29 lines
872 B
Markdown
29 lines
872 B
Markdown
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# EXEC
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It is a family of functions that do the same thing but actually no.
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When we call `exec()`, we never reutrn back to the callling program. The program
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called by the `exec()` function replaces itself with the calling progam. The only way
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that we could return to original process if `exec()` fails to execute.
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Thats why we usually use `fork() & exec()`, so that we can safely return to main process
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without losing anything :).
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what stays:
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- `PID`, `PPID`
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- opened file descriptors
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- current directory, root directory
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what does not:
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- code
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- stack
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- heap
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- data
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(new stack and new heap)
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sufixes:
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- `l` ~ arguments are passed as function arguments
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- `v` ~ arguments are passed by char array
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- `p` ~ search in `$PATH` for provided executable
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- `P` ~ specifying that we will provide a path to an executable
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- `e` ~ enviromental variables are provided in a char array
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