[PATCH 11/19] Support USDT wildcard provider descriptions

[eugene.loh@oracle.com]

From: Eugene Loh <eugene.loh@oracle.com>

This is rudimentary support.  We still need to:
- handle globs in dt_pid_create_probes_module()
- add process monitoring / inotify
- deal with FIXMEs

Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
---
 libdtrace/dt_pid.c                            | 76 +++++++++++++++----
 .../dtrace-util/tst.ListProbesFuncUSDT.sh     |  1 -
 .../dtrace-util/tst.ListProbesModuleUSDT.sh   |  1 -
 .../dtrace-util/tst.ListProbesNameUSDT.sh     |  1 -
 .../dtrace-util/tst.ListProbesProviderUSDT.sh |  1 -
 test/unittest/usdt/tst.forker.sh              |  1 -
 6 files changed, 60 insertions(+), 21 deletions(-)

diff --git a/libdtrace/dt_pid.c b/libdtrace/dt_pid.c
index 3f3453af..356e02a4 100644
--- a/libdtrace/dt_pid.c
+++ b/libdtrace/dt_pid.c
@@ -605,6 +605,9 @@ dt_pid_fix_mod(dt_pid_probe_t *pp, dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
 	return pmp;
 }
 
+/*
+ * Create pid probes for the specified process.
+ */
 static int
 dt_pid_create_pid_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
 			 dt_pcb_t *pcb, dt_proc_t *dpr)
@@ -702,6 +705,7 @@ dt_pid_create_pid_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
 
 	return ret;
 }
+
 /*
  * Read a file into a buffer and return it.
  */
@@ -780,8 +784,8 @@ validate_dof_record(const char *path, const dof_parsed_t *parsed,
 /*
  * Create underlying probes relating to the probespec passed on input.
  *
- * If dpr is set, just set up probes relating to mappings found in that one
- * process.  (dpr must in this case be locked.)
+ * dpr must be set and locked.  Just set up probes relating to mappings found
+ * in this one process.
  *
  * Return 0 on success or -1 on error.  (Failure to create specific underlying
  * probes is not an error.)
@@ -795,9 +799,6 @@ dt_pid_create_usdt_probes(dtrace_hdl_t *dtp, dt_proc_t *dpr, dtrace_probedesc_t
 	char *probepath = NULL;
 	glob_t probeglob = {0};
 
-	/*
-	 * Systemwide probing: not yet implemented.
-	 */
 	assert(dpr != NULL && dpr->dpr_proc);
 	assert(MUTEX_HELD(&dpr->dpr_lock));
 
@@ -1100,16 +1101,27 @@ dt_pid_create_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp, dt_pcb_t *pcb,
 	char provname[DTRACE_PROVNAMELEN];
 	dt_proc_t *dpr;
 	pid_t pid;
-	int err = 0;
+	int err = 0, i, nmatches = 0;
+	glob_t globbuf;
+	char *globpat = NULL;
 
 	assert(pcb != NULL);
 
-	if ((pid = dt_pid_get_pid(pdp, dtp, pcb, NULL)) == -1)
+	/* Exclude pid0 from being specifically requested. */
+	if (strcmp(pdp->prv, "pid0") == 0) {
+		dt_pid_error(dtp, pcb, NULL, D_PROC_BADPID,
+			     "pid0 does not contain a valid pid");
 		return -1;
+	}
 
-	snprintf(provname, sizeof(provname), "pid%d", (int)pid);
-
-	if ((usdt_only == 0) && gmatch(provname, pdp->prv) != 0) {
+	/*
+	 * Is this a pid$pid probe?
+	 */
+	provname[0] = '\0';
+	if ((pid = dt_pid_get_pid(pdp, dtp, pcb, NULL)) > 0 &&
+	    snprintf(provname, sizeof(provname), "pid%d", (int)pid) > 0 &&
+	    (usdt_only == 0) &&
+	    gmatch(provname, pdp->prv) != 0) {
 		if (dt_proc_grab_lock(dtp, pid, DTRACE_PROC_WAITING) < 0) {
 			dt_pid_error(dtp, pcb, NULL, D_PROC_GRAB,
 			    "failed to grab process %d", (int)pid);
@@ -1119,14 +1131,45 @@ dt_pid_create_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp, dt_pcb_t *pcb,
 		dpr = dt_proc_lookup(dtp, pid);
 		assert(dpr != NULL);
 
+		// FIXME How should err be handled?
+		/*
+		 * Nick writes (also, see USDT case below):
+		 * Well, if you get an error, probe creation failed. I guess we do what
+		 * DTrace normally does in that case: log an error about it and keep going
+		 * as long as any probes at all are left...
+ 		 */
 		err = dt_pid_create_pid_probes(pdp, dtp, pcb, dpr);
 		dt_proc_release_unlock(dtp, pid);
 	}
 
