whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2000 Silicon Graphics, Inc. All Rights Reserved. |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 3 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 4 | * This program is free software; you can redistribute it and/or modify it |
| 5 | * under the terms of version 2 of the GNU General Public License as |
| 6 | * published by the Free Software Foundation. |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 7 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 8 | * This program is distributed in the hope that it would be useful, but |
| 9 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 11 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 12 | * Further, this software is distributed without any warranty that it is |
| 13 | * free of the rightful claim of any third person regarding infringement |
| 14 | * or the like. Any license provided herein, whether implied or |
| 15 | * otherwise, applies only to this software file. Patent licenses, if |
| 16 | * any, provided herein do not apply to combinations of this program with |
| 17 | * other software, or any other product whatsoever. |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 18 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 19 | * You should have received a copy of the GNU General Public License along |
Wanlong Gao | fed9641 | 2012-10-24 10:10:29 +0800 | [diff] [blame] | 20 | * with this program; if not, write the Free Software Foundation, Inc., |
| 21 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 22 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 23 | * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, |
| 24 | * Mountain View, CA 94043, or: |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 25 | * |
| 26 | * http://www.sgi.com |
| 27 | * |
| 28 | * For further information regarding this notice, see: |
| 29 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 30 | * http://oss.sgi.com/projects/GenInfo/NoticeExplan/ |
| 31 | */ |
| 32 | /************************************************************** |
| 33 | * |
alaffin | cc2e555 | 2000-07-27 17:13:18 +0000 | [diff] [blame] | 34 | * OS Testing - Silicon Graphics, Inc. |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 35 | * |
| 36 | * FUNCTION NAME : forker |
| 37 | * background |
| 38 | * |
| 39 | * FUNCTION TITLE : fork desired number of copies of the current process |
| 40 | * fork a process and return control to caller |
| 41 | * |
| 42 | * SYNOPSIS: |
| 43 | * int forker(ncopies, mode, prefix) |
| 44 | * int ncopies; |
| 45 | * int mode; |
| 46 | * char *prefix; |
| 47 | * |
| 48 | * int background(prefix); |
| 49 | * char *prefix; |
| 50 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 51 | * AUTHOR : Richard Logan |
| 52 | * |
| 53 | * CO-PILOT(s) : Dean Roehrich |
| 54 | * |
| 55 | * INITIAL RELEASE : UNICOS 8.0 |
| 56 | * |
| 57 | * DESIGN DESCRIPTION |
| 58 | * The background function will do a fork of the current process. |
| 59 | * The parent process will then exit, thus orphaning the |
| 60 | * child process. Doing this will not nice the child process |
| 61 | * like executing a cmd in the background using "&" from the shell. |
| 62 | * If the fork fails and prefix is not NULL, a error message is printed |
| 63 | * to stderr and the process will exit with a value of errno. |
| 64 | * |
| 65 | * The forker function will fork <ncopies> minus one copies |
| 66 | * of the current process. There are two modes in how the forks |
| 67 | * will be done. Mode 0 (default) will have all new processes |
| 68 | * be childern of the parent process. Using Mode 1, |
| 69 | * the parent process will have one child and that child will |
| 70 | * fork the next process, if necessary, and on and on. |
| 71 | * The forker function will return the number of successful |
| 72 | * forks. This value will be different for the parent and each child. |
| 73 | * Using mode 0, the parent will get the total number of successful |
| 74 | * forks. Using mode 1, the newest child will get the total number |
| 75 | * of forks. The parent will get a return value of 1. |
| 76 | * |
| 77 | * The forker function also updates the global variables |
| 78 | * Forker_pids[] and Forker_npids. The Forker_pids array will |
| 79 | * be updated to contain the pid of each new process. The |
| 80 | * Forker_npids variable contains the number of entries |
| 81 | * in Forker_pids. Note, not all processes will have |
| 82 | * access to all pids via Forker_pids. If using mode 0, only the |
| 83 | * parent process and the last process will have all information. |
| 84 | * If using mode 1, only the last child process will have all information. |
| 85 | * |
| 86 | * If the prefix parameter is not NULL and the fork system call fails, |
| 87 | * a error message will be printed to stderr. The error message |
| 88 | * the be preceeded with prefix string. If prefix is NULL, |
| 89 | * no error message is printed. |
| 90 | * |
| 91 | * SPECIAL REQUIREMENTS |
| 92 | * None. |
| 93 | * |
| 94 | * UPDATE HISTORY |
