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init: make the command-line rewrite optional

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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 <nicolas.carrier@parrot.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Nicolas Carrier 2016-02-04 12:18:01 +01:00 committed by Denys Vlasenko
parent 383201e725
commit 29eae728e9
1 changed files with 22 additions and 5 deletions
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27
init/init.c
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@ -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) {