| | 1 | /* Open a pipe to read from a program without intermediary sh. |
| | 2 | Copyright (C) 1992, 1997 Free Software Foundation, Inc. |
| | 3 | |
| | 4 | This program is free software; you can redistribute it and/or modify |
| | 5 | it under the terms of the GNU General Public License as published by |
| | 6 | the Free Software Foundation; either version 2, or (at your option) |
| | 7 | any later version. |
| | 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 Foundation, |
| | 16 | Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ |
| | 17 | |
| | 18 | /* Written by David MacKenzie. */ |
| | 19 | |
| | 20 | #if HAVE_CONFIG_H |
| | 21 | # include <config.h> |
| | 22 | #endif |
| | 23 | |
| | 24 | #include <stdio.h> |
| | 25 | |
| | 26 | #if __STDC__ |
| | 27 | #include <stdarg.h> |
| | 28 | #else |
| | 29 | #include <varargs.h> |
| | 30 | #endif |
| | 31 | |
| | 32 | #if HAVE_UNISTD_H |
| | 33 | # include <unistd.h> |
| | 34 | #endif |
| | 35 | |
| | 36 | /* Open a pipe to read from a program without intermediary sh. Checks |
| | 37 | PATH. Sample use: |
| | 38 | |
| | 39 | stream = readpipe ("progname", "arg1", "arg2", (char *) 0); |
| | 40 | |
| | 41 | Return 0 on error. */ |
| | 42 | |
| | 43 | #if __STDC__ |
| | 44 | FILE * |
| | 45 | readpipe (char *progname, ...) |
| | 46 | #else |
| | 47 | FILE * |
| | 48 | readpipe (va_alist) |
| | 49 | #endif |
| | 50 | { |
| | 51 | #if ! __STDC__ |
| | 52 | char *progname; |
| | 53 | #endif |
| | 54 | int fds[2]; |
| | 55 | va_list ap; |
| | 56 | char *args[100]; |
| | 57 | int argno = 0; |
| | 58 | |
| | 59 | /* Copy arguments into `args'. */ |
| | 60 | #if __STDC__ |
| | 61 | va_start (ap, progname); |
| | 62 | #else |
| | 63 | va_start (ap); |
| | 64 | progname = va_arg (ap, char *); |
| | 65 | #endif |
| | 66 | args[argno++] = progname; |
| | 67 | while ((args[argno++] = va_arg (ap, char *)) != NULL) |
| | 68 | ; |
| | 69 | va_end (ap); |
| | 70 | |
| | 71 | if (pipe (fds) == -1) |
| | 72 | return 0; |
| | 73 | |
| | 74 | switch (fork ()) |
| | 75 | { |
| | 76 | case 0: /* Child. Write to pipe. */ |
| | 77 | close (fds[0]); /* Not needed. */ |
| | 78 | if (fds[1] != 1) /* Redirect 1 (stdout) only if needed. */ |
| | 79 | { |
| | 80 | close (1); /* We don't want the old stdout. */ |
| | 81 | if (dup (fds[1]) == 0)/* Maybe stdin was closed. */ |
| | 82 | { |
| | 83 | dup (fds[1]); /* Guaranteed to dup to 1 (stdout). */ |
| | 84 | close (0); |
| | 85 | } |
| | 86 | close (fds[1]); /* No longer needed. */ |
| | 87 | } |
| | 88 | execvp (args[0], args); |
| | 89 | _exit (2); /* 2 for `cmp'. */ |
| | 90 | case -1: /* Error. */ |
| | 91 | return 0; |
| | 92 | default: /* Parent. Read from pipe. */ |
| | 93 | close (fds[1]); /* Not needed. */ |
| | 94 | return fdopen (fds[0], "r"); |
| | 95 | } |
| | 96 | } |
projects / bison.git / blame_incremental