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" |
Adrian Hunter | 2a03068 | 2014-07-22 16:17:53 +0300 | [diff] [blame] | 14 | #include "machine.h" |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 15 | #include "linux/string.h" |
Jiri Olsa | 84f5d36 | 2014-07-14 23:46:48 +0200 | [diff] [blame] | 16 | #include "debug.h" |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 17 | |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 18 | #define VDSO__TEMP_FILE_NAME "/tmp/perf-vdso.so-XXXXXX" |
| 19 | |
| 20 | struct vdso_file { |
| 21 | bool found; |
| 22 | bool error; |
| 23 | char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)]; |
| 24 | const char *dso_name; |
| 25 | }; |
| 26 | |
| 27 | struct vdso_info { |
| 28 | struct vdso_file vdso; |
| 29 | }; |
| 30 | |
| 31 | static struct vdso_info vdso_info_ = { |
| 32 | .vdso = { |
| 33 | .temp_file_name = VDSO__TEMP_FILE_NAME, |
| 34 | .dso_name = VDSO__MAP_NAME, |
| 35 | }, |
| 36 | }; |
| 37 | |
| 38 | static struct vdso_info *vdso_info = &vdso_info_; |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 39 | |
| 40 | static int find_vdso_map(void **start, void **end) |
| 41 | { |
| 42 | FILE *maps; |
| 43 | char line[128]; |
| 44 | int found = 0; |
| 45 | |
| 46 | maps = fopen("/proc/self/maps", "r"); |
| 47 | if (!maps) { |
| 48 | pr_err("vdso: cannot open maps\n"); |
| 49 | return -1; |
| 50 | } |
| 51 | |
| 52 | while (!found && fgets(line, sizeof(line), maps)) { |
| 53 | int m = -1; |
| 54 | |
| 55 | /* We care only about private r-x mappings. */ |
| 56 | if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n", |
| 57 | start, end, &m)) |
| 58 | continue; |
| 59 | if (m < 0) |
| 60 | continue; |
| 61 | |
| 62 | if (!strncmp(&line[m], VDSO__MAP_NAME, |
| 63 | sizeof(VDSO__MAP_NAME) - 1)) |
| 64 | found = 1; |
| 65 | } |
| 66 | |
| 67 | fclose(maps); |
| 68 | return !found; |
| 69 | } |
| 70 | |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 71 | static char *get_file(struct vdso_file *vdso_file) |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 72 | { |
| 73 | char *vdso = NULL; |
| 74 | char *buf = NULL; |
| 75 | void *start, *end; |
| 76 | size_t size; |
| 77 | int fd; |
| 78 | |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 79 | if (vdso_file->found) |
| 80 | return vdso_file->temp_file_name; |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 81 | |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 82 | if (vdso_file->error || find_vdso_map(&start, &end)) |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 83 | return NULL; |
| 84 | |
| 85 | size = end - start; |
| 86 | |
| 87 | buf = memdup(start, size); |
| 88 | if (!buf) |
| 89 | return NULL; |
| 90 | |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 91 | fd = mkstemp(vdso_file->temp_file_name); |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 92 | if (fd < 0) |
| 93 | goto out; |
| 94 | |
| 95 | if (size == (size_t) write(fd, buf, size)) |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 96 | vdso = vdso_file->temp_file_name; |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 97 | |
| 98 | close(fd); |
| 99 | |
| 100 | out: |
| 101 | free(buf); |
| 102 | |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 103 | vdso_file->found = (vdso != NULL); |
| 104 | vdso_file->error = !vdso_file->found; |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 105 | return vdso; |
| 106 | } |
| 107 | |
| 108 | void vdso__exit(void) |
| 109 | { |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 110 | if (vdso_info->vdso.found) |
| 111 | unlink(vdso_info->vdso.temp_file_name); |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 112 | } |
| 113 | |
Adrian Hunter | 2a03068 | 2014-07-22 16:17:53 +0300 | [diff] [blame] | 114 | struct dso *vdso__dso_findnew(struct machine *machine) |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 115 | { |
Adrian Hunter | 2a03068 | 2014-07-22 16:17:53 +0300 | [diff] [blame] | 116 | struct dso *dso = dsos__find(&machine->user_dsos, VDSO__MAP_NAME, true); |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 117 | |
| 118 | if (!dso) { |
| 119 | char *file; |
| 120 | |
Adrian Hunter | 30f4f81 | 2014-07-22 16:17:54 +0300 | [diff] [blame^] | 121 | file = get_file(&vdso_info->vdso); |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 122 | if (!file) |
| 123 | return NULL; |
| 124 | |
| 125 | dso = dso__new(VDSO__MAP_NAME); |
| 126 | if (dso != NULL) { |
Adrian Hunter | 2a03068 | 2014-07-22 16:17:53 +0300 | [diff] [blame] | 127 | dsos__add(&machine->user_dsos, dso); |
Arnaldo Carvalho de Melo | 7e155d4 | 2013-12-10 15:08:44 -0300 | [diff] [blame] | 128 | dso__set_long_name(dso, file, false); |
Jiri Olsa | 7dbf4dc | 2012-09-10 18:50:19 +0200 | [diff] [blame] | 129 | } |
| 130 | } |
| 131 | |
| 132 | return dso; |
| 133 | } |