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| Both sides previous revisionPrevious revisionNext revision | Previous revision |
| projects:openssh [2019/12/25 16:11] – [Control flow] admin | projects:openssh [2026/10/25 19:30] (current) – external edit 127.0.0.1 |
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| ====== scp ====== | ====== scp ====== |
| ===== Control flow ===== | |
| - On client (copy remote to local case) | ==== 1) scp run on client (copy remote to local case) ==== |
| * construct ''scp'' command to be executed on the server via ssh. append ''-v -r -p -d'' flags as appropriate. Resulting command stored in ''cmd'' variable | * construct ''scp'' command to be executed on the server via ssh. append ''-v -r -p -d'' flags as appropriate. Resulting command stored in ''cmd'' variable |
| * call ''toremote()'' if destination is remote; ''tolocal()'' if destination is local (handles 'remote to local' and 'local to local' cases) | * call ''toremote()'' if destination is remote; ''tolocal()'' if destination is local (handles 'remote to local' and 'local to local' cases) |
| * for 'remote to local' case, append '''-f <src>''' to ''scp'' command to be run on the server | * for 'remote to local' case, append '''-f <src>''' to ''scp'' command to be run on the server |
| * call ''do_cmd()'' to run assembled ''scp'' command on the server | * call ''do_cmd()'' to run assembled ''scp'' command on the server |
| * ''do_cmd()'' forks a child which executes (via ''execvp()'') "''ssh -p <port> -l <remuser> --- <host> <cmd>''" scp command on the server. Connect parent and child via pipes. ''do_cmd_pid'' contains child's PID. | * ''do_cmd()'' forks a child which executes (via ''execvp()'') "''ssh -p <port> -l <remuser> --- <host> <cmd>''" scp command on the server. Connect parent and child via pipes. Parent accesses child's pipes via ''remin'' & ''remout''. ''do_cmd_pid'' contains child's PID. |
| - On server | * ''tolocal()->sink()'' receives file from child via ''remin'' & ''remout'' and stores it to the local destination |
| | * finaly wait for child to finish, check for errors, close ''remin'' & ''remout'' and exit |
| | ==== 2) client runs ssh to spawn server side of scp ==== |
| | ==== 3) server accepts ssh connection from client ==== |
| * for ''-t'' or ''-f'' private flags: ''remin = stdin''; ''remout = stdout'' | * for ''-t'' or ''-f'' private flags: ''remin = stdin''; ''remout = stdout'' |
