Allow "a.out" as an alias for the executable if no other matching entries

are found. This improves compatibility with Solaris' libproc and fixes a
number of failing DTrace tests that rely on this feature.

MFC after:	3 weeks

4 files changed, 63 insertions, 19 deletions

diff --git a/lib/libproc/_libproc.h b/lib/libproc/_libproc.h
index 8099ba1..ffc89cf 100644
--- a/lib/libproc/_libproc.h
+++ b/lib/libproc/_libproc.h
@@ -46,6 +46,8 @@ struct proc_handle {
 	size_t	rdobjsz;
 	size_t	nobjs;
 	struct lwpstatus lwps;
+	rd_loadobj_t *rdexec;		/* rdobj index of program executable. */
+	char	execname[MAXPATHLEN];	/* Path to program executable. */
 };
 
 #ifdef DEBUG
diff --git a/lib/libproc/proc_create.c b/lib/libproc/proc_create.c
index d02eccf..4a92580 100644
--- a/lib/libproc/proc_create.c
+++ b/lib/libproc/proc_create.c
@@ -26,8 +26,10 @@
  * $FreeBSD$
  */
 
-#include "_libproc.h"
-#include <stdio.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <sys/wait.h>
+
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
@@ -35,7 +37,37 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <sys/wait.h>
+
+#include "_libproc.h"
+
+static int	proc_init(pid_t, int, int, struct proc_handle *);
+
+static int
+proc_init(pid_t pid, int flags, int status, struct proc_handle *phdl)
+{
+	int mib[4], error;
+	size_t len;
+
+	memset(phdl, 0, sizeof(*phdl));
+	phdl->pid = pid;
+	phdl->flags = flags;
+	phdl->status = status;
+
+	mib[0] = CTL_KERN;
+	mib[1] = KERN_PROC;
+	mib[2] = KERN_PROC_PATHNAME;
+	mib[3] = pid;
+	len = sizeof(phdl->execname);
+	if (sysctl(mib, 4, phdl->execname, &len, NULL, 0) != 0) {
+		error = errno;
+		DPRINTF("ERROR: cannot get pathname for child process %d", pid);
+		return (error);
+	}
+	if (len == 0)
+		phdl->execname[0] = '\0';
+
+	return (0);
+}
 
 int
 proc_attach(pid_t pid, int flags, struct proc_handle **pphdl)
@@ -54,12 +86,12 @@ proc_attach(pid_t pid, int flags, struct proc_handle **pphdl)
 	if ((phdl = malloc(sizeof(struct proc_handle))) == NULL)
 		return (ENOMEM);
 
-	memset(phdl, 0, sizeof(struct proc_handle));
-	phdl->pid = pid;
-	phdl->flags = flags;
-	phdl->status = PS_RUN;
 	elf_version(EV_CURRENT);
 
+	error = proc_init(pid, flags, PS_RUN, phdl);
+	if (error != 0)
+		goto out;
+
 	if (ptrace(PT_ATTACH, phdl->pid, 0, 0) != 0) {
 		error = errno;
 		DPRINTF("ERROR: cannot ptrace child process %d", pid);
@@ -123,9 +155,9 @@ proc_create(const char *file, char * const *argv, proc_child_func *pcf,
 		_exit(2);
 	} else {
 		/* The parent owns the process handle. */
-		memset(phdl, 0, sizeof(struct proc_handle));
-		phdl->pid = pid;
-		phdl->status = PS_IDLE;
+		error = proc_init(pid, 0, PS_IDLE, phdl);
+		if (error != 0)
+			goto bad;
 
 		/* Wait for the child process to stop. */
 		if (waitpid(pid, &status, WUNTRACED) == -1) {
diff --git a/lib/libproc/proc_rtld.c b/lib/libproc/proc_rtld.c
index 5259049..8dff3b7 100644
--- a/lib/libproc/proc_rtld.c
+++ b/lib/libproc/proc_rtld.c
@@ -49,6 +49,9 @@ map_iter(const rd_loadobj_t *lop, void *arg)
 		if (phdl->rdobjs == NULL)
 			return (-1);
 	}
+	if (strcmp(lop->rdl_path, phdl->execname) == 0 &&
+	    (lop->rdl_prot & RD_RDL_X) != 0)
+		phdl->rdexec = &phdl->rdobjs[phdl->nobjs];
 	memcpy(&phdl->rdobjs[phdl->nobjs++], lop, sizeof(*lop));
 
 	return (0);
diff --git a/lib/libproc/proc_sym.c b/lib/libproc/proc_sym.c
index 2338895..3777a46 100644
--- a/lib/libproc/proc_sym.c
+++ b/lib/libproc/proc_sym.c
@@ -112,17 +112,23 @@ proc_obj2map(struct proc_handle *p, const char *objname)
 	rd_loadobj_t *rdl;
 	char path[MAXPATHLEN];
 
+	rdl = NULL;
 	for (i = 0; i < p->nobjs; i++) {
-		rdl = &p->rdobjs[i];
-		basename_r(rdl->rdl_path, path);
+		basename_r(p->rdobjs[i].rdl_path, path);
 		if (strcmp(path, objname) == 0) {
-			if ((map = malloc(sizeof(*map))) == NULL)
-				return (NULL);
-			proc_rdl2prmap(rdl, map);
-			return (map);
+			rdl = &p->rdobjs[i];
+			break;
 		}
 	}
-	return (NULL);
+	if (rdl == NULL && strcmp(objname, "a.out") == 0 && p->rdexec != NULL)
+		rdl = p->rdexec;
+	else
+		return (NULL);
+
+	if ((map = malloc(sizeof(*map))) == NULL)
+		return (NULL);
+	proc_rdl2prmap(rdl, map);
+	return (map);
 }
 
 int
@@ -386,8 +392,9 @@ proc_name2map(struct proc_handle *p, const char *name)
 		free(kves);
 		return (NULL);
 	}
-	if (name == NULL || strcmp(name, "a.out") == 0) {
-		map = proc_addr2map(p, p->rdobjs[0].rdl_saddr);
+	if ((name == NULL || strcmp(name, "a.out") == 0) &&
+	    p->rdexec != NULL) {
+		map = proc_addr2map(p, p->rdexec->rdl_saddr);
 		return (map);
 	}
 	for (i = 0; i < p->nobjs; i++) {