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-rw-r--r--third_party/git/archive-tar.c502
1 files changed, 502 insertions, 0 deletions
diff --git a/third_party/git/archive-tar.c b/third_party/git/archive-tar.c
new file mode 100644
index 000000000000..5a77701a15c2
--- /dev/null
+++ b/third_party/git/archive-tar.c
@@ -0,0 +1,502 @@
+/*
+ * Copyright (c) 2005, 2006 Rene Scharfe
+ */
+#include "cache.h"
+#include "config.h"
+#include "tar.h"
+#include "archive.h"
+#include "object-store.h"
+#include "streaming.h"
+#include "run-command.h"
+
+#define RECORDSIZE	(512)
+#define BLOCKSIZE	(RECORDSIZE * 20)
+
+static char block[BLOCKSIZE];
+static unsigned long offset;
+
+static int tar_umask = 002;
+
+static int write_tar_filter_archive(const struct archiver *ar,
+				    struct archiver_args *args);
+
+/*
+ * This is the max value that a ustar size header can specify, as it is fixed
+ * at 11 octal digits. POSIX specifies that we switch to extended headers at
+ * this size.
+ *
+ * Likewise for the mtime (which happens to use a buffer of the same size).
+ */
+#if ULONG_MAX == 0xFFFFFFFF
+#define USTAR_MAX_SIZE ULONG_MAX
+#else
+#define USTAR_MAX_SIZE 077777777777UL
+#endif
+#if TIME_MAX == 0xFFFFFFFF
+#define USTAR_MAX_MTIME TIME_MAX
+#else
+#define USTAR_MAX_MTIME 077777777777ULL
+#endif
+
+/* writes out the whole block, but only if it is full */
+static void write_if_needed(void)
+{
+	if (offset == BLOCKSIZE) {
+		write_or_die(1, block, BLOCKSIZE);
+		offset = 0;
+	}
+}
+
+/*
+ * queues up writes, so that all our write(2) calls write exactly one
+ * full block; pads writes to RECORDSIZE
+ */
+static void do_write_blocked(const void *data, unsigned long size)
+{
+	const char *buf = data;
+
+	if (offset) {
+		unsigned long chunk = BLOCKSIZE - offset;
+		if (size < chunk)
+			chunk = size;
+		memcpy(block + offset, buf, chunk);
+		size -= chunk;
+		offset += chunk;
+		buf += chunk;
+		write_if_needed();
+	}
+	while (size >= BLOCKSIZE) {
+		write_or_die(1, buf, BLOCKSIZE);
+		size -= BLOCKSIZE;
+		buf += BLOCKSIZE;
+	}
+	if (size) {
+		memcpy(block + offset, buf, size);
+		offset += size;
+	}
+}
+
+static void finish_record(void)
+{
+	unsigned long tail;
+	tail = offset % RECORDSIZE;
+	if (tail)  {
+		memset(block + offset, 0, RECORDSIZE - tail);
+		offset += RECORDSIZE - tail;
+	}
+	write_if_needed();
+}
+
+static void write_blocked(const void *data, unsigned long size)
+{
+	do_write_blocked(data, size);
+	finish_record();
+}
+
+/*
+ * The end of tar archives is marked by 2*512 nul bytes and after that
+ * follows the rest of the block (if any).
+ */
+static void write_trailer(void)
+{
+	int tail = BLOCKSIZE - offset;
+	memset(block + offset, 0, tail);
+	write_or_die(1, block, BLOCKSIZE);
+	if (tail < 2 * RECORDSIZE) {
+		memset(block, 0, offset);
+		write_or_die(1, block, BLOCKSIZE);
+	}
+}
+
+/*
+ * queues up writes, so that all our write(2) calls write exactly one
+ * full block; pads writes to RECORDSIZE
+ */
+static int stream_blocked(struct repository *r, const struct object_id *oid)
+{
+	struct git_istream *st;
+	enum object_type type;
+	unsigned long sz;
+	char buf[BLOCKSIZE];
+	ssize_t readlen;
+
+	st = open_istream(r, oid, &type, &sz, NULL);
+	if (!st)
+		return error(_("cannot stream blob %s"), oid_to_hex(oid));
+	for (;;) {
+		readlen = read_istream(st, buf, sizeof(buf));
+		if (readlen <= 0)
+			break;
+		do_write_blocked(buf, readlen);
+	}
+	close_istream(st);
+	if (!readlen)
+		finish_record();
+	return readlen;
+}
+
+/*
+ * pax extended header records have the format "%u %s=%s\n".  %u contains
+ * the size of the whole string (including the %u), the first %s is the
+ * keyword, the second one is the value.  This function constructs such a
+ * string and appends it to a struct strbuf.
