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git://git.gnupg.org/gnupg.git
synced 2025-07-14 21:47:19 +02:00
common: Add a stream interface to 'sh-exectool'.
* common/sh-exectool.c (struct copy_buffer): Add infrastructure for
copying between streams.
(copy_buffer_{init,shred,do_copy,flush}): New functions.
(sh_exec_tool_stream): Rework 'sh_exec_tool' to operate on streams.
(nop_free): New function.
(sh_exec_tool): Express this in terms of 'sh_exec_tool_stream'.
* common/sh-exectool.h (sh_exec_tool_stream): New prototype.
Signed-off-by: Justus Winter <justus@g10code.com>
This commit is contained in:
Justus Winter
parent
d955cb5e07
commit
a81aca6e1c
2 changed files with 218 additions and 87 deletions
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@ -24,13 +24,16 @@
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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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@ -113,56 +116,109 @@ read_and_log_stderr (read_and_log_buffer_t *state, es_poll_t *fderr)
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}
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}
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static gpg_error_t
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read_stdout (membuf_t *mb, es_poll_t *fdout, const char *pgmname)
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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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gpg_error_t err = 0;
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int c;
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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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for (;;)
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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 = es_fgetc (fdout->stream);
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if (c == EOF)
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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 (es_feof (fdout->stream))
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{
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fdout->ignore = 1; /* Ready. */
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}
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else if (es_ferror (fdout->stream))
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{
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err = gpg_error_from_syserror ();
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log_error ("error reading stdout of '%s': %s\n",
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pgmname, gpg_strerror (err));
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fdout->ignore = 1; /* Disable. */
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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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break;
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}
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else
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{
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char buf[1];
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*buf = c;
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put_membuf (mb, buf, 1);
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return gpg_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 gpg_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 = gpg_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_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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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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sh_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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sh_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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@ -171,19 +227,16 @@ sh_exec_tool (const char *pgmname, const char *argv[],
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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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membuf_t fdout_mb;
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size_t len, nwritten;
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struct copy_buffer cpbuf[2];
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*result = NULL;
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if (resultlen)
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*resultlen = 0;
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memset (fds, 0, sizeof fds);
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memset (&fderrstate, 0, sizeof fderrstate);
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init_membuf (&fdout_mb, 4096);
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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_string? &infp : NULL,
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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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@ -195,7 +248,7 @@ sh_exec_tool (const char *pgmname, const char *argv[],
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fds[0].stream = infp;
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fds[0].want_write = 1;
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if (!input_string)
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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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@ -221,53 +274,50 @@ sh_exec_tool (const char *pgmname, const char *argv[],
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if (fds[0].got_write)
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{
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len = strlen (input_string);
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log_debug ("writing '%s'\n", input_string);
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if (es_write (fds[0].stream, input_string, len, &nwritten))
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{
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if (errno != EAGAIN)
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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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err = gpg_error_from_syserror ();
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log_error ("error writing '%s': %s\n",
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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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else
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log_debug (" .. EAGAIN\n");
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}
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else
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{
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assert (nwritten <= len);
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input_string += nwritten;
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}
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if (es_fflush (fds[0].stream) && errno != EAGAIN)
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{
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err = gpg_error_from_syserror ();
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log_error ("error writing '%s' (flush): %s\n",
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pgmname, gpg_strerror (err));
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if (gpg_err_code (err) == GPG_ERR_EPIPE && !*input_string)
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{
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/* fixme: How can we tell whether estream has
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pending bytes after a HUP - which is an
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error? */
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}
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else
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goto leave;
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}
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if (!*input_string)
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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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read_stdout (&fdout_mb, fds + 1, pgmname); /* FIXME: Add error
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handling. */
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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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@ -280,17 +330,7 @@ sh_exec_tool (const char *pgmname, const char *argv[],
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leave:
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if (err)
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{
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gnupg_kill_process (pid);
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xfree (get_membuf (&fdout_mb, NULL));
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}
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else
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{
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put_membuf (&fdout_mb, "", 1); /* Make sure it is a string. */
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*result = get_membuf (&fdout_mb, resultlen);
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if (!*result)
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err = gpg_error_from_syserror ();
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}
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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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@ -299,5 +339,85 @@ sh_exec_tool (const char *pgmname, const char *argv[],
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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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sh_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 gpg_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 = gpg_error_from_syserror ();
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goto leave;
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}
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err = sh_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);
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if (*result == NULL)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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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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{
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assert (nread == len || !"short read on memstream");
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if (resultlen)
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*resultlen = len;
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}
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leave:
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if (input)
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es_fclose (input);
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es_fclose (output);
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return err;
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}
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