From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2155) id A78BD3857B8E; Wed, 29 Mar 2023 08:25:50 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org A78BD3857B8E DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1680078350; bh=L01KNOSyZKQ+WfOPwEBgiVYnD3X2bDYGykwHH4WTiAw=; h=From:To:Subject:Date:From; b=lkCcckM3cL3yWw53ADx8VT04lOiyvUH5pnftA55q0UgactB12QyMyI3d73qmayfFF hNsIcyPazi9jBlWJvFBgyZ9GOHVFNRHx5meSajDryNevs/uoY0Z2ukpJ5bzR8Kw9IY JKD5nz2wA1rb0KWrSZA/rWkFz/yhkgUMDTbw7xcY= Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable From: Corinna Vinschen To: cygwin-cvs@sourceware.org Subject: [newlib-cygwin/main] Allow deriving the current user's home directory via the HOME variable X-Act-Checkin: newlib-cygwin X-Git-Author: Johannes Schindelin X-Git-Refname: refs/heads/main X-Git-Oldrev: fc6e89c937c1bcdf2b0efc6806e29960c448b756 X-Git-Newrev: 27376c60a9b870e7ba456551165897a7408b5886 Message-Id: <20230329082550.A78BD3857B8E@sourceware.org> Date: Wed, 29 Mar 2023 08:25:50 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=3Dnewlib-cygwin.git;h=3D27376c60a9b= 870e7ba456551165897a7408b5886 commit 27376c60a9b870e7ba456551165897a7408b5886 Author: Johannes Schindelin AuthorDate: Tue Mar 28 10:17:14 2023 +0200 Commit: Corinna Vinschen CommitDate: Tue Mar 28 12:18:14 2023 +0200 Allow deriving the current user's home directory via the HOME variable =20 This patch hails from Git for Windows (where the Cygwin runtime is used in the form of a slightly modified MSYS2 runtime), where it is a well-established technique to let the `$HOME` variable define where the current user's home directory is, falling back to `$HOMEDRIVE$HOMEPATH` and `$USERPROFILE`. =20 The idea is that we want to share user-specific settings between programs, whether they be Cygwin, MSYS2 or not. Unfortunately, we cannot blindly activate the "db_home: windows" setting because in some setups, the user's home directory is set to a hidden directory via an UNC path (\\share\some\hidden\folder$) -- something many programs cannot handle correctly, e.g. `cmd.exe` and other native Windows applications that users want to employ as Git helpers. =20 The established technique is to allow setting the user's home directory via the environment variables mentioned above: `$HOMEDRIVE$HOMEPATH` or `$USERPROFILE`. This has the additional advantage that it is much faster than querying the Windows user database. =20 Of course this scheme needs to be opt-in. For that reason, it needs to be activated explicitly via `db_home: env` in `/etc/nsswitch.conf`. =20 Signed-off-by: Johannes Schindelin Diff: --- winsup/cygwin/local_includes/cygheap.h | 3 +- winsup/cygwin/uinfo.cc | 51 ++++++++++++++++++++++++++++++= ++++ winsup/doc/ntsec.xml | 22 +++++++++++++++ 3 files changed, 75 insertions(+), 1 deletion(-) diff --git a/winsup/cygwin/local_includes/cygheap.h b/winsup/cygwin/local_i= ncludes/cygheap.h index d885ca123085..b6acdf7f18b7 100644 --- a/winsup/cygwin/local_includes/cygheap.h +++ b/winsup/cygwin/local_includes/cygheap.h @@ -358,7 +358,8 @@ public: NSS_SCHEME_UNIX, NSS_SCHEME_DESC, NSS_SCHEME_PATH, - NSS_SCHEME_FREEATTR + NSS_SCHEME_FREEATTR, + NSS_SCHEME_ENV }; struct nss_scheme_t { nss_scheme_method method; diff --git a/winsup/cygwin/uinfo.cc b/winsup/cygwin/uinfo.cc index 30df6db6d8a3..baa670478dfe 100644 --- a/winsup/cygwin/uinfo.cc +++ b/winsup/cygwin/uinfo.cc @@ -733,6 +733,8 @@ cygheap_pwdgrp::nss_init_line (const char *line) scheme[idx].method =3D NSS_SCHEME_UNIX; else if (NSS_CMP ("desc")) scheme[idx].method =3D NSS_SCHEME_DESC; + else if (NSS_CMP ("env")) + scheme[idx].method =3D NSS_SCHEME_ENV; else if (NSS_NCMP ("/")) { const char *e =3D c + strcspn (c, " \t"); @@ -921,6 +923,42 @@ fetch_from_path (cyg_ldap *pldap, PUSER_INFO_3 