support/capture_subprocess.h

   1 /* Capture output from a subprocess.
   2    Copyright (C) 2017-2024 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #ifndef SUPPORT_CAPTURE_SUBPROCESS_H
  20 #define SUPPORT_CAPTURE_SUBPROCESS_H
  21
  22 #include <support/xmemstream.h>
  23
  24 struct support_capture_subprocess
  25 {
  26   struct xmemstream out;
  27   struct xmemstream err;
  28   int status;
  29 };
  30
  31 /* Invoke CALLBACK (CLOSURE) in a subprocess and capture standard
  32    output, standard error, and the exit status.  The out.buffer and
  33    err.buffer members in the result are null-terminated strings which
  34    can be examined by the caller (out.out and err.out are NULL).  */
  35 struct support_capture_subprocess support_capture_subprocess
  36   (void (*callback) (void *), void *closure);
  37
  38 /* Issue FILE with ARGV arguments by using posix_spawn and capture standard
  39    output, standard error, and the exit status.  The out.buffer and err.buffer
  40    are handle as support_capture_subprocess.  */
  41 struct support_capture_subprocess support_capture_subprogram
  42   (const char *file, char *const argv[]);
  43
  44 /* Copy the running program into a setgid binary and run it with CHILD_ID
  45    argument.  If execution is successful, return the exit status of the child
  46    program, otherwise return a non-zero failure exit code.  */
  47 int support_capture_subprogram_self_sgid
  48   (char *child_id);
  49
  50 /* Deallocate the subprocess data captured by
  51    support_capture_subprocess.  */
  52 void support_capture_subprocess_free (struct support_capture_subprocess *);
  53
  54 enum support_capture_allow
  55 {
  56   /* No output is allowed.  */
  57   sc_allow_none = 0x01,
  58   /* Output to stdout is permitted.  */
  59   sc_allow_stdout = 0x02,
  60   /* Output to standard error is permitted.  */
  61   sc_allow_stderr = 0x04,
  62 };
  63
  64 /* Check that the subprocess exited and that only the allowed outputs
  65    happened.  If STATUS_OR_SIGNAL is nonnegative, it is the expected
  66    (decoded) exit status of the process, as returned by WEXITSTATUS.
  67    If STATUS_OR_SIGNAL is negative, -STATUS_OR_SIGNAL is the expected
  68    termination signal, as returned by WTERMSIG.  ALLOWED is a
  69    combination of support_capture_allow flags.  Report errors under
  70    the CONTEXT message.  */
  71 void support_capture_subprocess_check (struct support_capture_subprocess *,
  72                                        const char *context,
  73                                        int status_or_signal, int allowed)
  74   __attribute__ ((nonnull (1, 2)));
  75
  76 #endif /* SUPPORT_CAPTURE_SUBPROCESS_H */