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d19d6e1856
* common/exectool.c (gnupg_exec_tool): Allocate extra byte. Allow zero length read. Append hidden byte. Release memory on error. -- Signed-off-by: Werner Koch <wk@gnupg.org>
450 lines
11 KiB
C
450 lines
11 KiB
C
/* exectool.c - Utility functions to execute a helper tool
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* Copyright (C) 2015 Werner Koch
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*
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* This file is part of GnuPG.
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*
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* This file is free software; you can redistribute it and/or modify
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* it under the terms of either
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*
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* - the GNU Lesser General Public License as published by the Free
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* Software Foundation; either version 3 of the License, or (at
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* your option) any later version.
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*
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* or
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*
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* - the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* or both in parallel, as here.
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*
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* This file is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdarg.h>
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#include <errno.h>
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#include <assert.h>
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#include <gpg-error.h>
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#include <assuan.h>
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#include "i18n.h"
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#include "logging.h"
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#include "membuf.h"
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#include "mischelp.h"
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#include "exechelp.h"
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#include "sysutils.h"
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#include "util.h"
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typedef struct
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{
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const char *pgmname;
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int cont;
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int used;
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char buffer[256];
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} read_and_log_buffer_t;
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static inline gpg_error_t
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my_error_from_syserror (void)
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{
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return gpg_err_make (default_errsource, gpg_err_code_from_syserror ());
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}
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static void
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read_and_log_stderr (read_and_log_buffer_t *state, es_poll_t *fderr)
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{
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gpg_error_t err;
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int c;
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if (!fderr)
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{
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/* Flush internal buffer. */
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if (state->used)
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{
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const char *pname;
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int len;
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state->buffer[state->used] = 0;
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state->used = 0;
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pname = strrchr (state->pgmname, '/');
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if (pname && pname != state->pgmname && pname[1])
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pname++;
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else
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pname = state->pgmname;
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/* If our pgmname plus colon is identical to the start of
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the output, print only the output. */
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len = strlen (pname);
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if (!state->cont
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&& !strncmp (state->buffer, pname, len)
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&& strlen (state->buffer) > strlen (pname)
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&& state->buffer[len] == ':' )
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log_info ("%s\n", state->buffer);
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else
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log_info ("%s%c %s\n",
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pname, state->cont? '+':':', state->buffer);
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}
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state->cont = 0;
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return;
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}
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for (;;)
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{
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c = es_fgetc (fderr->stream);
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if (c == EOF)
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{
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if (es_feof (fderr->stream))
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{
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fderr->ignore = 1; /* Not anymore needed. */
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}
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else if (es_ferror (fderr->stream))
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{
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err = my_error_from_syserror ();
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log_error ("error reading stderr of '%s': %s\n",
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state->pgmname, gpg_strerror (err));
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fderr->ignore = 1; /* Disable. */
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}
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break;
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}
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else if (c == '\n')
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{
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read_and_log_stderr (state, NULL);
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}
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else
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{
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if (state->used >= sizeof state->buffer - 1)
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{
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read_and_log_stderr (state, NULL);
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state->cont = 1;
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}
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state->buffer[state->used++] = c;
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}
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}
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}
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/* A buffer to copy from one stream to another. */
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struct copy_buffer
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{
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char buffer[4096];
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char *writep;
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size_t nread;
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};
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/* Initialize a copy buffer. */
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static void
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copy_buffer_init (struct copy_buffer *c)
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{
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c->writep = c->buffer;
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c->nread = 0;
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}
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/* Securely wipe a copy buffer. */
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static void
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copy_buffer_shred (struct copy_buffer *c)
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{
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wipememory (c->buffer, sizeof c->buffer);
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c->writep = NULL;
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c->nread = ~0U;
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}
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/* Copy data from SOURCE to SINK using copy buffer C. */
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static gpg_error_t
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copy_buffer_do_copy (struct copy_buffer *c, estream_t source, estream_t sink)
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{
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gpg_error_t err;
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size_t nwritten;
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if (c->nread == 0)
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{
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c->writep = c->buffer;
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err = es_read (source, c->buffer, sizeof c->buffer, &c->nread);
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if (err)
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{
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if (errno == EAGAIN)
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return 0; /* We will just retry next time. */
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return my_error_from_syserror ();
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}
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assert (c->nread <= sizeof c->buffer);
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}
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if (c->nread == 0)
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return 0; /* Done copying. */
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err = es_write (sink, c->writep, c->nread, &nwritten);
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if (err)
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{
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if (errno == EAGAIN)
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return 0; /* We will just retry next time. */
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return my_error_from_syserror ();
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}
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assert (nwritten <= c->nread);
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c->writep += nwritten;
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c->nread -= nwritten;
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assert (c->writep - c->buffer <= sizeof c->buffer);
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if (es_fflush (sink) && errno != EAGAIN)
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err = my_error_from_syserror ();
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return err;
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}
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/* Flush the remaining data to SINK. */
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static gpg_error_t
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copy_buffer_flush (struct copy_buffer *c, estream_t sink)
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{
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gpg_error_t err;
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while (c->nread > 0)
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{
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err = copy_buffer_do_copy (c, NULL, sink);
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if (err)
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return err;
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}
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return 0;
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}
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/* Run the program PGMNAME with the command line arguments given in
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the NULL terminates array ARGV. If INPUT is not NULL it will be
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fed to stdin of the process. stderr is logged using log_info and
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the process' stdout is written to OUTPUT. On error a diagnostic is
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printed, and an error code returned. */
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gpg_error_t
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gnupg_exec_tool_stream (const char *pgmname, const char *argv[],
