diff options
Diffstat (limited to 'src/port/tar.c')
| -rw-r--r-- | src/port/tar.c | 128 |
1 files changed, 90 insertions, 38 deletions
diff --git a/src/port/tar.c b/src/port/tar.c index 72fd4e13aca..52a2113a47e 100644 --- a/src/port/tar.c +++ b/src/port/tar.c @@ -3,21 +3,80 @@ #include <sys/stat.h> /* - * Utility routine to print possibly larger than 32 bit integers in a - * portable fashion. Filled with zeros. + * Print a numeric field in a tar header. The field starts at *s and is of + * length len; val is the value to be written. + * + * Per POSIX, the way to write a number is in octal with leading zeroes and + * one trailing space (or NUL, but we use space) at the end of the specified + * field width. + * + * However, the given value may not fit in the available space in octal form. + * If that's true, we use the GNU extension of writing \200 followed by the + * number in base-256 form (ie, stored in binary MSB-first). (Note: here we + * support only non-negative numbers, so we don't worry about the GNU rules + * for handling negative numbers.) */ static void -print_val(char *s, uint64 val, unsigned int base, size_t len) +print_tar_number(char *s, int len, uint64 val) { - int i; - - for (i = len; i > 0; i--) + if (val < (((uint64) 1) << ((len - 1) * 3))) + { + /* Use octal with trailing space */ + s[--len] = ' '; + while (len) + { + s[--len] = (val & 7) + '0'; + val >>= 3; + } + } + else { - int digit = val % base; + /* Use base-256 with leading \200 */ + s[0] = '\200'; + while (len > 1) + { + s[--len] = (val & 255); + val >>= 8; + } + } +} - s[i - 1] = '0' + digit; - val = val / base; + +/* + * Read a numeric field in a tar header. The field starts at *s and is of + * length len. + * + * The POSIX-approved format for a number is octal, ending with a space or + * NUL. However, for values that don't fit, we recognize the GNU extension + * of \200 followed by the number in base-256 form (ie, stored in binary + * MSB-first). (Note: here we support only non-negative numbers, so we don't + * worry about the GNU rules for handling negative numbers.) + */ +uint64 +read_tar_number(const char *s, int len) +{ + uint64 result = 0; + + if (*s == '\200') + { + /* base-256 */ + while (--len) + { + result <<= 8; + result |= (unsigned char) (*++s); + } } + else + { + /* octal */ + while (len-- && *s >= '0' && *s <= '7') + { + result <<= 3; + result |= (*s - '0'); + s++; + } + } + return result; } @@ -46,12 +105,12 @@ tarChecksum(char *header) /* * Fill in the buffer pointed to by h with a tar format header. This buffer - * must always have space for 512 characters, which is a requirement by + * must always have space for 512 characters, which is a requirement of * the tar format. */ enum tarError tarCreateHeader(char *h, const char *filename, const char *linktarget, - size_t size, mode_t mode, uid_t uid, gid_t gid, time_t mtime) + pgoff_t size, mode_t mode, uid_t uid, gid_t gid, time_t mtime) { if (strlen(filename) > 99) return TAR_NAME_TOO_LONG; @@ -59,12 +118,6 @@ tarCreateHeader(char *h, const char *filename, const char *linktarget, if (linktarget && strlen(linktarget) > 99) return TAR_SYMLINK_TOO_LONG; - /* - * Note: most of the fields in a tar header are not supposed to be - * null-terminated. We use sprintf, which will write a null after the - * required bytes; that null goes into the first byte of the next field. - * This is okay as long as we fill the fields in order. - */ memset(h, 0, 512); /* assume tar header size */ /* Name 100 */ @@ -84,46 +137,49 @@ tarCreateHeader(char *h, const char *filename, const char *linktarget, } /* Mode 8 - this doesn't include the file type bits (S_IFMT) */ - sprintf(&h[100], "%07o ", (int) (mode & 07777)); + print_tar_number(&h[100], 8, (mode & 07777)); /* User ID 8 */ - sprintf(&h[108], "%07o ", (int) uid); + print_tar_number(&h[108], 8, uid); /* Group 8 */ - sprintf(&h[116], "%07o ", (int) gid); + print_tar_number(&h[116], 8, gid); - /* File size 12 - 11 digits, 1 space; use print_val for 64 bit support */ + /* File size 12 */ if (linktarget != NULL || S_ISDIR(mode)) /* Symbolic link or directory has size zero */ - print_val(&h[124], 0, 8, 11); + print_tar_number(&h[124], 12, 0); else - print_val(&h[124], size, 8, 11); - sprintf(&h[135], " "); + print_tar_number(&h[124], 12, size); /* Mod Time 12 */ - sprintf(&h[136], "%011o ", (int) mtime); + print_tar_number(&h[136], 12, mtime); /* Checksum 8 cannot be calculated until we've filled all other fields */ if (linktarget != NULL) { /* Type - Symbolic link */ - sprintf(&h[156], "2"); + h[156] = '2'; /* Link Name 100 */ strlcpy(&h[157], linktarget, 100); } else if (S_ISDIR(mode)) + { /* Type - directory */ - sprintf(&h[156], "5"); + h[156] = '5'; + } else + { /* Type - regular file */ - sprintf(&h[156], "0"); + h[156] = '0'; + } /* Magic 6 */ - sprintf(&h[257], "ustar"); + strcpy(&h[257], "ustar"); /* Version 2 */ - sprintf(&h[263], "00"); + memcpy(&h[263], "00", 2); /* User 32 */ /* XXX: Do we need to care about setting correct username? */ @@ -134,19 +190,15 @@ tarCreateHeader(char *h, const char *filename, const char *linktarget, strlcpy(&h[297], "postgres", 32); /* Major Dev 8 */ - sprintf(&h[329], "%07o ", 0); + print_tar_number(&h[329], 8, 0); /* Minor Dev 8 */ - sprintf(&h[337], "%07o ", 0); + print_tar_number(&h[337], 8, 0); /* Prefix 155 - not used, leave as nulls */ - /* - * We mustn't overwrite the next field while inserting the checksum. - * Fortunately, the checksum can't exceed 6 octal digits, so we just write - * 6 digits, a space, and a null, which is legal per POSIX. - */ - sprintf(&h[148], "%06o ", tarChecksum(h)); + /* Finally, compute and insert the checksum */ + print_tar_number(&h[148], 8, tarChecksum(h)); return TAR_OK; } |