+++ /dev/null
-
-/*
- * server.c Set up and handle communications with a server process.
- *
- * Server Handling copyright 1992-1999, 2001 The Free Software Foundation
- *
- * Server Handling is free software.
- * You may redistribute it and/or modify it under the terms of the
- * GNU General Public License, as published by the Free Software
- * Foundation; either version 2, or (at your option) any later version.
- *
- * Server Handling 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with Server Handling. See the file "COPYING". If not,
- * write to: The Free Software Foundation, Inc.,
- * 59 Temple Place - Suite 330,
- * Boston, MA 02111-1307, USA.
- *
- * As a special exception, The Free Software Foundation gives
- * permission for additional uses of the text contained in his release
- * of ServerHandler.
- *
- * The exception is that, if you link the ServerHandler library with other
- * files to produce an executable, this does not by itself cause the
- * resulting executable to be covered by the GNU General Public License.
- * Your use of that executable is in no way restricted on account of
- * linking the ServerHandler library code into it.
- *
- * This exception does not however invalidate any other reasons why
- * the executable file might be covered by the GNU General Public License.
- *
- * This exception applies only to the code released by The Free
- * Software Foundation under the name ServerHandler. If you copy code
- * from other sources under the General Public License into a copy of
- * ServerHandler, as the General Public License permits, the exception
- * does not apply to the code that you add in this way. To avoid
- * misleading anyone as to the status of such modified files, you must
- * delete this exception notice from them.
- *
- * If you write modifications of your own for ServerHandler, it is your
- * choice whether to permit this exception to apply to your modifications.
- * If you do not wish that, delete this exception notice.
- */
-
-#include "fixlib.h"
-#include "server.h"
-
-STATIC volatile enum t_bool read_pipe_timeout;
-STATIC pid_t server_master_pid = NOPROCESS;
-
-tSCC* def_args[] =
-{ (char *) NULL, (char *) NULL };
-STATIC t_pf_pair server_pair =
-{ (FILE *) NULL, (FILE *) NULL };
-STATIC pid_t server_id = NULLPROCESS;
-/*
- * Arbitrary text that should not be found in the shell output.
- * It must be a single line and appear verbatim at the start of
- * the terminating output line.
- */
-tSCC z_done[] = "ShElL-OuTpUt-HaS-bEeN-cOmPlEtEd";
-tSCC* p_cur_dir = (char *) NULL;
-
-/*
- * load_data
- *
- * Read data from a file pointer (a pipe to a process in this context)
- * until we either get EOF or we get a marker line back.
- * The read data are stored in a malloc-ed string that is truncated
- * to size at the end. Input is assumed to be an ASCII string.
- */
-static char *
-load_data (FILE* fp)
-{
- char *pz_text;
- size_t text_size;
- char *pz_scan;
- char z_line[1024];
- t_bool got_done = BOOL_FALSE;
-
- text_size = sizeof (z_line) * 2;
- pz_scan = pz_text = xmalloc (text_size);
-
- for (;;)
- {
- size_t used_ct;
-
- alarm (10);
- read_pipe_timeout = BOOL_FALSE;
- if (fgets (z_line, sizeof (z_line), fp) == (char *) NULL)
- break;
-
- if (strncmp (z_line, z_done, sizeof (z_done) - 1) == 0)
- {
- got_done = BOOL_TRUE;
- break;
- }
-
- strcpy (pz_scan, z_line);
- pz_scan += strlen (z_line);
- used_ct = (size_t) (pz_scan - pz_text);
-
- if (text_size - used_ct < sizeof (z_line))
- {
- size_t off = (size_t) (pz_scan - pz_text);
-
- text_size += 4096;
- pz_text = xrealloc (pz_text, text_size);
- pz_scan = pz_text + off;
- }
- }
-
- alarm (0);
- if (read_pipe_timeout || ! got_done)
- {
- free ((void *) pz_text);
- return (char *) NULL;
- }
-
- while ((pz_scan > pz_text) && ISSPACE (pz_scan[-1]))
- pz_scan--;
- *pz_scan = NUL;
- return xrealloc (pz_text, strlen (pz_text) + 1);
-}
-
-
-/*
- * close_server
- *
- * Make certain the server process is dead, close the
- * pipes to it and from it, finally NULL out the file pointers
- */
-void
-close_server (void)
-{
- if ( (server_id != NULLPROCESS)
- && (server_master_pid == getpid ()))
- {
- kill ((pid_t) server_id, SIGKILL);
- server_id = NULLPROCESS;
- server_master_pid = NOPROCESS;
- fclose (server_pair.pf_read);
- fclose (server_pair.pf_write);
- server_pair.pf_read = server_pair.pf_write = (FILE *) NULL;
- }
-}
-
-/*
- * sig_handler really only handles the timeout and pipe signals.
