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authorDenis Vlasenko2006-11-25 23:56:50 +0000
committerDenis Vlasenko2006-11-25 23:56:50 +0000
commit7725d0ff5c3dd6209c0813344347431109bc6a7d (patch)
tree7b6bbba9c73e1e8a2c10d9cafde28ce49125f914 /archival/tar.c
parent2d27e4ccbbc29d6ec1b907849984cec30f24e734 (diff)
downloadbusybox-7725d0ff5c3dd6209c0813344347431109bc6a7d.zip
busybox-7725d0ff5c3dd6209c0813344347431109bc6a7d.tar.gz
tar: add support for FEATURE_TAR_GNU_EXTENSIONS so than we can save
long names now. We were able to read such tars, but not create. +275 bytes. Without FEATURE_TAR_GNU_EXTENSIONS: -25 bytes. We still cannot unpack Linux kernels, but not for long ;)
Diffstat (limited to 'archival/tar.c')
-rw-r--r--archival/tar.c123
1 files changed, 98 insertions, 25 deletions
diff --git a/archival/tar.c b/archival/tar.c
index c870d53..bf6786f 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -169,6 +169,72 @@ static void putOctal(char *cp, int len, off_t value)
/* Copy the string to the field */
memcpy(cp, tempString, len);
}
+#define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))
+
+static void chksum_and_xwrite(int fd, struct TarHeader* hp)
+{
+ const unsigned char *cp;
+ int chksum, size;
+
+ strcpy(hp->magic, "ustar ");
+
+ /* Calculate and store the checksum (i.e., the sum of all of the bytes of
+ * the header). The checksum field must be filled with blanks for the
+ * calculation. The checksum field is formatted differently from the
+ * other fields: it has 6 digits, a null, then a space -- rather than
+ * digits, followed by a null like the other fields... */
+ memset(hp->chksum, ' ', sizeof(hp->chksum));
+ cp = (const unsigned char *) hp;
+ chksum = 0;
+ size = sizeof(*hp);
+ do { chksum += *cp++; } while (--size);
+ putOctal(hp->chksum, sizeof(hp->chksum)-1, chksum);
+
+ /* Now write the header out to disk */
+ xwrite(fd, hp, sizeof(*hp));
+}
+
+#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+static void writeLongname(int fd, int type, const char *name, int dir)
+{
+ static const struct {
+ char mode[8]; /* 100-107 */
+ char uid[8]; /* 108-115 */
+ char gid[8]; /* 116-123 */
+ char size[12]; /* 124-135 */
+ char mtime[12]; /* 136-147 */
+ } prefilled = {
+ "0000000",
+ "0000000",
+ "0000000",
+ "00000000000",
+ "00000000000",
+ };
+ struct TarHeader header;
+ int size;
+
+ dir = !!dir; /* normalize: 0/1 */
+ size = strlen(name) + 1 + dir; /* GNU tar uses strlen+1 */
+ /* + dir: account for possible '/' */
+
+ bzero(&header, sizeof(header));
+ strcpy(header.name, "././@LongLink");
+ memcpy(header.mode, prefilled.mode, sizeof(prefilled));
+ PUT_OCTAL(header.size, size);
+ header.typeflag = type;
+ chksum_and_xwrite(fd, &header);
+
+ /* Write filename[/] and pad the block. */
+ /* dir=0: writes 'name<NUL>', pads */
+ /* dir=1: writes 'name', writes '/<NUL>', pads */
+ dir *= 2;
+ xwrite(fd, name, size - dir);
+ xwrite(fd, "/", dir);
+ size = (-size) & (TAR_BLOCK_SIZE-1);
+ bzero(&header, size);
+ xwrite(fd, &header, size);
+}
+#endif
/* Write out a tar header for the specified file/directory/whatever */
void BUG_tar_header_size(void);
@@ -176,25 +242,20 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
const char *header_name, const char *fileName, struct stat *statbuf)
{
struct TarHeader header;
- const unsigned char *cp;
- int chksum;
- int size;
if (sizeof(header) != 512)
BUG_tar_header_size();
bzero(&header, sizeof(struct TarHeader));
- safe_strncpy(header.name, header_name, sizeof(header.name));
+ strncpy(header.name, header_name, sizeof(header.name));
-#define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))
/* POSIX says to mask mode with 07777. */
PUT_OCTAL(header.mode, statbuf->st_mode & 07777);
PUT_OCTAL(header.uid, statbuf->st_uid);
PUT_OCTAL(header.gid, statbuf->st_gid);
memset(header.size, '0', sizeof(header.size)-1); /* Regular file size is handled later */
PUT_OCTAL(header.mtime, statbuf->st_mtime);
- strcpy(header.magic, "ustar ");
/* Enter the user and group names */
