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-rw-r--r--doc/sqfs2tar.19
-rw-r--r--include/tar.h5
-rw-r--r--lib/tar/checksum.c2
-rw-r--r--lib/tar/internal.h2
-rw-r--r--lib/tar/number.c8
-rw-r--r--lib/tar/write_header.c282
-rw-r--r--tar/sqfs2tar.c4
7 files changed, 132 insertions, 180 deletions
diff --git a/doc/sqfs2tar.1 b/doc/sqfs2tar.1
index a999dff..b732d06 100644
--- a/doc/sqfs2tar.1
+++ b/doc/sqfs2tar.1
@@ -18,10 +18,11 @@ Print help text and exit.
.TP
\fB\-\-version\fR, \fB\-V\fR
Print version information and exit.
-.SH LIMITATIONS
-To be compatible with as many tools as possible, the output format is POSIX tar
-using pax extensions if necessary, so the tools you intend to use should
-support the pax format.
+.SH COMPATIBILITY
+To be compatible with as many tools as possible, the output format is pre-POSIX
+ustar archive using GNU extensions where necessary. This seems to be more
+widely supported by many tar programs (besides GNU tar), even more than the
+newer POSIX format and PAX extensions.
It is not possible to store socket files in a tar or pax archive. Also, in the
current implementation, all extended attribuates are lost.
diff --git a/include/tar.h b/include/tar.h
index ef4fdec..fd701d9 100644
--- a/include/tar.h
+++ b/include/tar.h
@@ -89,9 +89,12 @@ typedef struct {
/*
Returns < 0 on failure, > 0 if cannot encode, 0 on success.
Prints error/warning messages to stderr.
+
+ The counter is an incremental record counter used if additional
+ headers need to be generated.
*/
int write_tar_header(int fd, const struct stat *sb, const char *name,
- const char *slink_target);
+ const char *slink_target, unsigned int counter);
/* calcuate and skip the zero padding */
int skip_padding(int fd, uint64_t size);
diff --git a/lib/tar/checksum.c b/lib/tar/checksum.c
index 925f942..a2a101a 100644
--- a/lib/tar/checksum.c
+++ b/lib/tar/checksum.c
@@ -11,7 +11,7 @@ void update_checksum(tar_header_t *hdr)
for (i = 0; i < sizeof(*hdr); ++i)
chksum += ((unsigned char *)hdr)[i];
- write_octal(hdr->chksum, chksum, 6);
+ sprintf(hdr->chksum, "%06o", chksum);
hdr->chksum[6] = '\0';
hdr->chksum[7] = ' ';
}
diff --git a/lib/tar/internal.h b/lib/tar/internal.h
index 6596987..3c0e27f 100644
--- a/lib/tar/internal.h
+++ b/lib/tar/internal.h
@@ -38,8 +38,6 @@ int read_binary(const char *str, int digits, uint64_t *out);
int read_number(const char *str, int digits, uint64_t *out);
-void write_octal(char *dst, unsigned int value, int digits);
-
int pax_read_decimal(const char *str, uint64_t *out);
void update_checksum(tar_header_t *hdr);
diff --git a/lib/tar/number.c b/lib/tar/number.c
index e85866d..009a4de 100644
--- a/lib/tar/number.c
+++ b/lib/tar/number.c
@@ -84,11 +84,3 @@ int pax_read_decimal(const char *str, uint64_t *out)
*out = result;
return 0;
}
-
-void write_octal(char *dst, unsigned int value, int digits)
-{
- char temp[64];
-
- sprintf(temp, "%0*o ", digits, value);
- memcpy(dst, temp, strlen(temp));
-}
diff --git a/lib/tar/write_header.c b/lib/tar/write_header.c
index b84324b..79fa49a 100644
--- a/lib/tar/write_header.c
+++ b/lib/tar/write_header.c
@@ -1,197 +1,166 @@
/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "internal.h"
-static unsigned long pax_hdr_counter = 0;
