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kernel/linux-imx6_3.14.28/tools/perf/util/vdso.c 1.74 KB
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  #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
  ");
  		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, true);
  
  	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, false);
  		}
  	}
  
  	return dso;
  }