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.Dd May 11, 2016 .Dt PCREATE 3PROC .Os .Sh NAME .Nm Pcreate , .Nm Pxcreate , .Nm Pcreate_callback .Nd create and control a process .Sh SYNOPSIS .Lb libproc n libproc.h .Ft "struct ps_prochandle *" .Fo Pcreate .Fa "const char *file" .Fa "char *const *argv" .Fa "int *perr" .Fa "char *path" .Fa "size_t len" .Fc .Ft "struct ps_prochandle *" .Fo Pxcreate .Fa "const char *file" .Fa "char *const *argv" .Fa "char *const *envp" .Fa "int *perr" .Fa "char *path" .Fa "size_t len" .Fc .Ft void .Fo Pcreate_callback .Fa "struct ps_prochandle *P" .Fc .Sh DESCRIPTION The .Fn Pcreate function creates a process controlled by the .Sy libproc library. The .Fn Pxcreate function does the same while also allowing the replacement of the environment via .Fa envp .

p Both functions cause the caller to .Xr fork 2 . Followed by the child calling .Xr exec 2 to load the new process image specified by .Fa file . The .Ev PATH is searched for .Fa file if it is not an absolute path, similar to .Xr execvp 2 .

p The process image will be invoked with the arguments specified by .Fa argv , which should be a .Dv NULL Ns -terminated array of character strings. Each entry in the array is an individual argument. The environment of the process image will be inherited from the running process if the .Fn Pcreate function is called or if the .Fn Pxcreate function is called and the value of .Fa envp is .Dv NULL . Otherwise, .Fa envp should be a .Dv NULL Ns -terminated array of character strings whose entries are in the form of .Em key=value . For more on the process environment, see .Xr environ 5 .

p The .Fn Pcreate_callback function allows a way for callers to inject a callback into the child process before the call to .Xr exec 2 . The symbol .Sy Pcreate_callback is a symbol that may be interposed on by consumers. It allows the chance for the modification of signal dispositions or any other changes that a caller may wish to make.

p If the caller's real user or group ID is not their effective user or group ID, then the child process's user and group IDs will all be reset to the real user and group id.

p The .Fa perr argument must be a

f non- Dv NULL pointer. If the .Fn Pcreate or .Fn Pxcreate functions fail, the value pointed to will be filled in with a more detailed error code listed in .Sx ERRORS . A human-readable error message is obtained with .Xr Pcreate_error 3PROC .

p Multiple executables named .Fa file may exist on the .Fa PATH . To determine the full path of the executable pass a non-NULL .Fa path pointer. Upon succesful completion of .Fn Pcreate or .Fn Pxcreate the .Fa path pointer will contain the full path up to .Fa len bytes, including the NUL character.

p Upon successful completion of the .Fn Pcreate or .Fn Pxcreate function, a handle to the process is returned. This handle is usable with other .Sy libproc routines and will persist until either .Xr Pfree 3PROC or .Xr Prelease 3PROC is called on the resulting handle. The process created is stopped just after return from the .Xr exec 2 family of system calls. The process will not run, unless the caller sets it running or releases its handle to the process.

p A 32-bit process cannot use this interface to launch or control a 64-bit process. However, a 64-bit process can create and control both 32-bit and 64-bit processes. .Sh RETURN VALUES Upon successful completion, both the .Fn Pcreate and .Fn Pxcreate functions create a new process and return a .Sy libproc handle to it. Otherwise, .Sy NULL is returned and .Fa perr is filled in with the corresponding error. .Sh ERRORS The .Fn Pcreate and .Fn Pxcreate functions will fail if: l -tag -width Er t Er C_FORK The call to .Xr fork 2 failed. t Er C_INTR The operation was interrupted by a signal. t Er C_LP64 The calling process is 32-bit, but it attempted to control a 64-bit process. t Er C_NOEXEC The specified .Fa file or the one found by searching .Dv PATH cannot be executed. t Er C_NOENT The specified .Fa file does not exist or it could not be found by searching .Dv PATH . t Er C_PERM The specified .Fa file or the one found by searching .Dv PATH is set-id or unreadable. t Er C_STRANGE An unanticipated system error occurred while trying to create the process and its handle. When this occurs, then the value of .Sy errno is meaningful. See .Xr errno 3C for more information and .Xr Intro 2 for the list of possible errors. .El .Sh INTERFACE STABILITY .Sy Uncommitted .Sh MT-LEVEL .Sy MT-Safe .Sh SEE ALSO .Xr exec 2 , .Xr execvp 2 , .Xr fork 2 , .Xr Intro 2 , .Xr errno 3C , .Xr libproc 3LIB , .Xr Pcreate_error 3PROC , .Xr Pfree 3PROC , .Xr Prelease 3PROC