sys-utils/nsenter.1

   1 .TH NSENTER 1 "June 2013" "util-linux" "User Commands"
   2 .SH NAME
   3 nsenter \- run program with namespaces of other processes
   4 .SH SYNOPSIS
   5 .B nsenter
   6 [options]
   7 .RI [ program
   8 .RI [ arguments ]]
   9 .SH DESCRIPTION
  10 Enters the namespaces of one or more other processes and then executes the specified
  11 \fIprogram\fP. If \fIprogram\fP is not given, then ``${SHELL}'' is run (default: /bin\:/sh).
  12 .PP
  13 Enterable namespaces are:
  14 .TP
  15 .B mount namespace
  16 Mounting and unmounting filesystems will not affect the rest of the system,
  17 except for filesystems which are explicitly marked as shared (with
  18 \fBmount --make-\:shared\fP; see \fI/proc\:/self\:/mountinfo\fP for the
  19 \fBshared\fP flag).
  20 For further details, see
  21 .BR mount_namespaces (7)
  22 and the discussion of the
  23 .BR CLONE_NEWNS
  24 flag in
  25 .BR clone (2).
  26 .TP
  27 .B UTS namespace
  28 Setting hostname or domainname will not affect the rest of the system.
  29 For further details, see
  30 .BR namespaces (7)
  31 and the discussion of the
  32 .BR CLONE_NEWUTS
  33 flag in
  34 .BR clone (2).
  35 .TP
  36 .B IPC namespace
  37 The process will have an independent namespace for POSIX message queues
  38 as well as System V message queues,
  39 semaphore sets and shared memory segments.
  40 For further details, see
  41 .BR namespaces (7)
  42 and the discussion of the
  43 .BR CLONE_NEWIPC
  44 flag in
  45 .BR clone (2).
  46 .TP
  47 .B network namespace
  48 The process will have independent IPv4 and IPv6 stacks, IP routing tables,
  49 firewall rules, the
  50 .I /proc\:/net
  51 and
  52 .I /sys\:/class\:/net
  53 directory trees, sockets, etc.
  54 For further details, see
  55 .BR namespaces (7)
  56 and the discussion of the
  57 .BR CLONE_NEWNET
  58 flag in
  59 .BR clone (2).
  60 .TP
  61 .B PID namespace
  62 Children will have a set of PID to process mappings separate from the
  63 .B nsenter
  64 process
  65 For further details, see
  66 .BR pid_namespaces (7)
  67 and
  68 the discussion of the
  69 .BR CLONE_NEWPID
  70 flag in
  71 .B nsenter
  72 will fork by default if changing the PID namespace, so that the new program
  73 and its children share the same PID namespace and are visible to each other.
  74 If \fB\-\-no\-fork\fP is used, the new program will be exec'ed without forking.
  75 .TP
  76 .B user namespace
  77 The process will have a distinct set of UIDs, GIDs and capabilities.
  78 For further details, see
  79 .BR user_namespaces (7)
  80 and the discussion of the
  81 .BR CLONE_NEWUSER
  82 flag in
  83 .BR clone (2).
  84 .TP
  85 .B cgroup namespace
  86 The process will have a virtualized view of \fI/proc\:/self\:/cgroup\fP, and new
  87 cgroup mounts will be rooted at the namespace cgroup root.
  88 For further details, see
  89 .BR cgroup_namespaces (7)
  90 and the discussion of the
  91 .BR CLONE_NEWCGROUP
  92 flag in
  93 .BR clone (2).
  94 .TP
  95 See \fBclone\fP(2) for the exact semantics of the flags.
  96 .SH OPTIONS
  97 Various of the options below that relate to namespaces take an optional
  98 .I file
  99 argument.
 100 This should be one of the
 101 .IR /proc/[pid]/ns/*
 102 files described in
 103 .BR namespaces (7).
 104 .TP
 105 \fB\-a\fR, \fB\-\-all\fR
 106 Enter all namespaces of the target process by the default
 107 .IR /proc/[pid]/ns/*
 108 namespace paths. The default paths to the target process namespaces may be
 109 overwritten by namespace specific options (e.g. --all --mount=[path]).
 110
 111 The user namespace will be ignored if the same as the caller's current user
 112 namespace. It prevents a caller that has dropped capabilities from regaining
 113 those capabilities via a call to setns().  See
 114 .BR setns (2)
 115 for more details.
 116 .TP
 117 \fB\-t\fR, \fB\-\-target\fR \fIpid\fP
 118 Specify a target process to get contexts from.  The paths to the contexts
 119 specified by
 120 .I pid
 121 are:
 122 .RS
 123 .PD 0
 124 .IP "" 20
 125 .TP
 126 /proc/\fIpid\fR/ns/mnt
 127 the mount namespace
 128 .TP
 129 /proc/\fIpid\fR/ns/uts
 130 the UTS namespace
 131 .TP
 132 /proc/\fIpid\fR/ns/ipc
 133 the IPC namespace
 134 .TP
 135 /proc/\fIpid\fR/ns/net
 136 the network namespace
 137 .TP
 138 /proc/\fIpid\fR/ns/pid
 139 the PID namespace
 140 .TP
 141 /proc/\fIpid\fR/ns/user
 142 the user namespace
 143 .TP
 144 /proc/\fIpid\fR/ns/cgroup
 145 the cgroup namespace
 146 .TP
 147 /proc/\fIpid\fR/root
 148 the root directory
 149 .TP
 150 /proc/\fIpid\fR/cwd
 151 the working directory respectively
 152 .PD
 153 .RE
 154 .TP
 155 \fB\-m\fR, \fB\-\-mount\fR[=\fIfile\fR]
 156 Enter the mount namespace.  If no file is specified, enter the mount namespace
 157 of the target process.
