From: Paul Eggert <eggert@cs.ucla.edu>
To: 23808@debbugs.gnu.org
Cc: Lars Ingebrigtsen <larsi@gnus.or>
Subject: bug#23808: Emacs 25 open-network-stream, make-network-process
Date: Thu, 11 Aug 2016 02:14:18 -0700 [thread overview]
Message-ID: <4dc79eb4-e2b6-9f33-cf61-af1971e10275@cs.ucla.edu> (raw)
In-Reply-To: <5767C0A3.9010902@cs.ucla.edu>
[-- Attachment #1: Type: text/plain, Size: 596 bytes --]
[CC'ing this to Lars, since this bug seems to have been introduced by the async
DNS changes in February.]
Attached is a proposed patch for Bug#23808. The patch attempts to fix the bug
reported by my anonymous correspondent, who writes "It appears that before the
refactoring, make-network-process would not create a process object if the
socket connection failed, or if it had been interrupted by ^G. However after the
new refactoring, the process object is created upfront with status 'run', before
the connection is attempted. The refactoring failed to preserve the semantics."
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: 0001-Fix-process-leak-with-make-network-process.patch --]
[-- Type: text/x-diff; name="0001-Fix-process-leak-with-make-network-process.patch", Size: 7822 bytes --]
From a21dfe515552c7d7f486950e9231b8ca2668f6cc Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 11 Aug 2016 01:56:16 -0700
Subject: [PATCH] Fix process leak with make-network-process
This problem was introduced by the recent async changes (Bug#23808).
* src/process.c (Fmake_process): Move USE_SAFE_ALLOCA later,
so that it follows the start_process_unwind unwind-protect.
Set pid to -1 while the process is being created.
(start_process_unwind): Omit unnecessary emacs_abort test.
(connect_network_socket): Simplify use of counts. Unwind
bind_polling_period a bit earlier, so that a remove_process
unwind-protect can be added when needed; this is the heart of
the fix. Undo the unwind-protect just before returning.
---
src/process.c | 49 ++++++++++++++++++-------------------------------
src/process.h | 9 +++++----
2 files changed, 23 insertions(+), 35 deletions(-)
diff --git a/src/process.c b/src/process.c
index fb32698..69d1b2a 100644
--- a/src/process.c
+++ b/src/process.c
@@ -238,6 +238,7 @@ static int process_output_delay_count;
static bool process_output_skip;
+static void start_process_unwind (Lisp_Object);
static void create_process (Lisp_Object, char **, Lisp_Object);
#ifdef USABLE_SIGIO
static bool keyboard_bit_set (fd_set *);
@@ -245,11 +246,8 @@ static bool keyboard_bit_set (fd_set *);
static void deactivate_process (Lisp_Object);
static int status_notify (struct Lisp_Process *, struct Lisp_Process *);
static int read_process_output (Lisp_Object, int);
-static void handle_child_signal (int);
static void create_pty (Lisp_Object);
-
-static Lisp_Object get_process (register Lisp_Object name);
-static void exec_sentinel (Lisp_Object proc, Lisp_Object reason);
+static void exec_sentinel (Lisp_Object, Lisp_Object);
/* Mask of bits indicating the descriptors that we wait for input on. */
@@ -1407,8 +1405,6 @@ DEFUN ("process-list", Fprocess_list, Sprocess_list, 0, 0, 0,
\f
/* Starting asynchronous inferior processes. */
-static void start_process_unwind (Lisp_Object proc);
-
DEFUN ("make-process", Fmake_process, Smake_process, 0, MANY, 0,
doc: /* Start a program in a subprocess. Return the process object for it.
@@ -1459,7 +1455,6 @@ usage: (make-process &rest ARGS) */)
Lisp_Object buffer, name, command, program, proc, contact, current_dir, tem;
Lisp_Object xstderr, stderrproc;
ptrdiff_t count = SPECPDL_INDEX ();
- USE_SAFE_ALLOCA;
if (nargs == 0)
return Qnil;
@@ -1508,10 +1503,6 @@ usage: (make-process &rest ARGS) */)
}
proc = make_process (name);
- /* If an error occurs and we can't start the process, we want to
- remove it from the process list. This means that each error
- check in create_process doesn't need to call remove_process
- itself; it's all taken care of here. */
record_unwind_protect (start_process_unwind, proc);
pset_childp (XPROCESS (proc), Qt);
@@ -1561,6 +1552,8 @@ usage: (make-process &rest ARGS) */)
BUF_ZV (XBUFFER (buffer)),
BUF_ZV_BYTE (XBUFFER (buffer)));
+ USE_SAFE_ALLOCA;
+
{
/* Decide coding systems for communicating with the process. Here
we don't setup the structure coding_system nor pay attention to
@@ -1719,18 +1712,11 @@ usage: (make-process &rest ARGS) */)
return unbind_to (count, proc);
}
-/* This function is the unwind_protect form for Fstart_process. If
- PROC doesn't have its pid set, then we know someone has signaled
- an error and the process wasn't started successfully, so we should
- remove it from the process list. */
+/* If PROC doesn't have its pid set, then an error was signaled and
+ the process wasn't started successfully, so remove it. */
static void
start_process_unwind (Lisp_Object proc)
{
- if (!PROCESSP (proc))
- emacs_abort ();
-
- /* Was PROC started successfully?
