xenstore utils dropped support for -s in 4.15

[Henrik Riomar <rio@xxxxxxxxx>]

Hi,

In Alpine and Debian (probably elsewhere as well), the -s flag removed in these 
two commits:
 * 
https://github.com/xen-project/xen/commit/fa06cb8c38832aafe597d719040ba1d216e367b8
 * 
https://github.com/xen-project/xen/commit/c65687ed16d2289ec91036ec2862a4b4bd34ea4f
is actually used in the init scripts.

On one of the systems I tested 4.15 on things just hangs due to this:
2222  open("/lib/libxentoolcore.so.1", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = -1 
ENOENT (No such file or directory)
2222  open("/usr/local/lib/libxentoolcore.so.1", 
O_RDONLY|O_LARGEFILE|O_CLOEXEC) = -1 ENOENT (No such file or directory)
2222  open("/usr/lib/libxentoolcore.so.1", O_RDONLY|O_LARGEFILE|O_CLOEXEC) = 3
2222  fcntl(3, F_SETFD, FD_CLOEXEC)     = 0
2222  fstat(3, {st_mode=S_IFREG|0755, st_size=14072, ...}) = 0
2222  read(3, 
"\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\240\20\0\0\0\0\0\0"..., 960) = 
960
2222  mmap(NULL, 20480, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f9925c02000
2222  mmap(0x7f9925c03000, 4096, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 
0x1000) = 0x7f9925c03000
2222  mmap(0x7f9925c04000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED, 3, 0x2000) = 
0x7f9925c04000
2222  mmap(0x7f9925c05000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 
3, 0x2000) = 0x7f9925c05000
2222  close(3)                          = 0
2222  mprotect(0x7f9925c0f000, 4096, PROT_READ) = 0
2222  mprotect(0x7f9925ca6000, 4096, PROT_READ) = 0
2222  mprotect(0x7f9925c05000, 4096, PROT_READ) = 0
2222  mprotect(0x5601e65dc000, 4096, PROT_READ) = 0
2222  stat("/var/run/xenstored/socket", 0x7ffd95b9f080) = -1 ENOENT (No such 
file or directory)
2222  access("/dev/xen/xenbus", F_OK)   = 0
2222  stat("/dev/xen/xenbus", {st_mode=S_IFCHR|0600, st_rdev=makedev(0xa, 
0x3e), ...}) = 0
2222  open("/dev/xen/xenbus", O_RDWR|O_LARGEFILE) = 3
2222  rt_sigaction(SIGPIPE, {sa_handler=SIG_IGN, sa_mask=[], 
sa_flags=SA_RESTORER, sa_restorer=0x7f9925c59c4b}, {sa_handler=SIG_DFL, 
sa_mask=[], sa_flags=0}, 8) = 0
2222  write(3, "\2\0\0\0\0\0\0\0\0\0\0\0\2\0\0\0", 16) = 16
2222  write(3, "/\0", 2)                = 2
2222  read(3, 

Reverting the two commits mentioned above restores a booting system.

The -s flag was introduced in 2005 or so, so I guess you can say that dropping 
it should
at least be mentioned in the release notices, and an alternative be described, 
or
-s functionally should be brought back.

Thanks,
 Henrik

How its used in Debian:
https://salsa.debian.org/xen-team/debian-xen/-/blob/master/debian/xen-utils-common.xen.init#L246

How its used in Alpine:
https://git.alpinelinux.org/aports/tree/main/xen/xenstored.initd#n25