From: Jonathan Nieder <jrnieder@xxxxxxxxx> Each window in a subversion delta (svndiff0-format file) starts with a window header, consisting of five integers with variable-length representation: source view offset source view length output length instructions length auxiliary data length Parse it. The result is not usable for deltas with nonempty postimage yet; in fact, this only adds support for deltas without any instructions or auxiliary data. This is a good place to stop, though, since that little support lets us add some simple passing tests concerning error handling to the test suite. Improved-by: Ramkumar Ramachandra <artagnon@xxxxxxxxx> Improved-by: David Barr <david.barr@xxxxxxxxxxxx> Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx> Signed-off-by: David Barr <david.barr@xxxxxxxxxxxx> --- t/t9011-svn-da.sh | 56 +++++++++++++++++++++++++++++++- vcs-svn/svndiff.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 142 insertions(+), 6 deletions(-) diff --git a/t/t9011-svn-da.sh b/t/t9011-svn-da.sh index 6d6a406..2ab580a 100755 --- a/t/t9011-svn-da.sh +++ b/t/t9011-svn-da.sh @@ -28,10 +28,64 @@ test_expect_success 'reject svndiff2' ' test_must_fail test-svn-fe -d preimage bad.filetype 4 ' -test_expect_failure 'one-window empty delta' ' +test_expect_success 'one-window empty delta' ' printf "SVNQ%s" "QQQQQ" | q_to_nul >clear.onewindow && test-svn-fe -d preimage clear.onewindow 9 >actual && test_cmp empty actual ' +test_expect_success 'reject incomplete window header' ' + printf "SVNQ%s" "QQQQQ" | q_to_nul >clear.onewindow && + printf "SVNQ%s" "QQ" | q_to_nul >clear.partialwindow && + test_must_fail test-svn-fe -d preimage clear.onewindow 6 && + test_must_fail test-svn-fe -d preimage clear.partialwindow 6 +' + +test_expect_success 'reject declared delta longer than actual delta' ' + printf "SVNQ%s" "QQQQQ" | q_to_nul >clear.onewindow && + printf "SVNQ%s" "QQ" | q_to_nul >clear.partialwindow && + test_must_fail test-svn-fe -d preimage clear.onewindow 14 && + test_must_fail test-svn-fe -d preimage clear.partialwindow 9 +' + +test_expect_success 'two-window empty delta' ' + printf "SVNQ%s%s" "QQQQQ" "QQQQQ" | q_to_nul >clear.twowindow && + test-svn-fe -d preimage clear.twowindow 14 >actual && + test_must_fail test-svn-fe -d preimage clear.twowindow 13 && + test_cmp empty actual +' + +test_expect_success 'noisy zeroes' ' + printf "SVNQ%s" \ + "RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRQQQQQ" | + tr R "\200" | + q_to_nul >clear.noisy && + len=$(wc -c <clear.noisy) && + test-svn-fe -d preimage clear.noisy $len && + test_cmp empty actual +' + +test_expect_success 'reject variable-length int in magic' ' + printf "SVNRQ" | tr R "\200" | q_to_nul >clear.badmagic && + test_must_fail test-svn-fe -d preimage clear.badmagic 5 +' + +test_expect_success 'reject truncated integer' ' + printf "SVNQ%s%s" "QQQQQ" "QQQQRRQ" | + tr R "\200" | + q_to_nul >clear.fullint && + printf "SVNQ%s%s" "QQQQQ" "QQQQRR" | + tr RT "\201" | + q_to_nul >clear.partialint && + test_must_fail test-svn-fe -d preimage clear.fullint 15 && + test-svn-fe -d preimage clear.fullint 16 && + test_must_fail test-svn-fe -d preimage clear.partialint 15 +' + +test_expect_success 'nonempty (but unused) preimage view' ' + printf "SVNQ%b" "Q\003QQQ" | q_to_nul >clear.readpreimage && + test-svn-fe -d preimage clear.readpreimage 9 >actual && + test_cmp