Assume KERN_PROC_PATHNAME is present on FreeBSD hosts.

FreeBSD kernels have included this sysctl since 6.0 release.  The most
recent release without support is 5.5 which was released in May of
2006.

Both the sysctl and the /proc/<pid>/exe file call the same function in
the kernel to obtain the path (vn_fullpath).  If the sysctl fails, the
readlink call will also fail, so there is no need to keep the readlink
fallback.

gdb/ChangeLog:

	* fbsd-nat.c (fbsd_nat_target::pid_to_exec_file): Always use
	sysctl and remove procfs fallback.

2 files changed, 5 insertions, 13 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8cfe349..68ecbf0 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2020-09-16  John Baldwin  <jhb@FreeBSD.org>
 
+	* fbsd-nat.c (fbsd_nat_target::pid_to_exec_file): Always use
+	sysctl and remove procfs fallback.
+
+2020-09-16  John Baldwin  <jhb@FreeBSD.org>
+
 	* fbsd-nat.c: Assume PT_LWPINFO is always defined.
 	* fbsd-nat.h: Likewise.
 
diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
index fc7136a..6193e0f 100644
--- a/gdb/fbsd-nat.c
+++ b/gdb/fbsd-nat.c
@@ -53,11 +53,7 @@
 char *
 fbsd_nat_target::pid_to_exec_file (int pid)
 {
-  ssize_t len;
   static char buf[PATH_MAX];
-  char name[PATH_MAX];
-
-#ifdef KERN_PROC_PATHNAME
   size_t buflen;
   int mib[4];
 
@@ -71,15 +67,6 @@ fbsd_nat_target::pid_to_exec_file (int pid)
        for processes without an associated executable such as kernel
        processes.  */
     return buflen == 0 ? NULL : buf;
-#endif
-
-  xsnprintf (name, PATH_MAX, "/proc/%d/exe", pid);
-  len = readlink (name, buf, PATH_MAX - 1);
-  if (len != -1)
-    {
-      buf[len] = '\0';
-      return buf;
-    }
 
   return NULL;
 }