Bug#438184: getpwnam and getgrnam astonishing inefficiency
Package: libc6
Version: 2.3.6.ds1-13
While stracing dpkg I saw something strange so I investigated.
Below is a fragment showing dpkg on sarge installing libadns1-bin.
This is from the unpack phase and convers the installation of two
files. I see similar behaviour on etch.
18 out of the 32 system calls for installing each file are the libc
reading /etc/{passwd,group} for get{pw,gr}nam in order to map "root"
to 0 for the nth time.
Surely it could be at least slightly more intelligent.
Ian.
00:54:58.376667 read(7, "./usr/bin/adnsheloex\0\0\0\0\0\0\0\0\0\0\0\0"..., 512) = 512
00:54:58.376735 open("/etc/passwd", O_RDONLY) = 8
00:54:58.376791 fcntl64(8, F_GETFD) = 0
00:54:58.376833 fcntl64(8, F_SETFD, FD_CLOEXEC) = 0
00:54:58.376876 _llseek(8, 0, [0], SEEK_CUR) = 0
00:54:58.376922 fstat64(8, {st_mode=S_IFREG|0644, st_size=5251, ...}) = 0
00:54:58.376996 mmap2(NULL, 5251, PROT_READ, MAP_SHARED, 8, 0) = 0x40022000
00:54:58.377041 _llseek(8, 5251, [5251], SEEK_SET) = 0
00:54:58.377093 munmap(0x40022000, 5251) = 0
00:54:58.377137 close(8) = 0
00:54:58.377185 open("/etc/group", O_RDONLY) = 8
00:54:58.377238 fcntl64(8, F_GETFD) = 0
00:54:58.377280 fcntl64(8, F_SETFD, FD_CLOEXEC) = 0
00:54:58.377321 _llseek(8, 0, [0], SEEK_CUR) = 0
00:54:58.377367 fstat64(8, {st_mode=S_IFREG|0644, st_size=1884, ...}) = 0
00:54:58.377440 mmap2(NULL, 1884, PROT_READ, MAP_SHARED, 8, 0) = 0x40022000
00:54:58.377487 _llseek(8, 1884, [1884], SEEK_SET) = 0
00:54:58.377538 munmap(0x40022000, 1884) = 0
00:54:58.377580 close(8) = 0
00:54:58.377635 lstat64("/usr/bin/adnsheloex", {st_mode=S_IFREG|0755, st_size=9720, ...}) = 0
00:54:58.377721 rmdir("/usr/bin/adnsheloex.dpkg-new") = -1 ENOENT (No such file or directory)
00:54:58.377829 rmdir("/usr/bin/adnsheloex.dpkg-tmp") = -1 ENOENT (No such file or directory)
00:54:58.377888 open("/usr/bin/adnsheloex.dpkg-new", O_WRONLY|O_CREAT|O_EXCL|O_LARGEFILE, 0) = 8
00:54:58.378071 read(7, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\2\0\3\0\1\0\0\0@\213\4"..., 9720) = 9720
00:54:58.378324 write(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\2\0\3\0\1\0\0\0@\213\4"..., 9720) = 9720
00:54:58.381611 read(7, "\0\0\0\0\0\0\0\0", 8) = 8
00:54:58.381688 fchown32(8, 0, 0) = 0
00:54:58.381746 fchmod(8, 0755) = 0
00:54:58.381794 close(8) = 0
00:54:58.381844 utime("/usr/bin/adnsheloex.dpkg-new", [2007/08/16-00:53:53, 2006/10/17-17:47:03]) = 0
00:54:58.381924 link("/usr/bin/adnsheloex", "/usr/bin/adnsheloex.dpkg-tmp") = 0
00:54:58.382067 rename("/usr/bin/adnsheloex.dpkg-new", "/usr/bin/adnsheloex") = 0
00:54:58.382224 read(7, "./usr/bin/adnsresfilter\0\0\0\0\0\0\0\0\0"..., 512) = 512
00:54:58.382410 open("/etc/passwd", O_RDONLY) = 8
00:54:58.382478 fcntl64(8, F_GETFD) = 0
00:54:58.382521 fcntl64(8, F_SETFD, FD_CLOEXEC) = 0
00:54:58.382566 _llseek(8, 0, [0], SEEK_CUR) = 0
00:54:58.382614 fstat64(8, {st_mode=S_IFREG|0644, st_size=5251, ...}) = 0
00:54:58.382689 mmap2(NULL, 5251, PROT_READ, MAP_SHARED, 8, 0) = 0x40022000
00:54:58.382739 _llseek(8, 5251, [5251], SEEK_SET) = 0
00:54:58.382853 munmap(0x40022000, 5251) = 0
00:54:58.382900 close(8) = 0
00:54:58.382952 open("/etc/group", O_RDONLY) = 8
00:54:58.383006 fcntl64(8, F_GETFD) = 0
00:54:58.383048 fcntl64(8, F_SETFD, FD_CLOEXEC) = 0
00:54:58.383092 _llseek(8, 0, [0], SEEK_CUR) = 0
00:54:58.383138 fstat64(8, {st_mode=S_IFREG|0644, st_size=1884, ...}) = 0
00:54:58.383211 mmap2(NULL, 1884, PROT_READ, MAP_SHARED, 8, 0) = 0x40022000
00:54:58.383257 _llseek(8, 1884, [1884], SEEK_SET) = 0
00:54:58.383307 munmap(0x40022000, 1884) = 0
00:54:58.383348 close(8) = 0
00:54:58.383404 lstat64("/usr/bin/adnsresfilter", {st_mode=S_IFREG|0755, st_size=11528, ...}) = 0
00:54:58.383492 rmdir("/usr/bin/adnsresfilter.dpkg-new") = -1 ENOENT (No such file or directory)
00:54:58.383598 rmdir("/usr/bin/adnsresfilter.dpkg-tmp") = -1 ENOENT (No such file or directory)
00:54:58.383659 open("/usr/bin/adnsresfilter.dpkg-new", O_WRONLY|O_CREAT|O_EXCL|O_LARGEFILE, 0) = 8
00:54:58.383826 read(7, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\2\0\3\0\1\0\0\0\0\213\4"..., 11528) = 11528
00:54:58.384050 write(8, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\2\0\3\0\1\0\0\0\0\213\4"..., 11528) = 11528
00:54:58.384206 read(7, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 248) = 248
00:54:58.384276 fchown32(8, 0, 0) = 0
00:54:58.384326 fchmod(8, 0755) = 0
00:54:58.384371 close(8) = 0
00:54:58.384413 utime("/usr/bin/adnsresfilter.dpkg-new", [2007/08/16-00:53:53, 2006/10/17-17:47:03]) = 0
00:54:58.384486 link("/usr/bin/adnsresfilter", "/usr/bin/adnsresfilter.dpkg-tmp") = 0
00:54:58.384622 rename("/usr/bin/adnsresfilter.dpkg-new", "/usr/bin/adnsresfilter") = 0
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