[git commit master 1/1] ash: fix execution of shell scripts without shebang
Denys Vlasenko
vda.linux at googlemail.com
Mon Mar 7 11:02:40 UTC 2011
commit: http://git.busybox.net/busybox/commit/?id=aefe1c260ec5aa691e8b6f773c7fa393bfad0f7b
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
We were assuming #!/bin/sh, whereas we had to simply re-enter ash.
Signed-off-by: Denys Vlasenko <vda.linux at googlemail.com>
---
shell/ash.c | 29 +++++++++++++++++++----------
1 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/shell/ash.c b/shell/ash.c
index c3c9536..09db046 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -7396,8 +7396,6 @@ static int builtinloc = -1; /* index in path of %builtin, or -1 */
static void
tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char **envp)
{
- int repeated = 0;
-
#if ENABLE_FEATURE_SH_STANDALONE
if (applet_no >= 0) {
if (APPLET_IS_NOEXEC(applet_no)) {
@@ -7421,25 +7419,36 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char **
#else
execve(cmd, argv, envp);
#endif
- if (repeated) {
+ if (cmd == (char*) bb_busybox_exec_path) {
+ /* We already visited ENOEXEC branch below, don't do it again */
+//TODO: try execve(initial_argv0_of_shell, argv, envp) before giving up?
free(argv);
return;
}
if (errno == ENOEXEC) {
+ /* Run "cmd" as a shell script:
+ * http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html
+ * "If the execve() function fails with ENOEXEC, the shell
+ * shall execute a command equivalent to having a shell invoked
+ * with the command name as its first operand,
+ * with any remaining arguments passed to the new shell"
+ *
+ * That is, do not use $SHELL, user's shell, or /bin/sh;
+ * just call ourselves.
+ */
char **ap;
char **new;
for (ap = argv; *ap; ap++)
continue;
- ap = new = ckmalloc((ap - argv + 2) * sizeof(ap[0]));
- ap[1] = cmd;
- ap[0] = cmd = (char *)DEFAULT_SHELL;
- ap += 2;
- argv++;
- while ((*ap++ = *argv++) != NULL)
+ new = ckmalloc((ap - argv + 2) * sizeof(new[0]));
+ new[0] = (char*) "ash";
+ new[1] = cmd;
+ ap = new + 2;
+ while ((*ap++ = *++argv) != NULL)
continue;
+ cmd = (char*) bb_busybox_exec_path;
argv = new;
- repeated++;
goto repeat;
}
}
--
1.7.3.4
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