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