X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd.exec.xml;h=207592dda70c7c42198d167b4a480edc4098b726;hp=b761832ed6bbdca94debe5df33cdb579d4c0376f;hb=99f098257f5e4135609edc3df965ebf27975df18;hpb=ea92ae33e0fbbf8a98cd2e08ca5a850d83d57fae diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml index b761832ed..207592dda 100644 --- a/man/systemd.exec.xml +++ b/man/systemd.exec.xml @@ -1,4 +1,3 @@ - @@ -58,7 +57,7 @@ Description Unit configuration files for services, sockets, - mount points and swap devices share a subset of + mount points, and swap devices share a subset of configuration options which define the execution environment of spawned processes. @@ -90,7 +89,7 @@ Takes an absolute directory path. Sets the working directory for executed processes. If - not set defaults to the root directory + not set, defaults to the root directory when systemd is running as a system instance and the respective user's home directory if run as @@ -105,7 +104,7 @@ directory for executed processes, with the chroot2 - system call. If this is used it must + system call. If this is used, it must be ensured that the process and all its auxiliary files are available in the chroot() @@ -234,7 +233,7 @@ CPUSchedulingResetOnFork= Takes a boolean - argument. If true elevated CPU + argument. If true, elevated CPU scheduling priorities and policies will be reset when the executed processes fork, and can hence not leak @@ -253,7 +252,7 @@ be specified more than once in which case the specificed CPU affinity masks are merged. If the empty string is - assigned the mask is reset, all + assigned, the mask is reset, all assignments prior to this will have no effect. See sched_setaffinity2 @@ -281,15 +280,15 @@ option may be specified more than once in which case all listed variables will be set. If the same variable is - set twice the later setting will + set twice, the later setting will override the earlier setting. If the empty string is assigned to this - option the list of environment + option, the list of environment variables is reset, all prior assignments have no effect. Variable expansion is not performed inside the strings, however, specifier - expansion is possible. $ character has + expansion is possible. The $ character has no special meaning. If you need to assign a value containing spaces to a variable, use double quotes (") @@ -327,13 +326,13 @@ absolute filename or wildcard expression, optionally prefixed with -, which indicates - that if the file does not exist it - won't be read and no error or warning + that if the file does not exist, it + will not be read and no error or warning message is logged. This option may be specified more than once in which case all specified files are read. If the empty string is assigned to this - option the list of file to read is + option, the list of file to read is reset, all prior assignments have no effect. @@ -344,7 +343,7 @@ with Environment=. If the same variable is set twice from - these files the files will be read in + these files, the files will be read in the order they are specified and the later setting will override the earlier setting. @@ -360,19 +359,19 @@ , or . If - is selected + is selected, standard input will be connected to /dev/null, i.e. all read attempts by the process will result in immediate EOF. If - is selected + is selected, standard input is connected to a TTY (as configured by TTYPath=, see below) and the executed process becomes the controlling process of the terminal. If the terminal is already - being controlled by another process the + being controlled by another process, the executed process waits until the current controlling process releases the terminal. @@ -394,7 +393,7 @@ file (see systemd.socket5 for details) specifies a single socket - only. If this option is set standard + only. If this option is set, standard input will be connected to the socket the service was activated from, which is primarily useful for compatibility @@ -419,19 +418,19 @@ , or . If set to - the file + , the file descriptor of standard input is duplicated for standard output. If set - to standard + to , standard output will be connected to /dev/null, i.e. everything written to it will be - lost. If set to + lost. If set to , standard output will be connected to a tty (as configured via TTYPath=, see below). If the TTY is used for output - only the executed process will not + only, the executed process will not become the controlling process of the terminal, and will not fail or wait for other processes to release the @@ -518,7 +517,7 @@ If the terminal device specified with TTYPath= is a - virtual console terminal try to + virtual console terminal, try to deallocate the TTY before and after execution. This ensures that the screen and scrollback buffer is @@ -529,7 +528,7 @@ SyslogIdentifier= Sets the process name to prefix log lines sent to syslog or - the kernel log buffer with. If not set + the kernel log buffer with. If not set, defaults to the process name of the executed process. This option is only useful when @@ -673,13 +672,13 @@ PAMName= Sets the PAM service - name to set up a session as. If set + name to set up a session as. If set, the executed process will be registered as a PAM session under the specified service name. This is only useful in conjunction with the User= setting. If - not set no PAM session will be opened + not set, no PAM session will be opened for the executed processes. See pam8 for details. @@ -688,7 +687,7 @@ TCPWrapName= If this is a - socket-activated service this sets the + socket-activated service, this sets the tcpwrap service name to check the permission for the current connection with. This is only useful in @@ -698,7 +697,7 @@ socket types (e.g. datagram/UDP) and on processes unrelated to socket-based activation. If the tcpwrap - verification fails daemon start-up + verification fails, daemon start-up will fail and the connection is terminated. See tcpd8 @@ -727,7 +726,7 @@ Capabilities listed will be included in the bounding set, all others are removed. If the list of capabilities - is prefixed with ~ + is prefixed with ~, all but the listed capabilities will be included, the effect of the assignment inverted. Note that this @@ -736,7 +735,7 @@ permitted and