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 .B 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 .B 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 .B 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 .B 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 .B nsenter
  66 will fork by default if changing the PID namespace, so that the new program
  67 and its children share the same PID namespace and are visible to each other.
  68 If \fB\-\-no\-fork\fP is used, the new program will be exec'ed without forking.
  69 For further details, see
  70 .BR pid_namespaces (7)
  71 and
  72 the discussion of the
  73 .B CLONE_NEWPID
  74 flag in
  75 .BR clone (2).
  76 .TP
  77 .B user namespace
  78 The process will have a distinct set of UIDs, GIDs and capabilities.
  79 For further details, see
  80 .BR user_namespaces (7)
  81 and the discussion of the
  82 .B CLONE_NEWUSER
  83 flag in
  84 .BR clone (2).
  85 .TP
  86 .B cgroup namespace
  87 The process will have a virtualized view of \fI/proc\:/self\:/cgroup\fP, and new
  88 cgroup mounts will be rooted at the namespace cgroup root.
  89 For further details, see
  90 .BR cgroup_namespaces (7)
  91 and the discussion of the
  92 .B CLONE_NEWCGROUP
  93 flag in
  94 .BR clone (2).
  95 .TP
  96 .B time namespace
  97 The process can have a distinct view of
  98 .B CLOCK_MONOTONIC
  99 and/or
 100 .B CLOCK_BOOTTIME
 101 which can be changed using \fI/proc/self/timens_offsets\fP.
 102 .TP
 103 See \fBclone\fP(2) for the exact semantics of the flags.
 104 .SH OPTIONS
 105 Various of the options below that relate to namespaces take an optional
 106 .I file
 107 argument.
 108 This should be one of the
 109 .I /proc/[pid]/ns/*
 110 files described in
 111 .BR namespaces (7).
 112 .TP
 113 \fB\-a\fR, \fB\-\-all\fR
 114 Enter all namespaces of the target process by the default
 115 .I /proc/[pid]/ns/*
 116 namespace paths. The default paths to the target process namespaces may be
 117 overwritten by namespace specific options (e.g., --all --mount=[path]).
 118
 119 The user namespace will be ignored if the same as the caller's current user
 120 namespace. It prevents a caller that has dropped capabilities from regaining
 121 those capabilities via a call to setns().  See
 122 .BR setns (2)
 123 for more details.
 124 .TP
 125 \fB\-t\fR, \fB\-\-target\fR \fIpid\fP
 126 Specify a target process to get contexts from.  The paths to the contexts
 127 specified by
 128 .I pid
 129 are:
 130 .RS
 131 .PD 0
 132 .IP "" 20
 133 .TP
 134 /proc/\fIpid\fR/ns/mnt
 135 the mount namespace
 136 .TP
 137 /proc/\fIpid\fR/ns/uts
 138 the UTS namespace
 139 .TP
 140 /proc/\fIpid\fR/ns/ipc
 141 the IPC namespace
 142 .TP
 143 /proc/\fIpid\fR/ns/net
 144 the network namespace
 145 .TP
 146 /proc/\fIpid\fR/ns/pid
 147 the PID namespace
 148 .TP
 149 /proc/\fIpid\fR/ns/user
 150 the user namespace
 151 .TP
 152 /proc/\fIpid\fR/ns/cgroup
 153 the cgroup namespace
 154 .TP
 155 /proc/\fIpid\fR/ns/time
 156 the time namespace
 157 .TP
 158 /proc/\fIpid\fR/root
 159 the root directory
 160 .TP
 161 /proc/\fIpid\fR/cwd
 162 the working directory respectively
 163 .PD
 164 .RE
 165 .TP
 166 \fB\-m\fR, \fB\-\-mount\fR[=\fIfile\fR]
 167 Enter the mount namespace.  If no file is specified, enter the mount namespace
 168 of the target process.
 169 If
 170 .I file
 171 is specified, enter the mount namespace
 172 specified by
 173 .IR file .
 174 .TP
 175 \fB\-u\fR, \fB\-\-uts\fR[=\fIfile\fR]
 176 Enter the UTS namespace.  If no file is specified, enter the UTS namespace of
 177 the target process.
 178 If
 179 .I file
 180 is specified, enter the UTS namespace specified by
 181 .IR file .
 182 .TP
 183 \fB\-i\fR, \fB\-\-ipc\fR[=\fIfile\fR]
 184 Enter the IPC namespace.  If no file is specified, enter the IPC namespace of
 185 the target process.
