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      1 /*
      2  *
      3  *   Copyright (c) International Business Machines  Corp., 2001
      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; either version 2 of the License, or
      8  *   (at your option) any later version.
      9  *
     10  *   This program is distributed in the hope that it will be useful,
     11  *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
     12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
     13  *   the GNU General Public License for more details.
     14  *
     15  *   You should have received a copy of the GNU General Public License
     16  *   along with this program;  if not, write to the Free Software
     17  *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
     18  */
     19 
     20 /*
     21  * Test Name: sigalstack01
     22  *
     23  * Test Description:
     24  *  Send a signal using the main stack. While executing the signal handler
     25  *  compare a variable's address lying on the main stack with the stack
     26  *  boundaries returned by sigaltstack().
     27  *
     28  * Expected Result:
     29  *  sigaltstack() should succeed to get/set signal alternate stack context.
     30  *
     31  * Algorithm:
     32  *  Setup:
     33  *   Setup signal handling.
     34  *   Pause for SIGUSR1 if option specified.
     35  *
     36  *  Test:
     37  *   Loop if the proper options are given.
     38  *   Execute system call
     39  *   Check return code, if system call failed (return=-1)
     40  *	Log the errno and Issue a FAIL message.
     41  *   Otherwise,
     42  *	Verify the Functionality of system call
     43  *      if successful,
     44  *		Issue Functionality-Pass message.
     45  *      Otherwise,
     46  *		Issue Functionality-Fail message.
     47  *  Cleanup:
     48  *   Print errno log and/or timing stats if options given
     49  *
     50  * Usage:  <for command-line>
     51  *  sigaltstack01 [-c n] [-e] [-f] [-i n] [-I x] [-p x] [-t]
     52  *	where,  -c n : Run n copies concurrently.
     53  *		-e   : Turn on errno logging.
     54  *		-f   : Turn off functionality Testing.
     55  *		-i n : Execute test n times.
     56  *		-I x : Execute test for x seconds.
     57  *		-P x : Pause for x seconds between iterations.
     58  *		-t   : Turn on syscall timing.
     59  *
     60  * History
     61  *	07/2001 John George
     62  *		-Ported
     63  *
     64  * Restrictions:
     65  *  This test should be run by 'super-user' (root) only and must run from
     66  *  shell which sets up for test.
     67  *
     68  */
     69 
     70 #include <stdio.h>
     71 #include <sys/types.h>
     72 #include <unistd.h>
     73 #include <signal.h>
     74 #include <string.h>
     75 #include <ucontext.h>
     76 #include <errno.h>
     77 
     78 #include "test.h"
     79 
     80 char *TCID = "sigaltstack01";
     81 int TST_TOTAL = 1;
     82 
     83 void *addr, *main_stk;		/* address of main stack for signal */
     84 int got_signal = 0;
     85 pid_t my_pid;			/* test process id */
     86 
     87 stack_t sigstk, osigstk;	/* signal stack storing struct. */
     88 struct sigaction act, oact;	/* sigaction() struct. */
     89 
     90 void setup(void);		/* Main setup function of test */
     91 void cleanup(void);		/* cleanup function for the test */
     92 void sig_handler(int);		/* signal catching function */
     93 
     94 int main(int ac, char **av)
     95 {
     96 	int lc;
     97 	void *alt_stk;		/* address of alternate stack for signal */
     98 
     99 	tst_parse_opts(ac, av, NULL, NULL);
    100 
    101 	setup();
    102 
    103 	for (lc = 0; TEST_LOOPING(lc); lc++) {
    104 
    105 		tst_count = 0;
    106 
    107 		/* Call sigaltstack() to set up an alternate stack */
    108 		sigstk.ss_size = SIGSTKSZ;
    109 		sigstk.ss_flags = 0;
    110 		TEST(sigaltstack(&sigstk, &osigstk));
    111 
    112 		if (TEST_RETURN == -1) {
    113 			tst_resm(TFAIL,
    114 				 "sigaltstack() Failed, errno=%d : %s",
    115 				 TEST_ERRNO, strerror(TEST_ERRNO));
    116 		} else {
    117 			/* Set up the signal handler for 'SIGUSR1' */
    118 			act.sa_flags = SA_ONSTACK;
    119 			act.sa_handler = (void (*)())sig_handler;
    120 			if ((sigaction(SIGUSR1, &act, &oact)) == -1) {
    121 				tst_brkm(TFAIL, cleanup, "sigaction() "
    122 					 "fails to trap signal "
    123 					 "delivered on alt. stack, "
    124 					 "error=%d", errno);
    125 			}
    126 
    127 			/* Deliver signal onto the alternate stack */
    128 			kill(my_pid, SIGUSR1);
    129 
    130 			/* wait till the signal arrives */
    131 			while (!got_signal) ;
    132 
    133 			got_signal = 0;
    134 			alt_stk = addr;
    135 
    136 			/*
    137 			 * First,
    138 			 * Check that alt_stk is within the
    139 			 * alternate stk boundaries
    140 			 *
    141 			 * Second,
    142 			 * Check that main_stk is outside the
    143 			 * alternate stk boundaries.