safe_strncpy(header.uname, get_cached_username(statbuf->st_uid), sizeof(header.uname));
@@ -205,24 +266,36 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
header.typeflag = LNKTYPE;
strncpy(header.linkname, tbInfo->hlInfo->name,
sizeof(header.linkname));
+#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+ /* Write out long linkname if needed */
+ if (header.linkname[sizeof(header.linkname)-1])
+ writeLongname(tbInfo->tarFd, GNULONGLINK,
+ tbInfo->hlInfo->name, 0);
+#endif
} else if (S_ISLNK(statbuf->st_mode)) {
char *lpath = xreadlink(fileName);
if (!lpath) /* Already printed err msg inside xreadlink() */
return FALSE;
header.typeflag = SYMTYPE;
strncpy(header.linkname, lpath, sizeof(header.linkname));
+#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+ /* Write out long linkname if needed */
+ if (header.linkname[sizeof(header.linkname)-1])
+ writeLongname(tbInfo->tarFd, GNULONGLINK, lpath, 0);
+#else
/* If it is larger than 100 bytes, bail out */
- if (header.linkname[sizeof(header.linkname)-1] /* at least 100? */
- && lpath[sizeof(header.linkname)] /* and 101th is also not zero */
- ) {
+ if (header.linkname[sizeof(header.linkname)-1]) {
free(lpath);
bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
return FALSE;
}
+#endif
free(lpath);
} else if (S_ISDIR(statbuf->st_mode)) {
header.typeflag = DIRTYPE;
- strncat(header.name, "/", sizeof(header.name));
+ /* Append '/' only if there is a space for it */
+ if (!header.name[sizeof(header.name)-1])
+ header.name[strlen(header.name)] = '/';
} else if (S_ISCHR(statbuf->st_mode)) {
header.typeflag = CHRTYPE;
PUT_OCTAL(header.devmajor, major(statbuf->st_rdev));
@@ -247,22 +320,17 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
bb_error_msg("%s: unknown file type", fileName);
return FALSE;
}
-#undef PUT_OCTAL
- /* Calculate and store the checksum (i.e., the sum of all of the bytes of
- * the header). The checksum field must be filled with blanks for the
- * calculation. The checksum field is formatted differently from the
- * other fields: it has [6] digits, a null, then a space -- rather than
- * digits, followed by a null like the other fields... */
- memset(header.chksum, ' ', sizeof(header.chksum));
- cp = (const unsigned char *) &header;
- chksum = 0;
- size = sizeof(struct TarHeader);
- do { chksum += *cp++; } while (--size);
- putOctal(header.chksum, sizeof(header.chksum)-1, chksum);
+#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
+ /* Write out long name if needed */
+ /* (we, like GNU tar, output long linkname *before* long name) */
+ if (header.name[sizeof(header.name)-1])
+ writeLongname(tbInfo->tarFd, GNULONGNAME,
+ header_name, S_ISDIR(statbuf->st_mode));
+#endif
/* Now write the header out to disk */
- xwrite(tbInfo->tarFd, &header, sizeof(struct TarHeader));
+ chksum_and_xwrite(tbInfo->tarFd, &header);
/* Now do the verbose thing (or not) */
if (tbInfo->verboseFlag) {
@@ -272,7 +340,9 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
vbFd = stderr;
/* GNU "tar cvvf" prints "extended" listing a-la "ls -l" */
/* We don't have such excesses here: for us "v" == "vv" */
- fprintf(vbFd, "%s\n", header.name);
+ /* '/' is probably a GNUism */
+ fprintf(vbFd, "%s%s\n", header_name,
+ S_ISDIR(statbuf->st_mode) ? "/" : "");
}
return TRUE;
@@ -352,10 +422,12 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
header_name++;
}
+#if !ENABLE_FEATURE_TAR_GNU_EXTENSIONS
if (strlen(fileName) >= NAME_SIZE) {
bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
return TRUE;
}
+#endif
if (header_name[0] == '\0')
return TRUE;
@@ -384,7 +456,8 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
/* write the file to the archive */
readSize = bb_copyfd_size(inputFileFd, tbInfo->tarFd, statbuf->st_size);
- if (readSize != statbuf->st_size) {
+ /* readSize < 0 means that error was already reported */
+ if (readSize != statbuf->st_size && readSize >= 0) {
/* Deadly. We record size into header first, */
/* and then write out file. If file shrinks in between, */
/* tar will be corrupted. So bail out. */