- * This ensures that we do not wait forever on a request
- * to our server, and also that if the server dies, we do not
- * die from a sigpipe problem.
- */
-static void
-sig_handler (int signo ATTRIBUTE_UNUSED)
-{
-#ifdef DEBUG
- /* FIXME: this is illegal to do in a signal handler. */
- fprintf (stderr,
- "fixincl ERROR: sig_handler: killed pid %ld due to %s\n",
- (long) server_id, signo == SIGPIPE ? "SIGPIPE" : "SIGALRM");
-#endif
- close_server ();
- read_pipe_timeout = BOOL_TRUE;
-}
-
-
-/*
- * server_setup Establish the signal handler for PIPE and ALARM.
- * Also establishes the current directory to give to the
- * server process at the start of every server command.
- */
-static void
-server_setup (void)
-{
- static int atexit_done = 0;
- char buff [MAXPATHLEN + 1];
-
- if (atexit_done++ == 0)
- atexit (close_server);
- else
- fputs ("NOTE: server restarted\n", stderr);
-
- server_master_pid = getpid ();
-
- signal (SIGPIPE, sig_handler);
- signal (SIGALRM, sig_handler);
-
- fputs ("trap : 1\n", server_pair.pf_write);
- fflush (server_pair.pf_write);
- getcwd (buff, MAXPATHLEN + 1);
- p_cur_dir = xstrdup (buff);
-}
-
-/*
- * find_shell
- *
- * Locate a shell suitable for use. For various reasons
- * (like the use of "trap" in server_setup(), it must be a
- * Bourne-like shell.
- *
- * Most of the time, /bin/sh is preferred, but sometimes
- * it's quite broken (like on Ultrix). autoconf lets you
- * override with $CONFIG_SHELL, so we do the same.
- */
-
-static const char *
-find_shell (void)
-{
- char * shell = getenv ("CONFIG_SHELL");
- if (shell)
- return shell;
-
- return "/bin/sh";
-}
-
-
-/*
- * run_shell
- *
- * Run a shell command on the server. The command string
- * passed in is wrapped inside the sequence:
- *
- * cd <original directory>
- * <command string>
- * echo
- * echo <end-of-command-marker>
- *
- * This ensures that all commands start at a known place in
- * the directory structure, that any incomplete output lines
- * are completed and that our special marker sequence appears on
- * a line by itself. We have chosen a marker that is
- * excessively unlikely to be reproduced in normal output:
- *
- * "ShElL-OuTpUt-HaS-bEeN-cOmPlEtEd"
- */
-char *
-run_shell (const char* pz_cmd)
-{
- tSCC zNoServer[] = "Server not running, cannot run:\n%s\n\n";
- t_bool retry = BOOL_TRUE;
-
- do_retry:
- /* IF the shell server process is not running yet,
- THEN try to start it. */
- if (server_id == NULLPROCESS)
- {
- def_args[0] = find_shell ();
-
- server_id = proc2_fopen (&server_pair, def_args);
- if (server_id > 0)
- server_setup ();
- }
-
- /* IF it is still not running, THEN return the nil string. */
- if (server_id <= 0)
- {
- fprintf (stderr, zNoServer, pz_cmd);
- return xcalloc (1, 1);
- }
-
- /* Make sure the process will pay attention to us, send the
- supplied command, and then have it output a special marker that
- we can find. */
- fprintf (server_pair.pf_write, "cd %s\n%s\n\necho\necho %s\n",
- p_cur_dir, pz_cmd, z_done);
- fflush (server_pair.pf_write);
-
- /* IF the server died and we received a SIGPIPE,
- THEN return an empty string. */
- if (server_id == NULLPROCESS)
- {
- fprintf (stderr, zNoServer, pz_cmd);
- return xcalloc (1, 1);
- }
-
- /* Now try to read back all the data. If we fail due to either a
- sigpipe or sigalrm (timeout), we will return the nil string. */
- {
- char *pz = load_data (server_pair.pf_read);
-
- if (pz == (char *) NULL)
- {
- close_server ();
-
- if (retry)
- {
- retry = BOOL_FALSE;
- goto do_retry;
- }
-
- fprintf (stderr, "CLOSING SHELL SERVER - command failure:\n\t%s\n",
- pz_cmd);
- pz = xcalloc (1, 1);
- }
-#ifdef DEBUG
- fprintf( stderr, "run_shell command success: %s\n", pz );
-#endif
- return pz;
- }
-}
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