+ */
+static void strbuf_append_ext_header(struct strbuf *sb, const char *keyword,
+				     const char *value, size_t valuelen)
+{
+	size_t orig_len = sb->len;
+	size_t len, tmp;
+
+	/* "%u %s=%s\n" */
+	len = 1 + 1 + strlen(keyword) + 1 + valuelen + 1;
+	for (tmp = 1; len / 10 >= tmp; tmp *= 10)
+		len++;
+
+	strbuf_grow(sb, len);
+	strbuf_addf(sb, "%"PRIuMAX" %s=", (uintmax_t)len, keyword);
+	strbuf_add(sb, value, valuelen);
+	strbuf_addch(sb, '\n');
+
+	if (len != sb->len - orig_len)
+		BUG("pax extended header length miscalculated as %"PRIuMAX
+		    ", should be %"PRIuMAX,
+		    (uintmax_t)len, (uintmax_t)(sb->len - orig_len));
+}
+
+/*
+ * Like strbuf_append_ext_header, but for numeric values.
+ */
+static void strbuf_append_ext_header_uint(struct strbuf *sb,
+					  const char *keyword,
+					  uintmax_t value)
+{
+	char buf[40]; /* big enough for 2^128 in decimal, plus NUL */
+	int len;
+
+	len = xsnprintf(buf, sizeof(buf), "%"PRIuMAX, value);
+	strbuf_append_ext_header(sb, keyword, buf, len);
+}
+
+static unsigned int ustar_header_chksum(const struct ustar_header *header)
+{
+	const unsigned char *p = (const unsigned char *)header;
+	unsigned int chksum = 0;
+	while (p < (const unsigned char *)header->chksum)
+		chksum += *p++;
+	chksum += sizeof(header->chksum) * ' ';
+	p += sizeof(header->chksum);
+	while (p < (const unsigned char *)header + sizeof(struct ustar_header))
+		chksum += *p++;
+	return chksum;
+}
+
+static size_t get_path_prefix(const char *path, size_t pathlen, size_t maxlen)
+{
+	size_t i = pathlen;
+	if (i > 1 && path[i - 1] == '/')
+		i--;
+	if (i > maxlen)
+		i = maxlen;
+	do {
+		i--;
+	} while (i > 0 && path[i] != '/');
+	return i;
+}
+
+static void prepare_header(struct archiver_args *args,
+			   struct ustar_header *header,
+			   unsigned int mode, unsigned long size)
+{
+	xsnprintf(header->mode, sizeof(header->mode), "%07o", mode & 07777);
+	xsnprintf(header->size, sizeof(header->size), "%011"PRIoMAX , S_ISREG(mode) ? (uintmax_t)size : (uintmax_t)0);
+	xsnprintf(header->mtime, sizeof(header->mtime), "%011lo", (unsigned long) args->time);
+
+	xsnprintf(header->uid, sizeof(header->uid), "%07o", 0);
+	xsnprintf(header->gid, sizeof(header->gid), "%07o", 0);
+	strlcpy(header->uname, "root", sizeof(header->uname));
+	strlcpy(header->gname, "root", sizeof(header->gname));
+	xsnprintf(header->devmajor, sizeof(header->devmajor), "%07o", 0);
+	xsnprintf(header->devminor, sizeof(header->devminor), "%07o", 0);
+
+	memcpy(header->magic, "ustar", 6);
+	memcpy(header->version, "00", 2);
+
+	xsnprintf(header->chksum, sizeof(header->chksum), "%07o", ustar_header_chksum(header));
+}
+
+static void write_extended_header(struct archiver_args *args,
+				  const struct object_id *oid,
+				  const void *buffer, unsigned long size)
+{
+	struct ustar_header header;
+	unsigned int mode;
+	memset(&header, 0, sizeof(header));
+	*header.typeflag = TYPEFLAG_EXT_HEADER;
+	mode = 0100666;
+	xsnprintf(header.name, sizeof(header.name), "%s.paxheader", oid_to_hex(oid));
+	prepare_header(args, &header, mode, size);
+	write_blocked(&header, sizeof(header));
+	write_blocked(buffer, size);
+}
+
+static int write_tar_entry(struct archiver_args *args,
+			   const struct object_id *oid,
+			   const char *path, size_t pathlen,
+			   unsigned int mode)
+{
+	struct ustar_header header;
