From e410a9c2e542bc550c7fa619db550242cda6b345 Mon Sep 17 00:00:00 2001
From: "aiyion.prime" <git@aiyionpri.me>
Date: Thu, 17 Jun 2021 22:25:05 +0200
Subject: [PATCH] gluon-core: implement popen3() in gluon/util.lua
[Matthias Schiffer: simplify close_fds() helper and use in child process]
---
.../luasrc/usr/lib/lua/gluon/util.lua | 74 +++++++++++++++++++
1 file changed, 74 insertions(+)
diff --git a/package/gluon-core/luasrc/usr/lib/lua/gluon/util.lua b/package/gluon-core/luasrc/usr/lib/lua/gluon/util.lua
index a5d13a5b..48b8340e 100644
--- a/package/gluon-core/luasrc/usr/lib/lua/gluon/util.lua
+++ b/package/gluon-core/luasrc/usr/lib/lua/gluon/util.lua
@@ -1,6 +1,8 @@
local bit = require 'bit'
+local posix_fcntl = require 'posix.fcntl'
local posix_glob = require 'posix.glob'
local posix_syslog = require 'posix.syslog'
+local posix_unistd = require 'posix.unistd'
local hash = require 'hash'
local sysconfig = require 'gluon.sysconfig'
local site = require 'gluon.site'
@@ -193,4 +195,76 @@ function M.log(message, verbose)
posix_syslog.syslog(posix_syslog.LOG_INFO, message)
end
+local function close_fds(fds)
+ for _, fd in pairs(fds) do
+ posix_unistd.close(fd)
+ end
+end
+
+M.subprocess = {}
+
+M.subprocess.DEVNULL = -1
+M.subprocess.PIPE = 1
+
+-- Execute a program found using command PATH search, like the shell.
+-- Return the pid, as well as the I/O streams as pipes or nil on error.
+function M.subprocess.popen(path, argt, options)
+ argt = argt or {}
+ local childfds = {}
+ local parentfds = {}
+ local stdiostreams = {stdin = 0, stdout = 1, stderr = 2}
+
+ for iostream in pairs(stdiostreams) do
+ if options[iostream] == M.subprocess.PIPE then
+ local piper, pipew = posix_unistd.pipe()
+ if iostream == "stdin" then
+ childfds[iostream] = piper
+ parentfds[iostream] = pipew
+ else
+ childfds[iostream] = pipew
+ parentfds[iostream] = piper
+ end
+ end
+ end
+
+ -- childfds: r0, w1, w2
+ -- parentfds: w0, r1, r2
+
+ local pid, errmsg, errnum = posix_unistd.fork()
+
+ if pid == nil then
+ close_fds(parentfds)
+ close_fds(childfds)
+ return nil, errmsg, errnum
+ elseif pid == 0 then
+ local null = -1
+ if M.contains(options, M.subprocess.DEVNULL) then
+ -- only open if there's anything to discard
+ null = posix_fcntl.open('/dev/null', posix_fcntl.O_RDWR)
+ end
+
+ for iostream, fd in pairs(stdiostreams) do
+ local option = options[iostream]
+ if option == M.subprocess.DEVNULL then
+ posix_unistd.dup2(null, fd)
+ elseif option == M.subprocess.PIPE then
+ posix_unistd.dup2(childfds[iostream], fd)
+ end
+ end
+ close_fds(childfds)
+ close_fds(parentfds)
+
+ -- close potential null
+ if null > 2 then
+ posix_unistd.close(null)
+ end
+
+ posix_unistd.execp(path, argt)
+ posix_unistd._exit(127)
+ end
+
+ close_fds(childfds)
+
+ return pid, parentfds
+end
return M
--
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