libiberty/pex-common.h

/* Utilities to execute a program in a subprocess (possibly linked by pipes
   with other subprocesses), and wait for it.  Shared logic.
   Copyright (C) 1996-2021 Free Software Foundation, Inc.

This file is part of the libiberty library.
Libiberty is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.

Libiberty is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Library General Public License for more details.

You should have received a copy of the GNU Library General Public
License along with libiberty; see the file COPYING.LIB.  If not,
write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
Boston, MA 02110-1301, USA.  */

#ifndef PEX_COMMON_H
#define PEX_COMMON_H

#include "config.h"
#include "libiberty.h"
#include <stdio.h>

/* pid_t is may defined by config.h or sys/types.h needs to be
   included.  */
#if !defined(pid_t) && defined(HAVE_SYS_TYPES_H)
#include <sys/types.h>
#endif

#define install_error_msg "installation problem, cannot exec `%s'"

/* stdin file number.  */
#define STDIN_FILE_NO 0

/* stdout file number.  */
#define STDOUT_FILE_NO 1

/* stderr file number.  */
#define STDERR_FILE_NO 2

/* value of `pipe': port index for reading.  */
#define READ_PORT 0

/* value of `pipe': port index for writing.  */
#define WRITE_PORT 1

/* The structure used by pex_init and friends.  */

struct pex_obj
{
  /* Flags.  */
  int flags;
  /* Name of calling program, for error messages.  */
  const char *pname;
  /* Base name to use for temporary files.  */
  const char *tempbase;
  /* Pipe to use as stdin for next process.  */
  int next_input;
  /* File name to use as stdin for next process.  */
  char *next_input_name;
  /* Whether next_input_name was allocated using malloc.  */
  int next_input_name_allocated;
  /* If not -1, stderr pipe from the last process.  */
  int stderr_pipe;
  /* Number of child processes.  */
  int count;
  /* PIDs of child processes; array allocated using malloc.  */
  pid_t *children;
  /* Exit statuses of child processes; array allocated using malloc.  */
  int *status;
  /* Time used by child processes; array allocated using malloc.  */
  struct pex_time *time;
  /* Number of children we have already waited for.  */
  int number_waited;
  /* FILE created by pex_input_file.  */
  FILE *input_file;
  /* FILE created by pex_read_output.  */
  FILE *read_output;
  /* FILE created by pex_read_err.  */
  FILE *read_err;
  /* Number of temporary files to remove.  */
  int remove_count;
  /* List of temporary files to remove; array allocated using malloc
     of strings allocated using malloc.  */
  char **remove;
  /* Pointers to system dependent functions.  */
  const struct pex_funcs *funcs;
  /* For use by system dependent code.  */
  void *sysdep;
};

/* Functions passed to pex_run_common.  */

struct pex_funcs
{
  /* Open file NAME for reading.  If BINARY is non-zero, open in
     binary mode.  Return >= 0 on success, -1 on error.  */
  int (*open_read) (struct pex_obj *, const char */* name */, int /* binary */);
  /* Open file NAME for writing.  If BINARY is non-zero, open in
     binary mode.  Return >= 0 on success, -1 on error.  */
  int (*open_write) (struct pex_obj *, const char */* name */,
                     int /* binary */, int /* append */);
  /* Execute a child process.  FLAGS, EXECUTABLE, ARGV, ERR are from
     pex_run.  IN, OUT, ERRDES, TOCLOSE are all descriptors, from
     open_read, open_write, or pipe, or they are one of STDIN_FILE_NO,
     STDOUT_FILE_NO or STDERR_FILE_NO; if IN, OUT, and ERRDES are not
     STD*_FILE_NO, they should be closed.  If the descriptor TOCLOSE
     is not -1, and the system supports pipes, TOCLOSE should be
     closed in the child process.  The function should handle the
     PEX_STDERR_TO_STDOUT flag.  Return >= 0 on success, or -1 on
     error and set *ERRMSG and *ERR.  */
  pid_t (*exec_child) (struct pex_obj *, int /* flags */,
                      const char */* executable */, char * const * /* argv */,
                      char * const * /* env */,
                      int /* in */, int /* out */, int /* errdes */,
		      int /* toclose */, const char **/* errmsg */,
		      int */* err */);
  /* Close a descriptor.  Return 0 on success, -1 on error.  */
  int (*close) (struct pex_obj *, int);
  /* Wait for a child to complete, returning exit status in *STATUS
     and time in *TIME (if it is not null).  CHILD is from fork.  DONE
     is 1 if this is called via pex_free.  ERRMSG and ERR are as in
     fork.  Return 0 on success, -1 on error.  */
  pid_t (*wait) (struct pex_obj *, pid_t /* child */, int * /* status */,
               struct pex_time * /* time */, int /* done */,
               const char ** /* errmsg */, int * /* err */);
  /* Create a pipe (only called if PEX_USE_PIPES is set) storing two
     descriptors in P[0] and P[1].  If BINARY is non-zero, open in
     binary mode.  Return 0 on success, -1 on error.  */
  int (*pipe) (struct pex_obj *, int * /* p */, int /* binary */);
  /* Get a FILE pointer to read from a file descriptor (only called if
     PEX_USE_PIPES is set).  If BINARY is non-zero, open in binary
     mode.  Return pointer on success, NULL on error.  */
  FILE * (*fdopenr) (struct pex_obj *, int /* fd */, int /* binary */);
  /* Get a FILE pointer to write to the file descriptor FD (only
     called if PEX_USE_PIPES is set).  If BINARY is non-zero, open in
     binary mode.  Arrange for FD not to be inherited by the child
     processes.  Return pointer on success, NULL on error.  */
  FILE * (*fdopenw) (struct pex_obj *, int /* fd */, int /* binary */);
  /* Free any system dependent data associated with OBJ.  May be
     NULL if there is nothing to do.  */
  void (*cleanup) (struct pex_obj *);
};

extern struct pex_obj *pex_init_common (int, const char *, const char *,
					const struct pex_funcs *);

#endif