| 95 | * This should contain the description, author, and date of any |
| 96 | * "interesting" modifications (i.e. info should helpful in |
| 97 | * maintaining/enhancing this module). |
| 98 | * username description |
| 99 | * ---------------------------------------------------------------- |
| 100 | * rrl This functions will first written during |
| 101 | * the SFS testing days, 1993. |
| 102 | * |
| 103 | * BUGS/LIMITATIONS |
| 104 | * The child pids are stored in the fixed array, Forker_pids. |
| 105 | * The array only has space for 4098 pids. Only the first |
| 106 | * 4098 pids will be stored in the array. |
| 107 | * |
| 108 | **************************************************************/ |
| 109 | |
| 110 | #include <stdio.h> |
| 111 | #include <errno.h> |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 112 | #include <unistd.h> /* fork, getpid, sleep */ |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 113 | #include <string.h> |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 114 | #include <stdlib.h> /* exit */ |
alaffin | cc2e555 | 2000-07-27 17:13:18 +0000 | [diff] [blame] | 115 | #include "forker.h" |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 116 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 117 | int Forker_pids[FORKER_MAX_PIDS]; /* holds pids of forked processes */ |
| 118 | int Forker_npids = 0; /* number of entries in Forker_pids */ |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 119 | |
| 120 | /*********************************************************************** |
| 121 | * |
| 122 | * This function will fork and the parent will exit zero and |
| 123 | * the child will return. This will orphan the returning process |
alaffin | cc2e555 | 2000-07-27 17:13:18 +0000 | [diff] [blame] | 124 | * putting it in the background. |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 125 | * |
| 126 | * Return Value |
| 127 | * 0 : if fork did not fail |
| 128 | * !0 : if fork failed, the return value will be the errno. |
| 129 | ***********************************************************************/ |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 130 | int background(prefix) |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 131 | char *prefix; |
| 132 | { |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 133 | switch (fork()) { |
| 134 | case -1: |
| 135 | if (prefix != NULL) |
| 136 | fprintf(stderr, |
| 137 | "%s: In %s background(), fork() failed, errno:%d %s\n", |
| 138 | prefix, __FILE__, errno, strerror(errno)); |
| 139 | exit(errno); |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 140 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 141 | case 0: /* child process */ |
| 142 | break; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 143 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 144 | default: |
| 145 | exit(0); |
| 146 | } |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 147 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 148 | return 0; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 149 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 150 | } /* end of background */ |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 151 | |
| 152 | /*********************************************************************** |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 153 | * Forker will fork ncopies-1 copies of self. |
| 154 | * |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 155 | ***********************************************************************/ |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 156 | int forker(ncopies, mode, prefix) |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 157 | int ncopies; |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 158 | int mode; /* 0 - all childern of parent, 1 - only 1 direct child */ |
| 159 | char *prefix; /* if ! NULL, an message will be printed to stderr */ |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 160 | /* if fork fails. The prefix (program name) will */ |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 161 | /* preceed the message */ |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 162 | { |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 163 | int cnt; |
| 164 | int pid; |
| 165 | static int ind = 0; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 166 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 167 | Forker_pids[ind] = 0; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 168 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 169 | for (cnt = 1; cnt < ncopies; cnt++) { |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 170 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 171 | switch (mode) { |
| 172 | case 1: /* only 1 direct child */ |
| 173 | if ((pid = fork()) == -1) { |
| 174 | if (prefix != NULL) |
| 175 | fprintf(stderr, |
| 176 | "%s: %s,forker(): fork() failed, errno:%d %s\n", |
| 177 | prefix, __FILE__, errno, |
| 178 | strerror(errno)); |
| 179 | return 0; |
| 180 | } |
