[PATCH 38/38] Systemwide USDT WIP

[eugene.loh@oracle.com]

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

need to:
- review tests
- 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_cc.c                             |   3 +-
 libdtrace/dt_pid.c                            | 133 +++++++++++++++---
 .../dtrace-util/tst.ListProbesNameUSDT.sh     |   1 -
 .../dtrace-util/tst.ListProbesProviderUSDT.sh |   1 -
 test/unittest/usdt/tst.forker.sh              |   1 -
 5 files changed, 119 insertions(+), 20 deletions(-)

diff --git a/libdtrace/dt_cc.c b/libdtrace/dt_cc.c
index d09a9775..3f316775 100644
--- a/libdtrace/dt_cc.c
+++ b/libdtrace/dt_cc.c
@@ -278,7 +278,8 @@ dt_setcontext(dtrace_hdl_t *dtp, const dtrace_probedesc_t *pdp)
 	 * and tag -- we just have to longjmp() out of here.
 	 */
 	if (pdp->prv && pdp->prv[0] &&
-	    isdigit(pdp->prv[strlen(pdp->prv) - 1]) &&
+	    (isdigit(pdp->prv[strlen(pdp->prv) - 1]) ||
+	             pdp->prv[strlen(pdp->prv) - 1] == '*') &&
 	    ((pvp = dt_provider_lookup(dtp, pdp->prv)) == NULL ||
 	     pvp->pv_flags & DT_PROVIDER_PID) &&
 	    dt_pid_create_probes((dtrace_probedesc_t *)pdp, dtp, yypcb) != 0) {
diff --git a/libdtrace/dt_pid.c b/libdtrace/dt_pid.c
index 996543b1..079377ec 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));
 
@@ -1094,22 +1095,99 @@ dt_pid_get_pid(const dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp, dt_pcb_t *pcb,
 	return pid;
 }
 
+static const char *
+convert_pidglob(const char *s)
+{
+	/*
+	 * Convert a glob for "pid[1-9][0-9]*" into one for just the numerical
+	 * portion.  It will always be a subset of the input string.  A NULL
+	 * pointer is returned if there is no such string -- e.g., if the input
+	 * string is "foo1234".
+	 *
+	 * There is no need to check the entire string for legality.  E.g., if
+	 * the input string is "pid*q*", we can simply return "*q*".  Then, this
+	 * string will not match any "[1-9][0-9]*";  we do not need to intervene.
+	 */
+	const char	*p;
+	int		nchars = 0;	/* number of chars of "pid" we have seen so far */
+
+	for (p = s; ; p++) {
+		switch (*p) {
+		case 'p':
+			if (nchars > 0)
+				return NULL;
+			nchars = 1;
+			break;
+		case 'i':
+			if (nchars > 1)
+				return NULL;
+			if (nchars < 1 && p[-1] != '*')
+				return NULL;
+			nchars = 2;
+			break;
+		case 'd':
+			if (nchars > 2)
+				return NULL;
+			if (nchars < 2 && p[-1] != '*')
+				return NULL;
+			nchars = 3;
+			break;
+		case '*':
+			break;
+		case '\0':
+			if (p == s)
+				return NULL;
+			if (p[-1] != '*')
+				return p;
+			return p - 1;
+		default:
+			if (*p < '0' || *p > '9')
+				return NULL;
+			if (p == s)
+				return NULL;
+			if (p[-1] != '*')
+				return p;
+			return p - 1;
+		}
+	}
+}
+
 int
 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;
 
 	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;
+	}
+
+	/*
+	 * Try pid probes.
+	 */
+	asprintf(&globpat, "/proc/%s/map_files", convert_pidglob(pdp->prv));
+	nmatches = glob(globpat, 0, NULL, &globbuf) ? 0 : globbuf.gl_pathc;
+	for (i = 0; i < nmatches; i++) {
+		if (strncmp(globbuf.gl_pathv[i], "/proc/self", 10) == 0)
+			continue;
+
+		pid = strtol(globbuf.gl_pathv[i] + strlen("/proc/"), NULL, 10);
 
-	snprintf(provname, sizeof(provname), "pid%d", (int)pid);
+#if 1
+		// FIXME: omit this check once we have confidence in convert_pidglob()
+		char provname[DTRACE_PROVNAMELEN];
+		snprintf(provname, sizeof(provname), "pid%d", (int)pid);
+		assert(gmatch(provname, pdp->prv) != 0);
+#endif
 
-	if (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 +1197,36 @@ 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?
 		err = dt_pid_create_pid_probes(pdp, dtp, pcb, dpr);
 		dt_proc_release_unlock(dtp, pid);
 	}
+	free(globpat);
+	globfree(&globbuf);
 
 	/*
-	 * If it's not strictly a pid provider, we might match a USDT provider.
+	 * Try USDT probes.
 	 */
-	if (strcmp(provname, pdp->prv) != 0) {
+	asprintf(&globpat, "%s/probes/*/%s", dtp->dt_dofstash_path, 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, '/');
+		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;
+// FIXME should also check dof_version, though that doesn't do much yet
+
 		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 +1237,18 @@ 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.ListProbesNameUSDT.sh b/test/unittest/dtrace-util/tst.ListProbesNameUSDT.sh
index c5dfc72b..9d8f06e9 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'>'
-- 
2.18.4