git/builtin-rerere.c
Jim Meyering 91c8d5905c detect close failure on just-written file handles
I audited git for potential undetected write failures.
In the cases fixed below, the diagnostics I add mimic the diagnostics
used in surrounding code, even when that means not reporting
the precise strerror(errno) cause of the error.

Signed-off-by: Jim Meyering <jim@meyering.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-06-26 21:48:53 -07:00

438 lines
10 KiB
C

#include "cache.h"
#include "path-list.h"
#include "xdiff/xdiff.h"
#include "xdiff-interface.h"
#include <time.h>
static const char git_rerere_usage[] =
"git-rerere [clear | status | diff | gc]";
/* these values are days */
static int cutoff_noresolve = 15;
static int cutoff_resolve = 60;
static char *merge_rr_path;
static const char *rr_path(const char *name, const char *file)
{
return git_path("rr-cache/%s/%s", name, file);
}
static void read_rr(struct path_list *rr)
{
unsigned char sha1[20];
char buf[PATH_MAX];
FILE *in = fopen(merge_rr_path, "r");
if (!in)
return;
while (fread(buf, 40, 1, in) == 1) {
int i;
char *name;
if (get_sha1_hex(buf, sha1))
die("corrupt MERGE_RR");
buf[40] = '\0';
name = xstrdup(buf);
if (fgetc(in) != '\t')
die("corrupt MERGE_RR");
for (i = 0; i < sizeof(buf) && (buf[i] = fgetc(in)); i++)
; /* do nothing */
if (i == sizeof(buf))
die("filename too long");
path_list_insert(buf, rr)->util = xstrdup(name);
}
fclose(in);
}
static struct lock_file write_lock;
static int write_rr(struct path_list *rr, int out_fd)
{
int i;
for (i = 0; i < rr->nr; i++) {
const char *path = rr->items[i].path;
int length = strlen(path) + 1;
if (write_in_full(out_fd, rr->items[i].util, 40) != 40 ||
write_in_full(out_fd, "\t", 1) != 1 ||
write_in_full(out_fd, path, length) != length)
die("unable to write rerere record");
}
if (close(out_fd) != 0)
die("unable to write rerere record");
return commit_lock_file(&write_lock);
}
struct buffer {
char *ptr;
int nr, alloc;
};
static void append_line(struct buffer *buffer, const char *line)
{
int len = strlen(line);
if (buffer->nr + len > buffer->alloc) {
buffer->alloc = alloc_nr(buffer->nr + len);
buffer->ptr = xrealloc(buffer->ptr, buffer->alloc);
}
memcpy(buffer->ptr + buffer->nr, line, len);
buffer->nr += len;
}
static void clear_buffer(struct buffer *buffer)
{
free(buffer->ptr);
buffer->ptr = NULL;
buffer->nr = buffer->alloc = 0;
}
static int handle_file(const char *path,
unsigned char *sha1, const char *output)
{
SHA_CTX ctx;
char buf[1024];
int hunk = 0, hunk_no = 0;
struct buffer minus = { NULL, 0, 0 }, plus = { NULL, 0, 0 };
struct buffer *one = &minus, *two = &plus;
FILE *f = fopen(path, "r");
FILE *out;
if (!f)
return error("Could not open %s", path);
if (output) {
out = fopen(output, "w");
if (!out) {
fclose(f);
return error("Could not write %s", output);
}
} else
out = NULL;
if (sha1)
SHA1_Init(&ctx);
while (fgets(buf, sizeof(buf), f)) {
if (!prefixcmp(buf, "<<<<<<< "))
hunk = 1;
else if (!prefixcmp(buf, "======="))
hunk = 2;
else if (!prefixcmp(buf, ">>>>>>> ")) {
int one_is_longer = (one->nr > two->nr);
int common_len = one_is_longer ? two->nr : one->nr;
int cmp = memcmp(one->ptr, two->ptr, common_len);
hunk_no++;
hunk = 0;
if ((cmp > 0) || ((cmp == 0) && one_is_longer)) {
struct buffer *swap = one;
one = two;
two = swap;
}
if (out) {
fputs("<<<<<<<\n", out);
fwrite(one->ptr, one->nr, 1, out);
fputs("=======\n", out);
fwrite(two->ptr, two->nr, 1, out);
fputs(">>>>>>>\n", out);
}
if (sha1) {
SHA1_Update(&ctx, one->ptr, one->nr);
SHA1_Update(&ctx, "\0", 1);
SHA1_Update(&ctx, two->ptr, two->nr);
SHA1_Update(&ctx, "\0", 1);
}
clear_buffer(one);
clear_buffer(two);
} else if (hunk == 1)
append_line(one, buf);
else if (hunk == 2)
append_line(two, buf);
else if (out)
fputs(buf, out);
}
fclose(f);
if (out)
fclose(out);
if (sha1)
SHA1_Final(sha1, &ctx);
return hunk_no;
}
static int find_conflict(struct path_list *conflict)
{
int i;
if (read_cache() < 0)
return error("Could not read index");
for (i = 0; i + 2 < active_nr; i++) {
struct cache_entry *e1 = active_cache[i];
struct cache_entry *e2 = active_cache[i+1];
struct cache_entry *e3 = active_cache[i+2];
if (ce_stage(e1) == 1 &&
ce_stage(e2) == 2 &&
