Modify DTRACEHIOC_ADDDOF to copy the DOF section from the target process.

r281257 added support for lazyload mode by allowing dtrace(1) to register
a DOF section on behalf of a traced process. This was implemented by
having libdtrace copy the DOF section into a heap-allocated buffer and
passing its address to the ioctl handler. However, DTrace uses the DOF
section address as a lookup key in certain cases, so the ioctl handler
should be given the target process' DOF section address instead. This
change modifies the ADDDOF handler to copy the DOF section in from the
target process, rather than from dtrace(1).

1 files changed, 4 insertions, 46 deletions

diff --git a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_pid.c b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_pid.c
index c61a710..5444477 100644
--- a/cddl/contrib/opensolaris/lib/libdtrace/common/dt_pid.c
+++ b/cddl/contrib/opensolaris/lib/libdtrace/common/dt_pid.c
@@ -571,12 +571,6 @@ dt_pid_usdt_mapping(void *data, const prmap_t *pmp, const char *oname)
 	prsyminfo_t sip;
 	dof_helper_t dh;
 	GElf_Half e_type;
-#ifdef __FreeBSD__
-	dof_hdr_t hdr;
-	size_t sz;
-	uint64_t dofmax;
-	void *dof;
-#endif
 	const char *mname;
 	const char *syms[] = { "___SUNW_dof", "__SUNW_dof" };
 	int i, fd = -1;
@@ -606,61 +600,25 @@ dt_pid_usdt_mapping(void *data, const prmap_t *pmp, const char *oname)
 			continue;
 		}
 
-#ifdef __FreeBSD__
+		dh.dofhp_dof = sym.st_value;
 		dh.dofhp_addr = (e_type == ET_EXEC) ? 0 : pmp->pr_vaddr;
-		if (Pread(P, &hdr, sizeof (hdr), sym.st_value) !=
-		    sizeof (hdr)) {
-			dt_dprintf("read of DOF header failed\n");
-			continue;
-		}
-
-		sz = sizeof(dofmax);
-		if (sysctlbyname("kern.dtrace.dof_maxsize", &dofmax, &sz,
-		    NULL, 0) != 0) {
-			dt_dprintf("failed to read dof_maxsize: %s\n",
-			    strerror(errno));
-			continue;
-		}
-		if (dofmax < hdr.dofh_loadsz) {
-			dt_dprintf("DOF load size exceeds maximum\n");
-			continue;
-		}
-
-		if ((dof = malloc(hdr.dofh_loadsz)) == NULL)
-			return (-1);
-
-		if (Pread(P, dof, hdr.dofh_loadsz, sym.st_value) !=
-		    hdr.dofh_loadsz) {
-			free(dof);
-			dt_dprintf("read of DOF section failed\n");
-			continue;
-		}
-
-		dh.dofhp_dof = (uintptr_t)dof;
-		dh.dofhp_pid = proc_getpid(P);
 
 		dt_pid_objname(dh.dofhp_mod, sizeof (dh.dofhp_mod),
 		    sip.prs_lmid, mname);
 
+#ifdef __FreeBSD__
+		dh.dofhp_pid = proc_getpid(P);
+
 		if (fd == -1 &&
 		    (fd = open("/dev/dtrace/helper", O_RDWR, 0)) < 0) {
 			dt_dprintf("open of helper device failed: %s\n",
 			    strerror(errno));
-			free(dof);
 			return (-1); /* errno is set for us */
 		}
 
 		if (ioctl(fd, DTRACEHIOC_ADDDOF, &dh, sizeof (dh)) < 0)
 			dt_dprintf("DOF was rejected for %s\n", dh.dofhp_mod);
-
-		free(dof);
 #else
-		dh.dofhp_dof = sym.st_value;
-		dh.dofhp_addr = (e_type == ET_EXEC) ? 0 : pmp->pr_vaddr;
-
-		dt_pid_objname(dh.dofhp_mod, sizeof (dh.dofhp_mod),
-		    sip.prs_lmid, mname);
-
 		if (fd == -1 &&
 		    (fd = pr_open(P, "/dev/dtrace/helper", O_RDWR, 0)) < 0) {
 			dt_dprintf("pr_open of helper device failed: %s\n",