+	struct strbuf ext_header = STRBUF_INIT;
+	unsigned int old_mode = mode;
+	unsigned long size, size_in_header;
+	void *buffer;
+	int err = 0;
+
+	memset(&header, 0, sizeof(header));
+
+	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
+		*header.typeflag = TYPEFLAG_DIR;
+		mode = (mode | 0777) & ~tar_umask;
+	} else if (S_ISLNK(mode)) {
+		*header.typeflag = TYPEFLAG_LNK;
+		mode |= 0777;
+	} else if (S_ISREG(mode)) {
+		*header.typeflag = TYPEFLAG_REG;
+		mode = (mode | ((mode & 0100) ? 0777 : 0666)) & ~tar_umask;
+	} else {
+		return error(_("unsupported file mode: 0%o (SHA1: %s)"),
+			     mode, oid_to_hex(oid));
+	}
+	if (pathlen > sizeof(header.name)) {
+		size_t plen = get_path_prefix(path, pathlen,
+					      sizeof(header.prefix));
+		size_t rest = pathlen - plen - 1;
+		if (plen > 0 && rest <= sizeof(header.name)) {
+			memcpy(header.prefix, path, plen);
+			memcpy(header.name, path + plen + 1, rest);
+		} else {
+			xsnprintf(header.name, sizeof(header.name), "%s.data",
+				  oid_to_hex(oid));
+			strbuf_append_ext_header(&ext_header, "path",
+						 path, pathlen);
+		}
+	} else
+		memcpy(header.name, path, pathlen);
+
+	if (S_ISREG(mode) && !args->convert &&
+	    oid_object_info(args->repo, oid, &size) == OBJ_BLOB &&
+	    size > big_file_threshold)
+		buffer = NULL;
+	else if (S_ISLNK(mode) || S_ISREG(mode)) {
+		enum object_type type;
+		buffer = object_file_to_archive(args, path, oid, old_mode, &type, &size);
+		if (!buffer)
+			return error(_("cannot read %s"), oid_to_hex(oid));
+	} else {
+		buffer = NULL;
+		size = 0;
+	}
+
+	if (S_ISLNK(mode)) {
+		if (size > sizeof(header.linkname)) {
+			xsnprintf(header.linkname, sizeof(header.linkname),
+				  "see %s.paxheader", oid_to_hex(oid));
+			strbuf_append_ext_header(&ext_header, "linkpath",
+			                         buffer, size);
+		} else
+			memcpy(header.linkname, buffer, size);
+	}
+
+	size_in_header = size;
+	if (S_ISREG(mode) && size > USTAR_MAX_SIZE) {
+		size_in_header = 0;
+		strbuf_append_ext_header_uint(&ext_header, "size", size);
+	}
+
+	prepare_header(args, &header, mode, size_in_header);
+
+	if (ext_header.len > 0) {
+		write_extended_header(args, oid, ext_header.buf,
+				      ext_header.len);
+	}
+	strbuf_release(&ext_header);
+	write_blocked(&header, sizeof(header));
+	if (S_ISREG(mode) && size > 0) {
+		if (buffer)
+			write_blocked(buffer, size);
+		else
+			err = stream_blocked(args->repo, oid);
+	}
+	free(buffer);
+	return err;
+}
+
+static void write_global_extended_header(struct archiver_args *args)
+{
+	const struct object_id *oid = args->commit_oid;
+	struct strbuf ext_header = STRBUF_INIT;
+	struct ustar_header header;
+	unsigned int mode;
+
+	if (oid)
+		strbuf_append_ext_header(&ext_header, "comment",
+					 oid_to_hex(oid),
+					 the_hash_algo->hexsz);
+	if (args->time > USTAR_MAX_MTIME) {
+		strbuf_append_ext_header_uint(&ext_header, "mtime",
+					      args->time);
+		args->time = USTAR_MAX_MTIME;
+	}
+
+	if (!ext_header.len)
+		return;
+
+	memset(&header, 0, sizeof(header));
+	*header.typeflag = TYPEFLAG_GLOBAL_HEADER;
+	mode = 0100666;
+	xsnprintf(header.name, sizeof(header.name), "pax_global_header");
+	prepare_header(args, &header, mode, ext_header.len);
+	write_blocked(&header, sizeof(header));
+	write_blocked(ext_header.buf, ext_header.len);
+	strbuf_release(&ext_header);
+}
+
+static struct archiver **tar_filters;
