From c270fd25b7ef0d73bc1fbdc5bb9e5dd7aa078cc0 Mon Sep 17 00:00:00 2001 From: Paul Osborne Date: Fri, 28 Oct 2016 16:47:35 -0400 Subject: unistd: add docs for exec* functions Signed-off-by: Paul Osborne --- src/unistd.rs | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/src/unistd.rs b/src/unistd.rs index 771a50fb..e37482a5 100644 --- a/src/unistd.rs +++ b/src/unistd.rs @@ -344,6 +344,12 @@ fn to_exec_array(args: &[CString]) -> Vec<*const c_char> { args_p } +/// Replace the current process image with a new one (see +/// [exec(3)](http://man7.org/linux/man-pages/man3/exec.3.html)). +/// +/// See the `::nix::unistd::execve` system call for additional details. `execv` +/// performs the same action but does not allow for customization of the +/// environment for the new process. #[inline] pub fn execv(path: &CString, argv: &[CString]) -> Result { let args_p = to_exec_array(argv); @@ -355,6 +361,24 @@ pub fn execv(path: &CString, argv: &[CString]) -> Result { Err(Error::Sys(Errno::last())) } + +/// Replace the current process image with a new one (see +/// [execve(2)](http://man7.org/linux/man-pages/man2/execve.2.html)). +/// +/// The execve system call allows for another process to be "called" which will +/// replace the current process image. That is, this process becomes the new +/// command that is run. On success, this function will not return. Instead, +/// the new program will run until it exits. +/// +/// If an error occurs, this function will return with an indication of the +/// cause of failure. See +/// [execve(2)#errors](http://man7.org/linux/man-pages/man2/execve.2.html#ERRORS) +/// for a list of potential problems that maight cause execv to fail. +/// +/// Both `::nix::unistd::execv` and `::nix::unistd::execve` take as arguments a +/// slice of `::std::ffi::CString`s for `args` and `env`. Each element in +/// the `args` list is an argument to the new process. Each element in the +/// `env` list should be a string in the form "key=value". #[inline] pub fn execve(path: &CString, args: &[CString], env: &[CString]) -> Result { let args_p = to_exec_array(args); @@ -367,6 +391,15 @@ pub fn execve(path: &CString, args: &[CString], env: &[CString]) -> Result Err(Error::Sys(Errno::last())) } +/// Replace the current process image with a new one and replicate shell `PATH` +/// searching behavior (see +/// [exec(3)](http://man7.org/linux/man-pages/man3/exec.3.html)). +/// +/// See `::nix::unistd::execve` for additoinal details. `execvp` behaves the +/// sme as execv except that it will examine the `PATH` environment variables +/// for file names not specified with a leading slash. For example, `execv` +/// would not work if I specified "bash" for the path argument, but `execvp` +/// would assuming that I had a bash executable on my `PATH`. #[inline] pub fn execvp(filename: &CString, args: &[CString]) -> Result { let args_p = to_exec_array(args); -- cgit v1.2.3