csum-file: introduce discard_hashfile()
The hashfile API is used to write out a "hashfile", which has a final checksum (typically SHA-1) at the end. An in-core hashfile structure has up to two file descriptors and a few buffers that can only be freed by calling a helper function that is private to the csum-file implementation. The usual flow of a user of the API is to first open a file descriptor for writing, obtain a hashfile associated with that write file descriptor by calling either hashfd() or hashfd_check(), call hashwrite() number of times to write data to the file, and then call finalize_hashfile(), which appends th checksum to the end of the file, closes file descriptors and releases associated buffers. But what if a caller finds some error after calling hashfd() to start the process and/or hashwrite() to send some data to the file, and wants to abort the operation? The underlying file descriptor is often managed by the tempfile API, so aborting will clean the file out of the filesystem, but the resources associated with the in-core hashfile structure is lost. Introduce discard_hashfile() API function to allow them to release the resources held by a hashfile structure the callers want to dispose of, and use that in read-cache.c:do_write_index(), which is a central place that writes the index file. Mark t2107 as leak-free, as this leak in "update-index --cacheinfo" test that deliberately makes it fail is now plugged. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Junio C Hamano committed
Jul 25, 2024 at 16:07 UTC
c3d034df1606beca8a4ba3bc8a8266f4c711f23c
4 files changed
+89
-21
csum-file.c
+9
@@ -102,6 +102,15 @@ int finalize_hashfile(struct hashfile *f, unsigned char *result,
102
return fd;
103
}
104
105
+void discard_hashfile(struct hashfile *f)
106
+{
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+ if (0 <= f->check_fd)
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+ close(f->check_fd);
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+ if (0 <= f->fd)
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+ close(f->fd);
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+ free_hashfile(f);
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+}
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+
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void hashwrite(struct hashfile *f, const void *buf, unsigned int count)
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{
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while (count) {
csum-file.h
+1
@@ -47,6 +47,7 @@ struct hashfile *hashfd(int fd, const char *name);
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struct hashfile *hashfd_check(const char *name);
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struct hashfile *hashfd_throughput(int fd, const char *name, struct progress *tp);
49
int finalize_hashfile(struct hashfile *, unsigned char *, enum fsync_component, unsigned int);
50
+void discard_hashfile(struct hashfile *);
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void hashwrite(struct hashfile *, const void *, unsigned int);
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void hashflush(struct hashfile *f);
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void crc32_begin(struct hashfile *);
read-cache.c
+78
-21
@@ -2963,7 +2963,7 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
2963
2964
if (err) {
2965
free(ieot);
2966
- return err;
2966
+ goto cleanup;
2967
}
2968
2969
offset = hashfile_total(f);
@@ -2992,8 +2992,14 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
2992
hashwrite(f, sb.buf, sb.len);
2993
strbuf_release(&sb);
2994
free(ieot);
2995
- if (err)
2996
- return -1;
2995
+ /*
2996
+ * NEEDSWORK: write_index_ext_header() never returns a failure,
2997
+ * and this part may want to be simplified.
2998
+ */
2999
+ if (err) {
3000
+ err = -1;
3001
+ goto cleanup;
3002
+ }
3003
}
3004
3005
if (write_extensions & WRITE_SPLIT_INDEX_EXTENSION &&
@@ -3008,8 +3014,14 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3014
sb.len) < 0;
3015
hashwrite(f, sb.buf, sb.len);
3016
strbuf_release(&sb);
3011
- if (err)
3012
- return -1;
3017
+ /*
3018
+ * NEEDSWORK: write_link_extension() never returns a failure,
3019
+ * and this part may want to be simplified.
3020
+ */
3021
+ if (err) {
3022
+ err = -1;
3023
+ goto cleanup;
3024
+ }
3025
}
3026
if (write_extensions & WRITE_CACHE_TREE_EXTENSION &&
3027
!drop_cache_tree && istate->cache_tree) {
@@ -3019,8 +3031,14 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3031
err = write_index_ext_header(f, eoie_c, CACHE_EXT_TREE, sb.len) < 0;
3032
hashwrite(f, sb.buf, sb.len);
3033
strbuf_release(&sb);
3022
- if (err)
3023
- return -1;
3034
+ /*
3035
+ * NEEDSWORK: write_index_ext_header() never returns a failure,
3036
+ * and this part may want to be simplified.
3037
+ */
3038
+ if (err) {
3039
+ err = -1;
3040
+ goto cleanup;
3041
+ }
3042
}
3043
if (write_extensions & WRITE_RESOLVE_UNDO_EXTENSION &&
3044
istate->resolve_undo) {
@@ -3031,8 +3049,14 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3049
sb.len) < 0;
3050
hashwrite(f, sb.buf, sb.len);
3051
strbuf_release(&sb);
3034
- if (err)
3035
- return -1;
3052
+ /*
3053
+ * NEEDSWORK: write_index_ext_header() never returns a failure,
3054
+ * and this part may want to be simplified.
