* [[wp>select (Unix)|select]]
  * [[http://www.cppfans.org/1417.html|浅析epoll-为何多路复用I/O要使用epoll]]
  * [[http://www.cppfans.org/1418.html|浅析epoll – epoll函数深入讲解]]
====== 訊號 ======
<code c>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>

// /usr/include/sys/ucontext.h
void segv_handler(int sig, siginfo_t *si, void *context)
{
    printf("Got SIGSEGV at address: 0x%lx\n", (long) si->si_addr);
    abort();
}

int main() {
    struct sigaction act;

    /* The SA_SIGINFO flag tells sigaction() to use the sa_sigaction field, not sa_handler. */
    act.sa_flags = SA_SIGINFO;

    /* Use the sa_sigaction field because the handles has two additional parameters */
    act.sa_sigaction = segv_handler;

    sigemptyset(&act.sa_mask);

    /* Register our signal handler. */
    sigaction(SIGSEGV, &act, NULL);

    /* Trigger segfault */
    *(char *) 0 = 0;
}
</code>
  * [[http://tinymicros.com/wiki/Linux_Overflow_Signal_Handler_Example|Linux Overflow Signal Handler Example]]
    * ''arch/x86/include/asm/sigcontext.h''
    * ''/usr/include/sys/ucontext.h''。<code c>
/* Context to describe whole processor state.  */
typedef struct
  {
    gregset_t gregs;
    /* Note that fpregs is a pointer.  */
    fpregset_t fpregs;
    unsigned long __reserved1 [8];
} mcontext_t;

/* Userlevel context.  */
typedef struct ucontext
  {
    unsigned long int uc_flags;
    struct ucontext *uc_link;
    stack_t uc_stack;
    mcontext_t uc_mcontext;
    __sigset_t uc_sigmask;
    struct _libc_fpstate __fpregs_mem;
  } ucontext_t;
</code>
    * [[http://stackoverflow.com/questions/12349169/where-is-uc-mcontext-definition|Where is uc_mcontext definition?]]
  * [[wp>SIGSEGV]]
    * [[http://www.daniweb.com/hardware-and-software/linux-and-unix/threads/267950/linux-signal-handling|Linux Signal Handling]]

  * [[http://stackoverflow.com/questions/2663456/write-a-signal-handler-to-catch-sigsegv|Write a signal handler to catch SIGSEGV]]
  * [[http://stackoverflow.com/questions/10202941/segmentation-fault-handling|Segmentation fault handling]]
  * [[http://stackoverflow.com/questions/122877/why-does-strcpy-trigger-a-segmentation-fault-with-global-variables|Why does strcpy trigger a segmentation fault with global variables?]]

<code c>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

void segv_handler(int sig, siginfo_t *si, void *context)
{
    fprintf(stderr, "Got SIGSEGV at address: 0x%lx\n", (long) si->si_addr);

    if (si->si_code == SEGV_MAPERR)
        fprintf(stderr, "Address not mapped to object\n");
    else if (si->si_code == SEGV_ACCERR)
        fprintf(stderr, "Invalid permissions for mapped object\n");
    else
        fprintf(stderr, "No such code\n");

    exit(1);
}

static void map_readonly(void *addr, long size)
{
    unsigned long start, end, page_size;

    page_size = getpagesize();
    start = (unsigned long)addr;
    start &= ~(page_size - 1);

    end = (unsigned long)addr + size;
    end += page_size - 1;
    end &= ~(page_size - 1);

    mprotect((void *)start, end - start,
             PROT_READ);
}

int main()
{
    sigset_t set;
    struct sigaction sigact;
    char *vaddr = 0;

    memset(&sigact, 0, sizeof(sigact));
    sigact.sa_flags = SA_SIGINFO;
    sigact.sa_sigaction = segv_handler;
    sigaction(SIGSEGV, &sigact, NULL);
    sigemptyset(&set);
    sigaddset(&set, SIGSEGV);

    //*vaddr = 'a'; // SEGV_MAPERR

    char *vaddr2 = (char *)malloc(4);

    map_readonly(vaddr2, 4);

    *vaddr2 = 'a'; // SEGV_ACCERR
}
</code>
  * [[http://stackoverflow.com/questions/1687415/malloc-results-in-segmentation-fault-after-mprotect|malloc results in segmentation fault after mprotect]]

  * [[http://fanqiang.chinaunix.net/a4/b2/20010508/113528_b.html|Linux下C語言編程--信號處理函數]]
====== 其它 ======
  * [[http://blog.roodo.com/rocksaying/archives/2333878.html|How to use the select(), an I/O Multiplexer]]

  * [[http://www.jollen.org/blog/2007/02/dynamic_loader_1_dlopen.html|研究 Dynamic Loader, #1: dlopen]]
  * [[http://blog.linux.org.tw/~jserv/archives/001561.html|dlopen 的 _init 與 _fini]]
  * [[http://stackoverflow.com/questions/4803152/mmap-fails-when-length-is-larger-the-4g|mmap fails when length is larger the 4G]]
====== 外部連結 ======
  * [[http://www.linuxprogrammingblog.com/|Linux Programming Blog]]
  * [[http://www.tldp.org/LDP/lpg/|The Linux Programmer's Guide]]
  * [[http://programminggroundup.blogspot.tw/|PROGRAMMING FROM THE GROUND UP]]
  * [[http://www.makelinux.net/ldd3/|Linux Device Drivers, 3rd Edition]]