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-rwxr-xr-xlclipd.lua50
1 files changed, 34 insertions, 16 deletions
diff --git a/lclipd.lua b/lclipd.lua
index 7c72259..3c76696 100755
--- a/lclipd.lua
+++ b/lclipd.lua
@@ -27,6 +27,8 @@ local function default_luarocks_modules()
end
default_luarocks_modules()
+-- we want to delete a pidfile if we wrote one
+local wrote_a_pidfile = false
local signal = require("posix.signal")
local argparse = require("argparse")
local sys_stat = require("posix.sys.stat")
@@ -85,7 +87,7 @@ local db_file_name = "/tmp/lclipd_db_name"
local function sleep(n) os.execute("sleep " .. tonumber(n)) end
--- We are not longer running.
-local function remove_pid_file() os.remove(pid_file) end
+local function remove_pid_file() if wrote_a_pidfile then os.remove(pid_file) end end
--- Adds LUA_PATH and LUA_CPATH to the current interpreters path.
@@ -113,16 +115,32 @@ local function check_uid_gid()
posix_syslog.LOG_INFO)
end
---- Checks to make sure that the pid file for clipd does not exist.
+--- Tries to determine whether another instance is running, if yes, quits
local function check_pid_file()
local f = sys_stat.stat(pid_file)
if f ~= nil then
- log_to_syslog("clipd is already running", posix_syslog.LOG_CRIT)
- lclip_exit(1)
+ local pid_file_handle = io.open(pid_file, "r")
+ local pid_file_content = pid_file_handle:read("*a")
+ pid_file_content = pid_file_content:gsub("\n", "")
+ log_to_syslog(pid_file_content, posix_syslog.LOG_INFO)
+
+ local old_pid_file = sys_stat.stat("/proc/" .. pid_file_content)
+ if old_pid_file ~= nil then
+ local pid_cmdline = io.open("/proc/" .. pid_file_content ..
+ "/cmdline", "r")
+ local pid_cmdline_content = pid_cmdline:read("*a")
+ if string.match(pid_cmdline_content, "lclipd") then
+ -- we assume a lclipd instance is already running at this point
+ log_to_syslog("clipd is already running", posix_syslog.LOG_CRIT)
+ lclip_exit(1)
+ end
+ -- the old pid file is stale, meaning the previous instance
+ -- died without being able to clean up after itself
+ end
end
end
---- instance running.
+--- Write a pidfile
local function write_pid_file()
local f = io.open(pid_file, "w")
if f == nil then
@@ -130,28 +148,28 @@ local function write_pid_file()
lclip_exit(1)
end
f:write(tostring(unistd.getpid()))
+ wrote_a_pidfile = true
end
--- Get the clipboard content from X or wayland.
local function get_clipboard_content()
- -- if we use a plain os.execute for clipnotify we wont get the ctrl-c
- -- when it is pressed. doing it manually though the parent receives
+ -- if we use a plain os.execute for clipnotify the parent wont get the
+ -- SIGINT when it is passed. if we fork though, the parent receives
-- the SIGINT just fine.
local pid, errmsg = unistd.fork()
- if pid == nil then
+ if pid == nil then -- error
log_to_syslog("could not fork", posix_syslog.LOG_CRIT)
log_to_syslog(errmsg, posix_syslog.LOG_CRIT)
- remove_pid_file()
- os.exit(1)
- elseif pid == 0 then
+ lclip_exit(1)
+ elseif pid == 0 then -- child
-- clipnotify exits when there is a new entry on the clipboard
-- so we do want a blocking call here
os.execute("clipnotify")
os.exit(0)
- else
+ else -- parent
posix_wait.wait(pid)
- -- we dont care whether all the calls to clipboard progs succeed
- -- or not. so we just mask the errors.
+ -- we dont care whether all the calls to the different clipboard apps
+ -- succeed or not so we just ignore the errors.
local _, handle_x = pcall(io.popen, "xsel -ob")
local last_clip_entry_x = handle_x:read("*a")
@@ -261,8 +279,8 @@ local function main()
end)
local args = parser:parse()
- -- check_pid_file()
- -- write_pid_file()
+ check_pid_file()
+ write_pid_file()
check_uid_gid()
local status, err = pcall(loop, args["hist_size"])
if status ~= true then log_to_syslog(err, posix_syslog.LOG_CRIT) end