3055
+ */
3056
+ if (err) {
3057
+ err = -1;
3058
+ goto cleanup;
3059
+ }
3060
}
3061
if (write_extensions & WRITE_UNTRACKED_CACHE_EXTENSION &&
3062
istate->untracked) {
@@ -3043,8 +3067,14 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3067
sb.len) < 0;
3068
hashwrite(f, sb.buf, sb.len);
3069
strbuf_release(&sb);
3046
- if (err)
3047
- return -1;
3070
+ /*
3071
+ * NEEDSWORK: write_index_ext_header() never returns a failure,
3072
+ * and this part may want to be simplified.
3073
+ */
3074
+ if (err) {
3075
+ err = -1;
3076
+ goto cleanup;
3077
+ }
3078
}
3079
if (write_extensions & WRITE_FSMONITOR_EXTENSION &&
3080
istate->fsmonitor_last_update) {
@@ -3054,12 +3084,25 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3084
err = write_index_ext_header(f, eoie_c, CACHE_EXT_FSMONITOR, sb.len) < 0;
3085
hashwrite(f, sb.buf, sb.len);
3086
strbuf_release(&sb);
3057
- if (err)
3058
- return -1;
3087
+ /*
3088
+ * NEEDSWORK: write_index_ext_header() never returns a failure,
3089
+ * and this part may want to be simplified.
3090
+ */
3091
+ if (err) {
3092
+ err = -1;
3093
+ goto cleanup;
3094
+ }
3095
}
3096
if (istate->sparse_index) {
3061
- if (write_index_ext_header(f, eoie_c, CACHE_EXT_SPARSE_DIRECTORIES, 0) < 0)
3062
- return -1;
3097
+ err = write_index_ext_header(f, eoie_c, CACHE_EXT_SPARSE_DIRECTORIES, 0);
3098
+ /*
3099
+ * NEEDSWORK: write_index_ext_header() never returns a failure,
3100
+ * and this part may want to be simplified.
3101
+ */
3102
+ if (err) {
3103
+ err = -1;
3104
+ goto cleanup;
3105
+ }
3106
}
3107
3108
/*
@@ -3075,8 +3118,14 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3118
err = write_index_ext_header(f, NULL, CACHE_EXT_ENDOFINDEXENTRIES, sb.len) < 0;
3119
hashwrite(f, sb.buf, sb.len);
3120
strbuf_release(&sb);
3078
- if (err)
3079
- return -1;
3121
+ /*
3122
+ * NEEDSWORK: write_index_ext_header() never returns a failure,
3123
+ * and this part may want to be simplified.
3124
+ */
3125
+ if (err) {
3126
+ err = -1;
3127
+ goto cleanup;
3128
+ }
3129
}
3130
3131
csum_fsync_flag = 0;
@@ -3085,13 +3134,16 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3134
3135
finalize_hashfile(f, istate->oid.hash, FSYNC_COMPONENT_INDEX,
3136
CSUM_HASH_IN_STREAM | csum_fsync_flag);
3137
+ f = NULL;
3138
3139
if (close_tempfile_gently(tempfile)) {
3090
- error(_("could not close '%s'"), get_tempfile_path(tempfile));
3091
- return -1;
3140
+ err = error(_("could not close '%s'"), get_tempfile_path(tempfile));
3141
+ goto cleanup;
3142
+ }
3143
+ if (stat(get_tempfile_path(tempfile), &st)) {
3144
+ err = error_errno(_("could not stat '%s'"), get_tempfile_path(tempfile));
3145
+ goto cleanup;
3146
}
3093
- if (stat(get_tempfile_path(tempfile), &st))
3094
- return -1;
3147
istate->timestamp.sec = (unsigned int)st.st_mtime;
3148
istate->timestamp.nsec = ST_MTIME_NSEC(st);
3149
trace_performance_since(start, "write index, changed mask = %x", istate->cache_changed);
@@ -3106,6 +3158,11 @@ static int do_write_index(struct index_state *istate, struct tempfile *tempfile,
3158
istate->cache_nr);
3159
3160
return 0;
3161
+
3162
+cleanup:
3163
+ if (f)
3164
+ discard_hashfile(f);
3165
+ return err;
3166
}
3167
3168
void set_alternate_index_output(const char *name)
t/t2107-update-index-basic.sh
+1
@@ -5,6 +5,7 @@ test_description='basic update-index tests
5
Tests for command-line parsing and basic operation.
6
'
7
8
+TEST_PASSES_SANITIZE_LEAK=true
9
. ./test-lib.sh
10
11
test_expect_success 'update-index --nonsense fails' '