Add a new command to read the content of a file after switching to the
given user. This command can be used to enforce Unix filesystem
permissions when accessing a file on behalf of a user.
(cherry picked from commit 285457a5f8284f21387753d7f245e3f51ce29248)
We have nm_strerror_native_r(), which is the wrapper around strerror_r() that
we want to use in glib components (it also will ensure that the string is valid
UTF-8). However, it's not usable from non-glib components.
Move the part that abstracts strerror_r() out to libnm-std-aux as _nm_strerror_r().
The purpose is that non-glib componenent can use the thread-safe wrapper around
strerror_r().
NM_STR_BUF_INIT() and nm_str_buf_init() were pretty much redundant. Drop one of
them.
Usually our pattern is that we don't have functions that return structs.
But NM_STR_BUF_INIT() returns a struct, because it's convenient to use
with
nm_auto_str_buf NMStrBuf strbuf = NM_STR_BUF_INIT(...);
So use that variant instead.
