| /* |
| * Copyright (C) Bull S.A. 1996 |
| * Copyright (c) International Business Machines Corp., 2001 |
| * |
| * This program is free software; you can 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 of the License, or |
| * (at your option) any later version. |
| * |
| * This program 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 this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| /*---------------------------------------------------------------------+ |
| | signal_test_04 | |
| | ==================================================================== | |
| | | |
| | Description: Verify default signal actions (for SIGSTOP & SIGCONT) | |
| | by spawning a child process and sending the signals | |
| | to the child. Meanwhile, checking to insure that the | |
| | child process takes the default action for each signal | |
| | received. | |
| | | |
| | Algorithm: o Use sigaction (SIG_DFL) to take the default action | |
| | for all signals except for SIGCHLD, SIGUSR1 | |
| | SIGUSR2 | |
| | | |
| | o Spawn a child | |
| | | |
| | (parent) | |
| | o Ensure that child process is running by waiting | |
| | for the child process to send a SIGUSR1 signal | |
| | o Send a SIGSTOP signal to stop the execution of the | |
| | child process | |
| | o Verify that the child process received the SIGSTOP | |
| | signal by waiting for the childs SIGCHLD signal | |
| | o Send a SIGCONT signal to resume the execution of | |
| | child process. | |
| | o Verify that the child process resumed execution by | |
| | waiting for the child to send another SIGUSR1 | |
| | signal | |
| | o Kill child process with SIGUSR2 signal.. | |
| | | |
| | (child) | |
| | o Take default action for each received signal | |
| | o Continuously send SIGUSR1 signals to the parent | |
| | process | |
| | | |
| | | |
| | System calls: The following system calls are tested: | |
| | | |
| | sigaction () - specify the action to take upon | |
| | delivery of a signal | |
| | wait () - waits for a child process to stop or | |
| | terminate | |
| | kill () - sends a signal to a process | |
| | | |
| | Usage: signal_test_04 | |
| | | |
| | To compile: cc -o signal_test_04 signal_test_04 | |
| | | |
| | Last update: Ver. 1.3, 4/8/94 13:07:38 | |
| | | |
| | Change Activity | |
| | | |
| | Version Date Name Reason | |
| | 0.1 112993 DJK Initial program | |
| | 1.2 020794 DJK Move to "prod" directory | |
| | | |
| +---------------------------------------------------------------------*/ |
| |
| #include <stdio.h> |
| #include <string.h> |
| #ifdef _LINUX_ |
| # define __USE_XOPEN |
| #endif |
| #include <unistd.h> |
| #include <stdlib.h> |
| #include <sys/signal.h> |
| #include <sys/wait.h> |
| #include <errno.h> |
| |
| #ifdef _LINUX_ |
| // bits/signum.h defines _NSIG as 64 |
| #define SIGMAX 64 |
| #endif |
| |
| /* Function prototypes */ |
| void signal_init (); |
| void child (int); |
| void handler (int, int, struct sigcontext *); |
| void sys_error (const char *, int); |
| void error (const char *, int); |
| |
| /* Flag set upon receiving SIGCHLD signal */ |
| volatile int sigchld_flag = 0; |
| volatile int sigusr1_count = 0; |
| |
| /*---------------------------------------------------------------------+ |
| | main () | |
| | ==================================================================== | |
| | | |
| | Function: Main program (see prolog for more details) | |
| | | |
| +---------------------------------------------------------------------*/ |
| int main (int argc, char **argv) |
| { |
| pid_t pid = getpid (), /* Process ID (of parent process) */ |
| cpid; /* Process ID (of child process) */ |
| int sigusr1_interrupts; /* xxx */ |
| int status; /* Child's exit status */ |
| int timeout = 10; /* How long to wait for SIGCHILD */ |
| char msg [100]; /* Buffer for error message */ |
| |
| /* Print out program header */ |
