mirror of git://gcc.gnu.org/git/gcc.git
219 lines
6.3 KiB
C
219 lines
6.3 KiB
C
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/*
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* server.c Set up and handle communications with a server process.
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*
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* Server Handling copyright 1992-1999, 2004 The Free Software Foundation
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*
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* Server Handling is free software.
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* You may redistribute it and/or modify it under the terms of the
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* GNU General Public License, as published by the Free Software
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* Foundation; either version 2, or (at your option) any later version.
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*
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* Server Handling 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 Server Handling. See the file "COPYING". If not,
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* write to: The Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*
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* As a special exception, The Free Software Foundation gives
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* permission for additional uses of the text contained in his release
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* of ServerHandler.
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*
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* The exception is that, if you link the ServerHandler library with other
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* files to produce an executable, this does not by itself cause the
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* resulting executable to be covered by the GNU General Public License.
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* Your use of that executable is in no way restricted on account of
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* linking the ServerHandler library code into it.
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*
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* This exception does not however invalidate any other reasons why
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* the executable file might be covered by the GNU General Public License.
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*
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* This exception applies only to the code released by The Free
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* Software Foundation under the name ServerHandler. If you copy code
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* from other sources under the General Public License into a copy of
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* ServerHandler, as the General Public License permits, the exception
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* does not apply to the code that you add in this way. To avoid
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* misleading anyone as to the status of such modified files, you must
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* delete this exception notice from them.
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*
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* If you write modifications of your own for ServerHandler, it is your
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* choice whether to permit this exception to apply to your modifications.
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* If you do not wish that, delete this exception notice.
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*/
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#include "fixlib.h"
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#include "server.h"
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STATIC const char* def_args[] =
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{ (char *) NULL, (char *) NULL };
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/*
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* chain_open
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*
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* Given an FD for an inferior process to use as stdin,
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* start that process and return a NEW FD that that process
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* will use for its stdout. Requires the argument vector
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* for the new process and, optionally, a pointer to a place
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* to store the child's process id.
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*/
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int
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chain_open (int stdin_fd, tCC** pp_args, pid_t* p_child)
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{
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t_fd_pair stdout_pair;
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pid_t ch_id;
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tCC *pz_cmd;
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stdout_pair.read_fd = stdout_pair.write_fd = -1;
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/*
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* Create a pipe it will be the child process' stdout,
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* and the parent will read from it.
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*/
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if (pipe ((int *) &stdout_pair) < 0)
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{
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if (p_child != (pid_t *) NULL)
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*p_child = NOPROCESS;
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return -1;
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}
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/*
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* If we did not get an arg list, use the default
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*/
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if (pp_args == (tCC **) NULL)
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pp_args = def_args;
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/*
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* If the arg list does not have a program,
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* assume the "SHELL" from the environment, or, failing
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* that, then sh. Set argv[0] to whatever we decided on.
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*/
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if (pz_cmd = *pp_args,
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(pz_cmd == (char *) NULL) || (*pz_cmd == '\0'))
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{
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pz_cmd = getenv ("SHELL");
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if (pz_cmd == (char *) NULL)
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pz_cmd = "sh";
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}
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#ifdef DEBUG_PRINT
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printf ("START: %s\n", pz_cmd);
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{
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int idx = 0;
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while (pp_args[++idx] != (char *) NULL)
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printf (" ARG %2d: %s\n", idx, pp_args[idx]);
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}
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#endif
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/*
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* Call fork() and see which process we become
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*/
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ch_id = fork ();
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switch (ch_id)
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{
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case NOPROCESS: /* parent - error in call */
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close (stdout_pair.read_fd);
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close (stdout_pair.write_fd);
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if (p_child != (pid_t *) NULL)
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*p_child = NOPROCESS;
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return -1;
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default: /* parent - return opposite FD's */
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if (p_child != (pid_t *) NULL)
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*p_child = ch_id;
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#ifdef DEBUG_PRINT
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printf ("for pid %d: stdin from %d, stdout to %d\n"
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"for parent: read from %d\n",
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ch_id, stdin_fd, stdout_pair.write_fd, stdout_pair.read_fd);
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#endif
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close (stdin_fd);
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close (stdout_pair.write_fd);
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return stdout_pair.read_fd;
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case NULLPROCESS: /* child - continue processing */
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break;
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}
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/*
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* Close the pipe end handed back to the parent process
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*/
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close (stdout_pair.read_fd);
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/*
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* Close our current stdin and stdout
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*/
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close (STDIN_FILENO);
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close (STDOUT_FILENO);
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/*
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* Make the fd passed in the stdin, and the write end of
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* the new pipe become the stdout.
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*/
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dup2 (stdout_pair.write_fd, STDOUT_FILENO);
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dup2 (stdin_fd, STDIN_FILENO);
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if (*pp_args == (char *) NULL)
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*pp_args = pz_cmd;
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execvp (pz_cmd, (char**)pp_args);
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fprintf (stderr, "Error %d: Could not execvp( '%s', ... ): %s\n",
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errno, pz_cmd, xstrerror (errno));
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exit (EXIT_PANIC);
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}
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/*
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* proc2_open
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*
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* Given a pointer to an argument vector, start a process and
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* place its stdin and stdout file descriptors into an fd pair
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* structure. The "write_fd" connects to the inferior process
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* stdin, and the "read_fd" connects to its stdout. The calling
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* process should write to "write_fd" and read from "read_fd".
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* The return value is the process id of the created process.
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*/
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pid_t
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proc2_open (t_fd_pair* p_pair, tCC** pp_args)
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{
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pid_t ch_id;
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/* Create a bi-directional pipe. Writes on 0 arrive on 1 and vice
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versa, so the parent and child processes will read and write to
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opposite FD's. */
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if (pipe ((int *) p_pair) < 0)
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return NOPROCESS;
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p_pair->read_fd = chain_open (p_pair->read_fd, pp_args, &ch_id);
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if (ch_id == NOPROCESS)
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close (p_pair->write_fd);
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return ch_id;
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}
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/*
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* proc2_fopen
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*
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* Identical to "proc2_open()", except that the "fd"'s are
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* "fdopen(3)"-ed into file pointers instead.
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*/
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pid_t
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proc2_fopen (t_pf_pair* pf_pair, tCC** pp_args)
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{
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t_fd_pair fd_pair;
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pid_t ch_id = proc2_open (&fd_pair, pp_args);
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if (ch_id == NOPROCESS)
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return ch_id;
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pf_pair->pf_read = fdopen (fd_pair.read_fd, "r");
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pf_pair->pf_write = fdopen (fd_pair.write_fd, "w");
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return ch_id;
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}
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