-static char buffer[4096];
-
-static int name_to_tar_header(tar_header_t *hdr, const char *path)
+static void write_binary(char *dst, uint64_t value, int digits)
{
- size_t len = strlen(path);
- const char *ptr;
+ memset(dst, 0, digits);
- if ((len + 1) <= sizeof(hdr->name)) {
- memcpy(hdr->name, path, len);
- return 0;
+ while (digits > 0) {
+ ((unsigned char *)dst)[digits - 1] = value & 0xFF;
+ --digits;
+ value >>= 8;
}
- for (ptr = path; ; ++ptr) {
- ptr = strchr(ptr, '/');
- if (ptr == NULL)
- return -1;
-
- len = ptr - path;
- if (len >= sizeof(hdr->tail.posix.prefix))
- continue;
- if (strlen(ptr + 1) >= sizeof(hdr->name))
- continue;
- break;
- }
-
- memcpy(hdr->tail.posix.prefix, path, ptr - path);
- memcpy(hdr->name, ptr + 1, strlen(ptr + 1));
- return 0;
+ ((unsigned char *)dst)[0] |= 0x80;
}
-static void init_header(tar_header_t *hdr, const struct stat *sb,
- const char *name, const char *slink_target)
+static void write_number(char *dst, uint64_t value, int digits)
{
- memset(hdr, 0, sizeof(*hdr));
-
- name_to_tar_header(hdr, name);
- memcpy(hdr->magic, TAR_MAGIC, sizeof(hdr->magic));
- memcpy(hdr->version, TAR_VERSION, sizeof(hdr->version));
- write_octal(hdr->mode, sb->st_mode & ~S_IFMT, 6);
- write_octal(hdr->uid, sb->st_uid, 6);
- write_octal(hdr->gid, sb->st_gid, 6);
- write_octal(hdr->mtime, sb->st_mtime, 11);
- write_octal(hdr->size, 0, 11);
- write_octal(hdr->devmajor, 0, 6);
- write_octal(hdr->devminor, 0, 6);
-
- switch (sb->st_mode & S_IFMT) {
- case S_IFREG:
- write_octal(hdr->size, sb->st_size & 077777777777L, 11);
- break;
- case S_IFLNK:
- if (sb->st_size < (off_t)sizeof(hdr->linkname))
- strcpy(hdr->linkname, slink_target);
- break;
- case S_IFCHR:
- case S_IFBLK:
- write_octal(hdr->devmajor, major(sb->st_rdev), 6);
- write_octal(hdr->devminor, minor(sb->st_rdev), 6);
- break;
+ uint64_t mask = 0;
+ char buffer[64];
+ int i;
+
+ for (i = 0; i < (digits - 1); ++i)
+ mask = (mask << 3) | 7;
+
+ if (value <= mask) {
+ sprintf(buffer, "%0*o ", digits - 1, (unsigned int)value);
+ memcpy(dst, buffer, digits);
+ } else if (value <= ((mask << 3) | 7)) {
+ sprintf(buffer, "%0*o", digits, (unsigned int)value);
+ memcpy(dst, buffer, digits);
+ } else {
+ write_binary(dst, value, digits);
}
-
- sprintf(hdr->uname, "%u", sb->st_uid);
- sprintf(hdr->gname, "%u", sb->st_gid);
}
-static bool need_pax_header(const struct stat *sb, const char *name)
+static void write_number_signed(char *dst, int64_t value, int digits)
{
- tar_header_t tmp;
-
- if (sb->st_uid > 0777777 || sb->st_gid > 0777777)
- return true;
-
- if (S_ISREG(sb->st_mode) && sb->st_size > 077777777777L)
- return true;
-
- if (S_ISLNK(sb->st_mode) && sb->st_size >= (off_t)sizeof(tmp.linkname))
- return true;
-
- if (name_to_tar_header(&tmp, name))
- return true;
+ uint64_t neg;
- return false;
+ if (value < 0) {
+ neg = -value;
+ write_binary(dst, ~neg + 1, digits);
+ } else {
+ write_number(dst, value, digits);
+ }
}
-static char *write_pax_entry(char *dst, const char *key, const char *value)
+static int write_header(int fd, const struct stat *sb, const char *name,
+ const char *slink_target, int type)
{
- size_t i, len, prefix = 0, oldprefix;
+ int maj = 0, min = 0;
+ uint64_t size = 0;