+static int nr_tar_filters;
+static int alloc_tar_filters;
+
+static struct archiver *find_tar_filter(const char *name, int len)
+{
+	int i;
+	for (i = 0; i < nr_tar_filters; i++) {
+		struct archiver *ar = tar_filters[i];
+		if (!strncmp(ar->name, name, len) && !ar->name[len])
+			return ar;
+	}
+	return NULL;
+}
+
+static int tar_filter_config(const char *var, const char *value, void *data)
+{
+	struct archiver *ar;
+	const char *name;
+	const char *type;
+	int namelen;
+
+	if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name)
+		return 0;
+
+	ar = find_tar_filter(name, namelen);
+	if (!ar) {
+		ar = xcalloc(1, sizeof(*ar));
+		ar->name = xmemdupz(name, namelen);
+		ar->write_archive = write_tar_filter_archive;
+		ar->flags = ARCHIVER_WANT_COMPRESSION_LEVELS;
+		ALLOC_GROW(tar_filters, nr_tar_filters + 1, alloc_tar_filters);
+		tar_filters[nr_tar_filters++] = ar;
+	}
+
+	if (!strcmp(type, "command")) {
+		if (!value)
+			return config_error_nonbool(var);
+		free(ar->data);
+		ar->data = xstrdup(value);
+		return 0;
+	}
+	if (!strcmp(type, "remote")) {
+		if (git_config_bool(var, value))
+			ar->flags |= ARCHIVER_REMOTE;
+		else
+			ar->flags &= ~ARCHIVER_REMOTE;
+		return 0;
+	}
+
+	return 0;
+}
+
+static int git_tar_config(const char *var, const char *value, void *cb)
+{
+	if (!strcmp(var, "tar.umask")) {
+		if (value && !strcmp(value, "user")) {
+			tar_umask = umask(0);
+			umask(tar_umask);
+		} else {
+			tar_umask = git_config_int(var, value);
+		}
+		return 0;
+	}
+
+	return tar_filter_config(var, value, cb);
+}
+
+static int write_tar_archive(const struct archiver *ar,
+			     struct archiver_args *args)
+{
+	int err = 0;
+
+	write_global_extended_header(args);
+	err = write_archive_entries(args, write_tar_entry);
+	if (!err)
+		write_trailer();
+	return err;
+}
+
+static int write_tar_filter_archive(const struct archiver *ar,
+				    struct archiver_args *args)
+{
+	struct strbuf cmd = STRBUF_INIT;
+	struct child_process filter = CHILD_PROCESS_INIT;
+	const char *argv[2];
+	int r;
+
+	if (!ar->data)
+		BUG("tar-filter archiver called with no filter defined");
+
+	strbuf_addstr(&cmd, ar->data);
+	if (args->compression_level >= 0)
+		strbuf_addf(&cmd, " -%d", args->compression_level);
+
+	argv[0] = cmd.buf;
+	argv[1] = NULL;
+	filter.argv = argv;
+	filter.use_shell = 1;
+	filter.in = -1;
+
+	if (start_command(&filter) < 0)
+		die_errno(_("unable to start '%s' filter"), argv[0]);
+	close(1);
+	if (dup2(filter.in, 1) < 0)
+		die_errno(_("unable to redirect descriptor"));
+	close(filter.in);
+
+	r = write_tar_archive(ar, args);
+
+	close(1);
+	if (finish_command(&filter) != 0)
+		die(_("'%s' filter reported error"), argv[0]);
+
+	strbuf_release(&cmd);
+	return r;
+}
+
+static struct archiver tar_archiver = {
+	"tar",
+	write_tar_archive,
+	ARCHIVER_REMOTE
+};
+
+void init_tar_archiver(void)
+{
+	int i;
+	register_archiver(&tar_archiver);
+
+	tar_filter_config("tar.tgz.command", "gzip -cn", NULL);
+	tar_filter_config("tar.tgz.remote", "true", NULL);
+	tar_filter_config("tar.tar.gz.command", "gzip -cn", NULL);
+	tar_filter_config("tar.tar.gz.remote", "true", NULL);
+	git_config(git_tar_config, NULL);
+	for (i = 0; i < nr_tar_filters; i++) {
+		/* omit any filters that never had a command configured */
+		if (tar_filters[i]->data)
+			register_archiver(tar_filters[i]);
+	}
+}