diff options
| -rw-r--r-- | shell/ash.c | 31 |
1 files changed, 11 insertions, 20 deletions
diff --git a/shell/ash.c b/shell/ash.c index 8bf02e6..133b2d4 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -7467,13 +7467,7 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char ** #else execve(cmd, argv, envp); #endif - 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) { + if (cmd != (char*) bb_busybox_exec_path && 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 @@ -7490,19 +7484,13 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char ** * message and exit code 126. For one, this prevents attempts * to interpret foreign ELF binaries as shell scripts. */ - char **ap; - char **new; - - for (ap = argv; *ap; ap++) - continue; - new = ckmalloc((ap - argv + 2) * sizeof(new[0])); - new[0] = (char*) "ash"; - new[1] = cmd; - ap = new + 2; - while ((*ap++ = *++argv) != NULL) - continue; + argv[0] = cmd; cmd = (char*) bb_busybox_exec_path; - argv = new; + /* NB: this is only possible because all callers of shellexec() + * ensure that the argv[-1] slot exists! + */ + argv--; + argv[0] = (char*) "ash"; goto repeat; } } @@ -7510,6 +7498,7 @@ tryexec(IF_FEATURE_SH_STANDALONE(int applet_no,) char *cmd, char **argv, char ** /* * Exec a program. Never returns. If you change this routine, you may * have to change the find_command routine as well. + * argv[-1] must exist and be writable! See tryexec() for why. */ static void shellexec(char **, const char *, int) NORETURN; static void @@ -9415,7 +9404,9 @@ evalcommand(union node *cmd, int flags) argc++; } - argv = nargv = stalloc(sizeof(char *) * (argc + 1)); + /* Reserve one extra spot at the front for shellexec. */ + nargv = stalloc(sizeof(char *) * (argc + 2)); + argv = ++nargv; for (sp = arglist.list; sp; sp = sp->next) { TRACE(("evalcommand arg: %s\n", sp->text)); *nargv++ = sp->text; |