+ tar_header_t hdr;
+ ssize_t ret;
- do {
- len = prefix + 1 + strlen(key) + 1 + strlen(value) + 1;
+ if (S_ISCHR(sb->st_mode) || S_ISBLK(sb->st_mode)) {
+ maj = major(sb->st_rdev);
+ min = minor(sb->st_rdev);
+ }
+
+ if (S_ISREG(sb->st_mode))
+ size = sb->st_size;
+
+ memset(&hdr, 0, sizeof(hdr));
+
+ memcpy(hdr.name, name, strlen(name));
+ write_number(hdr.mode, sb->st_mode & ~S_IFMT, sizeof(hdr.mode));
+ write_number(hdr.uid, sb->st_uid, sizeof(hdr.uid));
+ write_number(hdr.gid, sb->st_gid, sizeof(hdr.gid));
+ write_number(hdr.size, size, sizeof(hdr.size));
+ write_number_signed(hdr.mtime, sb->st_mtime, sizeof(hdr.mtime));
+ hdr.typeflag = type;
+ if (slink_target != NULL)
+ memcpy(hdr.linkname, slink_target, sb->st_size);
+ memcpy(hdr.magic, TAR_MAGIC_OLD, sizeof(hdr.magic));
+ memcpy(hdr.version, TAR_VERSION_OLD, sizeof(hdr.version));
+ sprintf(hdr.uname, "%u", sb->st_uid);
+ sprintf(hdr.gname, "%u", sb->st_gid);
+ write_number(hdr.devmajor, maj, sizeof(hdr.devmajor));
+ write_number(hdr.devminor, min, sizeof(hdr.devminor));
- oldprefix = prefix;
- prefix = 1;
+ update_checksum(&hdr);
- for (i = len; i >= 10; i /= 10)
- ++prefix;
- } while (oldprefix != prefix);
+ ret = write_retry(fd, &hdr, sizeof(hdr));
+ if (ret < 0) {
+ perror("writing header record");
+ return -1;
+ }
- sprintf(dst, "%zu %s=%s\n", len, key, value);
+ if ((size_t)ret < sizeof(hdr)) {
+ fputs("writing header record: truncated write\n", stderr);
+ return -1;
+ }
- return dst + len;
+ return 0;
}
-static int write_pax_header(int fd, const struct stat *sb, const char *name,
- const char *slink_target)
+static int write_gnu_header(int fd, const struct stat *orig,
+ const char *payload, size_t payload_len,
+ int type, const char *name)
{
- char temp[64], *ptr;
- struct stat fakesb;
- tar_header_t hdr;
+ struct stat sb;
ssize_t ret;
- size_t len;
-
- memset(buffer, 0, sizeof(buffer));
- memset(&fakesb, 0, sizeof(fakesb));
- fakesb.st_mode = S_IFREG | 0644;
-
- sprintf(temp, "pax%lu", pax_hdr_counter);
- init_header(&hdr, &fakesb, temp, NULL);
- hdr.typeflag = TAR_TYPE_PAX;
-
- sprintf(temp, "%u", sb->st_uid);
- ptr = buffer;
- ptr = write_pax_entry(ptr, "uid", temp);
- ptr = write_pax_entry(ptr, "uname", temp);
- sprintf(temp, "%lu", sb->st_mtime);
- ptr = write_pax_entry(ptr, "mtime", temp);
+ sb = *orig;
+ sb.st_mode = S_IFREG | 0644;
+ sb.st_size = payload_len;
- sprintf(temp, "%u", sb->st_gid);
- ptr = write_pax_entry(ptr, "gid", temp);
- ptr = write_pax_entry(ptr, "gname", temp);
+ if (write_header(fd, &sb, name, NULL, type))
+ return -1;
- ptr = write_pax_entry(ptr, "path", name);
-
- if (S_ISLNK(sb->st_mode)) {
- write_pax_entry(ptr, "linkpath", slink_target);
- } else if (S_ISREG(sb->st_mode)) {
- sprintf(temp, "%lu", sb->st_size);
- write_pax_entry(ptr, "size", temp);
+ ret = write_retry(fd, payload, payload_len);
+ if (ret < 0) {
+ perror("writing GNU extension header");
+ return -1;
}
- len = strlen(buffer);
- write_octal(hdr.size, len, 11);
- update_checksum(&hdr);
+ if ((size_t)ret < payload_len) {
+ fputs("writing GNU extension header: truncated write\n", stderr);
+ return -1;
+ }
- ret = write_retry(fd, &hdr, sizeof(hdr));
- if (ret < 0)
- goto fail_wr;
- if ((size_t)ret < sizeof(hdr))
