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Diffstat (limited to 'Utilities/cmlibarchive/examples/untar.c')
| -rw-r--r-- | Utilities/cmlibarchive/examples/untar.c | 262 |
1 files changed, 0 insertions, 262 deletions
diff --git a/Utilities/cmlibarchive/examples/untar.c b/Utilities/cmlibarchive/examples/untar.c deleted file mode 100644 index f0d54c2..0000000 --- a/Utilities/cmlibarchive/examples/untar.c +++ /dev/null @@ -1,262 +0,0 @@ -/* - * 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> -__FBSDID("$FreeBSD$"); - -#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_file(a, filename, 10240))) - fail("archive_read_open_file()", - 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_finish(a); - exit(0); -} - -static int -copy_data(struct archive *ar, struct archive *aw) -{ - int r; - const void *buff; - size_t size; - off_t offset; - - 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); -} |