From 29eae728e959a382841bd0a32cc1a8d1bcdc9150 Mon Sep 17 00:00:00 2001 From: Nicolas Carrier Date: Thu, 4 Feb 2016 12:18:01 +0100 Subject: [PATCH] init: make the command-line rewrite optional When launched as PID 1 and after parsing its arguments, init wipes all all of them except argv[0] and rewrites argv[0] to contain only "init", so that its command-line appears solely as "init" in tools such as ps. This patch adds the FEATURE_INIT_MODIFY_CMDLINE which, if set to n, will make init preserve all its arguments including argv[0], be they parsed or ignored. The original command-line used to launch init can then be retrieved in /proc/1/cmdline on Linux, for example. Signed-off-by: Nicolas Carrier Signed-off-by: Denys Vlasenko --- init/init.c | 27 ++++++++++++++++++++++----- 1 file changed, 22 insertions(+), 5 deletions(-) diff --git a/init/init.c b/init/init.c index 2040a59e8..25bfaec8c 100644 --- a/init/init.c +++ b/init/init.c @@ -102,6 +102,21 @@ //config: //config: Note that on Linux, init attempts to detect serial terminal and //config: sets TERM to "vt102" if one is found. +//config: +//config:config FEATURE_INIT_MODIFY_CMDLINE +//config: bool "Modify the command-line to \"init\"" +//config: default y +//config: depends on INIT +//config: help +//config: When launched as PID 1 and after parsing its arguments, init +//config: wipes all the arguments but argv[0] and rewrites argv[0] to +//config: contain only "init", so that its command-line appears solely as +//config: "init" in tools such as ps. +//config: If this option is set to Y, init will keep its original behavior, +//config: otherwise, all the arguments including argv[0] will be preserved, +//config: be they parsed or ignored by init. +//config: The original command-line used to launch init can then be +//config: retrieved in /proc/1/cmdline on Linux, for example. //applet:IF_INIT(APPLET(init, BB_DIR_SBIN, BB_SUID_DROP)) //applet:IF_FEATURE_INITRD(APPLET_ODDNAME(linuxrc, init, BB_DIR_ROOT, BB_SUID_DROP, linuxrc)) @@ -1138,11 +1153,13 @@ int init_main(int argc UNUSED_PARAM, char **argv) } #endif - /* Make the command line just say "init" - thats all, nothing else */ - strncpy(argv[0], "init", strlen(argv[0])); - /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */ - while (*++argv) - nuke_str(*argv); + if (ENABLE_FEATURE_INIT_MODIFY_CMDLINE) { + /* Make the command line just say "init" - that's all, nothing else */ + strncpy(argv[0], "init", strlen(argv[0])); + /* Wipe argv[1]-argv[N] so they don't clutter the ps listing */ + while (*++argv) + nuke_str(*argv); + } /* Set up signal handlers */ if (!DEBUG_INIT) {