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.Dd February 18, 2011 .Dt RUMPHIJACK 3 .Os .Sh NAME .Nm rumphijack .Nd System call hijack library .Sh LIBRARY used by .Xr ld.so 1 .Sh DESCRIPTION The .Xr ld.so 1 runtime linker can be instructed to load .Nm between the main object and other libraries. This enables .Nm to capture and redirect system call requests to a rump kernel instead of the host kernel.
p The behaviour of hijacked applications is affected by the following environment variables: l -tag -width 12345 t Ev RUMPHIJACK If present, this variable specifies which system calls should be hijacked. The string is parsed as a comma-separated list of .Dq name=value tuples. The possible lefthandside names are: l -tag -width xxsocketxx t Dq path Pathname-based system calls are hijacked if the path the system call is directed to resides under .Ar value . In case of an absolute pathname argument, a literal prefix comparison is made. In case of a relative pathname, the current working direct is examined. This also implies that neither .Dq .. nor symbolic links will cause the namespace to be switched. t Dq socket The specifier .Ar value contains a colon-separated list of which protocol families should be hijacked. The special value .Dq all can be specified as the first element. It indicates that all protocol families should be hijacked. Some can then be disabled by prepending .Dq no to the name of the protocol family.
p For example, .Dq inet:inet6 specifies that only .Dv PF_INET and .Dv PF_INET6 sockets should be hijacked, while .Dq all:noinet specifies that all protocol families except .Dv PF_INET should be hijacked. .El
p If the environment variable is unset, the default value .Qq path=/rump,socket=all:nolocal is used. The rationale for this is to have networked X clients work out-of-the-box: X clients use local sockets to communicate with the server, so local sockets must be used as a host service.
p An empty string as a value means no calls are hijacked. t Ev RUMPHIJACK_RETRYCONNECT Change how .Xr rumpclient 3 attempts to reconnect to the server in case the connection is lost. Acceptable values are: l -tag -width xxinftimexx t Dq inftime retry indefinitely t Dq once retry once, when that connection fails, give up t Dq die call .Xr exit 3 if connection failure is detected t n Attempt reconnect for n seconds. The value 0 means reconnection is not attempted. The value n must be a positive integer. .El
p See .Xr rumpclient 3 for more discussion. .El .Sh EXAMPLES Use an alternate TCP/IP stack for firefox with a persistent server connection: d -literal -offset indent $ setenv RUMP_SERVER unix:///tmp/tcpip $ setenv LD_PRELOAD /usr/lib/librumphijack.so $ setenv RUMPHIJACK_RETRYCONNECT inftime $ firefox .Ed .Sh SEE ALSO .Xr ld.so 1 , .Xr rump_server 1 , .Xr rump 3 , .Xr rumpclient 3 , .Xr rump_sp 7
Indexes created Mon Oct 20 11:09:49 GMT 2025