Cleanup: split read_header.c in libtar.a

Simply moving the pax header decoding to a separate file and splitting
out the common helper functions should be a good start.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 183 insertions, 0 deletions

diff --git a/lib/tar/pax_header.c b/lib/tar/pax_header.c
new file mode 100644
index 0000000..4eeabf5
--- /dev/null
+++ b/lib/tar/pax_header.c
@@ -0,0 +1,183 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * pax_header.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "internal.h"
+
+static tar_xattr_t *mkxattr(const char *key, size_t keylen,
+			    const char *value, size_t valuelen)
+{
+	tar_xattr_t *xattr;
+
+	xattr = calloc(1, sizeof(*xattr) + keylen + 1 + valuelen + 1);
+	if (xattr == NULL)
+		return NULL;
+
+	xattr->key = xattr->data;
+	xattr->value = (sqfs_u8 *)xattr->data + keylen + 1;
+	xattr->value_len = valuelen;
+	memcpy(xattr->key, key, keylen);
+	memcpy(xattr->value, value, valuelen);
+	return xattr;
+}
+
+int read_pax_header(FILE *fp, sqfs_u64 entsize, unsigned int *set_by_pax,
+		    tar_header_decoded_t *out)
+{
+	char *buffer, *line, *key, *ptr, *value, *end;
+	sparse_map_t *sparse_last = NULL, *sparse;
+	sqfs_u64 field, offset = 0, num_bytes = 0;
+	tar_xattr_t *xattr;
+	long len;
+
+	buffer = record_to_memory(fp, entsize);
+	if (buffer == NULL)
+		return -1;
+
+	end = buffer + entsize;
+
+	for (line = buffer; line < end; line += len) {
+		len = strtol(line, &ptr, 10);
+		if (ptr == line || !isspace(*ptr) || len <= 0)
+			goto fail_malformed;
+
+		if (len > (end - line))
+			goto fail_ov;
+
+		line[len - 1] = '\0';
+
+		while (ptr < end && isspace(*ptr))
+			++ptr;
+
+		if (ptr >= end || (ptr - line) >= len)
+			goto fail_malformed;
+
+		if (!strncmp(ptr, "uid=", 4)) {
+			if (pax_read_decimal(ptr + 4, &field))
+				goto fail;
+			out->sb.st_uid = field;
+			*set_by_pax |= PAX_UID;
+		} else if (!strncmp(ptr, "gid=", 4)) {
+			if (pax_read_decimal(ptr + 4, &field))
+				goto fail;
+			out->sb.st_gid = field;
+			*set_by_pax |= PAX_GID;
+		} else if (!strncmp(ptr, "path=", 5)) {
+			free(out->name);
+			out->name = strdup(ptr + 5);
+			if (out->name == NULL)
+				goto fail_errno;
+			*set_by_pax |= PAX_NAME;
+		} else if (!strncmp(ptr, "size=", 5)) {
+			if (pax_read_decimal(ptr + 5, &out->record_size))
+				goto fail;
+			*set_by_pax |= PAX_SIZE;
+		} else if (!strncmp(ptr, "linkpath=", 9)) {
+			free(out->link_target);
+			out->link_target = strdup(ptr + 9);
+			if (out->link_target == NULL)
+				goto fail_errno;
+			*set_by_pax |= PAX_SLINK_TARGET;
+		} else if (!strncmp(ptr, "mtime=", 6)) {
+			if (ptr[6] == '-') {
+				if (pax_read_decimal(ptr + 7, &field))
+					goto fail;
+				out->mtime = -((sqfs_s64)field);
+			} else {
+				if (pax_read_decimal(ptr + 6, &field))
+					goto fail;
+				out->mtime = field;
+			}
+			*set_by_pax |= PAX_MTIME;
+		} else if (!strncmp(ptr, "GNU.sparse.name=", 16)) {
+			free(out->name);
+			out->name = strdup(ptr + 16);
+			if (out->name == NULL)
+				goto fail_errno;
+			*set_by_pax |= PAX_NAME;
+		} else if (!strncmp(ptr, "GNU.sparse.map=", 15)) {
+			free_sparse_list(out->sparse);
+			sparse_last = NULL;
+
+			out->sparse = read_sparse_map(ptr + 15);
+			if (out->sparse == NULL)
+				goto fail;
+		} else if (!strncmp(ptr, "GNU.sparse.size=", 16)) {
+			if (pax_read_decimal(ptr + 16, &out->actual_size))
+				goto fail;
+			*set_by_pax |= PAX_SPARSE_SIZE;
+		} else if (!strncmp(ptr, "GNU.sparse.offset=", 18)) {
+			if (pax_read_decimal(ptr + 18, &offset))
+				goto fail;
+		} else if (!strncmp(ptr, "GNU.sparse.numbytes=", 20)) {
+			if (pax_read_decimal(ptr + 20, &num_bytes))
+				goto fail;
+			sparse = calloc(1, sizeof(*sparse));
+			if (sparse == NULL)
+				goto fail_errno;
+			sparse->offset = offset;
+			sparse->count = num_bytes;
+			if (sparse_last == NULL) {
+				free_sparse_list(out->sparse);
+				out->sparse = sparse_last = sparse;
+			} else {
+				sparse_last->next = sparse;
+				sparse_last = sparse;
+			}
+		} else if (!strncmp(ptr, "SCHILY.xattr.", 13)) {
+			key = ptr + 13;
+
+			ptr = strrchr(key, '=');
+			if (ptr == NULL || ptr == key)
+				continue;
+
+			value = ptr + 1;
+
+			xattr = mkxattr(key, ptr - key,
+					value, len - (value - line) - 1);
+			if (xattr == NULL)
+				goto fail_errno;
+
+			xattr->next = out->xattr;
+			out->xattr = xattr;
+		} else if (!strncmp(ptr, "LIBARCHIVE.xattr.", 17)) {
+			key = ptr + 17;
+
+			ptr = strrchr(key, '=');
+			if (ptr == NULL || ptr == key)
+				continue;
+
+			value = ptr + 1;
+
+			xattr = mkxattr(key, ptr - key, value, strlen(value));
+			if (xattr == NULL)
+				goto fail_errno;
+
+			urldecode(xattr->key);
+			xattr->value_len = base64_decode(xattr->value, value,
+							 xattr->value_len);
+
+			xattr->next = out->xattr;
+			out->xattr = xattr;
+		}
+	}
+
+	free(buffer);
+	return 0;
+fail_malformed:
+	fputs("Found a malformed PAX header.\n", stderr);
+	goto fail;
+fail_ov:
+	fputs("Numeric overflow in PAX header.\n", stderr);
+	goto fail;
+fail_errno:
+	perror("reading pax header");
+	goto fail;
+fail:
+	free(buffer);
+	return -1;
+}