 158 If
 159 .I file
 160 is specified, enter the mount namespace
 161 specified by
 162 .IR file .
 163 .TP
 164 \fB\-u\fR, \fB\-\-uts\fR[=\fIfile\fR]
 165 Enter the UTS namespace.  If no file is specified, enter the UTS namespace of
 166 the target process.
 167 If
 168 .I file
 169 is specified, enter the UTS namespace specified by
 170 .IR file .
 171 .TP
 172 \fB\-i\fR, \fB\-\-ipc\fR[=\fIfile\fR]
 173 Enter the IPC namespace.  If no file is specified, enter the IPC namespace of
 174 the target process.
 175 If
 176 .I file
 177 is specified, enter the IPC namespace specified by
 178 .IR file .
 179 .TP
 180 \fB\-n\fR, \fB\-\-net\fR[=\fIfile\fR]
 181 Enter the network namespace.  If no file is specified, enter the network
 182 namespace of the target process.
 183 If
 184 .I file
 185 is specified, enter the network namespace specified by
 186 .IR file .
 187 .TP
 188 \fB\-p\fR, \fB\-\-pid\fR[=\fIfile\fR]
 189 Enter the PID namespace.  If no file is specified, enter the PID namespace of
 190 the target process.
 191 If
 192 .I file
 193 is specified, enter the PID namespace specified by
 194 .IR file .
 195 .TP
 196 \fB\-U\fR, \fB\-\-user\fR[=\fIfile\fR]
 197 Enter the user namespace.  If no file is specified, enter the user namespace of
 198 the target process.
 199 If
 200 .I file
 201 is specified, enter the user namespace specified by
 202 .IR file .
 203 See also the \fB\-\-setuid\fR and \fB\-\-setgid\fR options.
 204 .TP
 205 \fB\-C\fR, \fB\-\-cgroup\fR[=\fIfile\fR]
 206 Enter the cgroup namespace.  If no file is specified, enter the cgroup namespace of
 207 the target process.
 208 If
 209 .I file
 210 is specified, enter the cgroup namespace specified by
 211 .IR file .
 212 .TP
 213 \fB\-G\fR, \fB\-\-setgid\fR \fIgid\fR
 214 Set the group ID which will be used in the entered namespace and drop
 215 supplementary groups.
 216 .BR nsenter (1)
 217 always sets GID for user namespaces, the default is 0.
 218 .TP
 219 \fB\-S\fR, \fB\-\-setuid\fR \fIuid\fR
 220 Set the user ID which will be used in the entered namespace.
 221 .BR nsenter (1)
 222 always sets UID for user namespaces, the default is 0.
 223 .TP
 224 \fB\-\-preserve\-credentials\fR
 225 Don't modify UID and GID when enter user namespace. The default is to
 226 drops supplementary groups and sets GID and UID to 0.
 227 .TP
 228 \fB\-r\fR, \fB\-\-root\fR[=\fIdirectory\fR]
 229 Set the root directory.  If no directory is specified, set the root directory to
 230 the root directory of the target process.  If directory is specified, set the
 231 root directory to the specified directory.
 232 .TP
 233 \fB\-w\fR, \fB\-\-wd\fR[=\fIdirectory\fR]
 234 Set the working directory.  If no directory is specified, set the working
 235 directory to the working directory of the target process.  If directory is
 236 specified, set the working directory to the specified directory.
 237 .TP
 238 \fB\-F\fR, \fB\-\-no\-fork\fR
 239 Do not fork before exec'ing the specified program.  By default, when entering a
 240 PID namespace, \fBnsenter\fP calls \fBfork\fP before calling \fBexec\fP so that
 241 any children will also be in the newly entered PID namespace.
 242 .TP
 243 \fB\-Z\fR, \fB\-\-follow\-context\fR
 244 Set the SELinux security context used for executing a new process according to
 245 already running process specified by \fB\-\-target\fR PID. (The util-linux has
 246 to be compiled with SELinux support otherwise the option is unavailable.)
 247 .TP
 248 \fB\-V\fR, \fB\-\-version\fR
 249 Display version information and exit.
 250 .TP
 251 \fB\-h\fR, \fB\-\-help\fR
 252 Display help text and exit.
 253 .SH SEE ALSO
 254 .BR clone (2),
 255 .BR setns (2),
 256 .BR namespaces (7)
 257 .SH AUTHORS
 258 .UR biederm@xmission.com
 259 Eric Biederman
 260 .UE
 261 .br
 262 .UR kzak@redhat.com
 263 Karel Zak
 264 .UE
 265 .SH AVAILABILITY
 266 The nsenter command is part of the util-linux package and is available from
 267 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
 268 Linux Kernel Archive
 269 .UE .