Bug 51673

Sorry, forgot version info.
db3-3.1.17-7
mysql-server-3.23.36-1
BTW main(){getservbyname("mysql","tcp");} doesn't segfault with 'db' at the
beginning of the 'passwd' 'shadow' 'group' 'protocols' 'rpc' and 'services'
lines.  Maybe a conflict between the libraries?

MySQL comes with it's own version of db, causing namespace collision (a generic
problem with using db as an authentication method with apps using db). Not
really fixable, but you should be able to work around it by using nscd or
avoiding the use of db as an authentication method.

Hm, starting nscd doesn't work around this problem.  Is there more that I need to do to "use" nscd?  (I see the lack of documentation for nscd has already 
been reported.)

No, starting it should be sufficient and should run the lookups in a different
space (which also helps when using static rpms using methods with dynamic
modules). The mysql user can be looked up in the db?

Mysqld uses the nscd socket, if present.  However, it also loads /etc/nsswitch.conf and reads the files/databases directly.
This behavior is probably buried in some header file.
[pid 16112] open("/etc/nsswitch.conf", O_RDONLY) = 3
[pid 16112] fstat64(3, {st_mode=S_IFREG|0644, st_size=1759, ...}) = 0
[pid 16112] mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40018000
[pid 16112] read(3, "#\n# /etc/nsswitch.conf\n#\n# An ex"..., 4096) = 1759
[pid 16112] read(3, "", 4096)           = 0
[pid 16112] close(3)                    = 0
[pid 16112] munmap(0x40018000, 4096)    = 0
[pid 16112] open("/etc/ld.so.cache", O_RDONLY) = 3
[pid 16112] fstat64(3, {st_mode=S_IFREG|0644, st_size=35199, ...}) = 0
[pid 16112] old_mmap(NULL, 35199, PROT_READ, MAP_PRIVATE, 3, 0) = 0x40018000
[pid 16112] close(3)                    = 0
[pid 16112] open("/lib/libnss_files.so.2", O_RDONLY) = 3
[pid 16112] read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0`\"\0\000"..., 1024) = 1024
[pid 16112] fstat64(3, {st_mode=S_IFREG|0755, st_size=275531, ...}) = 0
[pid 16112] old_mmap(NULL, 43432, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x40225000
[pid 16112] mprotect(0x4022f000, 2472, PROT_NONE) = 0
[pid 16112] old_mmap(0x4022f000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x9000) = 0x4022f000
[pid 16112] close(3)                    = 0
[pid 16112] munmap(0x40018000, 35199)   = 0
[pid 16112] open("/etc/services", O_RDONLY) = 3
[pid 16112] fcntl64(3, F_GETFD)         = 0
[pid 16112] fcntl64(3, F_SETFD, FD_CLOEXEC) = 0
[pid 16112] fstat64(3, {st_mode=S_IFREG|0644, st_size=17639, ...}) = 0
[pid 16112] mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x40018000
[pid 16112] read(3, "# /etc/services:\n# $Id: services"..., 4096) = 4096
[pid 16112] read(3, "ios-ns\t137/udp\nnetbios-dgm\t138/t"..., 4096) = 4096
[pid 16112] read(3, "ell\t\t514/tcp\t\tcmd\t\t# no password"..., 4096) = 4096
[pid 16112] close(3)                    = 0
[pid 16112] munmap(0x40018000, 4096)    = 0
[pid 16112] socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
[pid 16112] setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
[pid 16112] bind(3, {sin_family=AF_INET, sin_port=htons(3306), sin_addr=inet_addr("0.0.0.0")}}, 16) = 0
[pid 16112] listen(3, 50)               = 0
[pid 16112] geteuid32()                 = 0
[pid 16112] socket(PF_UNIX, SOCK_STREAM, 0) = 4
[pid 16112] connect(4, {sin_family=AF_UNIX, path="                             
                                                         /var/run/.nscd_socket"}, 110) = 0
[pid 16112] write(4, "\2\0\0\0\0\0\0\0\6\0\0\0", 12) = 12
[pid 16112] write(4, "mysql\0", 6)      = 6
[pid 16112] read(4, "\10_\27@\1\0\0\0\6\0\0\0\2\0\0\0\33\0\0\0\33\0\0\0\r\0"..., 36) = 36
[pid 16112] read(4, "mysql\0x\0MySQL Server\0/var/lib/my"..., 46) = 46
[pid 16112] close(4)                    = 0
[pid 16112] open("/etc/ld.so.cache", O_RDONLY) = 4
[pid 16112] fstat64(4, {st_mode=S_IFREG|0644, st_size=35199, ...}) = 0
[pid 16112] old_mmap(NULL, 35199, PROT_READ, MAP_PRIVATE, 4, 0) = 0x40018000
[pid 16112] close(4)                    = 0
[pid 16112] open("/lib/libnss_db.so.2", O_RDONLY) = 4
[pid 16112] read(4, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0 \30\0\000"..., 1024) = 1024
[pid 16112] fstat64(4, {st_mode=S_IFREG|0755, st_size=250631, ...}) = 0
[pid 16112] old_mmap(NULL, 21648, PROT_READ|PROT_EXEC, MAP_PRIVATE, 4, 0) = 0x40230000
[pid 16112] mprotect(0x40235000, 1168, PROT_NONE) = 0
[pid 16112] old_mmap(0x40235000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 4, 0x4000) = 0x40235000
[pid 16112] close(4)                    = 0
[pid 16112] open("/lib/libdb-3.1.so", O_RDONLY) = 4
[pid 16112] read(4, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0\3\0\1\0\0\0\200\364"..., 1024) = 1024
[pid 16112] fstat64(4, {st_mode=S_IFREG|0755, st_size=555898, ...}) = 0
[pid 16112] old_mmap(NULL, 495084, PROT_READ|PROT_EXEC, MAP_PRIVATE, 4, 0) = 0x40236000
[pid 16112] mprotect(0x402ad000, 7660, PROT_NONE) = 0
[pid 16112] old_mmap(0x402ad000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 4, 0x76000) = 0x402ad000
[pid 16112] close(4)                    = 0
[pid 16112] munmap(0x40018000, 35199)   = 0
[pid 16112] --- SIGSEGV (Segmentation fault) ---

It will still look at the file, but shouldn't use the information...