Program execution: ./pipex infile cmd1 cmd2 outfile
Infile and outfile - file names
cmd1 and cmd2 - shell commands with their parameters
The program should behave as the shell command < infile cmd1 | cmd2 > outfile
Example: ./pipex infile "grep a" "cat -e" outfile should behave like < infile grep a | cat -e > outfile
Playlist on Unix processes from Code Vault
Reactive guide with some edge cases
Validate the input.
Open the infile. Check access rights. Redirect to standard input.
Create path array from env.
Create pipe.
Fork the process.
Child process deals with command 1.
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Redirect the stdout to pipe.
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Get path.
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Check path access.
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Split the command input.
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Execve the path and command 1.
Parent process deals with command 2.
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Redirect the stdin to pipe.
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Open / create the outfile. Redirect to stdout.
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Get path.
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Check path access.
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Split the command input.
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Execve the path and command2.
fork() returns PID of the child process to the parent.
Find command path with whereis.
Check your fds currently open with the command ls -la /proc/$$/fd
To see what is inside envp, type env in your terminal.
This project has to be written in accordance with the Norm, which is the coding standard of the school 42.
The Norm includes:
- Forbidden: for, do...while, switch, case, goto, ternary operators and variable-length arrays
- Maximum of 25 lines per function
- Maximum line length: 80 columns
- Maximum 4 parameters per function
- Variable assignments and declarations must be on separate lines
- etc...
Line PATH in env contains all possible paths to the command binaries. PATH=/nfs/homes/arepsa/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
Split, using : as delimiter. Add a / at the end for the path to work correctly.
Valgrind check with --trace-children=yes.