Attachment 7193 Details for Bug 15946 – reproducing code

reproducing code

bug.c (text/x-csrc), 3.88 KB, created by arnaud.lb on 2013-09-12 09:50:17 UTC

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Filename:

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Creator: arnaud.lb

Created: 2013-09-12 09:50:17 UTC

Size: 3.88 KB

patch

obsolete

>
>// gcc -o bug bug.c -lpthread && ./bug
>
>#include <sys/types.h>                                                   
>#include <sys/stat.h>                                                    
>#include <stdio.h>
>#include <sys/socket.h>                                                  
>#include <netdb.h>
>#include <errno.h>
>#include <sys/un.h>
>#include <stdlib.h>
>#include <pthread.h>
>#include <unistd.h>
>
>#define LOOKUP_THREADS 1000
>#define SOCKET_PATH "/tmp/test.sock"
>
>void* lookup_thread(void *_) {
>
>    for (;;) {
>        struct addrinfo *res;
>        struct addrinfo hints;
>
>        memset(&hints, 0, sizeof(hints));
>
>        if (0 == getaddrinfo("example.com", NULL, &hints, &res)) {
>            freeaddrinfo(res);
>        }
>    }
>
>    return NULL;
>}
>
>void lookup() {
>
>    int i;
>
>    for (i = 0; i < LOOKUP_THREADS; i++) {
>
>        pthread_t t;
>        pthread_attr_t ta;
>
>        pthread_attr_init(&ta);
>
>        pthread_attr_setstacksize(&ta, 100<<10);
>
>        if (0 != pthread_create(&t, &ta, lookup_thread, (void*)(uintptr_t)i)) {
>            perror("pthread_create lookup thread");
>            exit(1);
>        }
>
>        pthread_attr_destroy(&ta);
>    }
>}
>
>void* server_thread(void *_) {
>
>    struct sockaddr_un saddr;
>    int s = socket(AF_UNIX, SOCK_STREAM, 0);
>
>    memset(&saddr, 0, sizeof(saddr));
>
>    if (s == -1) {
>        perror("server socket");
>        return NULL;
>    }
>
>    saddr.sun_family = AF_UNIX;
>    strncpy(saddr.sun_path, SOCKET_PATH, sizeof(saddr.sun_path)-1);
>
>    if (bind(s, (struct sockaddr *)&saddr, sizeof(struct sockaddr_un)) == -1) {
>        perror("bind");
>        close(s);
>        return NULL;
>    }
>
>    if (-1 == listen(s, 0)) {
>        perror("listen");
>        close(s);
>        return NULL;
>    }
>
>    for (;;) {
>
>        struct sockaddr_un paddr;
>        socklen_t paddrlen;
>
>        int fd = accept(s, (struct sockaddr*) &paddr, &paddrlen);
>
>        if (fd == -1) {
>            perror("accept");
>            close(s);
>            return NULL;
>        }
>
>        for (;;) {
>            char c;
>            int n = read(fd, &c, 1);
>
>            fprintf(stderr, "BUG: has read char 0x%02hhx: %c\a\n", (unsigned int) c, c);
>
>            if (n == 0) {
>                break;
>            }
>        }
>
>        close(fd);
>    }
>
>    return NULL;
>}
>
>void sock() {
>
>    int s, i, m;
>
>    struct sockaddr_un saddr;
>
>    // open a client socket to SOCKET_PATH
>
>    for (;;) {
>
>        s = socket(AF_UNIX, SOCK_STREAM, 0);
>
>        if (s == -1) {
>            perror("socket");
>            sleep(1);
>            continue;
>        }
>
>        memset(&saddr, 0, sizeof(saddr));
>
>        saddr.sun_family = AF_UNIX;
>        strncpy(saddr.sun_path, SOCKET_PATH, sizeof(saddr.sun_path)-1);
>
>        if (connect(s, (struct sockaddr *)&saddr, sizeof(struct sockaddr_un)) == -1) {
>            perror("connect");
>            close(s);
>            sleep(1);
>            continue;
>        }
>
>        break;
>    }
>
>    // repeatedly fill the file descriptor space with dups of the socket, and close the dups
>
>    int fds[65536];
>
>    for (;;) {
>
>        for (i = 0, m = 0; i < sizeof(fds)/sizeof(*fds); i++) {
>
>            int fd = dup(s);
>
>            if (fd == -1) {
>                if (errno == EMFILE) {
>                    break;
>                } else {
>                    perror("dup");
>                }
>            }
>
>            fds[i] = fd;
>            m = i;
>        }
>
>        for (i = 0; i <= m; i++) {
>            close(fds[i]);
>        }
>
>        continue;
>    }
>}
>
>int main() {
>
>    // Listen on SOCKET_PATH; if we receive something on this socket, we have
>    // successfuly reproduced the bug
>
>    unlink(SOCKET_PATH);
>
>    pthread_t t;
>    if (0 != pthread_create(&t, NULL, server_thread, NULL)) {
>        perror("pthread_create server thread");
>        return 1;
>    }
>
>    // Do many getaddrinfo() in parallel
>
>    lookup();
>
>    // Connect to SOCKET_PATH and dup()&close() the fd repeatedly
>
>    sock();
>
>    return 0;
>}
>

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