There are three reasons to use the getcwd module: 1. POSIX says getcwd(NULL,0) is unspecified, but most modern systems behave like glibc (anyone know which systems don't malloc()? Even Solaris 8 man page says that it mallocs, and mingw mallocs).
2. Linux still has issues with super-deep directories, where we can work around some (but not all) of those issues by iterating over readdir() calls to progressively longer ../../ sequences (or more efficiently, rely on openat() to speed that up). 3. Old systems didn't have getcwd(). But none in the latest matrix. The first fix is the most important - I've audited and found several bugs where libvirt wasn't correctly using a POSIX-compliant ERANGE/realloc() loop in all getcwd() clients, and it is certainly much more convenient to just rely on the native version to malloc (or make a replacement that does it for the few broken systems). The second fix drags in lots of code, including GPL-only stuff. Letting software fail rather than trying to handle long paths may be better off, for software that isn't trying to recover from such a directory (or put another way, GPL coreutils must continue to be as robust as possible, but LPGL libvirt could reliably get by with reliably passing errors back to the caller if used from such a deep directory). The third is a candidate for our recent obsoletion cleanups. But since we already handle it as part of 2, I didn't try very hard. Here's my take at a series to separate the issue 1 into a lighter-weight module. Any thoughts before it is worth committing? Eric Blake (3): getcwd: consolidate m4 files getcwd-lgpl: new module getcwd: enhance tests ChangeLog | 24 +++ MODULES.html.sh | 1 + doc/posix-functions/getcwd.texi | 13 +- lib/getcwd.c | 208 +++++++++++++++++---------- m4/getcwd-abort-bug.m4 | 106 ------------- m4/getcwd-path-max.m4 | 188 ----------------------- m4/getcwd.m4 | 313 ++++++++++++++++++++++++++++++++++++++- modules/getcwd | 2 - modules/getcwd-lgpl | 25 +++ modules/getcwd-lgpl-tests | 12 ++ modules/getcwd-tests | 6 +- tests/test-getcwd-lgpl.c | 76 ++++++++++ tests/test-getcwd.c | 220 ++++++++++++++++++++++----- 13 files changed, 776 insertions(+), 418 deletions(-) delete mode 100644 m4/getcwd-abort-bug.m4 delete mode 100644 m4/getcwd-path-max.m4 create mode 100644 modules/getcwd-lgpl create mode 100644 modules/getcwd-lgpl-tests create mode 100644 tests/test-getcwd-lgpl.c -- 1.7.4.4
