112 lines
1.7 KiB
C
112 lines
1.7 KiB
C
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#include <unistd.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <linux/kernel.h>
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#include "vdso.h"
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#include "util.h"
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#include "symbol.h"
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#include "linux/string.h"
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static bool vdso_found;
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static char vdso_file[] = "/tmp/perf-vdso.so-XXXXXX";
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static int find_vdso_map(void **start, void **end)
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{
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FILE *maps;
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char line[128];
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int found = 0;
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maps = fopen("/proc/self/maps", "r");
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if (!maps) {
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pr_err("vdso: cannot open maps\n");
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return -1;
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}
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while (!found && fgets(line, sizeof(line), maps)) {
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int m = -1;
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/* We care only about private r-x mappings. */
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if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n",
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start, end, &m))
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continue;
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if (m < 0)
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continue;
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if (!strncmp(&line[m], VDSO__MAP_NAME,
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sizeof(VDSO__MAP_NAME) - 1))
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found = 1;
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}
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fclose(maps);
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return !found;
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}
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static char *get_file(void)
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{
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char *vdso = NULL;
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char *buf = NULL;
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void *start, *end;
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size_t size;
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int fd;
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if (vdso_found)
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return vdso_file;
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if (find_vdso_map(&start, &end))
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return NULL;
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size = end - start;
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buf = memdup(start, size);
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if (!buf)
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return NULL;
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fd = mkstemp(vdso_file);
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if (fd < 0)
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goto out;
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if (size == (size_t) write(fd, buf, size))
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vdso = vdso_file;
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close(fd);
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out:
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free(buf);
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vdso_found = (vdso != NULL);
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return vdso;
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}
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void vdso__exit(void)
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{
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if (vdso_found)
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unlink(vdso_file);
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}
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struct dso *vdso__dso_findnew(struct list_head *head)
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{
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struct dso *dso = dsos__find(head, VDSO__MAP_NAME, true);
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if (!dso) {
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char *file;
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file = get_file();
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if (!file)
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return NULL;
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dso = dso__new(VDSO__MAP_NAME);
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if (dso != NULL) {
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dsos__add(head, dso);
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dso__set_long_name(dso, file);
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}
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}
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return dso;
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}
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