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estream_t input,
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estream_t output)
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{
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gpg_error_t err;
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pid_t pid;
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estream_t infp = NULL;
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estream_t outfp, errfp;
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es_poll_t fds[3];
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int count;
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read_and_log_buffer_t fderrstate;
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struct copy_buffer cpbuf[2];
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memset (fds, 0, sizeof fds);
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memset (&fderrstate, 0, sizeof fderrstate);
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copy_buffer_init (&cpbuf[0]);
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copy_buffer_init (&cpbuf[1]);
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err = gnupg_spawn_process (pgmname, argv, GPG_ERR_SOURCE_DEFAULT,
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NULL, GNUPG_SPAWN_NONBLOCK,
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input? &infp : NULL,
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&outfp, &errfp, &pid);
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if (err)
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{
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log_error ("error running '%s': %s\n", pgmname, gpg_strerror (err));
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return err;
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}
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fderrstate.pgmname = pgmname;
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fds[0].stream = infp;
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fds[0].want_write = 1;
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if (!input)
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fds[0].ignore = 1;
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fds[1].stream = outfp;
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fds[1].want_read = 1;
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fds[2].stream = errfp;
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fds[2].want_read = 1;
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/* Now read as long as we have something to poll. We continue
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reading even after EOF or error on stdout so that we get the
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other error messages or remaining outut. */
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while (!fds[1].ignore && !fds[2].ignore)
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{
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count = es_poll (fds, DIM(fds), -1);
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if (count == -1)
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{
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err = my_error_from_syserror ();
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log_error ("error polling '%s': %s\n", pgmname, gpg_strerror (err));
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goto leave;
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}
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if (!count)
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{
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log_debug ("unexpected timeout while polling '%s'\n", pgmname);
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break;
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}
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if (fds[0].got_write)
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{
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err = copy_buffer_do_copy (&cpbuf[0], input, fds[0].stream);
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if (err)
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{
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log_error ("error feeding data to '%s': %s\n",
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pgmname, gpg_strerror (err));
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goto leave;
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}
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if (es_feof (input))
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{
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err = copy_buffer_flush (&cpbuf[0], fds[0].stream);
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if (err)
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{
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log_error ("error feeding data to '%s': %s\n",
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pgmname, gpg_strerror (err));
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goto leave;
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}
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fds[0].ignore = 1; /* ready. */
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es_fclose (infp); infp = NULL;
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}
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}
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if (fds[1].got_read)
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{
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err = copy_buffer_do_copy (&cpbuf[1], fds[1].stream, output);
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if (err)
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{
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log_error ("error reading data from '%s': %s\n",
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pgmname, gpg_strerror (err));
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goto leave;
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}
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}
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if (fds[2].got_read)
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read_and_log_stderr (&fderrstate, fds + 2);
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}
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err = copy_buffer_flush (&cpbuf[1], output);
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if (err)
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{
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log_error ("error reading data from '%s': %s\n",
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pgmname, gpg_strerror (err));
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goto leave;
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}
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read_and_log_stderr (&fderrstate, NULL); /* Flush. */
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es_fclose (infp); infp = NULL;
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es_fclose (outfp); outfp = NULL;
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es_fclose (errfp); errfp = NULL;
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err = gnupg_wait_process (pgmname, pid, 1, NULL);
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pid = (pid_t)(-1);
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leave:
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if (err)
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gnupg_kill_process (pid);
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es_fclose (infp);
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es_fclose (outfp);
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es_fclose (errfp);
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if (pid != (pid_t)(-1))
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gnupg_wait_process (pgmname, pid, 1, NULL);
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gnupg_release_process (pid);
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copy_buffer_shred (&cpbuf[0]);
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copy_buffer_shred (&cpbuf[1]);
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return err;
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}
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/* A dummy free function to pass to 'es_mopen'. */
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static void
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nop_free (void *ptr)
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{
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(void) ptr;
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}
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/* Run the program PGMNAME with the command line arguments given in
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the NULL terminates array ARGV. If INPUT_STRING is not NULL it
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will be fed to stdin of the process. stderr is logged using
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log_info and the process' stdout is returned in a newly malloced
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buffer RESULT with the length stored at RESULTLEN if not given as
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NULL. A hidden Nul is appended to the output. On error NULL is
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stored at RESULT, a diagnostic is printed, and an error code
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returned. */
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gpg_error_t
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gnupg_exec_tool (const char *pgmname, const char *argv[],
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const char *input_string,
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char **result, size_t *resultlen)
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{
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gpg_error_t err;
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estream_t input = NULL;
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estream_t output;
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size_t len;
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size_t nread;
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*result = NULL;
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if (resultlen)
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*resultlen = 0;
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if (input_string)
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{
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len = strlen (input_string);
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input = es_mopen ((char *) input_string, len, len,
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0 /* don't grow */, NULL, nop_free, "rb");
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if (! input)
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return my_error_from_syserror ();
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}
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output = es_fopenmem (0, "wb");
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if (! output)
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{
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err = my_error_from_syserror ();
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goto leave;
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}
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err = gnupg_exec_tool_stream (pgmname, argv, input, output);
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if (err)
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goto leave;
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len = es_ftello (output);
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err = es_fseek (output, 0, SEEK_SET);
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if (err)
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goto leave;
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*result = xtrymalloc (len + 1);
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if (!*result)
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{
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err = my_error_from_syserror ();
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goto leave;
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}
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if (len)
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{
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err = es_read (output, *result, len, &nread);
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if (err)
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goto leave;
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if (nread != len)
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log_fatal ("%s: short read from memstream\n", __func__);
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}
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(*result)[len] = 0;
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if (resultlen)
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*resultlen = len;
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leave:
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es_fclose (input);
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es_fclose (output);
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if (err)
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{
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xfree (*result);
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*result = NULL;
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}
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return err;
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}
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