ui, cyg= psid &sid, PCWSTR str, return ret; } =20 +static char * +fetch_home_env (void) +{ + /* If `HOME` is set, prefer it */ + const char *home =3D getenv ("HOME"); + if (home) + return strdup (home); + + /* If `HOME` is unset, fall back to `HOMEDRIVE``HOMEPATH` + (without a directory separator, as `HOMEPATH` starts with one). */ + const char *home_drive =3D getenv ("HOMEDRIVE"); + if (home_drive) + { + const char *home_path =3D getenv ("HOMEPATH"); + if (home_path) + { + tmp_pathbuf tp; + char *p =3D tp.c_get (), *q; + + // concatenate HOMEDRIVE and HOMEPATH + q =3D stpncpy (p, home_drive, NT_MAX_PATH); + strlcpy (q, home_path, NT_MAX_PATH - (q - p)); + return (char *) cygwin_create_path (CCP_WIN_A_TO_POSIX, p); + } + } + + /* If neither `HOME` nor `HOMEDRIVE``HOMEPATH` are set, fall back + to `USERPROFILE`; In corporate setups, this might point to a + disconnected network share, hence this is the last fall back. */ + home =3D getenv ("USERPROFILE"); + if (home) + return (char *) cygwin_create_path (CCP_WIN_A_TO_POSIX, home); + + return NULL; +} + char * cygheap_pwdgrp::get_home (cyg_ldap *pldap, cygpsid &sid, PCWSTR dom, PCWSTR dnsdomain, PCWSTR name, bool full_qualified) @@ -980,6 +1018,10 @@ cygheap_pwdgrp::get_home (cyg_ldap *pldap, cygpsid &s= id, PCWSTR dom, } } break; + case NSS_SCHEME_ENV: + if (RtlEqualSid (sid, cygheap->user.sid ())) + home =3D fetch_home_env (); + break; } } return home; @@ -1012,6 +1054,10 @@ cygheap_pwdgrp::get_home (PUSER_INFO_3 ui, cygpsid &= sid, PCWSTR dom, home =3D fetch_from_path (NULL, ui, sid, home_scheme[idx].attrib, dom, NULL, name, full_qualified); break; + case NSS_SCHEME_ENV: + if (RtlEqualSid (sid, cygheap->user.sid ())) + home =3D fetch_home_env (); + break; } } return home; @@ -1031,6 +1077,7 @@ cygheap_pwdgrp::get_shell (cyg_ldap *pldap, cygpsid &= sid, PCWSTR dom, case NSS_SCHEME_FALLBACK: return NULL; case NSS_SCHEME_WINDOWS: + case NSS_SCHEME_ENV: break; case NSS_SCHEME_CYGWIN: if (pldap->fetch_ad_account (sid, false, dnsdomain)) @@ -1095,6 +1142,7 @@ cygheap_pwdgrp::get_shell (PUSER_INFO_3 ui, cygpsid &= sid, PCWSTR dom, case NSS_SCHEME_CYGWIN: case NSS_SCHEME_UNIX: case NSS_SCHEME_FREEATTR: + case NSS_SCHEME_ENV: break; case NSS_SCHEME_DESC: if (ui) @@ -1176,6 +1224,8 @@ cygheap_pwdgrp::get_gecos (cyg_ldap *pldap, cygpsid &= sid, PCWSTR dom, sys_wcstombs_alloc (&gecos, HEAP_NOTHEAP, val); } break; + case NSS_SCHEME_ENV: + break; } } if (gecos) @@ -1202,6 +1252,7 @@ cygheap_pwdgrp::get_gecos (PUSER_INFO_3 ui, cygpsid &= sid, PCWSTR dom, case NSS_SCHEME_CYGWIN: case NSS_SCHEME_UNIX: case NSS_SCHEME_FREEATTR: + case NSS_SCHEME_ENV: break; case NSS_SCHEME_DESC: if (ui) diff --git a/winsup/doc/ntsec.xml b/winsup/doc/ntsec.xml index c6871ecf051e..1678ff65753b 100644 --- a/winsup/doc/ntsec.xml +++ b/winsup/doc/ntsec.xml @@ -1203,6 +1203,17 @@ schemata are the following: See for a more detailed description. + + env + Derives the home directory of the current user from the + environment variable HOME (falling back to + HOMEDRIVE\HOMEPATH and + USERPROFILE, in that order). This is faster + than the windows schema at the + expense of determining only the current user's home directory + correctly. This schema is skipped for any other account. + + =20 @@ -1335,6 +1346,17 @@ of each schema when used with db_home: See for a detailed description. + + env + Derives the home directory of the current user from the + environment variable HOME (falling back to + HOMEDRIVE\HOMEPATH and + USERPROFILE, in that order). This is faster + than the windows schema at the + expense of determining only the current user's home directory + correctly. This schema is skipped for any other account. + + @ad_attribute AD only: The user's home directory is set to the path given