/* layout.c - where things live in a 32-bit AIX process. C89. */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <signal.h>
#include <setjmp.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/mman.h>

int g_init = 42;
int g_bss[1024];
static jmp_buf jb;
static void onsegv(int s) { longjmp(jb, 1); }

int main(int argc, char **argv)
{
    int local = 0;
    char *m1, *m2;
    void *p;
    int i, n;
    int ids[32];
    volatile int *zero = (volatile int *)0;

    setvbuf(stdout, 0, _IONBF, 0);
    printf("pagesize      %ld\n", sysconf(_SC_PAGESIZE));
    printf("main          %p\n", (void *)main);
    printf("g_init        %p\n", (void *)&g_init);
    printf("g_bss         %p\n", (void *)g_bss);
    m1 = malloc(100); m2 = malloc(1 << 20);
    printf("malloc(100)   %p\n", (void *)m1);
    printf("malloc(1M)    %p\n", (void *)m2);
    printf("sbrk(0)       %p\n", sbrk(0));
    printf("local         %p\n", (void *)&local);
    printf("argv          %p\n", (void *)argv);
    printf("argv[0]       %p\n", (void *)argv[0]);
    printf("printf        %p\n", (void *)printf);
    printf("malloc        %p\n", (void *)malloc);
    printf("errno         %p\n", (void *)&errno);
    printf("environ       %p\n", (void *)environ);

    /* reading and writing address 0 */
    { struct sigaction sa; memset(&sa, 0, sizeof sa); sa.sa_handler = onsegv; sigaction(SIGSEGV, &sa, 0); }
    if (setjmp(jb) == 0) { int v = *zero; printf("read *0       ok, value %d\n", v); }
    else printf("read *0       SIGSEGV\n");
    if (setjmp(jb) == 0) { *zero = 1; printf("write *0      ok\n"); }
    else printf("write *0      SIGSEGV\n");
    if (setjmp(jb) == 0) { int v = *(volatile int *)0x1000; printf("read 0x1000   ok, value %d\n", v); }
    else printf("read 0x1000   SIGSEGV\n");
    if (setjmp(jb) == 0) { int v = *(volatile int *)0x100000; printf("read 0x100000 ok, value %d\n", v); }
    else printf("read 0x100000 SIGSEGV\n");
    signal(SIGSEGV, SIG_DFL);

    /* anonymous mmap */
    p = mmap(0, 1 << 20, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
    printf("mmap anon 1M  %p%s\n", p, p == MAP_FAILED ? strerror(errno) : "");
    p = mmap(0, 1 << 20, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
    printf("mmap anon 1M  %p%s\n", p, p == MAP_FAILED ? strerror(errno) : "");

    /* shmat until it fails */
    n = argc > 1 ? atoi(argv[1]) : 16;
    for (i = 0; i < n; i++) {
        ids[i] = shmget(IPC_PRIVATE, 1 << 20, IPC_CREAT | 0600);
        if (ids[i] < 0) { printf("shmget %d      failed: %s\n", i + 1, strerror(errno)); break; }
        p = shmat(ids[i], 0, 0);
        if (p == (void *)-1) { printf("shmat %2d      failed: %s\n", i + 1, strerror(errno)); shmctl(ids[i], IPC_RMID, 0); break; }
        printf("shmat %2d      %p\n", i + 1, p);
        shmctl(ids[i], IPC_RMID, 0);   /* removed when detached at exit */
    }
    return 0;
}