ENH: Add process_name key to support broken/missing _NET_WM_PID

README.md

@@ -63,10 +63,11 @@ Install binary package for your GNU/Linux distribution:
 #### From Source
 
 ```bash
-# Install dependencies, namely GLib, Libwnck, procps
+# Install dependencies, namely GLib, Libwnck, libprocps, procps
 # on Debian / Ubuntu / Mint:
 sudo apt install libglib2.0-dev \
                  libwnck-3-dev  \
+                 libprocps-dev  \
                  procps         \
                  make cmake gcc pkg-config
 

data/xsuspender.conf

@@ -34,6 +34,11 @@
 #     # Also suspend descendant processes that match this regex.
 #     suspend_subtree_pattern = .
 #
+#     # Assume that all windows matching this rule belong to the
+#     # process with this name. This is a workaround for
+#     # missing or incorrect _NET_WM_PID values, e.g. with Flatpak.
+#     process_name = ...
+#
 #     # Whether to apply the rule only when on battery power.
 #     only_on_battery = true
 #

doc/xsuspender.1

@@ -202,6 +202,13 @@ This setting only applies when
 .B send_signals
 is also true.
 .TP
+.BR process_name
+If provided, XSuspender will ignore _NET_WM_PID and instead detect
+the process a window matching this rule belongs to by looking for
+a process whose process name (cmdline[0]) matches this string verbatim.
+There should be only one such process not including its child processes.
+This is useful when _NET_WM_PID is incorrect or unset, e.g. with flatpak.
+.TP
 .BR exec_suspend
 .TQ
 .BR exec_resume

src/CMakeLists.txt

@@ -2,19 +2,20 @@ find_package (PkgConfig REQUIRED)
 
 pkg_check_modules (GLIB REQUIRED glib-2.0)
 pkg_check_modules (WNCK REQUIRED libwnck-3.0)
+pkg_check_modules (PROCPS REQUIRED libprocps)
 
 add_definitions (-DWNCK_I_KNOW_THIS_IS_UNSTABLE
                  -D_POSIX_SOURCE
                  -DG_LOG_DOMAIN="xsuspender")
 
-add_compile_options (${GLIB_CFLAGS} ${WNCK_CFLAGS})
+add_compile_options (${GLIB_CFLAGS} ${WNCK_CFLAGS} ${PROCPS_CFLAGS})
 
 file (GLOB SOURCES "*.[ch]")
 add_executable (${PROJECT_NAME} ${SOURCES})
 
 # pkg-config recipe for libwnck may be a bit overzealos; trim linked libs to essentials
 set (CMAKE_EXE_LINKER_FLAGS "-Wl,--as-needed -Wl,--no-undefined")
 
-target_link_libraries (${PROJECT_NAME} PRIVATE ${GLIB_LDFLAGS} ${WNCK_LDFLAGS})
+target_link_libraries (${PROJECT_NAME} PRIVATE ${GLIB_LDFLAGS} ${WNCK_LDFLAGS} ${PROCPS_LDFLAGS})
 
 install (TARGETS ${PROJECT_NAME} DESTINATION bin)

src/config.c

@@ -145,6 +145,9 @@ read_section (GKeyFile *file,
     str = g_key_file_get_value (file, section, CONFIG_KEY_SUBTREE_PATTERN, &err);
     if (! is_error (&err)) reassign_str (&rule->subtree_pattern, str);
 
+    str = g_key_file_get_value (file, section, CONFIG_KEY_PROCESS_NAME, &err);
+    if ( !is_error (&err)) reassign_str (&rule->process_name, str);
+
     char **argv;
 
     argv = parse_command (file, section, CONFIG_KEY_EXEC_SUSPEND, &err);
@@ -190,6 +193,7 @@ debug_print_rule (Rule *rule)
                  "only_on_battery = %d\n"
                  "send_signals = %d\n"
                  "subtree_pattern = %s\n"
+                 "process_name = %s\n"
                  "downclock_on_battery = %d\n"
                  "exec_suspend = %s\n"
                  "exec_resume = %s\n",
@@ -202,6 +206,7 @@ debug_print_rule (Rule *rule)
              rule->only_on_battery,
              rule->send_signals,
              rule->subtree_pattern,
+             rule->process_name,
              rule->downclock_on_battery,
              (rule->exec_suspend ? rule->exec_suspend[2] : NULL),
              (rule->exec_resume ? rule->exec_resume[2] : NULL)
@@ -222,6 +227,8 @@ parse_config ()
 
         .subtree_pattern = NULL,
 
+        .process_name = NULL,
+
         .downclock_on_battery = 0,
 
         .delay = 10,

src/config.h

@@ -17,6 +17,7 @@
 #define CONFIG_KEY_AUTO_ON_BATTERY         "auto_suspend_on_battery"
 #define CONFIG_KEY_SEND_SIGNALS            "send_signals"
 #define CONFIG_KEY_SUBTREE_PATTERN         "suspend_subtree_pattern"
