Use a deterministic hash for USDT symbol names.
Previously libdtrace used ftok(3), which hashes the inode number of the input object file. To increase reproducibility of builds that embed USDT probes, include a hash of the object file path in the symbol name instead. Reported and tested by: bdrewery Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
This commit is contained in:
parent
accd6aa25e
commit
938acb0869
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=356477
@ -57,7 +57,6 @@
|
|||||||
#include <sys/mman.h>
|
#include <sys/mman.h>
|
||||||
#endif
|
#endif
|
||||||
#include <assert.h>
|
#include <assert.h>
|
||||||
#include <sys/ipc.h>
|
|
||||||
|
|
||||||
#include <dt_impl.h>
|
#include <dt_impl.h>
|
||||||
#include <dt_provider.h>
|
#include <dt_provider.h>
|
||||||
@ -1249,13 +1248,32 @@ dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_link_pair_t *bufs,
|
|||||||
return (dt_set_errno(dtp, EDT_COMPILER));
|
return (dt_set_errno(dtp, EDT_COMPILER));
|
||||||
}
|
}
|
||||||
|
|
||||||
|
/*
|
||||||
|
* Provide a unique identifier used when adding global symbols to an object.
|
||||||
|
* This is the FNV-1a hash of an absolute path for the file.
|
||||||
|
*/
|
||||||
|
static unsigned int
|
||||||
|
hash_obj(const char *obj, int fd)
|
||||||
|
{
|
||||||
|
char path[PATH_MAX];
|
||||||
|
unsigned int h;
|
||||||
|
|
||||||
|
if (realpath(obj, path) == NULL)
|
||||||
|
return (-1);
|
||||||
|
|
||||||
|
for (h = 2166136261u, obj = &path[0]; *obj != '\0'; obj++)
|
||||||
|
h = (h ^ *obj) * 16777619;
|
||||||
|
h &= 0x7fffffff;
|
||||||
|
return (h);
|
||||||
|
}
|
||||||
|
|
||||||
static int
|
static int
|
||||||
process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp)
|
process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp)
|
||||||
{
|
{
|
||||||
static const char dt_prefix[] = "__dtrace";
|
static const char dt_prefix[] = "__dtrace";
|
||||||
static const char dt_enabled[] = "enabled";
|
static const char dt_enabled[] = "enabled";
|
||||||
static const char dt_symprefix[] = "$dtrace";
|
static const char dt_symprefix[] = "$dtrace";
|
||||||
static const char dt_symfmt[] = "%s%ld.%s";
|
static const char dt_symfmt[] = "%s%u.%s";
|
||||||
static const char dt_weaksymfmt[] = "%s.%s";
|
static const char dt_weaksymfmt[] = "%s.%s";
|
||||||
char probename[DTRACE_NAMELEN];
|
char probename[DTRACE_NAMELEN];
|
||||||
int fd, i, ndx, eprobe, mod = 0;
|
int fd, i, ndx, eprobe, mod = 0;
|
||||||
@ -1272,7 +1290,7 @@ process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp)
|
|||||||
dt_probe_t *prp;
|
dt_probe_t *prp;
|
||||||
uint32_t off, eclass, emachine1, emachine2;
|
uint32_t off, eclass, emachine1, emachine2;
|
||||||
size_t symsize, osym, nsym, isym, istr, len;
|
size_t symsize, osym, nsym, isym, istr, len;
|
||||||
key_t objkey;
|
unsigned int objkey;
|
||||||
dt_link_pair_t *pair, *bufs = NULL;
|
dt_link_pair_t *pair, *bufs = NULL;
|
||||||
dt_strtab_t *strtab;
|
dt_strtab_t *strtab;
|
||||||
void *tmp;
|
void *tmp;
|
||||||
@ -1350,10 +1368,9 @@ process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp)
|
|||||||
* system in order to disambiguate potential conflicts between files of
|
* system in order to disambiguate potential conflicts between files of
|
||||||
* the same name which contain identially named local symbols.
|
* the same name which contain identially named local symbols.
|
||||||
*/
|
*/
|
||||||
if ((objkey = ftok(obj, 0)) == (key_t)-1) {
|
if ((objkey = hash_obj(obj, fd)) == (unsigned int)-1)
|
||||||
return (dt_link_error(dtp, elf, fd, bufs,
|
return (dt_link_error(dtp, elf, fd, bufs,
|
||||||
"failed to generate unique key for object file: %s", obj));
|
"failed to generate unique key for object file: %s", obj));
|
||||||
}
|
|
||||||
|
|
||||||
scn_rel = NULL;
|
scn_rel = NULL;
|
||||||
while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) {
|
while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) {
|
||||||
|
Loading…
Reference in New Issue
Block a user