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author | Kartik K. Agaram <vc@akkartik.com> | 2022-03-07 10:35:23 -0800 |
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committer | Kartik K. Agaram <vc@akkartik.com> | 2022-03-07 10:55:18 -0800 |
commit | 38063812b6e931740f9d9d7b4bc95429dcfb3aa6 (patch) | |
tree | 3d71c8c5dba878c99551aebbba760a4c4e0deab7 /src/teliva.c | |
parent | 7a315e3d9f1c668b54d57b472b612c7f6d738ede (diff) | |
download | teliva-38063812b6e931740f9d9d7b4bc95429dcfb3aa6.tar.gz |
zet.tlv: switch file writes to new API
The interface for apps looks much nicer now, see 'main' in zet.tlv. However there are some open issues: - It can still be confusing to the computer owner that an app tries to write to some temporary file that isn't mentioned anywhere. - File renames can fail if /tmp is on a different volume. - What happens if an app overrides start_writing()? The computer owner may think they've audited the caller of start_writing and give it blanket file permissions. Teliva tunnels through start_writing when computing the caller. If the app can control what start_writing does, the app could be performing arbitrary malicious file operations. Right now things actually seem perfectly secure. Overriding start_writing has no effect. Our approach for loading .tlv files (in reverse chronological order, preventing older versions from overriding newer ones) has the accidentally _great_ property that Teliva apps can never override system definitions. So we have a new reason to put standard libraries in a .lua file: if we need to prevent apps from overriding it. This feels like something that needs an automated test, both to make sure I'm running the right experiment and to ensure I don't accidentally cause a regression in the future. I can totally imagine a future rewrite that tried a different approach than reverse-chronological.
Diffstat (limited to 'src/teliva.c')
-rw-r--r-- | src/teliva.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/src/teliva.c b/src/teliva.c index 71576b5..db59428 100644 --- a/src/teliva.c +++ b/src/teliva.c @@ -337,6 +337,17 @@ char* get_caller(lua_State* L) { return result; } +char* get_caller_of_caller(lua_State* L) { + static char result[1024] = {0}; + lua_Debug ar; + lua_getstack(L, 2, &ar); + lua_getinfo(L, "n", &ar); + memset(result, '\0', 1024); + if (ar.name) + strncpy(result, ar.name, 1020); + return result; +} + void save_caller_as(lua_State* L, const char* name, const char* caller_name) { // push table of caller tables luaL_newmetatable(L, "__teliva_caller"); |