execve.2: Since Linux 2.6.28, recursive script interpretation is supported

Reported-by: Valery Reznic <valery_reznic@yahoo.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

1 files changed, 16 insertions, 2 deletions

diff --git a/man2/execve.2 b/man2/execve.2
index 73657d1331..4a57b57a6c 100644
--- a/man2/execve.2
+++ b/man2/execve.2
@@ -273,8 +273,7 @@ permission enabled and whose first line is of the form:
 
 The
 .I interpreter
-must be a valid pathname for an
-executable which is not itself a script.
+must be a valid pathname for an executable file.
 If the
 .I filename
 argument of
@@ -302,6 +301,13 @@ For portable use,
 .I optional-arg
 should either be absent, or be specified as a single word (i.e., it
 should not contain white space); see NOTES below.
+
+Since Linux 2.6.28,
+.\" commit bf2a9a39639b8b51377905397a5005f444e9a892
+the kernel permits the interpreter of a script to itself be a script.
+This permission is recursive, up to a limit of four recursions,
+so that the interpreter may be a script which is interpreted by script,
+and so on.
 .SS Limits on size of arguments and environment
 Most UNIX implementations impose some limit on the total size
 of the command-line argument
@@ -426,6 +432,14 @@ Too many symbolic links were encountered in resolving
 .I filename
 or the name of a script or ELF interpreter.
 .TP
+.B ELOOP
+The maximum recursion limit was reached during recursive script
+interpretation (see "Interpreter scripts", above).
+Before Linux 3.8,
+.\" commit d740269867021faf4ce38a449353d2b986c34a67
+the error produced for this case was
+.BR ENOEXEC .
+.TP
 .B EMFILE
 The per-process limit on the number of open file descriptors has been reached.
 .TP