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Diffstat (limited to 'ltp_framework/lib/forker.c')
| -rw-r--r-- | ltp_framework/lib/forker.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/ltp_framework/lib/forker.c b/ltp_framework/lib/forker.c new file mode 100644 index 0000000..ad8b4a7 --- /dev/null +++ b/ltp_framework/lib/forker.c @@ -0,0 +1,281 @@ +/* + * Copyright (c) 2000 Silicon Graphics, Inc. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of version 2 of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + * + * Further, this software is distributed without any warranty that it is + * free of the rightful claim of any third person regarding infringement + * or the like. Any license provided herein, whether implied or + * otherwise, applies only to this software file. Patent licenses, if + * any, provided herein do not apply to combinations of this program with + * other software, or any other product whatsoever. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write the Free Software Foundation, Inc., 59 + * Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, + * Mountain View, CA 94043, or: + * + * http://www.sgi.com + * + * For further information regarding this notice, see: + * + * http://oss.sgi.com/projects/GenInfo/NoticeExplan/ + */ +/************************************************************** + * + * OS Testing - Silicon Graphics, Inc. + * + * FUNCTION NAME : forker + * background + * + * FUNCTION TITLE : fork desired number of copies of the current process + * fork a process and return control to caller + * + * SYNOPSIS: + * int forker(ncopies, mode, prefix) + * int ncopies; + * int mode; + * char *prefix; + * + * int background(prefix); + * char *prefix; + * + * AUTHOR : Richard Logan + * + * CO-PILOT(s) : Dean Roehrich + * + * INITIAL RELEASE : UNICOS 8.0 + * + * DESIGN DESCRIPTION + * The background function will do a fork of the current process. + * The parent process will then exit, thus orphaning the + * child process. Doing this will not nice the child process + * like executing a cmd in the background using "&" from the shell. + * If the fork fails and prefix is not NULL, a error message is printed + * to stderr and the process will exit with a value of errno. + * + * The forker function will fork <ncopies> minus one copies + * of the current process. There are two modes in how the forks + * will be done. Mode 0 (default) will have all new processes + * be childern of the parent process. Using Mode 1, + * the parent process will have one child and that child will + * fork the next process, if necessary, and on and on. + * The forker function will return the number of successful + * forks. This value will be different for the parent and each child. + * Using mode 0, the parent will get the total number of successful + * forks. Using mode 1, the newest child will get the total number + * of forks. The parent will get a return value of 1. + * + * The forker function also updates the global variables + * Forker_pids[] and Forker_npids. The Forker_pids array will + * be updated to contain the pid of each new process. The + * Forker_npids variable contains the number of entries + * in Forker_pids. Note, not all processes will have + * access to all pids via Forker_pids. If using mode 0, only the + * parent process and the last process will have all information. + * If using mode 1, only the last child process will have all information. + * + * If the prefix parameter is not NULL and the fork system call fails, + * a error message will be printed to stderr. The error message + * the be preceeded with prefix string. If prefix is NULL, + * no error message is printed. + * + * SPECIAL REQUIREMENTS + * None. + * + * UPDATE HISTORY + * This should contain the description, author, and date of any + * "interesting" modifications (i.e. info should helpful in + * maintaining/enhancing this module). + * username description + * ---------------------------------------------------------------- + * rrl This functions will first written during + * the SFS testing days, 1993. + * + * BUGS/LIMITATIONS + * The child pids are stored in the fixed array, Forker_pids. + * The array only has space for 4098 