command-exec.c (2147B)
1 // $Id$ --*- c -*-- 2 3 // Copyright (C) 2004 Enrico Scholz <enrico.scholz@informatik.tu-chemnitz.de> 4 // 5 // This program is free software; you can redistribute it and/or modify 6 // it under the terms of the GNU General Public License as published by 7 // the Free Software Foundation; version 2 of the License. 8 // 9 // This program is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU General Public License for more details. 13 // 14 // You should have received a copy of the GNU General Public License 15 // along with this program; if not, write to the Free Software 16 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 17 18 19 #ifdef HAVE_CONFIG_H 20 # include <config.h> 21 #endif 22 23 #include "command.h" 24 #include "util.h" 25 26 #include <unistd.h> 27 #include <fcntl.h> 28 #include <errno.h> 29 #include <assert.h> 30 31 static inline bool 32 initPipes(int p[2]) 33 { 34 return (pipe(p)!=-1 && 35 fcntl(p[1], F_SETFD, FD_CLOEXEC)!=-1); 36 } 37 38 bool 39 Command_exec(struct Command *cmd, bool do_fork) 40 { 41 int p[2]; 42 43 if (cmd->params_style_==parVEC) 44 Vector_zeroEnd(&cmd->params.v); 45 46 if (!do_fork) 47 cmd->pid = 0; 48 else if (!initPipes(p) || 49 (cmd->pid = fork())==-1) { 50 cmd->err = errno; 51 return false; 52 } 53 54 if (cmd->pid==0) { 55 char const ** argv = { 0 }; 56 57 if (do_fork) close(p[0]); 58 59 switch (cmd->params_style_) { 60 case parVEC : argv = cmd->params.v.data; break; 61 case parDATA : argv = cmd->params.d; break; 62 default : break; 63 } 64 65 execv(cmd->filename ? cmd->filename : argv[0], 66 reinterpret_cast(char **const)(argv)); 67 cmd->err = errno; 68 assert(cmd->err != 0); 69 70 if (do_fork) { 71 TEMP_FAILURE_RETRY(write(p[1], &cmd->err, sizeof(cmd->err))); 72 _exit(1); // implicates 'close(p[1])' 73 } 74 } 75 else { 76 close(p[1]); 77 if (read(p[0], &cmd->err, sizeof(cmd->err))==0) 78 cmd->err = 0; 79 else // cleanup zombies 80 while (wait4(cmd->pid, 0,0,0)==-1 && 81 (errno==EINTR || errno==EAGAIN)) {}; 82 close(p[0]); 83 } 84 85 return cmd->err==0; 86 }