Hi Corinna, On Mon, 3 Apr 2023, Johannes Schindelin wrote:
> On Tue, 28 Mar 2023, Corinna Vinschen wrote: > > > On Mar 28 10:17, Johannes Schindelin wrote: > > > In particular when we cannot figure out a uid for the current user, we > > > should still respect the `db_home: env` setting. Such a situation occurs > > > for example when the domain returned by `LookupAccountSid()` is not our > > > machine name and at the same time our machine is no domain member: In > > > that case, we have nobody to ask for the POSIX offset necessary to come > > > up with the uid. > > > > > > It is important that even in such cases, the `HOME` environment variable > > > can be used to override the home directory, e.g. when Git for Windows is > > > used by an account that was generated on the fly, e.g. for transient use > > > in a cloud scenario. > > > > How does this kind of account look like? I'd like to see the contants > > of name, domain, and the SID. Isn't that just an account closely > > resembling Micorosft Accounts or AzureAD accounts? Can't we somehow > > handle them alike? > > [...] > > What I _can_ do is try to recreate the problem (the report said that this > happens in a Kudu console of an Azure Web App, see > https://github.com/projectkudu/kudu/wiki/Kudu-console) by creating a new > Azure Web App and opening that console and run Cygwin within it, which is > what I am going to do now. So here is what is going on: - The domain is 'IIS APPPOOL' - The name is the name of the Azure Web App - The sid is 'S-1-5-82-3932326390-3052311582-2886778547-4123178866-1852425102' The program I am trying to make work as expected (i.e. to respect the `db_home: env` line in `/etc/nsswitch.conf` in conjunction with the `HOME` variable being set to `C:\home`) is `ssh-keygen.exe`: We want it to default to creating the file `/cygdrive/c/home/.ssh/id_rsa`. But what it _does_, without this patch, is to default to creating the file `//.ssh/id_rsa` (which does not make sense because that would refer to a file share called `id_rsa` on a server whose name is `.ssh`). Condensed to the bare minimum reproducer, the code boils down to this: -- snip -- #include <stdio.h> #include <sys/types.h> #include <unistd.h> #include <pwd.h> int main(int argc, char **argv) { uid_t uid = getuid(); struct passwd *pw = getpwuid(uid); printf("uid=%u, pw_dir='%s'\n", (unsigned)uid, pw->pw_dir); return 0; } -- snap -- In the Kudu console scenario, this program prints the UID 4294967295 (which is 0xffffffff) and _without_ this patch, it prints the `pw_dir` as being `/`, even if the `HOME` environment variable should override that for the current user. _With_ patch 3/3, it prints out the same `uid`, but it does print the `pw_dir` as `/cygdrive/c/home`. I will distill the above into a new-and-improved commit message. Ciao, Johannes