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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 ;)
This commit is contained in:
Denis Vlasenko
parent
2d27e4ccbb
commit
7725d0ff5c
123
archival/tar.c
123
archival/tar.c
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@ -169,6 +169,72 @@ static void putOctal(char *cp, int len, off_t value)
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/* Copy the string to the field */
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memcpy(cp, tempString, len);
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}
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#define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))
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static void chksum_and_xwrite(int fd, struct TarHeader* hp)
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{
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const unsigned char *cp;
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int chksum, size;
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strcpy(hp->magic, "ustar ");
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/* Calculate and store the checksum (i.e., the sum of all of the bytes of
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* the header). The checksum field must be filled with blanks for the
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* calculation. The checksum field is formatted differently from the
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* other fields: it has 6 digits, a null, then a space -- rather than
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* digits, followed by a null like the other fields... */
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memset(hp->chksum, ' ', sizeof(hp->chksum));
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cp = (const unsigned char *) hp;
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chksum = 0;
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size = sizeof(*hp);
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do { chksum += *cp++; } while (--size);
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putOctal(hp->chksum, sizeof(hp->chksum)-1, chksum);
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/* Now write the header out to disk */
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xwrite(fd, hp, sizeof(*hp));
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}
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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static void writeLongname(int fd, int type, const char *name, int dir)
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{
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static const struct {
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char mode[8]; /* 100-107 */
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char uid[8]; /* 108-115 */
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char gid[8]; /* 116-123 */
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char size[12]; /* 124-135 */
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char mtime[12]; /* 136-147 */
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} prefilled = {
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"0000000",
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"0000000",
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"0000000",
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"00000000000",
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"00000000000",
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};
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struct TarHeader header;
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int size;
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dir = !!dir; /* normalize: 0/1 */
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size = strlen(name) + 1 + dir; /* GNU tar uses strlen+1 */
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/* + dir: account for possible '/' */
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bzero(&header, sizeof(header));
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strcpy(header.name, "././@LongLink");
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memcpy(header.mode, prefilled.mode, sizeof(prefilled));
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PUT_OCTAL(header.size, size);
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header.typeflag = type;
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chksum_and_xwrite(fd, &header);
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/* Write filename[/] and pad the block. */
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/* dir=0: writes 'name<NUL>', pads */
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/* dir=1: writes 'name', writes '/<NUL>', pads */
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dir *= 2;
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xwrite(fd, name, size - dir);
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xwrite(fd, "/", dir);
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size = (-size) & (TAR_BLOCK_SIZE-1);
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bzero(&header, size);
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xwrite(fd, &header, size);
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}
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#endif
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/* Write out a tar header for the specified file/directory/whatever */
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void BUG_tar_header_size(void);
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@ -176,25 +242,20 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
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const char *header_name, const char *fileName, struct stat *statbuf)
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{
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struct TarHeader header;
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const unsigned char *cp;
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int chksum;
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int size;
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if (sizeof(header) != 512)
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BUG_tar_header_size();
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bzero(&header, sizeof(struct TarHeader));
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safe_strncpy(header.name, header_name, sizeof(header.name));
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strncpy(header.name, header_name, sizeof(header.name));
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#define PUT_OCTAL(a, b) putOctal((a), sizeof(a), (b))
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/* POSIX says to mask mode with 07777. */
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PUT_OCTAL(header.mode, statbuf->st_mode & 07777);
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PUT_OCTAL(header.uid, statbuf->st_uid);
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PUT_OCTAL(header.gid, statbuf->st_gid);
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memset(header.size, '0', sizeof(header.size)-1); /* Regular file size is handled later */
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PUT_OCTAL(header.mtime, statbuf->st_mtime);
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strcpy(header.magic, "ustar ");
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/* Enter the user and group names */
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safe_strncpy(header.uname, get_cached_username(statbuf->st_uid), sizeof(header.uname));
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@ -205,24 +266,36 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
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header.typeflag = LNKTYPE;
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strncpy(header.linkname, tbInfo->hlInfo->name,
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sizeof(header.linkname));
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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/* Write out long linkname if needed */
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if (header.linkname[sizeof(header.linkname)-1])