 	/*
-	 * If it's not strictly a pid provider, we might match a USDT provider.
+	 * If it's strictly a pid provider, we're done.
+	 */
+	if (pid > 0 && strcmp(provname, pdp->prv) == 0)
+		return err ? -1 : 0;
+
+	/*
+	 * Look for USDT probes.
 	 */
-	if (strcmp(provname, pdp->prv) != 0) {
+	asprintf(&globpat, "%s/probes/*/%s", dtp->dt_dofstash_path, pdp->prv[0] ? pdp->prv : "*");
+	nmatches = glob(globpat, 0, NULL, &globbuf) ? 0 : globbuf.gl_pathc;
+	for (i = 0; i < nmatches; i++) {
+		char *s = globbuf.gl_pathv[i]
+			  + strlen(dtp->dt_dofstash_path)
+			  + strlen("/probes/");
+		dtrace_probedesc_t pdptmp;
+
+		pdptmp.prv = strchr(s, '/') + 1;
+		pdptmp.mod = pdp->mod[0] == '\0' ? "*" : pdp->mod;
+		pdptmp.fun = pdp->fun[0] == '\0' ? "*" : pdp->fun;
+		pdptmp.prb = pdp->prb[0] == '\0' ? "*" : pdp->prb;
+
+		pid = atoll(s);
+
+		// Check, since dtprobed takes a while to clean up dead processes.
+		if (!Pexists(pid))
+			continue;
+
 		if (dt_proc_grab_lock(dtp, pid, DTRACE_PROC_WAITING |
 				      DTRACE_PROC_SHORTLIVED) < 0) {
 			dt_pid_error(dtp, pcb, NULL, D_PROC_GRAB,
@@ -1137,17 +1180,18 @@ dt_pid_create_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp, dt_pcb_t *pcb,
 		dpr = dt_proc_lookup(dtp, pid);
 		assert(dpr != NULL);
 
-		err = dt_pid_create_usdt_probes(dtp, dpr, pdp, pcb);
+		// FIXME: How should err be handled?
+		err = dt_pid_create_usdt_probes(dtp, dpr, &pdptmp, pcb);
 
 		/*
 		 * Put the module name in its canonical form.
 		 */
-		dt_pid_fix_mod(NULL, pdp, dtp, dpr->dpr_pid);
+		dt_pid_fix_mod(NULL, &pdptmp, dtp, dpr->dpr_pid);
 
 		dt_proc_release_unlock(dtp, pid);
 	}
-
-	/* (USDT systemwide probing goes here.)  */
+	free(globpat);
+	globfree(&globbuf);
 
 	return err ? -1 : 0;
 }
diff --git a/test/unittest/dtrace-util/tst.ListProbesFuncUSDT.sh b/test/unittest/dtrace-util/tst.ListProbesFuncUSDT.sh
index bd0552dc..99ae995e 100755
--- a/test/unittest/dtrace-util/tst.ListProbesFuncUSDT.sh
+++ b/test/unittest/dtrace-util/tst.ListProbesFuncUSDT.sh
@@ -5,7 +5,6 @@
 # Licensed under the Universal Permissive License v 1.0 as shown at
 # http://oss.oracle.com/licenses/upl.
 #
-# @@xfail: dtv2
 
 ##
 #
diff --git a/test/unittest/dtrace-util/tst.ListProbesModuleUSDT.sh b/test/unittest/dtrace-util/tst.ListProbesModuleUSDT.sh
index 7b9c6a5f..5ae087fb 100755
--- a/test/unittest/dtrace-util/tst.ListProbesModuleUSDT.sh
+++ b/test/unittest/dtrace-util/tst.ListProbesModuleUSDT.sh
@@ -5,7 +5,6 @@
 # Licensed under the Universal Permissive License v 1.0 as shown at
 # http://oss.oracle.com/licenses/upl.
 #
-# @@xfail: dtv2
 
 ##
 #
diff --git a/test/unittest/dtrace-util/tst.ListProbesNameUSDT.sh b/test/unittest/dtrace-util/tst.ListProbesNameUSDT.sh
index f9b1d8bf..5c0509d8 100755
--- a/test/unittest/dtrace-util/tst.ListProbesNameUSDT.sh
+++ b/test/unittest/dtrace-util/tst.ListProbesNameUSDT.sh
@@ -5,7 +5,6 @@
 # Licensed under the Universal Permissive License v 1.0 as shown at
 # http://oss.oracle.com/licenses/upl.
 #
-# @@xfail: dtv2
 
 ##
 #
diff --git a/test/unittest/dtrace-util/tst.ListProbesProviderUSDT.sh b/test/unittest/dtrace-util/tst.ListProbesProviderUSDT.sh
index 644da2ac..6eae82ed 100755
--- a/test/unittest/dtrace-util/tst.ListProbesProviderUSDT.sh
+++ b/test/unittest/dtrace-util/tst.ListProbesProviderUSDT.sh
@@ -5,7 +5,6 @@
 # Licensed under the Universal Permissive License v 1.0 as shown at
 # http://oss.oracle.com/licenses/upl.
 #
-# @@xfail: dtv2
 
 ##
 #
diff --git a/test/unittest/usdt/tst.forker.sh b/test/unittest/usdt/tst.forker.sh
index 7cfa9eb5..92513eb5 100755
--- a/test/unittest/usdt/tst.forker.sh
+++ b/test/unittest/usdt/tst.forker.sh
@@ -7,7 +7,6 @@
 #
 #
 # @@timeout: 120
-# @@xfail: dtv2 USDT wildcard
 
 if [ $# != 1 ]; then
 	echo expected one argument: '<'dtrace-path'>'
-- 
2.43.5