- -2 is used for a pty with no process, eg for gdb. */
if (XPROCESS (proc)->pid <= 0 && XPROCESS (proc)->pid != -2)
remove_process (proc);
}
@@ -3124,7 +3110,6 @@ connect_network_socket (Lisp_Object proc, Lisp_Object addrinfos,
Lisp_Object use_external_socket_p)
{
ptrdiff_t count = SPECPDL_INDEX ();
- ptrdiff_t count1;
int s = -1, outch, inch;
int xerrno = 0;
int family;
@@ -3145,7 +3130,6 @@ connect_network_socket (Lisp_Object proc, Lisp_Object addrinfos,
}
/* Do this in case we never enter the while-loop below. */
- count1 = SPECPDL_INDEX ();
s = -1;
while (!NILP (addrinfos))
@@ -3313,7 +3297,7 @@ connect_network_socket (Lisp_Object proc, Lisp_Object addrinfos,
immediate_quit = 0;
/* Discard the unwind protect closing S. */
- specpdl_ptr = specpdl + count1;
+ specpdl_ptr = specpdl + count;
emacs_close (s);
s = -1;
if (0 <= socket_to_use)
@@ -3398,10 +3382,7 @@ connect_network_socket (Lisp_Object proc, Lisp_Object addrinfos,
p->outfd = outch;
/* Discard the unwind protect for closing S, if any. */
- specpdl_ptr = specpdl + count1;
-
- /* Unwind bind_polling_period and request_sigio. */
- unbind_to (count, Qnil);
+ specpdl_ptr = specpdl + count;
if (p->is_server && p->socktype != SOCK_DGRAM)
pset_status (p, Qlisten);
@@ -3925,7 +3906,12 @@ usage: (make-network-process &rest ARGS) */)
if (!NILP (buffer))
buffer = Fget_buffer_create (buffer);
+
+ /* Unwind bind_polling_period. */
+ unbind_to (count, Qnil);
+
proc = make_process (name);
+ record_unwind_protect (remove_process, proc);
p = XPROCESS (proc);
pset_childp (p, contact);
pset_plist (p, Fcopy_sequence (Fplist_get (contact, QCplist)));
@@ -3956,8 +3942,6 @@ usage: (make-network-process &rest ARGS) */)
set_network_socket_coding_system (proc, host, service, name);
- unbind_to (count, Qnil);
-
/* :server BOOL */
tem = Fplist_get (contact, QCserver);
if (!NILP (tem))
@@ -3974,6 +3958,7 @@ usage: (make-network-process &rest ARGS) */)
&& !NILP (Fplist_get (contact, QCnowait)))
p->is_non_blocking_client = true;
+ bool postpone_connection = false;
#ifdef HAVE_GETADDRINFO_A
/* With async address resolution, the list of addresses is empty, so
postpone connecting to the server. */
@@ -3981,11 +3966,13 @@ usage: (make-network-process &rest ARGS) */)
{
p->dns_request = dns_request;
p->status = list1 (Qconnect);
- return proc;
+ postpone_connection = true;
}
#endif
+ if (! postpone_connection)
+ connect_network_socket (proc, addrinfos, use_external_socket_p);
- connect_network_socket (proc, addrinfos, use_external_socket_p);
+ specpdl_ptr = specpdl + count;
return proc;
}
diff --git a/src/process.h b/src/process.h
index 6c227bc..9926050 100644
--- a/src/process.h
+++ b/src/process.h
@@ -118,10 +118,11 @@ struct Lisp_Process
/* After this point, there are no Lisp_Objects any more. */
/* alloc.c assumes that `pid' is the first such non-Lisp slot. */
- /* Number of this process.
- allocate_process assumes this is the first non-Lisp_Object field.
- A value 0 is used for pseudo-processes such as network or serial
- connections. */
+ /* Process ID. A positive value is a child process ID.
+ Zero is for pseudo-processes such as network or serial connections,
+ or for processes that have not been fully created yet.
+ -1 is for a process that was not created successfully.
+ -2 is for a pty with no process, e.g., for GDB. */
pid_t pid;
/* Descriptor by which we read from this process. */
int infd;
--
2.5.5
next prev parent reply other threads:[~2016-08-11 9:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-20 10:08 bug#23808: Emacs 25 open-network-stream, make-network-process Paul Eggert
2016-06-20 12:41 ` Lars Ingebrigtsen
2016-06-20 22:03 ` Paul Eggert
2016-08-11 9:14 ` Paul Eggert [this message]
2016-08-11 10:41 ` Lars Ingebrigtsen
2016-08-11 10:42 ` Lars Ingebrigtsen
2016-08-11 18:26 ` Paul Eggert
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