- goto fail_trunc;
-
- ret = write_retry(fd, buffer, len);
- if (ret < 0)
- goto fail_wr;
- if ((size_t)ret < len)
- goto fail_trunc;
-
- return padd_file(fd, len, 512);
-fail_wr:
- perror("writing pax header");
- return -1;
-fail_trunc:
- fputs("writing pax header: truncated write\n", stderr);
- return -1;
+ return padd_file(fd, payload_len, 512);
}
int write_tar_header(int fd, const struct stat *sb, const char *name,
- const char *slink_target)
+ const char *slink_target, unsigned int counter)
{
const char *reason;
- tar_header_t hdr;
- ssize_t ret;
+ char buffer[64];
+ int type;
- if (need_pax_header(sb, name)) {
- if (write_pax_header(fd, sb, name, slink_target))
+ if (!S_ISLNK(sb->st_mode))
+ slink_target = NULL;
+
+ if (S_ISLNK(sb->st_mode) && sb->st_size >= 100) {
+ sprintf(buffer, "gnu/target%u", counter);
+ if (write_gnu_header(fd, sb, slink_target, sb->st_size,
+ TAR_TYPE_GNU_SLINK, buffer))
return -1;
+ slink_target = NULL;
+ }
+
+ if (strlen(name) >= 100) {
+ sprintf(buffer, "gnu/name%u", counter);
- sprintf(buffer, "pax%lu_data", pax_hdr_counter++);
+ if (write_gnu_header(fd, sb, name, strlen(name),
+ TAR_TYPE_GNU_PATH, buffer)) {
+ return -1;
+ }
+
+ sprintf(buffer, "gnu/data%u", counter);
name = buffer;
}
- init_header(&hdr, sb, name, slink_target);
-
switch (sb->st_mode & S_IFMT) {
- case S_IFCHR: hdr.typeflag = TAR_TYPE_CHARDEV; break;
- case S_IFBLK: hdr.typeflag = TAR_TYPE_BLOCKDEV; break;
- case S_IFLNK: hdr.typeflag = TAR_TYPE_SLINK; break;
- case S_IFREG: hdr.typeflag = TAR_TYPE_FILE; break;
- case S_IFDIR: hdr.typeflag = TAR_TYPE_DIR; break;
- case S_IFIFO: hdr.typeflag = TAR_TYPE_FIFO; break;
+ case S_IFCHR: type = TAR_TYPE_CHARDEV; break;
+ case S_IFBLK: type = TAR_TYPE_BLOCKDEV; break;
+ case S_IFLNK: type = TAR_TYPE_SLINK; break;
+ case S_IFREG: type = TAR_TYPE_FILE; break;
+ case S_IFDIR: type = TAR_TYPE_DIR; break;
+ case S_IFIFO: type = TAR_TYPE_FIFO; break;
case S_IFSOCK:
reason = "cannot pack socket";
goto out_skip;
@@ -200,20 +169,7 @@ int write_tar_header(int fd, const struct stat *sb, const char *name,
goto out_skip;
}
- update_checksum(&hdr);
-
- ret = write_retry(fd, &hdr, sizeof(hdr));
-
- if (ret < 0) {
- perror("writing header record");
- } else if ((size_t)ret < sizeof(hdr)) {
- fputs("writing header record: truncated write\n", stderr);
- ret = -1;
- } else {
- ret = 0;
- }
-
- return ret;
+ return write_header(fd, sb, name, slink_target, type);
out_skip:
fprintf(stderr, "WARNING: skipping '%s' (%s)\n", name, reason);
return 1;
diff --git a/tar/sqfs2tar.c b/tar/sqfs2tar.c
index e8b8736..e568bb4 100644
--- a/tar/sqfs2tar.c
+++ b/tar/sqfs2tar.c
@@ -42,6 +42,7 @@ static const char *usagestr =
"\n";
static const char *filename;
+static unsigned int record_counter;
static void process_args(int argc, char **argv)
{
@@ -121,7 +122,8 @@ static int write_tree_dfs(fstree_t *fs, tree_node_t *n, data_reader_t *data)
fstree_node_stat(fs, n, &sb);
target = S_ISLNK(sb.st_mode) ? n->data.slink_target : NULL;
- ret = write_tar_header(STDOUT_FILENO, &sb, name, target);
+ ret = write_tar_header(STDOUT_FILENO, &sb, name, target,
+ record_counter++);
free(name);
if (ret < 0)
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-24 18:39:40 +0000