add-shell, remove-shell: new applets

function                                             old     new   delta
add_remove_shell_main                                  -     259    +259
packed_usage                                       27408   27438     +30
applet_names                                        2326    2349     +23
applet_main                                         1364    1372      +8
applet_nameofs                                       682     686      +4
run_applet_and_exit                                  700     703      +3
dont_add                                               -       2      +2
applet_install_loc                                   171     172      +1
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 6/0 up/down: 330/0)             Total: 330 bytes

Signed-off-by: Alexander Shishkin <virtuoso@slind.org>
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>

1 files changed, 127 insertions, 0 deletions

diff --git a/loginutils/add-remove-shell.c b/loginutils/add-remove-shell.c
new file mode 100644
index 000000000..986fe57c5
--- /dev/null
+++ b/loginutils/add-remove-shell.c
@@ -0,0 +1,127 @@
+/*
+ * add-shell and remove-shell implementation for busybox
+ *
+ * Copyright (C) 2010 Nokia Corporation. All rights reserved.
+ * Written by Alexander Shishkin <virtuoso@slind.org>
+ *
+ * Licensed under GPLv2 or later, see the LICENSE file in this source tree
+ * for details.
+ */
+
+//applet:IF_ADD_SHELL(   APPLET_ODDNAME(add-shell   , add_remove_shell, _BB_DIR_USR_BIN, _BB_SUID_DROP, add_shell   ))
+//applet:IF_REMOVE_SHELL(APPLET_ODDNAME(remove-shell, add_remove_shell, _BB_DIR_USR_BIN, _BB_SUID_DROP, remove_shell))
+
+//kbuild:lib-$(CONFIG_ADD_SHELL)    += add-remove-shell.o
+//kbuild:lib-$(CONFIG_REMOVE_SHELL) += add-remove-shell.o
+
+//config:config ADD_SHELL
+//config:       bool "add-shell"
+//config:       default y if DESKTOP
+//config:       help
+//config:         Add shells to /etc/shells.
+//config:
+//config:config REMOVE_SHELL
+//config:       bool "remove-shell"
+//config:       default y if DESKTOP
+//config:       help
+//config:         Remove shells from /etc/shells.
+
+//usage:#define add_shell_trivial_usage
+//usage:       "SHELL..."
+//usage:#define add_shell_full_usage "\n\n"
+//usage:       "Add SHELLs to /etc/shells"
+
+//usage:#define remove_shell_trivial_usage
+//usage:       "SHELL..."
+//usage:#define remove_shell_full_usage "\n\n"
+//usage:       "Remove SHELLs from /etc/shells"
+
+#include "libbb.h"
+
+#define SHELLS_FILE "/etc/shells"
+
+#define REMOVE_SHELL (ENABLE_REMOVE_SHELL && (!ENABLE_ADD_SHELL || applet_name[0] == 'r'))
+#define ADD_SHELL    (ENABLE_ADD_SHELL && (!ENABLE_REMOVE_SHELL || applet_name[0] == 'a'))
+
+/* NB: we use the _address_, not the value, of this string
+ * as a "special value of pointer" in the code.
+ */
+static const char dont_add[] ALIGN1 = "\n";
+
+int add_remove_shell_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int add_remove_shell_main(int argc UNUSED_PARAM, char **argv)
+{
+	FILE *orig_fp;
+	char *orig_fn;
+	char *new_fn;
+
+	argv++;
+
+	orig_fn = xmalloc_follow_symlinks(SHELLS_FILE);
+	if (!orig_fn)
+		return EXIT_FAILURE;
+	orig_fp = fopen_for_read(orig_fn);
+
+	new_fn = xasprintf("%s.tmp", orig_fn);
+	xmove_fd(xopen(new_fn, O_WRONLY | O_CREAT | O_EXCL), STDOUT_FILENO);
+
+	/* TODO:
+	struct stat sb;
+	fstat(fileno(orig_fp), &sb);
+	xfchown(STDOUT_FILENO, sb.st_uid, sb.st_gid);
+	xfchmod(STDOUT_FILENO, sb.st_mode);
+	*/
+
+	if (orig_fp) {
+		/* Copy old file, possibly skipping removed shell names */
+		char *line;
+		while ((line = xmalloc_fgetline(orig_fp)) != NULL) {
+			char **cpp = argv;
+			while (*cpp) {
+				if (strcmp(*cpp, line) == 0) {
+					/* Old file has this shell name */
+					if (REMOVE_SHELL) {
+						/* we are remove-shell */
+						/* delete this name by not copying it */
+						goto next_line;
+					}
+					/* we are add-shell */
+					/* mark this name as "do not add" */
+					*cpp = (char*)dont_add;
+				}
+				cpp++;
+			}
+			/* copy shell name from old to new file */
+			printf("%s\n", line);
+ next_line:
+			free(line);
+		}
+		if (ENABLE_FEATURE_CLEAN_UP)
+			fclose(orig_fp);
+	}
+
+	if (ADD_SHELL) {
+		char **cpp = argv;
+		while (*cpp) {
+			if (*cpp != dont_add)
+				printf("%s\n", *cpp);
+			cpp++;
+		}
+	}
+
+	/* Ensure we wrote out everything */
+	if (fclose(stdout) != 0) {
+		xunlink(new_fn);
+		bb_perror_msg_and_die("%s: write error", new_fn);
+	}
+
+	/* Small hole: if rename fails, /etc/shells.tmp is not removed */
+	xrename(new_fn, orig_fn);
+
+	if (ENABLE_FEATURE_CLEAN_UP) {
+		free(orig_fn);
+		free(new_fn);
+	}
+
+	return EXIT_SUCCESS;
+}