 186 If
 187 .I file
 188 is specified, enter the IPC namespace specified by
 189 .IR file .
 190 .TP
 191 \fB\-n\fR, \fB\-\-net\fR[=\fIfile\fR]
 192 Enter the network namespace.  If no file is specified, enter the network
 193 namespace of the target process.
 194 If
 195 .I file
 196 is specified, enter the network namespace specified by
 197 .IR file .
 198 .TP
 199 \fB\-p\fR, \fB\-\-pid\fR[=\fIfile\fR]
 200 Enter the PID namespace.  If no file is specified, enter the PID namespace of
 201 the target process.
 202 If
 203 .I file
 204 is specified, enter the PID namespace specified by
 205 .IR file .
 206 .TP
 207 \fB\-U\fR, \fB\-\-user\fR[=\fIfile\fR]
 208 Enter the user namespace.  If no file is specified, enter the user namespace of
 209 the target process.
 210 If
 211 .I file
 212 is specified, enter the user namespace specified by
 213 .IR file .
 214 See also the \fB\-\-setuid\fR and \fB\-\-setgid\fR options.
 215 .TP
 216 \fB\-C\fR, \fB\-\-cgroup\fR[=\fIfile\fR]
 217 Enter the cgroup namespace.  If no file is specified, enter the cgroup namespace of
 218 the target process.
 219 If
 220 .I file
 221 is specified, enter the cgroup namespace specified by
 222 .IR file .
 223 .TP
 224 \fB\-T\fR, \fB\-\-time\fR[=\fIfile\fR]
 225 Enter the time namespace.  If no file is specified, enter the time namespace of
 226 the target process.
 227 If
 228 .I file
 229 is specified, enter the time namespace specified by
 230 .IR file .
 231 .TP
 232 \fB\-G\fR, \fB\-\-setgid\fR \fIgid\fR
 233 Set the group ID which will be used in the entered namespace and drop
 234 supplementary groups.
 235 .BR nsenter (1)
 236 always sets GID for user namespaces, the default is 0.
 237 .TP
 238 \fB\-S\fR, \fB\-\-setuid\fR \fIuid\fR
 239 Set the user ID which will be used in the entered namespace.
 240 .BR nsenter (1)
 241 always sets UID for user namespaces, the default is 0.
 242 .TP
 243 \fB\-\-preserve\-credentials\fR
 244 Don't modify UID and GID when enter user namespace. The default is to
 245 drops supplementary groups and sets GID and UID to 0.
 246 .TP
 247 \fB\-r\fR, \fB\-\-root\fR[=\fIdirectory\fR]
 248 Set the root directory.  If no directory is specified, set the root directory to
 249 the root directory of the target process.  If directory is specified, set the
 250 root directory to the specified directory.
 251 .TP
 252 \fB\-w\fR, \fB\-\-wd\fR[=\fIdirectory\fR]
 253 Set the working directory.  If no directory is specified, set the working
 254 directory to the working directory of the target process.  If directory is
 255 specified, set the working directory to the specified directory.
 256 .TP
 257 \fB\-F\fR, \fB\-\-no\-fork\fR
 258 Do not fork before exec'ing the specified program.  By default, when entering a
 259 PID namespace, \fBnsenter\fP calls \fBfork\fP before calling \fBexec\fP so that
 260 any children will also be in the newly entered PID namespace.
 261 .TP
 262 \fB\-Z\fR, \fB\-\-follow\-context\fR
 263 Set the SELinux security context used for executing a new process according to
 264 already running process specified by \fB\-\-target\fR PID. (The util-linux has
 265 to be compiled with SELinux support otherwise the option is unavailable.)
 266 .TP
 267 \fB\-V\fR, \fB\-\-version\fR
 268 Display version information and exit.
 269 .TP
 270 \fB\-h\fR, \fB\-\-help\fR
 271 Display help text and exit.
 272 .SH SEE ALSO
 273 .BR clone (2),
 274 .BR setns (2),
 275 .BR namespaces (7)
 276 .SH AUTHORS
 277 .UR biederm@xmission.com
 278 Eric Biederman
 279 .UE
 280 .br
 281 .UR kzak@redhat.com
 282 Karel Zak
 283 .UE
 284 .SH AVAILABILITY
 285 The nsenter command is part of the util-linux package and is available from
 286 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
 287 Linux Kernel Archive
 288 .UE .