empty actual +' + test_done diff --git a/vcs-svn/svndiff.c b/vcs-svn/svndiff.c index 5916036..249efb6 100644 --- a/vcs-svn/svndiff.c +++ b/vcs-svn/svndiff.c @@ -13,8 +13,16 @@ * See http://svn.apache.org/repos/asf/subversion/trunk/notes/svndiff. * * svndiff0 ::= 'SVN\0' window* + * window ::= int int int int int instructions inline_data; + * int ::= highdigit* lowdigit; + * highdigit ::= # binary 1000 0000 OR-ed with 7 bit value; + * lowdigit ::= # 7 bit value; */ +#define VLI_CONTINUE 0x80 +#define VLI_DIGIT_MASK 0x7f +#define VLI_BITS_PER_DIGIT 7 + static int error_short_read(struct line_buffer *input) { if (buffer_ferror(input)) @@ -28,17 +36,84 @@ static int read_magic(struct line_buffer *in, off_t *len) struct strbuf sb = STRBUF_INIT; if (*len < sizeof(magic) || - buffer_read_binary(in, &sb, sizeof(magic)) != sizeof(magic)) - return error_short_read(in); + buffer_read_binary(in, &sb, sizeof(magic)) != sizeof(magic)) { + error_short_read(in); + strbuf_release(&sb); + return -1; + } - if (memcmp(sb.buf, magic, sizeof(magic))) + if (memcmp(sb.buf, magic, sizeof(magic))) { + strbuf_release(&sb); return error("invalid delta: unrecognized file type"); + } *len -= sizeof(magic); strbuf_release(&sb); return 0; } +static int read_int(struct line_buffer *in, uintmax_t *result, off_t *len) +{ + uintmax_t rv = 0; + off_t sz; + for (sz = *len; sz; sz--) { + const int ch = buffer_read_char(in); + if (ch == EOF) + break; + + rv <<= VLI_BITS_PER_DIGIT; + rv += (ch & VLI_DIGIT_MASK); + if (ch & VLI_CONTINUE) + continue; + + *result = rv; + *len = sz - 1; + return 0; + } + return error_short_read(in); +} + +static int read_offset(struct line_buffer *in, off_t *result, off_t *len) +{ + uintmax_t val; + if (read_int(in, &val, len)) + return -1; + if (val > maximum_signed_value_of_type(off_t)) + return error("unrepresentable offset in delta: %"PRIuMAX"", val); + *result = val; + return 0; +} + +static int read_length(struct line_buffer *in, size_t *result, off_t *len) +{ + uintmax_t val; + if (read_int(in, &val, len)) + return -1; + if (val > SIZE_MAX) + return error("unrepresentable length in delta: %"PRIuMAX"", val); + *result = val; + return 0; +} + +static int apply_one_window(struct line_buffer *delta, off_t *delta_len) +{ + size_t out_len; + size_t instructions_len; + size_t data_len; + assert(delta_len); + + /* "source view" offset and length already handled; */ + if (read_length(delta, &out_len, delta_len) || + read_length(delta, &instructions_len, delta_len) || + read_length(delta, &data_len, delta_len)) + return -1; + if (instructions_len) + return error("What do you think I am? A delta applier?"); + if (data_len) + return error("No support for inline data yet"); + return 0; +} + int svndiff0_apply(struct line_buffer *delta, off_t delta_len, struct sliding_view *preimage, FILE *postimage) { @@ -46,7 +121,14 @@ int svndiff0_apply(struct line_buffer *delta, off_t delta_len, if (read_magic(delta, &delta_len)) return -1; - if (delta_len) - return error("What do you think I am? A delta applier?"); + while (delta_len) { /* For each window: */ + off_t pre_off; + size_t pre_len; + + if (read_offset(delta, &pre_off, &delta_len) || + read_length(delta, &pre_len, &delta_len) || + apply_one_window(delta, &delta_len)) + return -1; + } return 0; } -- 1.7.3.2.846.gf4b062 -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html