inheritable capability sets, on top of what Capabilities= - does. If this option is not used the + does. If this option is not used, the capability bounding set is not modified on process execution, hence no limits on the capabilities of the @@ -744,11 +743,11 @@ appear more than once in which case the bounding sets are merged. If the empty string is assigned to this - option the bounding set is reset to + option, the bounding set is reset to the empty capability set, and all prior settings have no effect. If set to ~ (without any - further argument) the bounding set is + further argument), the bounding set is reset to the full set of available capabilities, also undoing any previous settings. @@ -769,7 +768,7 @@ option may appear more than once in which case the secure bits are ORed. If the empty string is assigned - to this option the bits are reset to + to this option, the bits are reset to 0. @@ -826,7 +825,7 @@ directories listed will have limited access from within the namespace. If the empty string is assigned to this - option the specific list is reset, and + option, the specific list is reset, and all prior assignments have no effect. Paths in @@ -835,7 +834,7 @@ InaccessibleDirectories= may be prefixed with -, in which case - they will be ignored when they don't + they will be ignored when they do not exist. @@ -843,13 +842,13 @@ PrivateTmp= Takes a boolean - argument. If true sets up a new file + argument. If true, sets up a new file system namespace for the executed processes and mounts private /tmp and - /var/tmp directories - inside it, that are not shared by - processes outside of the + /var/tmp + directories inside it, that are not + shared by processes outside of the namespace. This is useful to secure access to temporary files of the process, but makes sharing between @@ -857,16 +856,24 @@ /tmp or /var/tmp impossible. All temporary data created - by service will be removed after service - is stopped. Defaults to - false. + by service will be removed after + service is stopped. Defaults to + false. Note that it is possible to run + two or more units within the same + private /tmp and + /var/tmp + namespace by using the + JoinsNamespaceOf= + directive, see + systemd.unit5 + for details. PrivateNetwork= Takes a boolean - argument. If true sets up a new + argument. If true, sets up a new network namespace for the executed processes and configures only the loopback network device @@ -875,8 +882,14 @@ available to the executed process. This is useful to securely turn off network access by the executed - process. Defaults to - false. + process. Defaults to false. Note that + it is possible to run two or more + units within the same private network + namespace by using the + JoinsNamespaceOf= + directive, see + systemd.unit5 + for details. @@ -908,7 +921,7 @@ entries must be created and cleared before and after execution. If the configured string is longer than four - characters it is truncated and the + characters, it is truncated and the terminal four characters are used. This setting interprets %I style string replacements. This setting is @@ -956,11 +969,11 @@ termination with the SIGSYS signal (whitelisting). If the first character - of the list is ~ + of the list is ~, the effect is inverted: only the listed system calls will result in immediate process termination - (blacklisting). If this option is used + (blacklisting). If this option is used, NoNewPrivileges=yes is implied. This feature makes use of the Secure Computing Mode 2 interfaces @@ -972,12 +985,12 @@ sigreturn, exit_group, exit system calls - are implicitly whitelisted and don't + are implicitly whitelisted and do not need to be listed explicitly. This option may be specified more than once in which case the filter masks are merged. If the empty string is - assigned the filter is reset, all + assigned, the filter is reset, all prior assignments will have no effect. @@ -985,6 +998,135 @@ + + Environment variables in spawned processes + + Processes started by the system are executed in + a clean environment in which select variables + listed below are set. System processes started by systemd + do not inherit variables from PID 1, but processes + started by user systemd instances inherit all + environment variables from the user systemd instance. + + + + + $PATH + + Colon-separated list + of directiories to use when launching + executables. Systemd uses a fixed + value of + /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin. + + + + + $LANG + + Locale. Can be set in + locale.conf5 + or on the kernel command line (see + systemd1 + and + kernel-command-line7). + + + + + $USER + $LOGNAME + $HOME + $SHELL + + User name (twice), home + directory, and the login shell. + The variables are set for the units that + have User= set, + which includes user + systemd instances. + See + passwd5. + + + + + $XDG_RUNTIME_DIR + + The directory for volatile + state. Set for the user systemd + instance, and also in user sessions. + See + pam_systemd8. + + + + + $XDG_SESSION_ID + $XDG_SEAT + $XDG_VTNR + + The identifier of the + session, the seat name, and + virtual terminal of the session. Set + by + pam_systemd8 + for login sessions. + $XDG_SEAT and + $XDG_VTNR will + only be set when attached to a seat and a + tty. + + + + $MANAGERPID + + The PID of the user + systemd instance, + set for processes spawned by it. + + + + + $LISTEN_FDS + $LISTEN_PID + + Information about file + descriptors passed to a service for + socket activation. See + sd_listen_fds3. + + + + + $TERM + + Terminal type, set + only for units connected to a terminal + (StandardInput=tty, + StandardOutput=tty, + or + StandardError=tty). + See + termcap5. + + + + + Additional variables may be configured by the + following means: for processes spawned in specific + units, use the Environment= and + EnvironmentFile= options above; to + specify variables globally, use + DefaultEnvironment= (see + systemd-system.conf5) + or the kernel option + systemd.setenv= (see + systemd1). Additional + variables may also be set through PAM, + c.f. pam_env8. + + See Also @@ -997,8 +1139,9 @@ systemd.swap5, systemd.mount5, systemd.kill5, - systemd.cgroup5, - systemd.directives7 + systemd.resource-control5, + systemd.directives7, + exec3