| printf ("%s: IPC TestSuite program\n\n", *argv); |
| fflush (stdout); |
| |
| /* Set up our signal handler */ |
| signal_init (); |
| |
| /* |
| * Spawn a child process & have the child process send SIGUSR1 |
| * signals to the parent. |
| */ |
| switch (cpid = fork ()) { |
| case -1: /* Unable to create child process */ |
| sys_error ("fork failed", __LINE__); |
| exit (-1); |
| |
| case 0: /* Child process */ |
| child (pid); |
| |
| default: /* Parent process */ |
| break; |
| } |
| |
| /* |
| * Interrupt the child process |
| * |
| * Send SIGSTOP signal to child process (child process will |
| * stop upon receiving the signal). |
| * |
| * Wait for the child process to receive the SIGSTOP signal |
| * and send a corresponding SIGCLD interrupt to the parent. |
| * |
| * Send SIGKILL signal to child process (child process |
| * will exit upon receiving the signal). |
| */ |
| printf ("\tWait for SIGUSR1 signal from child process\n"); |
| #ifdef _IA64 |
| while (sigusr1_count < 1) sleep(1); |
| #else |
| while (sigusr1_count < 1) ; |
| #endif |
| printf ("\tReceived SIGUSR1 (30)\n"); |
| sigusr1_interrupts = sigusr1_count; |
| |
| printf ("\n\tStop the child process\n"); |
| kill (cpid, SIGSTOP); |
| |
| printf ("\n\tWait for SIGCHLD signal from stopped child process\n"); |
| alarm (timeout); |
| while (sigchld_flag < 1) ; |
| printf ("\tReceived SIGCHLD (20)\n"); |
| |
| printf ("\n\tResume child process & wait for it to send SIGUSR1 signal\n"); |
| kill (cpid, SIGCONT); |
| |
| #ifdef _IA64 |
| while (sigusr1_interrupts == sigusr1_count) sleep(1) ; |
| #else |
| while (sigusr1_interrupts == sigusr1_count) ; |
| #endif |
| printf ("\tReceived SIGUSR1 (20)\n"); |
| |
| printf ("\n\tNow kill the child process with SIGUSR2 signal\n"); |
| kill (cpid, SIGUSR2); |
| |
| /* |
| * Wait for the child process to abort |
| * |
| * Suspend execution of the parent process until the SIGCHLD signal |
| * is received upon termination of the child process. |
| * |
| * Check the child process's exit status (with POSIX macros) to |
| * verify that the child process terminated due to the SIGKILL signal |
| * from the parent. |
| * |
| * Additionally verify that the number of SIGCHLD signals received |
| * has increased. |
| */ |
| printf ("\n\tWait for SIGCHLD signal from killed child process\n"); |
| |
| wait (&status); |
| |
| if (WIFSIGNALED (status)) { |
| if (WTERMSIG (status) != SIGUSR2) { |
| sprintf (msg, "child process was killed with signal (%d)", |
| WTERMSIG (status)); |
| error (msg, __LINE__); |
| } |
| } else { |
| error ("child process did not receive SIGUSR2 signal", __LINE__); |
| } |
| if (sigchld_flag < 2) |
| error ("child process failed to send SIGCHLD signal", __LINE__); |
| |
| printf ("\tReceived SIGCHLD (30)\n"); |
| |
| /* Program completed successfully -- exit */ |
| printf ("\nsuccessful!\n"); |
| |
| return 0; |
| } |
| |
| /*---------------------------------------------------------------------+ |
| | child () | |
| | ==================================================================== | |
| | | |
| | Function: Child process -- loop until killed. | |
| | o continuously send SIGUSR1 interrupts to parent | |
| | | |
| +---------------------------------------------------------------------*/ |
| void child (pid_t pid) |
| { |
| while (1) { |
| sleep (2); |
| #ifdef _IA64 |
| if (kill (pid, SIGUSR1) < 0) |
| perror("child: kill"); |
| #else |
| kill (pid, SIGUSR1); |
| #endif |
| } |
| |
| error ("child process failed to terminate correctly", __LINE__); |
| } |
| |
| /*---------------------------------------------------------------------+ |
| | handler () | |
| | ==================================================================== | |
| | | |
| | Function: Signal handler | |
| | | |
| | Parms: signal - signal number caught | |
| | | |
| | Returns: Aborts if an unexpected signal is caught | |
| | | |