pids. Only the first + * 4098 pids will be stored in the array. + * + **************************************************************/ + +#include <stdio.h> +#include <errno.h> +#include <unistd.h> /* fork, getpid, sleep */ +#include <string.h> +#include <stdlib.h> /* exit */ +#include "forker.h" + +int Forker_pids[FORKER_MAX_PIDS]; /* holds pids of forked processes */ +int Forker_npids=0; /* number of entries in Forker_pids */ + +/*********************************************************************** + * + * This function will fork and the parent will exit zero and + * the child will return. This will orphan the returning process + * putting it in the background. + * + * Return Value + * 0 : if fork did not fail + * !0 : if fork failed, the return value will be the errno. + ***********************************************************************/ +int +background(prefix) +char *prefix; +{ + switch (fork()) { + case -1: + if (prefix != NULL) + fprintf(stderr, "%s: In %s background(), fork() failed, errno:%d %s\n", + prefix, __FILE__, errno, strerror(errno)); + exit(errno); + + case 0: /* child process */ + break; + + default: + exit(0); + } + + return 0; + +} /* end of background */ + +/*********************************************************************** + * Forker will fork ncopies-1 copies of self. + * + ***********************************************************************/ +int +forker(ncopies, mode, prefix) +int ncopies; +int mode; /* 0 - all childern of parent, 1 - only 1 direct child */ +char *prefix; /* if ! NULL, an message will be printed to stderr */ + /* if fork fails. The prefix (program name) will */ + /* preceed the message */ +{ + int cnt; + int pid; + static int ind = 0; + + Forker_pids[ind]=0; + + for (cnt=1; cnt < ncopies; cnt++) { + + switch ( mode ) { + case 1 : /* only 1 direct child */ + if ((pid = fork()) == -1) { + if (prefix != NULL) + fprintf(stderr, "%s: %s,forker(): fork() failed, errno:%d %s\n", + prefix, __FILE__, errno, strerror(errno)); + return 0; + } + Forker_npids++; + + switch (pid ) { + case 0: /* child - continues the forking */ + + if (Forker_npids < FORKER_MAX_PIDS) + Forker_pids[Forker_npids-1]=getpid(); + break; + + default: /* parent - stop the forking */ + if (Forker_npids < FORKER_MAX_PIDS) + Forker_pids[Forker_npids-1]=pid; + return cnt-1; + } + + break; + + default : /* all new processes are childern of parent */ + if ((pid = fork()) == -1) { + if (prefix != NULL) + fprintf(stderr, "%s: %s,forker(): fork() failed, errno:%d %s\n", + prefix, __FILE__, errno, strerror(errno)); + return cnt-1; + } + Forker_npids++; + + switch (pid ) { + case 0: /* child - stops the forking */ + if (Forker_npids < FORKER_MAX_PIDS) + Forker_pids[Forker_npids-1]=getpid(); + return cnt; + + default: /* parent - continues the forking */ + if (Forker_npids < FORKER_MAX_PIDS) + Forker_pids[Forker_npids-1]=pid; + break; + } + break; + } + } + + if (Forker_npids < FORKER_MAX_PIDS) + Forker_pids[Forker_npids]=0; + return cnt-1; + +} /* end of forker */ + + +#if UNIT_TEST + +/* + * The following is a unit test main for the background and forker + * functions. + */ + +int +main(argc, argv) +int argc; +char **argv; +{ + int ncopies=1; + int mode=0; + int ret; + int ind; + + if (argc == 1) { + printf("Usage: %s ncopies [mode]\n", argv[0]); + exit(1); + } + + if (sscanf(argv[1], "%i", &ncopies) != 1) { + printf("%s: ncopies argument must be integer\n", argv[0]); + exit(1); + } + + if (argc == 3) + if (sscanf(argv[2], "%i", &mode) != 1) { + printf("%s: mode argument must be integer\n", argv[0]); + exit(1); + } + + printf("Starting Pid = %d\n", getpid()); + ret=background(argv[0]); + printf("After background() ret:%d, pid = %d\n", ret, getpid()); + + ret=forker(ncopies, mode, argv[0]); + + printf("forker(%d, %d, %s) ret:%d, pid = %d, sleeping 30 seconds.\n", + ncopies, mode, argv[0], ret, getpid()); + + printf("%d My version of Forker_pids[], Forker_npids = %d\n", + getpid(), Forker_npids); + + for (ind=0; ind<Forker_npids; ind++) { + printf("%d ind:%-2d pid:%d\n", getpid(), ind, Forker_pids[ind]); + } + + sleep(30); + exit(0); +} + +#endif /* UNIT_TEST */
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