Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 1 | |
| 2 | #include <unistd.h> |
| 3 | #include <stdio.h> |
| 4 | #include <string.h> |
| 5 | #include <sys/types.h> |
| 6 | #include <sys/stat.h> |
| 7 | #include <fcntl.h> |
| 8 | #include <stdlib.h> |
| 9 | #include <linux/kernel.h> |
| 10 | |
| 11 | #include "vdso.h" |
| 12 | #include "util.h" |
| 13 | #include "symbol.h" |
| 14 | #include "linux/string.h" |
| 15 | |
| 16 | static bool vdso_found; |
| 17 | static char vdso_file[] = "/tmp/perf-vdso.so-XXXXXX"; |
| 18 | |
| 19 | static int find_vdso_map(void **start, void **end) |
| 20 | { |
| 21 | FILE *maps; |
| 22 | char line[128]; |
| 23 | int found = 0; |
| 24 | |
| 25 | maps = fopen("/proc/self/maps", "r"); |
| 26 | if (!maps) { |
| 27 | pr_err("vdso: cannot open maps\n"); |
| 28 | return -1; |
| 29 | } |
| 30 | |
| 31 | while (!found && fgets(line, sizeof(line), maps)) { |
| 32 | int m = -1; |
| 33 | |
| 34 | /* We care only about private r-x mappings. */ |
| 35 | if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n", |
| 36 | start, end, &m)) |
| 37 | continue; |
| 38 | if (m < 0) |
| 39 | continue; |
| 40 | |
| 41 | if (!strncmp(&line[m], VDSO__MAP_NAME, |
| 42 | sizeof(VDSO__MAP_NAME) - 1)) |
| 43 | found = 1; |
| 44 | } |
| 45 | |
| 46 | fclose(maps); |
| 47 | return !found; |
| 48 | } |
| 49 | |
| 50 | static char *get_file(void) |
| 51 | { |
| 52 | char *vdso = NULL; |
| 53 | char *buf = NULL; |
| 54 | void *start, *end; |
| 55 | size_t size; |
| 56 | int fd; |
| 57 | |
| 58 | if (vdso_found) |
| 59 | return vdso_file; |
| 60 | |
| 61 | if (find_vdso_map(&start, &end)) |
| 62 | return NULL; |
| 63 | |
| 64 | size = end - start; |
| 65 | |
| 66 | buf = memdup(start, size); |
| 67 | if (!buf) |
| 68 | return NULL; |
| 69 | |
| 70 | fd = mkstemp(vdso_file); |
| 71 | if (fd < 0) |
| 72 | goto out; |
| 73 | |
| 74 | if (size == (size_t) write(fd, buf, size)) |
| 75 | vdso = vdso_file; |
| 76 | |
| 77 | close(fd); |
| 78 | |
| 79 | out: |
| 80 | free(buf); |
| 81 | |
| 82 | vdso_found = (vdso != NULL); |
| 83 | return vdso; |
| 84 | } |
| 85 | |
| 86 | void vdso__exit(void) |
| 87 | { |
| 88 | if (vdso_found) |
| 89 | unlink(vdso_file); |
| 90 | } |
| 91 | |
| 92 | struct dso *vdso__dso_findnew(struct list_head *head) |
| 93 | { |
Waiman Long | f9ceffb | 2013-05-09 10:42:48 -0400 | [diff] [blame] | 94 | struct dso *dso = dsos__find(head, VDSO__MAP_NAME, true); |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 95 | |
| 96 | if (!dso) { |
| 97 | char *file; |
| 98 | |
| 99 | file = get_file(); |
| 100 | if (!file) |
| 101 | return NULL; |
| 102 | |
| 103 | dso = dso__new(VDSO__MAP_NAME); |
| 104 | if (dso != NULL) { |
| 105 | dsos__add(head, dso); |
Arnaldo Carvalho de Melo | 7e155d4 | 2013-12-10 15:08:44 -0300 | [diff] [blame] | 106 | dso__set_long_name(dso, file, false); |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 107 | } |
| 108 | } |
| 109 | |
| 110 | return dso; |
| 111 | } |