+#define CONFIG_KEY_PROCESS_NAME            "process_name"
 #define CONFIG_KEY_DOWNCLOCK_ON_BATTERY    "downclock_on_battery"
 #define CONFIG_KEY_WM_NAME_CONTAINS        "match_wm_name_contains"
 #define CONFIG_KEY_WM_CLASS_CONTAINS       "match_wm_class_contains"
@@ -26,6 +27,7 @@
                             CONFIG_KEY_AUTO_ON_BATTERY,          \
                             CONFIG_KEY_SEND_SIGNALS,             \
                             CONFIG_KEY_SUBTREE_PATTERN,          \
+                            CONFIG_KEY_PROCESS_NAME,             \
                             CONFIG_KEY_DOWNCLOCK_ON_BATTERY,     \
                             CONFIG_KEY_SUSPEND_DELAY,            \
                             CONFIG_KEY_RESUME_EVERY,             \

src/entry.c

@@ -3,14 +3,15 @@
 #include <glib.h>
 #include <libwnck/libwnck.h>
 
+#include "proc.h"
 
 WindowEntry*
 xsus_window_entry_new (WnckWindow *window,
                        Rule *rule)
 {
     WindowEntry *entry = g_malloc (sizeof (WindowEntry));
     entry->rule = rule;
-    entry->pid = wnck_window_get_pid (window);
+    entry->pid = xsus_window_get_pid (window);
     entry->xid = wnck_window_get_xid (window);
     entry->wm_name = g_strdup (wnck_window_get_name (window));
     return entry;
@@ -44,7 +45,7 @@ xsus_entry_find_for_window_rule (WnckWindow *window,
 {
     // If suspending by signals, find entry by PID ...
     if (rule->send_signals) {
-        pid_t pid = wnck_window_get_pid (window);
+        pid_t pid = xsus_window_get_pid (window);
         for (; list; list = list->next) {
             WindowEntry *entry = list->data;
             if (entry->pid == pid)

src/events.c

@@ -8,6 +8,7 @@
 
 #include "entry.h"
 #include "macros.h"
+#include "proc.h"
 
 
 void
@@ -69,7 +70,7 @@ windows_are_same_process (WnckWindow *w1,
     Rule *rule;
     return (WNCK_IS_WINDOW (w1) &&
             WNCK_IS_WINDOW (w2) &&
-            wnck_window_get_pid (w1) == wnck_window_get_pid (w2) &&
+            xsus_window_get_pid (w1) == xsus_window_get_pid (w2) &&
             (rule = xsus_window_get_rule (w1)) &&
             rule->send_signals &&
             rule == xsus_window_get_rule (w2));
@@ -104,7 +105,7 @@ pid_t
 window_entry_get_pid (WindowEntry *entry)
 {
     WnckWindow *window = wnck_window_get (entry->xid);
-    return window && wnck_window_get_pid (window) == entry->pid ? entry->pid : 0;
+    return window && xsus_window_get_pid (window) == entry->pid ? entry->pid : 0;
 }
 
 
@@ -411,7 +412,7 @@ on_update_downclocked_processes ()
             continue;
 
         // Skip any windows/PIDs we already know about
-        pid_t pid = wnck_window_get_pid (window);
+        pid_t pid = xsus_window_get_pid (window);
         if (g_hash_table_contains (old_pids, GINT_TO_POINTER (pid)) ||
             g_hash_table_contains (new_pids, GINT_TO_POINTER (pid)))
             continue;

src/proc.c

@@ -0,0 +1,88 @@
+#include "proc.h"
+#include <limits.h>
+#include <proc/readproc.h>
+#include "rule.h"
+
+
+static
+gboolean
+cmdline_matches (char **cmdline, char *s)
+{
+    if (cmdline == NULL)
+        return FALSE;
+
+    char *basename = g_path_get_basename (cmdline[0]);
+    gboolean result = g_strcmp0 (basename, s) == 0;
+    g_free (basename);
+    return result;
+}
+
+
+static
+proc_t*
+proc_by_pid (pid_t pid)
+{
+    pid_t arr[2] = {pid, 0};
+    PROCTAB *pt = openproc(PROC_FILLARG | PROC_FILLSTAT | PROC_PID, arr);
+    proc_t *result = readproc(pt, NULL);
+    closeproc(pt);
+    return result;
+}
+
+
+static
+pid_t
+process_name_get_pid (char *process_name)
+{
+    // Types match readproc.c
+    pid_t cand_pid = 0;
+    unsigned long long cand_start_time = ULLONG_MAX;  // NOLINT(runtime/int)
+
+    PROCTAB *pt = openproc(PROC_FILLARG | PROC_FILLSTAT);
+    proc_t *proc;
+
+    while ((proc = readproc(pt, NULL))) {
+        pid_t tree_cand_pid = 0;
+        unsigned long long tree_cand_start_time = ULLONG_MAX;  // NOLINT(runtime/int)
+
+        // Some applications use multiple processes with the same name -- find the root one
+        pid_t ppid;
