@matheusbsbs / matheus-bagliano / commits / fb8952077d

fsck: use strbuf_getline() to read skiplist file

The buffer is unlikely to contain a NUL character, so printing its contents using %s in a die() format is unsafe (detected with ASan). Use an idiomatic strbuf_getline() loop instead, which ensures the buffer is always NUL-terminated, supports CRLF files as well, accepts files without a newline after the last line, supports any hash length automatically, and is shorter. This fixes a bug where emitting an error about an invalid line on say line 1 would continue printing subsequent lines, and usually continue into uninitialized memory. The performance impact of this, on a CentOS 7 box with RedHat GCC 4.8.5-28: $ GIT_PERF_REPEAT_COUNT=5 GIT_PERF_MAKE_OPTS='-j56 CFLAGS="-O3"' ./run HEAD~ HEAD p1451-fsck-skip-list.sh Test HEAD~ HEAD ---------------------------------------------------------------------------------------- 1450.3: fsck with 0 skipped bad commits 7.75(7.39+0.35) 7.68(7.29+0.39) -0.9% 1450.5: fsck with 1 skipped bad commits 7.70(7.30+0.40) 7.80(7.42+0.37) +1.3% 1450.7: fsck with 10 skipped bad commits 7.77(7.37+0.40) 7.87(7.47+0.40) +1.3% 1450.9: fsck with 100 skipped bad commits 7.82(7.41+0.40) 7.88(7.43+0.44) +0.8% 1450.11: fsck with 1000 skipped bad commits 7.88(7.49+0.39) 7.84(7.43+0.40) -0.5% 1450.13: fsck with 10000 skipped bad commits 8.02(7.63+0.39) 8.07(7.67+0.39) +0.6% 1450.15: fsck with 100000 skipped bad commits 8.01(7.60+0.41) 8.08(7.70+0.38) +0.9% 1450.17: fsck with 1000000 skipped bad commits 7.60(7.10+0.50) 7.37(7.18+0.19) -3.0% Helped-by: Jeff King <peff@peff.net> Signed-off-by: Rene Scharfe <l.s.r@web.de> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

René Scharfe committed Sep 3, 2018 at 14:49 UTC fb8952077dfa11dc1534b5a9d965cbb39b043af4

2 files changed +13 -14

fsck.c

+12 -13

@@ -183,8 +183,9 @@ static int fsck_msg_type(enum fsck_msg_id msg_id,

183 static void init_skiplist(struct fsck_options *options, const char *path)

184 {

185 static struct oid_array skiplist = OID_ARRAY_INIT;

186 - int sorted, fd;

187 - char buffer[GIT_MAX_HEXSZ + 1];

186 + int sorted;

187 + FILE *fp;

188 + struct strbuf sb = STRBUF_INIT;

189 struct object_id oid;

190

191 if (options->skiplist)

@@ -194,25 +195,23 @@ static void init_skiplist(struct fsck_options *options, const char *path)

195 options->skiplist = &skiplist;

196 }

197

197 - fd = open(path, O_RDONLY);

198 - if (fd < 0)

198 + fp = fopen(path, "r");

199 + if (!fp)

200 die("Could not open skip list: %s", path);

200 - for (;;) {

201 + while (!strbuf_getline(&sb, fp)) {

202 const char *p;

202 - int result = read_in_full(fd, buffer, sizeof(buffer));

203 - if (result < 0)

204 - die_errno("Could not read '%s'", path);

205 - if (!result)

206 - break;

207 - if (parse_oid_hex(buffer, &oid, &p) || *p != '\n')

208 - die("Invalid SHA-1: %s", buffer);

203 + if (parse_oid_hex(sb.buf, &oid, &p) || *p != '\0')

204 + die("Invalid SHA-1: %s", sb.buf);

205 oid_array_append(&skiplist, &oid);

206 if (sorted && skiplist.nr > 1 &&

207 oidcmp(&skiplist.oid[skiplist.nr - 2],

208 &oid) > 0)

209 sorted = 0;

210 }

215 - close(fd);

211 + if (ferror(fp))

212 + die_errno("Could not read '%s'", path);

213 + fclose(fp);

214 + strbuf_release(&sb);

215

216 if (sorted)

217 skiplist.sorted = 1;

t/t5504-fetch-receive-strict.sh

+1 -1

@@ -185,7 +185,7 @@ test_expect_success 'fsck with invalid or bogus skipList input (comments & empty

185 test_i18ngrep "^fatal: Invalid SHA-1: " err-with-empty-line

186 '

187

188 -test_expect_failure 'fsck no garbage output from comments & empty lines errors' '

188 +test_expect_success 'fsck no garbage output from comments & empty lines errors' '

189 test_line_count = 1 err-with-comment &&

190 test_line_count = 1 err-with-empty-line

191 '