Date: Tue, 21 Jan 2020 15:07:23 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r356941 - stable/12/cddl/contrib/opensolaris/lib/libdtrace/common Message-ID: <202001211507.00LF7Nk7078903@repo.freebsd.org>
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Author: markj Date: Tue Jan 21 15:07:23 2020 New Revision: 356941 URL: https://svnweb.freebsd.org/changeset/base/356941 Log: MFC r356477: Use a deterministic hash for USDT symbol names. Modified: stable/12/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c Directory Properties: stable/12/ (props changed) Modified: stable/12/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c ============================================================================== --- stable/12/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c Tue Jan 21 13:22:35 2020 (r356940) +++ stable/12/cddl/contrib/opensolaris/lib/libdtrace/common/dt_link.c Tue Jan 21 15:07:23 2020 (r356941) @@ -57,7 +57,6 @@ #include <sys/mman.h> #endif #include <assert.h> -#include <sys/ipc.h> #include <dt_impl.h> #include <dt_provider.h> @@ -1249,13 +1248,32 @@ dt_link_error(dtrace_hdl_t *dtp, Elf *elf, int fd, dt_ 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 process_obj(dtrace_hdl_t *dtp, const char *obj, int *eprobesp) { static const char dt_prefix[] = "__dtrace"; static const char dt_enabled[] = "enabled"; 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"; char probename[DTRACE_NAMELEN]; int fd, i, ndx, eprobe, mod = 0; @@ -1272,7 +1290,7 @@ process_obj(dtrace_hdl_t *dtp, const char *obj, int *e dt_probe_t *prp; uint32_t off, eclass, emachine1, emachine2; size_t symsize, osym, nsym, isym, istr, len; - key_t objkey; + unsigned int objkey; dt_link_pair_t *pair, *bufs = NULL; dt_strtab_t *strtab; void *tmp; @@ -1350,10 +1368,9 @@ process_obj(dtrace_hdl_t *dtp, const char *obj, int *e * system in order to disambiguate potential conflicts between files of * 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, "failed to generate unique key for object file: %s", obj)); - } scn_rel = NULL; while ((scn_rel = elf_nextscn(elf, scn_rel)) != NULL) {
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