为什么 IPC::SysV->shmget 响应 EINVAL？

Question

我目前正在服务器上运行 perl 5.8.8，并尝试安装 5.14。

我将其配置为 usethreads 和 use64bitint 以及它建议的默认值。

make 运行没有问题，但 make test 失败，

../cpan/IPC-SysV/t/ipcsysv.t
../cpan/IPC-SysV/t/shm.t

因此：

# ./perl harness ../cpan/IPC-SysV/t/shm.t ../cpan/IPC-SysV/t/ipcsysv.t 
../cpan/IPC-SysV/t/shm.t ...... IPC::SharedMem->new failed: Invalid argument at t/shm.t line 54.
../cpan/IPC-SysV/t/shm.t ...... Dubious, test returned 22 (wstat 5632, 0x1600)
No subtests run
../cpan/IPC-SysV/t/ipcsysv.t .. 1/38 shmget failed: Invalid argument at t/ipcsysv.t line 100.
# Looks like you planned 38 tests but ran 17.
# Looks like your test exited with 22 just after 17.
../cpan/IPC-SysV/t/ipcsysv.t .. Dubious, test returned 22 (wstat 5632, 0x1600)
Failed 21/38 subtests

Test Summary Report
-------------------
../cpan/IPC-SysV/t/shm.t    (Wstat: 5632 Tests: 0 Failed: 0)
  Non-zero exit status: 22
  Parse errors: No plan found in TAP output
../cpan/IPC-SysV/t/ipcsysv.t (Wstat: 5632 Tests: 17 Failed: 0)
  Non-zero exit status: 22
  Parse errors: Bad plan.  You planned 38 tests but ran 17.
Files=2, Tests=17,  0 wallclock secs ( 0.01 usr  0.00 sys +  0.13 cusr  0.00 csys =  0.14 CPU)
Result: FAIL

这两个测试都报告“无效参数”，但是当我查看源代码时，我看不到任何看起来无效的内容。我不太确定如何继续......有什么指示吗？

更新

我在两台服务器上运行

 strace perl -MIPC::SysV=IPC_PRIVATE,S_IRWXU -e 'shmget(IPC_PRIVATE, 8, S_IRWXU) or die $!'

：一台存在这些问题，另一台则没有。

有很多输出，但看起来有趣的是：

GOOD:

.
.
.
stat64("/usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-multi/auto/IPC/SysV", 0x9d7f0c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/site_perl/5.8.8/auto/IPC/SysV", 0x9d7f0c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/site_perl/auto/IPC/SysV", 0x9d7f0c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/IPC/SysV", 0x9d7f0c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/vendor_perl/5.8.8/auto/IPC/SysV", 0x9d7f0c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/vendor_perl/auto/IPC/SysV", 0x9d7f0c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
stat64("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV/SysV.so", {st_mode=S_IFREG|0755, st_size=15072, ...}) = 0
stat64("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV/SysV.bs", 0x9d7f0c8) = -1 ENOENT (No such file or directory)
futex(0x4d106c, FUTEX_WAKE_PRIVATE, 2147483647) = 0
open("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV/SysV.so", O_RDONLY) = 4
read(4, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0 \v\0\0004\0\0\0"..., 512) = 512
fstat64(4, {st_mode=S_IFREG|0755, st_size=15072, ...}) = 0
mmap2(NULL, 17948, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x588000
mmap2(0x58c000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x3) = 0x58c000
close(4)                                = 0
close(3)                                = 0
shmget(IPC_PRIVATE, 8, 0700)            = 7438344
exit_group(0)                      

BAD:

.
.
.
stat64("/usr/lib/perl5/site_perl/5.8.8/i386-linux-thread-multi/auto/IPC/SysV", 0x8d290c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/site_perl/5.8.8/auto/IPC/SysV", 0x8d290c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/site_perl/auto/IPC/SysV", 0x8d290c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/auto/IPC/SysV", 0x8d290c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/vendor_perl/5.8.8/auto/IPC/SysV", 0x8d290c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/vendor_perl/auto/IPC/SysV", 0x8d290c8) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
stat64("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV/SysV.so", {st_mode=S_IFREG|0755, st_size=15072, ...}) = 0
stat64("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV/SysV.bs", 0x8d290c8) = -1 ENOENT (No such file or directory)
futex(0x94306c, FUTEX_WAKE_PRIVATE, 2147483647) = 0
open("/usr/lib/perl5/5.8.8/i386-linux-thread-multi/auto/IPC/SysV/SysV.so", O_RDONLY) = 4
read(4, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0 \v\0\0004\0\0\0"..., 512) = 512
fstat64(4, {st_mode=S_IFREG|0755, st_size=15072, ...}) = 0
mmap2(NULL, 17948, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 4, 0) = 0x6a4000
mmap2(0x6a8000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 4, 0x3) = 0x6a8000
close(4)                                = 0
close(3)                                = 0
shmget(IPC_PRIVATE, 8, 0700)            = -1 EINVAL (Invalid argument)
open("/usr/share/locale/locale.alias", O_RDONLY) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=2528, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7dbe000
read(3, "# Locale name alias data base.\n#"..., 4096) = 2528
read(3, "", 4096)                       = 0
close(3)                                = 0
munmap(0xb7dbe000, 4096)                = 0
open("/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, "Invalid argument at -e line 1.\n", 31Invalid argument at -e line 1.
) = 31
exit_group(22)                          = ?

所以，看来两台服务器上都发生了同样的事情，我明白，只是在一台服务器上发生了同样的事情 shmget(IPC_PRIVATE, 8, 0700) = 7438344

和另一个，我看到

shmget(IPC_PRIVATE, 8, 0700)            = -1 EINVAL (Invalid argument)

IPC::SysV 的版本在两台服务器上是相同的......但在我看来这不相关，问题是进行系统调用的代码...对吗？

接下来怎么办？

**更新2 **

经过一些谷歌搜索后，我运行了以下内容：

好：

#  cat /proc/sys/kernel/shmmax
4294967295

坏：

# cat /proc/sys/kernel/shmmax
0

所以，这解释了EINVAL，因为（来自手册页）

EINVAL

将创建一个新段，并且大小

SHMMIN 或大小> SHMMAX，或者没有新段 要创建时，具有给定键的段已存在，但大小大于大小 该段的。

现在，我的问题是，是否有充分的理由将其设置为零？

Answer 1

问题解决了。

/etc/sysctl.conf 文件包含以下内容：

kernel.shmmax = 137438953472

这是一个 64 位值，但系统是 32 位系统。

结果，SHMMAX 值被设置为 0，从而导致对 shmget 的所有调用失败。

将其更改为

kernel.shmmax = 4294967295

并使用

echo 4294967295 >/proc/sys/kernel/shmmax

我更改了 SHMMAX 的值，测试成功完成。