| 181 | Forker_npids++; |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 182 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 183 | switch (pid) { |
| 184 | case 0: /* child - continues the forking */ |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 185 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 186 | if (Forker_npids < FORKER_MAX_PIDS) |
| 187 | Forker_pids[Forker_npids - 1] = |
| 188 | getpid(); |
| 189 | break; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 190 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 191 | default: /* parent - stop the forking */ |
| 192 | if (Forker_npids < FORKER_MAX_PIDS) |
| 193 | Forker_pids[Forker_npids - 1] = pid; |
| 194 | return cnt - 1; |
| 195 | } |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 196 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 197 | break; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 198 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 199 | default: /* all new processes are childern of parent */ |
| 200 | if ((pid = fork()) == -1) { |
| 201 | if (prefix != NULL) |
| 202 | fprintf(stderr, |
| 203 | "%s: %s,forker(): fork() failed, errno:%d %s\n", |
| 204 | prefix, __FILE__, errno, |
| 205 | strerror(errno)); |
| 206 | return cnt - 1; |
| 207 | } |
| 208 | Forker_npids++; |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 209 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 210 | switch (pid) { |
| 211 | case 0: /* child - stops the forking */ |
| 212 | if (Forker_npids < FORKER_MAX_PIDS) |
| 213 | Forker_pids[Forker_npids - 1] = |
| 214 | getpid(); |
| 215 | return cnt; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 216 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 217 | default: /* parent - continues the forking */ |
| 218 | if (Forker_npids < FORKER_MAX_PIDS) |
| 219 | Forker_pids[Forker_npids - 1] = pid; |
| 220 | break; |
| 221 | } |
| 222 | break; |
| 223 | } |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 224 | } |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 225 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 226 | if (Forker_npids < FORKER_MAX_PIDS) |
| 227 | Forker_pids[Forker_npids] = 0; |
| 228 | return cnt - 1; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 229 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 230 | } /* end of forker */ |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 231 | |
| 232 | #if UNIT_TEST |
| 233 | |
| 234 | /* |
| 235 | * The following is a unit test main for the background and forker |
| 236 | * functions. |
| 237 | */ |
| 238 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 239 | int main(argc, argv) |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 240 | int argc; |
| 241 | char **argv; |
| 242 | { |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 243 | int ncopies = 1; |
| 244 | int mode = 0; |
| 245 | int ret; |
| 246 | int ind; |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 247 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 248 | if (argc == 1) { |
| 249 | printf("Usage: %s ncopies [mode]\n", argv[0]); |
| 250 | exit(1); |
| 251 | } |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 252 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 253 | if (sscanf(argv[1], "%i", &ncopies) != 1) { |
| 254 | printf("%s: ncopies argument must be integer\n", argv[0]); |
| 255 | exit(1); |
| 256 | } |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 257 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 258 | if (argc == 3) |
| 259 | if (sscanf(argv[2], "%i", &mode) != 1) { |
| 260 | printf("%s: mode argument must be integer\n", argv[0]); |
| 261 | exit(1); |
| 262 | } |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 263 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 264 | printf("Starting Pid = %d\n", getpid()); |
| 265 | ret = background(argv[0]); |
| 266 | printf("After background() ret:%d, pid = %d\n", ret, getpid()); |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 267 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 268 | ret = forker(ncopies, mode, argv[0]); |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 269 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 270 | printf("forker(%d, %d, %s) ret:%d, pid = %d, sleeping 30 seconds.\n", |
| 271 | ncopies, mode, argv[0], ret, getpid()); |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 272 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 273 | printf("%d My version of Forker_pids[], Forker_npids = %d\n", |
| 274 | getpid(), Forker_npids); |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 275 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 276 | for (ind = 0; ind < Forker_npids; ind++) { |
| 277 | printf("%d ind:%-2d pid:%d\n", getpid(), ind, Forker_pids[ind]); |
| 278 | } |
vapier | 45a8ba0 | 2009-07-20 10:59:32 +0000 | [diff] [blame] | 279 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 280 | sleep(30); |
| 281 | exit(0); |
whr | b973f2b | 2000-05-05 19:34:50 +0000 | [diff] [blame] | 282 | } |
| 283 | |
Wanlong Gao | 354ebb4 | 2012-12-07 10:10:04 +0800 | [diff] [blame] | 284 | #endif /* UNIT_TEST */ |