static char *get_file(struct vdso_file *vdso_file)
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{
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char *vdso = NULL;
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char *buf = NULL;
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void *start, *end;
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size_t size;
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int fd;
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if (vdso_file->found)
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return vdso_file->temp_file_name;
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if (vdso_file->error || find_vdso_map(&start, &end))
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return NULL;
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size = end - start;
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buf = memdup(start, size);
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if (!buf)
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return NULL;
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fd = mkstemp(vdso_file->temp_file_name);
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if (fd < 0)
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goto out;
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if (size == (size_t) write(fd, buf, size))
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vdso = vdso_file->temp_file_name;
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close(fd);
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out:
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free(buf);
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vdso_file->found = (vdso != NULL);
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vdso_file->error = !vdso_file->found;
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return vdso;
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}
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void vdso__exit(struct machine *machine)
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{
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struct vdso_info *vdso_info = machine->vdso_info;
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if (!vdso_info)
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return;
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if (vdso_info->vdso.found)
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unlink(vdso_info->vdso.temp_file_name);
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zfree(&machine->vdso_info);
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}
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static struct dso *vdso__new(struct machine *machine, const char *short_name,
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const char *long_name)
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{
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struct dso *dso;
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dso = dso__new(short_name);
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if (dso != NULL) {
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dsos__add(&machine->user_dsos, dso);
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dso__set_long_name(dso, long_name, false);
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}
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return dso;
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}
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struct dso *vdso__dso_findnew(struct machine *machine,
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struct thread *thread __maybe_unused)
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{
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struct vdso_info *vdso_info;
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struct dso *dso;
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if (!machine->vdso_info)
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machine->vdso_info = vdso_info__new();
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vdso_info = machine->vdso_info;
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if (!vdso_info)
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return NULL;
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dso = dsos__find(&machine->user_dsos, DSO__NAME_VDSO, true);
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if (!dso) {
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char *file;
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file = get_file(&vdso_info->vdso);
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if (!file)
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return NULL;
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dso = vdso__new(machine, DSO__NAME_VDSO, file);
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}
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return dso;
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}
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bool dso__is_vdso(struct dso *dso)
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{
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return !strcmp(dso->short_name, DSO__NAME_VDSO);
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}
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