WIP: transient /etc #2970
WIP: transient /etc #2970
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Skipping CI for Draft Pull Request. |
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This currently depends on #2958 (and changing how we build ostree images to include an empty But, we can and probably should sever that dependency by detecting the missing |
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But, we can and probably should sever that dependency by detecting the missing etc and instead making the whole sysroot an overlayfs and making the etc directory there.
At the moment we check if there is a lower etc dir, if true we mount an overlay to TMP_SYSROOT/etc. Is this what was meant with "making the etc directory there"?
The image boots without crashing but I did not have the time to investigate selinux policies or persisting of various files such as machine-id yet
| } | ||
| else if (errno != ENOENT) | ||
| { | ||
| return glnx_throw_errno_prefix (error, "failed to stat etc"); |
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| return glnx_throw_errno_prefix (error, "failed to stat etc"); | |
| return glnx_throw_errno_prefix (error, "failed to stat usr/etc"); |
| return glnx_throw_errno_prefix (error, "failed to stat etc"); | ||
| } | ||
| *out_path = NULL; | ||
| return TRUE; |
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| return TRUE; | |
| return FALSE; |
If there is no lower etc dir, shouldnt this function return false so that https://github.com/cgwalters/ostree/blob/c9a38dfb7fcebeb0b678d27ded78e92580be79a5/src/switchroot/ostree-prepare-root.c#L633-L637 evaluates to false?
if (!find_etc (&etc_lower, &error))
| if (!ot_keyfile_get_value_with_default (config, SYSROOT_KEY, ETC_KEY, "persistent", &etc_config, | ||
| error)) |
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| if (!ot_keyfile_get_value_with_default (config, SYSROOT_KEY, ETC_KEY, "persistent", &etc_config, | |
| error)) | |
| if (!ot_keyfile_get_value_with_default (config, SYSROOT_KEY, ETC_KEY, "persistent", &etc_config, | |
| &error)) |
| } | ||
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| // Look for /usr/etc | ||
| if (fstatat (AT_FDCWD, "usr/etc") == 0) |
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| if (fstatat (AT_FDCWD, "usr/etc") == 0) | |
| if (!glnx_fstatat (AT_FDCWD, "usr/etc", &stbuf, AT_SYMLINK_NOFOLLOW, error)) |
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I am not entirely sure if I used the correct flag here.
| find_etc (const char **out_path, GError **error) | ||
| { | ||
| // Look for /etc | ||
| if (fstatat (AT_FDCWD, "etc") == 0) |
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| if (fstatat (AT_FDCWD, "etc") == 0) | |
| if (!glnx_fstatat (AT_FDCWD, "etc", &stbuf, AT_SYMLINK_NOFOLLOW, error)) |
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I am not entirely sure if I used the correct flag here.
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If using plain glnx_fstatat you need to use g_error_matches(error, ...), not errno. Easiest fix is to use
glnx_fstatat_allow_noent() which keeps errno for ENOENT.
| static gboolean | ||
| find_etc (const char **out_path, GError **error) | ||
| { | ||
| // Look for /etc |
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| // Look for /etc | |
| struct stat stbuf; | |
| // Look for /etc |
| if (etc_lower) | ||
| { | ||
| g_autofree char etc_ovl_options | ||
| = g_strdup_printf ("lowerdir=%s,upperdir=%s,workdir=%s", etc_lower, upper, work); | ||
| if (g_str_equal ("")) |
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| if (etc_lower) | |
| { | |
| g_autofree char etc_ovl_options | |
| = g_strdup_printf ("lowerdir=%s,upperdir=%s,workdir=%s", etc_lower, upper, work); | |
| if (g_str_equal ("")) | |
| g_autofree char *etc_ovl_options | |
| = g_strdup_printf ("lowerdir=%s,upperdir=%s,workdir=%s", etc_lower, upper, work); | |
| if (mount ("overlay", TMP_SYSROOT "/etc", "overlay", MS_SILENT, etc_ovl_options) < 0) | |
| err (EXIT_FAILURE, "failed to mount transient etc overlayfs"); |
| if (!ot_keyfile_get_value_with_default (config, SYSROOT_KEY, ETC_KEY, "persistent", &etc_config, | ||
| error)) | ||
| errx (EXIT_FAILURE, "failed to parse %s.%s: %s", SYSROOT_KEY, ETC_KEY, error->message); | ||
| bool etc_transient = FALSE; |
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Weird mix of FALSE and false/true.
| /* Do we have a persistent overlayfs for /usr? If so, mount it now. */ | ||
| g_autofree char *etc_ovldir | ||
| = g_build_filename (OTCORE_RUN_OSTREE_PRIVATE, "etc-transient", NULL); | ||
| if (mkdirat (AT_FDCWD, etc_ovldir, 0700) < 0) |
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Did you boot test this? Because when I tried something like this the selinux context on the initramfs at this point was uninitialized, which was carried over into boot for the overlayfs lowerdir, and without etc_t selinux context on /tmp a bunch of stuff broke at boot.
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Closing in favor of #2972 |
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