cmds: add ns/clone

usage: ns/clone pid cmd [args...]

It starts cmd with provided arguments in a clone of the namespace
available to pid.
This commit is contained in:
Giacomo Tesio 2017-10-25 01:02:26 +02:00
parent 9d04fba8f2
commit 2a4b3f26d6
2 changed files with 65 additions and 1 deletions

View File

@ -5,7 +5,8 @@
],
"Install": "/arch/$ARCH/cmd/ns/",
"SourceFilesCmd": [
"cat.c"
"cat.c",
"clone.c"
]
}
}

63
sys/src/cmd/ns/clone.c Normal file
View File

@ -0,0 +1,63 @@
/*
* This file is part of Jehanne.
*
* Copyright (C) 2017 Giacomo Tesio <giacomo@tesio.it>
*
* This is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, version 3 of the License.
*
* Jehanne is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with Jehanne. If not, see <http://www.gnu.org/licenses/>.
*/
#include <u.h>
#include <lib9.h>
#include <envvars.h>
void
main(int argc, char *argv[])
{
int fd, npaths;
char buf[256], *cmd, **args, *paths[17];
rfork(RFNAMEG);
if(argc < 3){
fprint(2, "usage: ns/clone pid cmd [args...]\n");
exits("usage");
}
snprint(buf, sizeof(buf), "/proc/%s/ns", argv[1]);
fd = open(buf, OWRITE);
if(fd < 0){
print("cannot open %s\n", buf);
exits("invalid target pid");
}
write(fd, "clone", 6);
close(fd);
cmd = strdup(argv[2]);
args = &argv[2];
if(cmd[0] == '/'
||(cmd[0] == '.' && (cmd[1] == '/' || (cmd[1] == '.' && cmd[2] == '/')))){
exec(cmd, args);
sysfatal("exec %s failed: %r", cmd);
}
npaths = getfields(getenv(ENV_PATH), paths, nelem(paths), 1, ":");
if(npaths == nelem(paths))
--npaths; // ignore last (possibly spurious) path
fd = 0;
while(fd < npaths){
snprint(buf, sizeof(buf), "%s/%s", paths[fd], cmd);
exec(buf, args);
++fd;
}
sysfatal("exec %s failed: %r", cmd);
}