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writeLongname(tbInfo->tarFd, GNULONGLINK,
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tbInfo->hlInfo->name, 0);
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#endif
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} else if (S_ISLNK(statbuf->st_mode)) {
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char *lpath = xreadlink(fileName);
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if (!lpath) /* Already printed err msg inside xreadlink() */
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return FALSE;
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header.typeflag = SYMTYPE;
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strncpy(header.linkname, lpath, sizeof(header.linkname));
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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/* Write out long linkname if needed */
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if (header.linkname[sizeof(header.linkname)-1])
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writeLongname(tbInfo->tarFd, GNULONGLINK, lpath, 0);
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#else
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/* If it is larger than 100 bytes, bail out */
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if (header.linkname[sizeof(header.linkname)-1] /* at least 100? */
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&& lpath[sizeof(header.linkname)] /* and 101th is also not zero */
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) {
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if (header.linkname[sizeof(header.linkname)-1]) {
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free(lpath);
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bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
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return FALSE;
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}
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#endif
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free(lpath);
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} else if (S_ISDIR(statbuf->st_mode)) {
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header.typeflag = DIRTYPE;
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strncat(header.name, "/", sizeof(header.name));
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/* Append '/' only if there is a space for it */
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if (!header.name[sizeof(header.name)-1])
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header.name[strlen(header.name)] = '/';
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} else if (S_ISCHR(statbuf->st_mode)) {
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header.typeflag = CHRTYPE;
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PUT_OCTAL(header.devmajor, major(statbuf->st_rdev));
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@ -247,22 +320,17 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
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bb_error_msg("%s: unknown file type", fileName);
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return FALSE;
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}
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#undef PUT_OCTAL
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/* Calculate and store the checksum (i.e., the sum of all of the bytes of
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* the header). The checksum field must be filled with blanks for the
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* calculation. The checksum field is formatted differently from the
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* other fields: it has [6] digits, a null, then a space -- rather than
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* digits, followed by a null like the other fields... */
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memset(header.chksum, ' ', sizeof(header.chksum));
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cp = (const unsigned char *) &header;
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chksum = 0;
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size = sizeof(struct TarHeader);
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do { chksum += *cp++; } while (--size);
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putOctal(header.chksum, sizeof(header.chksum)-1, chksum);
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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/* Write out long name if needed */
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/* (we, like GNU tar, output long linkname *before* long name) */
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if (header.name[sizeof(header.name)-1])
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writeLongname(tbInfo->tarFd, GNULONGNAME,
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header_name, S_ISDIR(statbuf->st_mode));
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#endif
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/* Now write the header out to disk */
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xwrite(tbInfo->tarFd, &header, sizeof(struct TarHeader));
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chksum_and_xwrite(tbInfo->tarFd, &header);
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/* Now do the verbose thing (or not) */
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if (tbInfo->verboseFlag) {
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@ -272,7 +340,9 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
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vbFd = stderr;
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/* GNU "tar cvvf" prints "extended" listing a-la "ls -l" */
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/* We don't have such excesses here: for us "v" == "vv" */
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fprintf(vbFd, "%s\n", header.name);
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/* '/' is probably a GNUism */
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fprintf(vbFd, "%s%s\n", header_name,
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S_ISDIR(statbuf->st_mode) ? "/" : "");
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}
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return TRUE;
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@ -352,10 +422,12 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
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header_name++;
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}
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#if !ENABLE_FEATURE_TAR_GNU_EXTENSIONS
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if (strlen(fileName) >= NAME_SIZE) {
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bb_error_msg("names longer than "NAME_SIZE_STR" chars not supported");
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return TRUE;
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}
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#endif
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if (header_name[0] == '\0')
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return TRUE;
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@ -384,7 +456,8 @@ static int writeFileToTarball(const char *fileName, struct stat *statbuf,
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/* write the file to the archive */
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readSize = bb_copyfd_size(inputFileFd, tbInfo->tarFd, statbuf->st_size);
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if (readSize != statbuf->st_size) {
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/* readSize < 0 means that error was already reported */
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if (readSize != statbuf->st_size && readSize >= 0) {
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/* Deadly. We record size into header first, */
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/* and then write out file. If file shrinks in between, */
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/* tar will be corrupted. So bail out. */
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