33f9dc08e
Denys Vlasenko
2010-01-17
Subject
ftpd: code shrink
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networking/ftpd.c+30 -21
| @@ -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]) { | |