Qt/QML edition

dependencies/libarchive-3.4.2/examples/untar.c

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+/*
+ * This file is in the public domain.
+ * Use it as you wish.
+ */
+
+/*
+ * This is a compact tar extraction program using libarchive whose
+ * primary goal is small executable size.  Statically linked, it can
+ * be very small, depending in large part on how cleanly factored your
+ * system libraries are.  Note that this uses the standard libarchive,
+ * without any special recompilation.  The only functional concession
+ * is that this program uses the uid/gid from the archive instead of
+ * doing uname/gname lookups.  (Add a call to
+ * archive_write_disk_set_standard_lookup() to enable uname/gname
+ * lookups, but be aware that this can add 500k or more to a static
+ * executable, depending on the system libraries, since user/group
+ * lookups frequently pull in password, YP/LDAP, networking, and DNS
+ * resolver libraries.)
+ *
+ * To build:
+ * $ gcc -static -Wall -o untar untar.c -larchive
+ * $ strip untar
+ *
+ * NOTE: On some systems, you may need to add additional flags
+ * to ensure that untar.c is compiled the same way as libarchive
+ * was compiled.  In particular, Linux users will probably
+ * have to add -D_FILE_OFFSET_BITS=64 to the command line above.
+ *
+ * For fun, statically compile the following simple hello.c program
+ * using the same flags as for untar and compare the size:
+ *
+ * #include <stdio.h>
+ * int main(int argc, char **argv) {
+ *    printf("hello, world\n");
+ *    return(0);
+ * }
+ *
+ * You may be even more surprised by the compiled size of true.c listed here:
+ *
+ * int main(int argc, char **argv) {
+ *    return (0);
+ * }
+ *
+ * On a slightly customized FreeBSD 5 system that I used around
+ * 2005, hello above compiled to 89k compared to untar of 69k.  So at
+ * that time, libarchive's tar reader and extract-to-disk routines
+ * compiled to less code than printf().
+ *
+ * On my FreeBSD development system today (August, 2009):
+ *  hello: 195024 bytes
+ *  true: 194912 bytes
+ *  untar: 259924 bytes
+ */
+
+#include <sys/types.h>
+
+#include <sys/stat.h>
+
+#include <archive.h>
+#include <archive_entry.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static void	errmsg(const char *);
+static void	extract(const char *filename, int do_extract, int flags);
+static void	fail(const char *, const char *, int);
+static int	copy_data(struct archive *, struct archive *);
+static void	msg(const char *);
+static void	usage(void);
+static void	warn(const char *, const char *);
+
+static int verbose = 0;
+
+int
+main(int argc, const char **argv)
+{
+	const char *filename = NULL;
+	int compress, flags, mode, opt;
+
+	(void)argc;
+	mode = 'x';
+	verbose = 0;
+	compress = '\0';
+	flags = ARCHIVE_EXTRACT_TIME;
+
+	/* Among other sins, getopt(3) pulls in printf(3). */
+	while (*++argv != NULL && **argv == '-') {
+		const char *p = *argv + 1;
+
+		while ((opt = *p++) != '\0') {
+			switch (opt) {
+			case 'f':
+				if (*p != '\0')
+					filename = p;
+				else
+					filename = *++argv;
+				p += strlen(p);
+				break;
+			case 'p':
+				flags |= ARCHIVE_EXTRACT_PERM;
+				flags |= ARCHIVE_EXTRACT_ACL;
+				flags |= ARCHIVE_EXTRACT_FFLAGS;
+				break;
+			case 't':
+				mode = opt;
+				break;
+			case 'v':
+				verbose++;
+				break;
+			case 'x':
+				mode = opt;
+				break;
+			default:
+				usage();
+			}
+		}
+	}
+
+	switch (mode) {
+	case 't':
+		extract(filename, 0, flags);
+		break;
+	case 'x':
+		extract(filename, 1, flags);
+		break;
+	}
+
+	return (0);
+}
+
+
+static void
+extract(const char *filename, int do_extract, int flags)
+{
+	struct archive *a;
+	struct archive *ext;
+	struct archive_entry *entry;
+	int r;
+
+	a = archive_read_new();
+	ext = archive_write_disk_new();
+	archive_write_disk_set_options(ext, flags);
+	/*
+	 * Note: archive_write_disk_set_standard_lookup() is useful
+	 * here, but it requires library routines that can add 500k or
+	 * more to a static executable.
