为什么 Clam 防病毒守护程序不会以无法分配内存错误开始？

Question

/etc/init.d/clamd start

错误：

[FAILED] log gives ERROR: daemonize() failed: Cannot Allocate Memory

在 Cent OS

total Mem: 510876kb

/etc/init.d/clamd start

在 /var/log/clamav

ERROR: daemonize() failed: Cannot Allocate Memory?

这是一个可以解决的问题吗？

我以为Clamd只需要20 - 40 mb

说 Memory Free: 273844k

strace 的结果：

waitpid(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 1}], 0) = 1658
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
--- SIGCHLD (Child exited) @ 0 (0) ---
waitpid(-1, 0xbff84a2c, WNOHANG)        = -1 ECHILD (No child processes)
sigreturn()                             = ? (mask now [])
rt_sigaction(SIGINT, {SIG_DFL, [], 0}, {0x80810f0, [], 0}, 8) = 0
rt_sigprocmask(SIG_BLOCK, NULL, [], 8)  = 0
read(255, "", 1694)                     = 0
exit_group(1)                           = ?

strace -f 的结果：

strace -f -o /tmp/clamd.txt service clamd start

几乎相同，我是在寻找某种错误吗？

Answer 1

我也遇到了同样的问题。
我观察到它clamd在内存中一次又一次地增长，然后因错误而崩溃：

Jun  6 08:08:32 <server> clamd[5086]: Received 0 file descriptor(s) from systemd.
Jun  6 08:08:32 <server> clamd[5086]: clamd daemon 0.99.4 (OS: linux-gnu, ARCH: x86_64, CPU: x86_64)
Jun  6 08:08:32 <server> clamd[5086]: Running as user clamupdate (UID 992, GID 990)
Jun  6 08:08:32 <server> clamd[5086]: Log file size limited to 1048576 bytes.
Jun  6 08:08:32 <server> clamd[5086]: Reading databases from /var/lib/clamav
Jun  6 08:08:32 <server> clamd[5086]: Not loading PUA signatures.
Jun  6 08:08:32 <server> clamd[5086]: Bytecode: Security mode set to "TrustSigned".
Jun  6 08:08:46 <server> clamd[5086]: Loaded 6538218 signatures.
Jun  6 08:08:48 <server> clamd[5086]: LOCAL: Unix socket file /var/run/clamd/clamd.sock
Jun  6 08:08:48 <server> clamd[5086]: LOCAL: Setting connection queue length to 4
Jun  6 08:08:48 <server> clamd[5086]: daemonize() failed: Cannot allocate memory
Jun  6 08:08:48 <server> clamd[5086]: Closing the main socket.
Jun  6 08:08:48 <server> clamd[5086]: Socket file removed.

我观察到clamd内存增长到532 MB

# ps -o pid,size,rss,etime,start,cmd -p 16114|more
  PID  SIZE   RSS     ELAPSED  STARTED CMD
16114 580024 545672     00:15 08:18:21 /usr/sbin/clamd -c /etc/clamd.d/clamd.conf
# echo "scale=3; 545672/1024"|bc -l
532.882

我认为 532 MB 会很紧，但我仍然可以适应小型服务器

# free -m
              total        used        free      shared  buff/cache   available
Mem:           1834         532         626          89         675        1004
Swap:             0           0           0

将clamd被都知道要消耗很多记忆，但也似乎在几年得到较大。
所以我想知道什么会消耗这么多内存并使用strace.
我发现它实际上是将所有数据库文件读入内存，因为它在日志中声明Reading databases from /var/lib/clamav并创建了一个内存索引6538218 signatures：

openat(AT_FDCWD, "/var/lib/clamav", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 5
getdents(5, /* 6 entries */, 32768)     = 176
stat("/var/lib/clamav/daily.cld", {st_mode=S_IFREG|0644, st_size=141535744, ...}) = 0
stat("/var/lib/clamav/main.cvd", {st_mode=S_IFREG|0644, st_size=117892267, ...}) = 0
stat("/var/lib/clamav/bytecode.cvd", {st_mode=S_IFREG|0644, st_size=153228, ...}) = 0
getdents(5, /* 0 entries */, 32768)     = 0
close(5)                                = 0
stat("/var/log/clamd/clamd.log", {st_mode=S_IFREG|0600, st_size=266784, ...}) = 0
write(3, "Wed Jun  6 08:08:46 2018 -> Load"..., 55) = 55
sendto(4, "<22>Jun  6 08:08:46 clamd[5086]:"..., 59, MSG_NOSIGNAL, NULL, 0) = 59

在将所有病毒定义读入内存后，它最终尝试fork使用子进程尝试克隆 532 MB 的内存索引

clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7fd70bb64b10) = -1 ENOMEM (Cannot allocate memory)
stat("/var/log/clamd/clamd.log", {st_mode=S_IFREG|0600, st_size=266989, ...}) = 0
write(3, "Wed Jun  6 08:08:48 2018 -> ERRO"..., 78) = 78
write(2, "ERROR: daemonize() failed: Canno"..., 50) = 50
sendto(4, "<19>Jun  6 08:08:48 clamd[5086]:"..., 75, MSG_NOSIGNAL, NULL, 0) = 75

所以实际上在启动的那一刻，它会消耗两倍的内存量，这使得它的内存索引。

现在为了能够启动和运行这个服务，我至少需要创建一个交换分区来克服这个启动序列。
正如其他人也评论说增加系统内存可以帮助您克服这种启动内存增加。