    144 			 */
    145 			if ((alt_stk < sigstk.ss_sp) &&
    146 			    (alt_stk > (sigstk.ss_sp + SIGSTKSZ))) {
    147 				tst_resm(TFAIL,
    148 					 "alt. stack is not within the "
    149 					 "alternate stk boundaries");
    150 			} else if ((main_stk >= sigstk.ss_sp) &&
    151 				   (main_stk <=
    152 				    (sigstk.ss_sp + SIGSTKSZ))) {
    153 				tst_resm(TFAIL,
    154 					 "main stk. not outside the "
    155 					 "alt. stack boundaries");
    156 			} else {
    157 				tst_resm(TPASS,
    158 					 "Functionality of "
    159 					 "sigaltstack() successful");
    160 			}
    161 		}
    162 		tst_count++;	/* incr. TEST_LOOP counter */
    163 	}
    164 
    165 	cleanup();
    166 	tst_exit();
    167 }
    168 
    169 /*
    170  * void
    171  * setup() - performs all ONE TIME setup for this test.
    172  * Capture SIGUSR1 on the main stack.
    173  * send the signal 'SIGUSER1' to the process.
    174  * wait till the signal arrives.
    175  * Allocate memory for the alternative stack.
    176  */
    177 void setup(void)
    178 {
    179 
    180 	tst_sig(FORK, DEF_HANDLER, cleanup);
    181 
    182 	TEST_PAUSE;
    183 
    184 	/* Get the process id of test process */
    185 	my_pid = getpid();
    186 
    187 	/* Capture SIGUSR1 on the main stack */
    188 	act.sa_handler = (void (*)(int))sig_handler;
    189 	if ((sigaction(SIGUSR1, &act, &oact)) == -1) {
    190 		tst_brkm(TFAIL, cleanup,
    191 			 "sigaction() fails in setup, errno=%d", errno);
    192 	}
    193 
    194 	/* Send the signal to the test process */
    195 	kill(my_pid, SIGUSR1);
    196 
    197 	/* Wait till the signal arrives */
    198 	while (!got_signal) ;
    199 
    200 	got_signal = 0;
    201 	main_stk = addr;
    202 
    203 	/* Allocate memory for the alternate stack */
    204 	if ((sigstk.ss_sp = malloc(SIGSTKSZ)) == NULL) {
    205 		tst_brkm(TFAIL, cleanup,
    206 			 "could not allocate memory for the alternate stack");
    207 	}
    208 }
    209 
    210 /*
    211  * void
    212  * sig_handler() - signal catching function.
    213  *  This functions is called when the signal 'SIGUSR1' is delivered to
    214  *  the test process and trapped by sigaction().
    215  *
    216  *  This function updates 'addr' variable and sets got_signal value.
    217  */
    218 void sig_handler(int n)
    219 {
    220 	int i;
    221 
    222 	(void) n;
    223 	addr = &i;
    224 	got_signal = 1;
    225 }
    226 
    227 /*
    228  * void
    229  * cleanup() - performs all ONE TIME cleanup for this test at
    230  *             completion or premature exit.
    231  *  Free the memory allocated for alternate stack.
    232  */
    233 void cleanup(void)
    234 {
    235 
    236 	free(sigstk.ss_sp);
    237 
    238 }
    239