| +---------------------------------------------------------------------*/ |
| void handler (int signal, int code, struct sigcontext *scp) |
| { |
| char msg [100]; |
| |
| if (signal == SIGCHLD) { |
| sigchld_flag++; |
| } else if (signal == SIGUSR1) { |
| sigusr1_count++; |
| } else if (signal == SIGALRM) { |
| sprintf (msg, "Timed out waiting for SIGCHLD signal from child, defect # 124551"); |
| error (msg, __LINE__); |
| } else { |
| sprintf (msg, "caught an unexpected signal (%d)", signal); |
| error (msg, __LINE__); |
| } |
| } |
| |
| /*---------------------------------------------------------------------+ |
| | signal_init () | |
| | ==================================================================== | |
| | | |
| | Function: Take default action for all signals except for SIGCHLD. | |
| | Particularily interrested in the following: | |
| | | |
| | o SIGSTOP (17) - default action: stop | |
| | o SIGCONT (19) - default action: stop | |
| | o SIGKILL (09) - default action: abort process | |
| | | |
| | Process signal handler upon receiving the following: | |
| | (Sent when child process stops or exits) | |
| | | |
| | o SIGCHLD (20) | |
| | | |
| | Returns: n/a | |
| | | |
| +---------------------------------------------------------------------*/ |
| void signal_init () |
| { |
| struct sigaction action; |
| char msg [100]; |
| int i; |
| |
| for (i=1; i<=SIGMAX; i++) { |
| |
| /* Do not ignore SIGCHILD signal */ |
| #ifdef _IA64 /* SIGWAITING not supported, RESERVED */ |
| if (i == SIGCHLD || i == SIGALRM || |
| i == SIGUSR1 || i == SIGWAITING) continue; |
| #else |
| # ifdef _LINUX_ |
| if ((i == SIGKILL) || (i == SIGSTOP) || ((i>=32)&&(i<=34))) continue; |
| # else |
| if ((i == SIGKILL) || (i == SIGSTOP) || (i == SIGCONT)) continue; |
| # endif |
| #endif |
| |
| action.sa_handler = SIG_DFL; |
| sigfillset (&action.sa_mask); |
| action.sa_flags = SA_RESTART; |
| |
| if (sigaction (i, &action, (struct sigaction *) NULL) < 0) { |
| sprintf (msg, "sigaction failed on signal %d", i); |
| error (msg, __LINE__); |
| } |
| } |
| |
| /* Setup signal handler for SIGCHLD & SIGUSR1 signals */ |
| action.sa_handler = (void (*)(int)) handler; |
| sigfillset (&action.sa_mask); |
| |
| /* changing */ |
| /*action.sa_flags = 0;*/ |
| action.sa_flags = SA_RESTART; |
| |
| if (sigaction (SIGCHLD, &action, (struct sigaction *) NULL) < 0) |
| sys_error ("sigaction (SIGCHLD) failed", __LINE__); |
| |
| /* changing */ |
| action.sa_flags = SA_RESTART; |
| /* end of changing */ |
| |
| if (sigaction (SIGUSR1, &action, (struct sigaction *) NULL) < 0) |
| sys_error ("sigaction (SIGUSR1) failed", __LINE__); |
| |
| /* Setup signal handler for SIGALRM */ |
| action.sa_handler = (void (*)(int)) handler; |
| if (sigaction (SIGALRM, &action, (struct sigaction *) NULL) < 0) |
| sys_error ("sigaction (SIGCHLD) failed", __LINE__); |
| } |
| |
| /*---------------------------------------------------------------------+ |
| | sys_error () | |
| | ==================================================================== | |
| | | |
| | Function: Creates system error message and calls error () | |
| | | |
| +---------------------------------------------------------------------*/ |
| void sys_error (const char *msg, int line) |
| { |
| char syserr_msg [256]; |
| |
| sprintf (syserr_msg, "%s: %s\n", msg, strerror (errno)); |
| error (syserr_msg, line); |
| } |
| |
| /*---------------------------------------------------------------------+ |
| | error () | |
| | ==================================================================== | |
| | | |
| | Function: Prints out message and exits... | |
| | | |
| +---------------------------------------------------------------------*/ |
| void error (const char *msg, int line) |
| { |
| fprintf (stderr, "ERROR [line: %d] %s\n", line, msg); |
| #ifdef _IA64 |
| fflush(stderr); |
| #endif |
| exit (-1); |
| } |