Question

在下面，你可以看到我运行的wu-ftpd的'cat proc / pid / maps'输出：

00400000-00427000 r-xp 00000000 ca:01 64883                              /usr/sbin/wu-ftpd
00626000-00627000 r--p 00026000 ca:01 64883                              /usr/sbin/wu-ftpd
00627000-00629000 rw-p 00027000 ca:01 64883                              /usr/sbin/wu-ftpd
00629000-00644000 rw-p 00000000 00:00 0
0245f000-02480000 rw-p 00000000 00:00 0                                  [heap]
7f1db9d70000-7f1db9d7c000 r-xp 00000000 ca:01 483644                     /lib/x86_64-linux-gnu/libnss_files-2.15.so
7f1db9d7c000-7f1db9f7b000 ---p 0000c000 ca:01 483644                     /lib/x86_64-linux-gnu/libnss_files-2.15.so
7f1db9f7b000-7f1db9f7c000 r--p 0000b000 ca:01 483644                     /lib/x86_64-linux-gnu/libnss_files-2.15.so
7f1db9f7c000-7f1db9f7d000 rw-p 0000c000 ca:01 483644                     /lib/x86_64-linux-gnu/libnss_files-2.15.so
7f1db9f7d000-7f1db9f7f000 r-xp 00000000 ca:01 483655                     /lib/x86_64-linux-gnu/libdl-2.15.so
7f1db9f7f000-7f1dba17f000 ---p 00002000 ca:01 483655                     /lib/x86_64-linux-gnu/libdl-2.15.so
7f1dba17f000-7f1dba180000 r--p 00002000 ca:01 483655                     /lib/x86_64-linux-gnu/libdl-2.15.so
7f1dba180000-7f1dba181000 rw-p 00003000 ca:01 483655                     /lib/x86_64-linux-gnu/libdl-2.15.so
7f1dba181000-7f1dba336000 r-xp 00000000 ca:01 483640                     /lib/x86_64-linux-gnu/libc-2.15.so
7f1dba336000-7f1dba536000 ---p 001b5000 ca:01 483640                     /lib/x86_64-linux-gnu/libc-2.15.so
7f1dba536000-7f1dba53a000 r--p 001b5000 ca:01 483640                     /lib/x86_64-linux-gnu/libc-2.15.so
7f1dba53a000-7f1dba53c000 rw-p 001b9000 ca:01 483640                     /lib/x86_64-linux-gnu/libc-2.15.so
7f1dba53c000-7f1dba541000 rw-p 00000000 00:00 0
7f1dba541000-7f1dba54d000 r-xp 00000000 ca:01 482456                     /lib/x86_64-linux-gnu/libpam.so.0.83.0
7f1dba54d000-7f1dba74d000 ---p 0000c000 ca:01 482456                     /lib/x86_64-linux-gnu/libpam.so.0.83.0
7f1dba74d000-7f1dba74e000 r--p 0000c000 ca:01 482456                     /lib/x86_64-linux-gnu/libpam.so.0.83.0
7f1dba74e000-7f1dba74f000 rw-p 0000d000 ca:01 482456                     /lib/x86_64-linux-gnu/libpam.so.0.83.0
7f1dba74f000-7f1dba758000 r-xp 00000000 ca:01 483641                     /lib/x86_64-linux-gnu/libcrypt-2.15.so
7f1dba758000-7f1dba958000 ---p 00009000 ca:01 483641                     /lib/x86_64-linux-gnu/libcrypt-2.15.so
7f1dba958000-7f1dba959000 r--p 00009000 ca:01 483641                     /lib/x86_64-linux-gnu/libcrypt-2.15.so
7f1dba959000-7f1dba95a000 rw-p 0000a000 ca:01 483641                     /lib/x86_64-linux-gnu/libcrypt-2.15.so
7f1dba95a000-7f1dba988000 rw-p 00000000 00:00 0
7f1dba988000-7f1dba9aa000 r-xp 00000000 ca:01 483652                     /lib/x86_64-linux-gnu/ld-2.15.so
7f1dbab9e000-7f1dbaba2000 rw-p 00000000 00:00 0
7f1dbaba8000-7f1dbabaa000 rw-p 00000000 00:00 0
7f1dbabaa000-7f1dbabab000 r--p 00022000 ca:01 483652                     /lib/x86_64-linux-gnu/ld-2.15.so
7f1dbabab000-7f1dbabad000 rw-p 00023000 ca:01 483652                     /lib/x86_64-linux-gnu/ld-2.15.so
7fff20555000-7fff20576000 rw-p 00000000 00:00 0                          [stack]
7fff205fe000-7fff20600000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]

有一些内存范围，例如：

00629000-00644000（第4行）或
7f1dba95a000-7f1dba988000（/lib/x86_64-linux-gnu/libcrypt-2.15.so之后的第21行）

没有描述（如堆，堆栈或共享库）。这些地区是什么？他们用了什么？

谢谢！

Answer 1

这些是mmap()使用MAP_ANONYMOUS标志创建的匿名映射。在这种情况下，它们可能对应于映射二进制文件的BSS段（例如，第一个是/usr/sbin/wu-ftpd的BSS段。）

BSS是初始化为零的静态分配对象的映射 - 它是一个不占用二进制本身空间的段，因为存储一堆零没有意义。

使用malloc()进行大量分配也可能产生匿名映射 - 从堆中满足小分配，但是大分配通常会得到自己的匿名映射。

Linux / proc / <pid> / map的输出详细</pid>

1 个答案: