• Jeff King's avatar
    common-main: stop munging argv[0] path · 6854a8f5
    Jeff King authored
    Since 650c4492 (common-main: call git_extract_argv0_path(),
    2016-07-01), the argv[0] that is seen in cmd_main() of
    individual programs is always the basename of the
    executable, as common-main strips off the full path. This
    can produce confusing results for git-daemon, which wants to
    re-exec itself.
    
    For instance, if the program was originally run as
    "/usr/lib/git/git-daemon", it will try just re-execing
    "git-daemon", which will find the first instance in $PATH.
    If git's exec-path has not been prepended to $PATH, we may
    find the git-daemon from a different version (or no
    git-daemon at all).
    
    Normally this isn't a problem. Git commands are run as "git
    daemon", the git wrapper puts the exec-path at the front of
    $PATH, and argv[0] is already "daemon" anyway. But running
    git-daemon via its full exec-path, while not really a
    recommended method, did work prior to 650c4492. Let's make
    it work again.
    
    The real goal of 650c4492 was not to munge argv[0], but to
    reliably set the argv0_path global. The only reason it
    munges at all is that one caller, the git.c wrapper,
    piggy-backed on that computation to find the command
    basename.  Instead, let's leave argv[0] untouched in
    common-main, and have git.c do its own basename computation.
    
    While we're at it, let's drop the return value from
    git_extract_argv0_path(). It was only ever used in this one
    callsite, and its dual purposes is what led to this
    confusion in the first place.
    
    Note that by changing the interface, the compiler can
    confirm for us that there are no other callers storing the
    return value. But the compiler can't tell us whether any of
    the cmd_main() functions (besides git.c) were relying on the
    basename munging. However, we can observe that prior to
    650c4492, no other cmd_main() functions did that munging,
    and no new cmd_main() functions have been introduced since
    then. So we can't be regressing any of those cases.
    Signed-off-by: default avatarJeff King <peff@peff.net>
    Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
    6854a8f5
common-main.c 1.08 KB