add libbb/appletlib.c

1 files changed, 139 insertions, 0 deletions

diff --git a/libbb/appletlib.c b/libbb/appletlib.c
new file mode 100644
index 000000000..626c25a8f
--- /dev/null
+++ b/libbb/appletlib.c
@@ -0,0 +1,139 @@
+/* vi: set sw=4 ts=4: */
+/*
+ * Support for main() which needs to end up in libbusybox, not busybox,
+ * if one builds libbusybox.
+ *
+ * Copyright (C) 2007 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2, see file License in this tarball for details.
+ */
+
+#include <assert.h>
+#include "busybox.h"
+
+
+/* Declare <applet>_main() */
+#define PROTOTYPES
+#include "applets.h"
+#undef PROTOTYPES
+
+#if ENABLE_SHOW_USAGE && !ENABLE_FEATURE_COMPRESS_USAGE
+/* Define usage_messages[] */
+static const char usage_messages[] ALIGN1 = ""
+#define MAKE_USAGE
+#include "usage.h"
+#include "applets.h"
+;
+#undef MAKE_USAGE
+#else
+#define usage_messages 0
+#endif /* SHOW_USAGE */
+
+/* Define struct bb_applet applets[] */
+#include "applets.h"
+
+#if ENABLE_FEATURE_SH_STANDALONE
+/* -1 because last entry is NULL */
+const unsigned short NUM_APPLETS = ARRAY_SIZE(applets) - 1;
+#endif
+
+
+#if ENABLE_FEATURE_COMPRESS_USAGE
+
+#include "usage_compressed.h"
+#include "unarchive.h"
+
+static const char *unpack_usage_messages(void)
+{
+	char *outbuf = NULL;
+	bunzip_data *bd;
+	int i;
+
+	i = start_bunzip(&bd,
+			/* src_fd: */ -1,
+			/* inbuf:  */ packed_usage,
+			/* len:    */ sizeof(packed_usage));
+	/* read_bunzip can longjmp to start_bunzip, and ultimately
+	 * end up here with i != 0 on read data errors! Not trivial */
+	if (!i) {
+		/* Cannot use xmalloc: will leak bd in NOFORK case! */
+		outbuf = malloc_or_warn(SIZEOF_usage_messages);
+		if (outbuf)
+			read_bunzip(bd, outbuf, SIZEOF_usage_messages);
+	}
+	dealloc_bunzip(bd);
+	return outbuf;
+}
+#define dealloc_usage_messages(s) free(s)
+
+#else
+
+#define unpack_usage_messages() usage_messages
+#define dealloc_usage_messages(s) ((void)(s))
+
+#endif /* FEATURE_COMPRESS_USAGE */
+
+
+void bb_show_usage(void)
+{
+	if (ENABLE_SHOW_USAGE) {
+		const char *format_string;
+		const char *p;
+		const char *usage_string = p = unpack_usage_messages();
+		const struct bb_applet *ap = find_applet_by_name(applet_name);
+		int i;
+
+		if (!ap) /* never happens, paranoia */
+			xfunc_die();
+
+		i = ap - applets;
+		while (i) {
+			while (*p++) continue;
+			i--;
+		}
+
+		fprintf(stderr, "%s multi-call binary\n", bb_banner);
+		format_string = "\nUsage: %s %s\n\n";
+		if (*p == '\b')
+			format_string = "\nNo help available.\n\n";
+		fprintf(stderr, format_string, applet_name, p);
+		dealloc_usage_messages((char*)usage_string);
+	}
+	xfunc_die();
+}
+
+
+static int applet_name_compare(const void *name, const void *vapplet)
+{
+	const struct bb_applet *applet = vapplet;
+
+	return strcmp(name, applet->name);
+}
+
+const struct bb_applet *find_applet_by_name(const char *name)
+{
+	/* Do a binary search to find the applet entry given the name. */
+	return bsearch(name, applets, ARRAY_SIZE(applets)-1, sizeof(applets[0]),
+				applet_name_compare);
+}
+
+
+#ifdef __GLIBC__
+/* Make it reside in R/W memory: */
+int *const bb_errno __attribute__ ((section (".data")));
+#endif
+
+void bbox_prepare_main(char **argv)
+{
+#ifdef __GLIBC__
+	(*(int **)&bb_errno) = __errno_location();
+#endif
+
+	/* Set locale for everybody except 'init' */
+	if (ENABLE_LOCALE_SUPPORT && getpid() != 1)
+		setlocale(LC_ALL, "");
+
+	/* Redundant for busybox, but needed for individual applets */
+        if (argv[1] && strcmp(argv[1], "--help") == 0)
+		bb_show_usage();
+}