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[/] [openrisc/] [tags/] [gnu-src/] [gcc-4.5.1/] [gcc-4.5.1-or32-1.0rc3/] [fixincludes/] [procopen.c] - Rev 595
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/* * server.c Set up and handle communications with a server process. * * Server Handling copyright 1992-1999, 2004 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., * 51 Franklin Street, Fifth Floor, * Boston, MA 02110-1301, 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 const char* def_args[] = { (char *) NULL, (char *) NULL }; /* * chain_open * * Given an FD for an inferior process to use as stdin, * start that process and return a NEW FD that that process * will use for its stdout. Requires the argument vector * for the new process and, optionally, a pointer to a place * to store the child's process id. */ int chain_open (int stdin_fd, tCC** pp_args, pid_t* p_child) { t_fd_pair stdout_pair; pid_t ch_id; tCC *pz_cmd; stdout_pair.read_fd = stdout_pair.write_fd = -1; /* * Create a pipe it will be the child process' stdout, * and the parent will read from it. */ if (pipe ((int *) &stdout_pair) < 0) { if (p_child != (pid_t *) NULL) *p_child = NOPROCESS; return -1; } /* * If we did not get an arg list, use the default */ if (pp_args == (tCC **) NULL) pp_args = def_args; /* * If the arg list does not have a program, * assume the "SHELL" from the environment, or, failing * that, then sh. Set argv[0] to whatever we decided on. */ if (pz_cmd = *pp_args, (pz_cmd == (char *) NULL) || (*pz_cmd == '\0')) { pz_cmd = getenv ("SHELL"); if (pz_cmd == (char *) NULL) pz_cmd = "sh"; } #ifdef DEBUG_PRINT printf ("START: %s\n", pz_cmd); { int idx = 0; while (pp_args[++idx] != (char *) NULL) printf (" ARG %2d: %s\n", idx, pp_args[idx]); } #endif /* * Call fork() and see which process we become */ ch_id = fork (); switch (ch_id) { case NOPROCESS: /* parent - error in call */ close (stdout_pair.read_fd); close (stdout_pair.write_fd); if (p_child != (pid_t *) NULL) *p_child = NOPROCESS; return -1; default: /* parent - return opposite FD's */ if (p_child != (pid_t *) NULL) *p_child = ch_id; #ifdef DEBUG_PRINT printf ("for pid %d: stdin from %d, stdout to %d\n" "for parent: read from %d\n", ch_id, stdin_fd, stdout_pair.write_fd, stdout_pair.read_fd); #endif close (stdin_fd); close (stdout_pair.write_fd); return stdout_pair.read_fd; case NULLPROCESS: /* child - continue processing */ break; } /* * Close the pipe end handed back to the parent process */ close (stdout_pair.read_fd); /* * Close our current stdin and stdout */ close (STDIN_FILENO); close (STDOUT_FILENO); /* * Make the fd passed in the stdin, and the write end of * the new pipe become the stdout. */ dup2 (stdout_pair.write_fd, STDOUT_FILENO); dup2 (stdin_fd, STDIN_FILENO); if (*pp_args == (char *) NULL) *pp_args = pz_cmd; execvp (pz_cmd, (char**)pp_args); fprintf (stderr, "Error %d: Could not execvp( '%s', ... ): %s\n", errno, pz_cmd, xstrerror (errno)); exit (EXIT_PANIC); } /* * proc2_open * * Given a pointer to an argument vector, start a process and * place its stdin and stdout file descriptors into an fd pair * structure. The "write_fd" connects to the inferior process * stdin, and the "read_fd" connects to its stdout. The calling * process should write to "write_fd" and read from "read_fd". * The return value is the process id of the created process. */ pid_t proc2_open (t_fd_pair* p_pair, tCC** pp_args) { pid_t ch_id; /* Create a bi-directional pipe. Writes on 0 arrive on 1 and vice versa, so the parent and child processes will read and write to opposite FD's. */ if (pipe ((int *) p_pair) < 0) return NOPROCESS; p_pair->read_fd = chain_open (p_pair->read_fd, pp_args, &ch_id); if (ch_id == NOPROCESS) close (p_pair->write_fd); return ch_id; } /* * proc2_fopen * * Identical to "proc2_open()", except that the "fd"'s are * "fdopen(3)"-ed into file pointers instead. */ pid_t proc2_fopen (t_pf_pair* pf_pair, tCC** pp_args) { t_fd_pair fd_pair; pid_t ch_id = proc2_open (&fd_pair, pp_args); if (ch_id == NOPROCESS) return ch_id; pf_pair->pf_read = fdopen (fd_pair.read_fd, "r"); pf_pair->pf_write = fdopen (fd_pair.write_fd, "w"); return ch_id; }
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