+        do {
+            if (cmdline_matches(proc->cmdline, process_name)) {
+                tree_cand_pid = proc->tid;
+                tree_cand_start_time = proc->start_time;
+            }
+            ppid = proc->ppid;
+            freeproc(proc);
+        } while ((proc = proc_by_pid(ppid)));
+
+        if (tree_cand_pid != 0 && tree_cand_pid != cand_pid) {
+            if (cand_pid != 0)
+                g_warning("Multiple processes named '%s': %u and %u",
+                          process_name, cand_pid, tree_cand_pid);
+
+            if (tree_cand_start_time < cand_start_time ||
+                (tree_cand_start_time == cand_start_time &&
+                 tree_cand_pid < cand_pid)) {
+                // Update
+                cand_pid = tree_cand_pid;
+                cand_start_time = tree_cand_start_time;
+            }
+        }
+    }
+
+    closeproc(pt);
+    return cand_pid;
+}
+
+
+pid_t
+xsus_window_get_pid (WnckWindow *window)
+{
+    Rule *rule = xsus_window_get_rule (window);
+    char *process_name = rule ? rule->process_name : NULL;
+    pid_t pid_by_process_name = process_name ? process_name_get_pid(process_name) : 0;
+    // Prefer getting the PID by process name so we can override _NET_WM_PID if it's wrong
+    // (e.g. when using flatpak)
+    return pid_by_process_name ? pid_by_process_name : wnck_window_get_pid(window);
+}

src/proc.h

@@ -0,0 +1,7 @@
+#ifndef XSUSPENDER_PROC_H
+#define XSUSPENDER_PROC_H
+#include <libwnck/libwnck.h>
+
+int xsus_window_get_pid (WnckWindow *window);
+
+#endif  // XSUSPENDER_PROC_H

src/rule.c

@@ -4,6 +4,7 @@
 #include <libwnck/libwnck.h>
 
 #include "xsuspender.h"
+#include "proc.h"
 
 Rule*
 xsus_rule_copy (Rule *orig)
@@ -15,6 +16,8 @@ xsus_rule_copy (Rule *orig)
     rule->needle_wm_class = g_strdup (orig->needle_wm_class);
     rule->needle_wm_class_group = g_strdup (orig->needle_wm_class_group);
 
+    rule->process_name = g_strdup (orig->process_name);
+
     rule->exec_suspend = g_strdupv (orig->exec_suspend);
     rule->exec_resume = g_strdupv (orig->exec_resume);
 
@@ -29,6 +32,8 @@ xsus_rule_free (Rule *rule)
     g_free (rule->needle_wm_class_group);
     g_free (rule->needle_wm_name);
 
+    g_free (rule->process_name);
+
     g_strfreev (rule->exec_suspend);
     g_strfreev (rule->exec_resume);
 

src/rule.h

@@ -16,6 +16,8 @@ typedef struct Rule {
 
     char*  subtree_pattern;
 
+    char*  process_name;
+
     guint16 delay;
     guint16 resume_every;
     guint16 resume_for;

src/xsuspender.c

@@ -13,6 +13,7 @@
 #include "events.h"
 #include "exec.h"
 #include "macros.h"
+#include "proc.h"
 #include "rule.h"
 
 
@@ -108,7 +109,7 @@ xsus_window_resume (WnckWindow *window)
     if ((entry = xsus_entry_find_for_window_rule (window, rule, queued_entries))) {
         g_debug ("Removing window %#lx (%d) from suspension queue: %s",
                  wnck_window_get_xid (window),
-                 wnck_window_get_pid (window),
+                 xsus_window_get_pid (window),
                  wnck_window_get_name (window));
         queued_entries = g_slist_remove (queued_entries, entry);
         xsus_window_entry_free (entry);
@@ -119,7 +120,7 @@ xsus_window_resume (WnckWindow *window)
     if ((entry = xsus_entry_find_for_window_rule (window, rule, suspended_entries))) {
         g_debug ("Resuming window %#lx (%d): %s",
                  wnck_window_get_xid (window),
-                 wnck_window_get_pid (window),
+                 xsus_window_get_pid (window),
                  wnck_window_get_name (window));
         xsus_signal_continue (entry);
         return;
@@ -150,7 +151,7 @@ xsus_window_suspend (WnckWindow *window)
     g_debug ("Suspending window in %ds: %#lx (%d): %s",
              rule->delay,
              wnck_window_get_xid (window),
-             wnck_window_get_pid (window),
+             xsus_window_get_pid (window),
              wnck_window_get_name (window));
     WindowEntry *entry = xsus_window_entry_new (window, rule);
     xsus_window_entry_enqueue (entry, rule->delay);