When execvp reports EACCES, it can be one of two things:
1. We found a file to execute, but did not have
permissions to do so.
2. We did not have permissions to look in some directory
in the $PATH.
In the former case, we want to consider this a
permissions problem and report it to the user as such (since
getting this for something like "git foo" is likely a
configuration error).
In the latter case, there is a good chance that the
inaccessible directory does not contain anything of
interest. Reporting "permission denied" is confusing to the
user (and prevents our usual "did you mean...?" lookup). It
also prevents git from trying alias lookup, since we do so
only when an external command does not exist (not when it
exists but has an error).
This patch detects EACCES from execvp, checks whether we are
in case (2), and if so converts errno to ENOENT. This
behavior matches that of "bash" (but not of simpler shells
that use execvp more directly, like "dash").
Test stolen from Junio.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In git versions starting at v1.7.5-rc0~29^2 until v1.7.5-rc3~2 (Revert
"run-command: prettify -D_FORTIFY_SOURCE workaround", 2011-04-18)
fixed it, the run_command facility would write a truncated error
message when the command is present but cannot be executed for some
other reason. For example, if I add a 'hello' command to git:
$ echo 'echo hello' >git-hello
$ chmod +x git-hello
$ PATH=.:$PATH git hello
hello
and make it non-executable, this is what I normally get:
$ chmod -x git-hello
$ git hello
fatal: cannot exec 'git-hello': Permission denied
But with the problematic versions, we get disturbing output:
$ PATH=.:$PATH git hello
fatal: $
Add some tests to make sure it doesn't happen again.
The hello-script used in these tests uses cat instead of echo because
on Windows the bash spawned by git converts LF to CRLF in text written
by echo while the bash running tests does not, causing the test to
fail if "echo" is used. Thanks to Hannes for noticing.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Improved-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Previously, failures during execvp could be detected only by
finish_command. However, in some situations it is beneficial for the
parent process to know earlier that the child process will not run.
The idea to use a pipe to signal failures to the parent process and
the test case were lifted from patches by Ilari Liusvaara.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
