| |
| #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__new(void) |
| { |
| static const struct vdso_info vdso_info_init = { |
| .vdso = { |
| .temp_file_name = VDSO__TEMP_FILE_NAME, |
| .dso_name = DSO__NAME_VDSO, |
| }, |
| }; |
| |
| return memdup(&vdso_info_init, sizeof(vdso_info_init)); |
| } |
| |
| 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(struct machine *machine) |
| { |
| struct vdso_info *vdso_info = machine->vdso_info; |
| |
| if (!vdso_info) |
| return; |
| |
| if (vdso_info->vdso.found) |
| unlink(vdso_info->vdso.temp_file_name); |
| |
| zfree(&machine->vdso_info); |
| } |
| |
| static struct dso *vdso__new(struct machine *machine, const char *short_name, |
| const char *long_name) |
| { |
| struct dso *dso; |
| |
| dso = dso__new(short_name); |
| if (dso != NULL) { |
| dsos__add(&machine->user_dsos, dso); |
| dso__set_long_name(dso, long_name, false); |
| } |
| |
| return dso; |
| } |
| |
| struct dso *vdso__dso_findnew(struct machine *machine, |
| struct thread *thread __maybe_unused) |
| { |
| struct vdso_info *vdso_info; |
| struct dso *dso; |
| |
| if (!machine->vdso_info) |
| machine->vdso_info = vdso_info__new(); |
| |
| vdso_info = machine->vdso_info; |
| if (!vdso_info) |
| return NULL; |
| |
| dso = dsos__find(&machine->user_dsos, DSO__NAME_VDSO, true); |
| if (!dso) { |
| char *file; |
| |
| file = get_file(&vdso_info->vdso); |
| if (!file) |
| return NULL; |
| |
| dso = vdso__new(machine, DSO__NAME_VDSO, file); |
| } |
| |
| return dso; |
| } |
| |
| bool dso__is_vdso(struct dso *dso) |
| { |
| return !strcmp(dso->short_name, DSO__NAME_VDSO); |
| } |