+	 */
+	archive_read_support_format_tar(a);
+	/*
+	 * On my system, enabling other archive formats adds 20k-30k
+	 * each.  Enabling gzip decompression adds about 20k.
+	 * Enabling bzip2 is more expensive because the libbz2 library
+	 * isn't very well factored.
+	 */
+	if (filename != NULL && strcmp(filename, "-") == 0)
+		filename = NULL;
+	if ((r = archive_read_open_filename(a, filename, 10240)))
+		fail("archive_read_open_filename()",
+		    archive_error_string(a), r);
+	for (;;) {
+		r = archive_read_next_header(a, &entry);
+		if (r == ARCHIVE_EOF)
+			break;
+		if (r != ARCHIVE_OK)
+			fail("archive_read_next_header()",
+			    archive_error_string(a), 1);
+		if (verbose && do_extract)
+			msg("x ");
+		if (verbose || !do_extract)
+			msg(archive_entry_pathname(entry));
+		if (do_extract) {
+			r = archive_write_header(ext, entry);
+			if (r != ARCHIVE_OK)
+				warn("archive_write_header()",
+				    archive_error_string(ext));
+			else {
+				copy_data(a, ext);
+				r = archive_write_finish_entry(ext);
+				if (r != ARCHIVE_OK)
+					fail("archive_write_finish_entry()",
+					    archive_error_string(ext), 1);
+			}
+
+		}
+		if (verbose || !do_extract)
+			msg("\n");
+	}
+	archive_read_close(a);
+	archive_read_free(a);
+	
+	archive_write_close(ext);
+  	archive_write_free(ext);
+	exit(0);
+}
+
+static int
+copy_data(struct archive *ar, struct archive *aw)
+{
+	int r;
+	const void *buff;
+	size_t size;
+#if ARCHIVE_VERSION_NUMBER >= 3000000
+	int64_t offset;
+#else
+	off_t offset;
+#endif
+
+	for (;;) {
+		r = archive_read_data_block(ar, &buff, &size, &offset);
+		if (r == ARCHIVE_EOF)
+			return (ARCHIVE_OK);
+		if (r != ARCHIVE_OK)
+			return (r);
+		r = archive_write_data_block(aw, buff, size, offset);
+		if (r != ARCHIVE_OK) {
+			warn("archive_write_data_block()",
+			    archive_error_string(aw));
+			return (r);
+		}
+	}
+}
+
+/*
+ * These reporting functions use low-level I/O; on some systems, this
+ * is a significant code reduction.  Of course, on many server and
+ * desktop operating systems, malloc() and even crt rely on printf(),
+ * which in turn pulls in most of the rest of stdio, so this is not an
+ * optimization at all there.  (If you're going to pay 100k or more
+ * for printf() anyway, you may as well use it!)
+ */
+static void
+msg(const char *m)
+{
+	write(1, m, strlen(m));
+}
+
+static void
+errmsg(const char *m)
+{
+	write(2, m, strlen(m));
+}
+
+static void
+warn(const char *f, const char *m)
+{
+	errmsg(f);
+	errmsg(" failed: ");
+	errmsg(m);
+	errmsg("\n");
+}
+
+static void
+fail(const char *f, const char *m, int r)
+{
+	warn(f, m);
+	exit(r);
+}
+
+static void
+usage(void)
+{
+	const char *m = "Usage: untar [-tvx] [-f file] [file]\n";
+	errmsg(m);
+	exit(1);
+}