ftpd: code shrink

function                                             old     new   delta
MMU:
handle_dir_common                                    354     338     -16
NOMMU:
ftpd_main                                           2437    2442      +5
popen_ls                                             201     174     -27

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 30 insertions, 21 deletions

diff --git a/networking/ftpd.c b/networking/ftpd.c
index df8188cba..4e9f65ca3 100644
--- a/networking/ftpd.c
+++ b/networking/ftpd.c
@@ -616,18 +616,22 @@ handle_retr(void)
 static int
 popen_ls(const char *opt)
 {
-        char *cwd;
-        const char *argv[] = {
-                        "ftpd",
-                        opt,
-                        BB_MMU ? "--" : NULL,
-                        G.ftp_arg,
-                        NULL
-        };
+        const char *argv[5];
         struct fd_pair outfd;
         pid_t pid;
 
-        cwd = xrealloc_getcwd_or_warn(NULL);
+        argv[0] = "ftpd";
+        argv[1] = opt; /* "-l" or "-1" */
+#if BB_MMU
+        argv[2] = "--";
+#else
+        /* NOMMU ftpd ls helper chdirs to argv[2],
+         * preventing peer from seeing real root. */
+        argv[2] = xrealloc_getcwd_or_warn(NULL);
+#endif
+        argv[3] = G.ftp_arg;
+        argv[4] = NULL;
+
         xpiped_pair(outfd);
 
         /*fflush_all(); - so far we dont use stdio on output */
@@ -638,9 +642,14 @@ popen_ls(const char *opt)
         if (pid == 0) {
                 /* child */
 #if !BB_MMU
+                /* On NOMMU, we want to execute a child - copy of ourself.
+                 * In chroot we usually can't do it. Thus we chdir
+                 * out of the chroot back to original root,
+                 * and (see later below) execute bb_busybox_exec_path
+                 * relative to current directory */
                 if (fchdir(G.root_fd) != 0)
                         _exit(127);
-                close(G.root_fd);
+                /*close(G.root_fd); - close_on_exec_on() took care of this */
 #endif
                 /* NB: close _first_, then move fd! */
                 close(outfd.rd);
@@ -651,25 +660,23 @@ popen_ls(const char *opt)
                  * ls won't read it anyway */
                 close(STDIN_FILENO);
                 dup(STDOUT_FILENO); /* copy will become STDIN_FILENO */
-#if !BB_MMU
-                /* ftpd ls helper chdirs to argv[2],
-                 * preventing peer from seeing real root we are in now
-                 */
-                argv[2] = cwd;
+#if BB_MMU
+                /* memset(&G, 0, sizeof(G)); - ls_main does it */
+                exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv));
+#else
                 /* + 1: we must use relative path here if in chroot.
                  * For example, execv("/proc/self/exe") will fail, since
                  * it looks for "/proc/self/exe" _relative to chroot!_ */
                 execv(bb_busybox_exec_path + 1, (char**) argv);
                 _exit(127);
-#else
-                /* memset(&G, 0, sizeof(G)); - ls_main does it */
-                exit(ls_main(ARRAY_SIZE(argv) - 1, (char**) argv));
 #endif
         }
 
         /* parent */
         close(outfd.wr);
-        free(cwd);
+#if !BB_MMU
+        free((char*)argv[2]);
+#endif
         return outfd.rd;
 }
 
@@ -1108,8 +1115,9 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
         opts = getopt32(argv, "l1vS" IF_FEATURE_FTP_WRITE("w") "t:T:", &G.timeout, &abs_timeout, &G.verbose, &verbose_S);
         if (opts & (OPT_l|OPT_1)) {
                 /* Our secret backdoor to ls */
-/* TODO: pass -n too? */
-/* --group-directories-first would be nice, but ls don't do that yet */
+/* TODO: pass -n? It prevents user/group resolution, whicj may not work in chroot anyway */
+/* TODO: pass -A? It shows dot files */
+/* TODO: pass --group-directories-first? would be nice, but ls don't do that yet */
                 xchdir(argv[2]);
                 argv[2] = (char*)"--";
                 /* memset(&G, 0, sizeof(G)); - ls_main does it */
@@ -1151,6 +1159,7 @@ int ftpd_main(int argc UNUSED_PARAM, char **argv)
 
 #if !BB_MMU
         G.root_fd = xopen("/", O_RDONLY | O_DIRECTORY);
+        close_on_exec_on(G.root_fd);
 #endif
 
         if (argv[optind]) {