Merge from emacs-26

e62ad04963 Fix sgml-mode handling of quotes within parens (Bug#36347)
06b35b2f92 ; * lisp/frame.el: Enhance add-variable-watcher commentary.
572e34bb6f Rename 'make-symbolic-link' argument NEWNAME to LINKNAME
04477adedc Check that length of data returned by sysctl is non-zero
81535eeadb * test/lisp/progmodes/python-tests.el (python-virt-bin): D...
9d48979ca8 Fix Python tests depending on system-type
fcf6cc3177 Fix problem with wdired test when symlinks cannot be created.
4701e0663e Improve wording of documentation of click events

# Conflicts:
#	lisp/textmodes/sgml-mode.el
#	test/lisp/textmodes/sgml-mode-tests.el

1 files changed, 5 insertions, 5 deletions

diff --git a/src/sysdep.c b/src/sysdep.c
index f7fc99f147f..4f89e8aba10 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -3018,11 +3018,11 @@ list_system_processes (void)
 
   Lisp_Object proclist = Qnil;
 
-  if (sysctl (mib, 3, NULL, &len, NULL, 0) != 0)
+  if (sysctl (mib, 3, NULL, &len, NULL, 0) != 0 || len == 0)
     return proclist;
 
   procs = xmalloc (len);
-  if (sysctl (mib, 3, procs, &len, NULL, 0) != 0)
+  if (sysctl (mib, 3, procs, &len, NULL, 0) != 0 || len == 0)
     {
       xfree (procs);
       return proclist;
@@ -3616,7 +3616,7 @@ system_process_attributes (Lisp_Object pid)
   CONS_TO_INTEGER (pid, int, proc_id);
   mib[3] = proc_id;
 
-  if (sysctl (mib, 4, &proc, &proclen, NULL, 0) != 0)
+  if (sysctl (mib, 4, &proc, &proclen, NULL, 0) != 0 || proclen == 0)
     return attrs;
 
   attrs = Fcons (Fcons (Qeuid, INT_TO_INTEGER (proc.ki_uid)), attrs);
@@ -3739,7 +3739,7 @@ system_process_attributes (Lisp_Object pid)
 
   mib[2] = KERN_PROC_ARGS;
   len = MAXPATHLEN;
-  if (sysctl (mib, 4, args, &len, NULL, 0) == 0)
+  if (sysctl (mib, 4, args, &len, NULL, 0) == 0 && len != 0)
     {
       int i;
       for (i = 0; i < len; i++)
@@ -3785,7 +3785,7 @@ system_process_attributes (Lisp_Object pid)
   CONS_TO_INTEGER (pid, int, proc_id);
   mib[3] = proc_id;
 
-  if (sysctl (mib, 4, &proc, &proclen, NULL, 0) != 0)
+  if (sysctl (mib, 4, &proc, &proclen, NULL, 0) != 0 || proclen == 0)
     return attrs;
 
   uid = proc.kp_eproc.e_ucred.cr_uid;