mirror of
https://github.com/ioacademy-jikim/debugging
synced 2025-06-08 08:26:14 +00:00
72 lines
1.6 KiB
C
72 lines
1.6 KiB
C
/* x86 variant of the amd64-solaris/context_rflags.c test. */
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#include <assert.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <sys/ucontext.h>
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#define OBIT(eflags) (!!((eflags) & (1 << 11)))
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#define SBIT(eflags) (!!((eflags) & (1 << 7)))
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static siginfo_t si;
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static ucontext_t uc;
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static void sighandler(int sig, siginfo_t *sip, ucontext_t *ucp)
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{
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si = *sip;
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uc = *ucp;
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}
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int main(void)
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{
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struct sigaction sa;
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pid_t pid;
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int eflags;
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sa.sa_handler = sighandler;
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sa.sa_flags = SA_SIGINFO;
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if (sigfillset(&sa.sa_mask)) {
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perror("sigfillset");
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return 1;
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}
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if (sigaction(SIGUSR1, &sa, NULL)) {
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perror("sigaction");
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return 1;
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}
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pid = getpid();
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__asm__ __volatile__(
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/* Set overflow and sign flags. */
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"movl $1, %%edx\n"
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"addl $0x7fffffff, %%edx\n"
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/* Prepare syscall parameters. */
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"pushl %[sig]\n"
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"pushl %[pid]\n"
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"pushl $0xdeadbeef\n"
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"movl %[scall], %%eax\n"
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/* Trigger the signal handler. */
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"int $0x91\n"
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"pushfl\n"
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"popl %%edx\n"
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"addl $12, %%esp\n"
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: "=d" (eflags)
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: [scall] "i" (SYS_kill), [pid] "a" (pid), [sig] "i" (SIGUSR1)
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: "cc", "memory");
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printf("Values in the signal handler:\n");
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printf(" overflow=%d, sign=%d\n",
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OBIT(uc.uc_mcontext.gregs[EFL]), SBIT(uc.uc_mcontext.gregs[EFL]));
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printf("Values after the return from the signal handler:\n");
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printf(" overflow=%d, sign=%d\n", OBIT(eflags), SBIT(eflags));
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return 0;
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}
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