X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd.exec.xml;h=86ad7e223dd5a5c9da0008a0e81c673337ae1170;hp=ff8b812ef44087ab47278cde43bcc83e3614952a;hb=17df7223be064b1542dbe868e3b35cca977ee639;hpb=f4ae69117ba47e75ff89c7d847e180af9af7436a diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml index ff8b812ef..86ad7e223 100644 --- a/man/systemd.exec.xml +++ b/man/systemd.exec.xml @@ -57,7 +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. @@ -76,27 +76,6 @@ configuration options are configured in the [Service], [Socket], [Mount], or [Swap] sections, depending on the unit type. - - Processes started by the system systemd instance - are executed in a clean environment in which only the - $PATH and $LANG - variables are set by default. In order to add - additional variables, see the - Environment= and - EnvironmentFile= options below. To - specify variables globally, see - DefaultEnvironment= in - systemd-system.conf5 - or the kernel option - systemd.setenv= in - systemd1. Processes - started by the user systemd instances inherit all - environment variables from the user systemd instance, - and have $HOME, - $USER, - $XDG_RUNTIME_DIR defined, among - others. In addition, $MANAGERPID - contains the PID of the user systemd instance. @@ -110,7 +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 @@ -125,7 +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() @@ -254,7 +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 @@ -273,7 +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 @@ -301,24 +280,26 @@ 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 (") for the assignment. Example: - Environment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6" + Environment="VAR1=word1 word2" VAR2=word3 "VAR3=$word 5 6" gives three variables VAR1, - VAR2, VAR3. + VAR2, VAR3 + with the values word1 word2, + word3, $word 5 6. @@ -353,7 +334,7 @@ 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. @@ -364,7 +345,7 @@ 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. @@ -380,19 +361,19 @@ , 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. @@ -414,7 +395,7 @@ 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 @@ -439,19 +420,19 @@ , 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 @@ -538,7 +519,7 @@ 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 @@ -549,7 +530,7 @@ 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 @@ -693,13 +674,13 @@ 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. @@ -708,7 +689,7 @@ 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 @@ -718,7 +699,7 @@ 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 @@ -747,7 +728,7 @@ 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 @@ -756,7 +737,7 @@ 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 @@ -764,11 +745,11 @@ 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. @@ -789,7 +770,7 @@ 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. @@ -846,7 +827,7 @@ 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 @@ -863,13 +844,13 @@ 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 is not + shared by processes outside of the namespace. This is useful to secure access to temporary files of the process, but makes sharing between @@ -877,16 +858,24 @@ /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 + the 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 @@ -895,6 +884,30 @@ available to the executed process. This is useful to securely turn off network access by the executed + 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. + + + + PrivateDevices= + + Takes a boolean + argument. If true, sets up a new /dev + namespace for the executed processes + and only adds API pseudo devices such + as /dev/null, + /dev/zero or + /dev/random to + it, but no physical devices such as + /dev/sda. This is + useful to securely turn off physical + device access by the executed process. Defaults to false. @@ -928,7 +941,7 @@ 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 @@ -937,6 +950,23 @@ this service. + + SELinuxContext= + + Set the SELinux + security context of the executed + process. If set, this will override + the automated domain + transition. However, the policy still + needs to autorize the transition. This + directive is ignored if SELinux is + disabled. If prefixed by + -, all errors will + be ignored. See + setexeccon3 + for details. + + IgnoreSIGPIPE= @@ -971,16 +1001,16 @@ list of system call names. If this setting is used, all system calls executed by the unit - process except for the listed ones + processes except for the listed ones will result in immediate process 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 @@ -997,12 +1027,181 @@ 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. + effect. + + If you specify both types of + this option (i.e. whitelisting and + blacklisting) the first encountered + will take precedence and will dictate + the default action (termination or + approval of a system call). Then the + next occurrences of this option will + add or delete the listed system calls + from the set of the filtered system + calls, depending of its type and the + default action (e.g. You have started + with a whitelisting of + read and + write and right + after it add a blacklisting of + write, then + write will be + removed from the set). + + + + + SystemCallErrorNumber= + + Takes an + errno error number + name to return when the system call + filter configured with + SystemCallFilter= + is triggered, instead of terminating + the process immediately. Takes an + error name such as + EPERM, + EACCES or + EUCLEAN. When this + setting is not used, or when the empty + string is assigned the process will be + terminated immediately when the filter + is triggered. + + + + + + + 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. @@ -1017,8 +1216,9 @@ systemd.swap5, systemd.mount5, systemd.kill5, - systemd.cgroup5, - systemd.directives7 + systemd.resource-control5, + systemd.directives7, + exec3