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-rw-r--r--tools/perf/util/vdso.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/tools/perf/util/vdso.c b/tools/perf/util/vdso.c
new file mode 100644
index 000000000000..e60951fcdb12
--- /dev/null
+++ b/tools/perf/util/vdso.c
@@ -0,0 +1,111 @@
+
+#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 "linux/string.h"
+
+static bool vdso_found;
+static char vdso_file[] = "/tmp/perf-vdso.so-XXXXXX";
+
+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(void)
+{
+ char *vdso = NULL;
+ char *buf = NULL;
+ void *start, *end;
+ size_t size;
+ int fd;
+
+ if (vdso_found)
+ return vdso_file;
+
+ if (find_vdso_map(&start, &end))
+ return NULL;
+
+ size = end - start;
+
+ buf = memdup(start, size);
+ if (!buf)
+ return NULL;
+
+ fd = mkstemp(vdso_file);
+ if (fd < 0)
+ goto out;
+
+ if (size == (size_t) write(fd, buf, size))
+ vdso = vdso_file;
+
+ close(fd);
+
+ out:
+ free(buf);
+
+ vdso_found = (vdso != NULL);
+ return vdso;
+}
+
+void vdso__exit(void)
+{
+ if (vdso_found)
+ unlink(vdso_file);
+}
+
+struct dso *vdso__dso_findnew(struct list_head *head)
+{
+ struct dso *dso = dsos__find(head, VDSO__MAP_NAME);
+
+ if (!dso) {
+ char *file;
+
+ file = get_file();
+ if (!file)
+ return NULL;
+
+ dso = dso__new(VDSO__MAP_NAME);
+ if (dso != NULL) {
+ dsos__add(head, dso);
+ dso__set_long_name(dso, file);
+ }
+ }
+
+ return dso;
+}