ce_stage(e3) == 3 &&
ce_same_name(e1, e2) && ce_same_name(e1, e3) &&
S_ISREG(ntohl(e1->ce_mode)) &&
S_ISREG(ntohl(e2->ce_mode)) &&
S_ISREG(ntohl(e3->ce_mode))) {
path_list_insert((const char *)e1->name, conflict);
i += 2;
}
}
return 0;
}
static int merge(const char *name, const char *path)
{
int ret;
mmfile_t cur, base, other;
mmbuffer_t result = {NULL, 0};
xpparam_t xpp = {XDF_NEED_MINIMAL};
if (handle_file(path, NULL, rr_path(name, "thisimage")) < 0)
return 1;
if (read_mmfile(&cur, rr_path(name, "thisimage")) ||
read_mmfile(&base, rr_path(name, "preimage")) ||
read_mmfile(&other, rr_path(name, "postimage")))
return 1;
ret = xdl_merge(&base, &cur, "", &other, "",
&xpp, XDL_MERGE_ZEALOUS, &result);
if (!ret) {
FILE *f = fopen(path, "w");
if (!f)
return error("Could not write to %s", path);
fwrite(result.ptr, result.size, 1, f);
fclose(f);
}
free(cur.ptr);
free(base.ptr);
free(other.ptr);
free(result.ptr);
return ret;
}
static void unlink_rr_item(const char *name)
{
unlink(rr_path(name, "thisimage"));
unlink(rr_path(name, "preimage"));
unlink(rr_path(name, "postimage"));
rmdir(git_path("rr-cache/%s", name));
}
static void garbage_collect(struct path_list *rr)
{
struct path_list to_remove = { NULL, 0, 0, 1 };
char buf[1024];
DIR *dir;
struct dirent *e;
int len, i, cutoff;
time_t now = time(NULL), then;
strlcpy(buf, git_path("rr-cache"), sizeof(buf));
len = strlen(buf);
dir = opendir(buf);
strcpy(buf + len++, "/");
while ((e = readdir(dir))) {
const char *name = e->d_name;
struct stat st;
if (name[0] == '.' && (name[1] == '\0' ||
(name[1] == '.' && name[2] == '\0')))
continue;
i = snprintf(buf + len, sizeof(buf) - len, "%s", name);
strlcpy(buf + len + i, "/preimage", sizeof(buf) - len - i);
if (stat(buf, &st))
continue;
then = st.st_mtime;
strlcpy(buf + len + i, "/postimage", sizeof(buf) - len - i);
cutoff = stat(buf, &st) ? cutoff_noresolve : cutoff_resolve;
if (then < now - cutoff * 86400) {
buf[len + i] = '\0';
path_list_insert(xstrdup(name), &to_remove);
}
}
for (i = 0; i < to_remove.nr; i++)
unlink_rr_item(to_remove.items[i].path);
path_list_clear(&to_remove, 0);
}
static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
{
int i;
for (i = 0; i < nbuf; i++)
if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
return -1;
return 0;
}
static int diff_two(const char *file1, const char *label1,
const char *file2, const char *label2)
{
xpparam_t xpp;
xdemitconf_t xecfg;
xdemitcb_t ecb;
mmfile_t minus, plus;
if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
return 1;
printf("--- a/%s\n+++ b/%s\n", label1, label2);
fflush(stdout);
xpp.flags = XDF_NEED_MINIMAL;
xecfg.ctxlen = 3;
xecfg.flags = 0;
ecb.outf = outf;
xdl_diff(&minus, &plus, &xpp, &xecfg, &ecb);
free(minus.ptr);
free(plus.ptr);
return 0;
}
static int copy_file(const char *src, const char *dest)
{
FILE *in, *out;
char buffer[32768];
int count;
if (!(in = fopen(src, "r")))
return error("Could not open %s", src);
if (!(out = fopen(dest, "w")))
return error("Could not open %s", dest);
while ((count = fread(buffer, 1, sizeof(buffer), in)))
fwrite(buffer, 1, count, out);
fclose(in);
fclose(out);
return 0;
}
static int do_plain_rerere(struct path_list *rr, int fd)
{
struct path_list conflict = { NULL, 0, 0, 1 };
int i;
find_conflict(&conflict);
/*
* MERGE_RR records paths with conflicts immediately after merge
* failed. Some of the conflicted paths might have been hand resolved
* in the working tree since then, but the initial run would catch all
* and register their preimages.
*/
for (i = 0; i < conflict.nr; i++) {
const char *path = conflict.items[i].path;
if (!path_list_has_path(rr, path)) {
unsigned char sha1[20];
char *hex;
int ret;
ret = handle_file(path, sha1, NULL);
if (ret < 1)
continue;
hex = xstrdup(sha1_to_hex(sha1));
path_list_insert(path, rr)->util = hex;
if (mkdir(git_path("rr-cache/%s", hex), 0755))
continue;;
handle_file(path, NULL, rr_path(hex, "preimage"));
fprintf(stderr, "Recorded preimage for '%s'\n", path);
}
}
/*
* Now some of the paths that had conflicts earlier might have been
* hand resolved. Others may be similar to a conflict already that
* was resolved before.
*/
for (i = 0; i < rr->nr; i++) {
struct stat st;
int ret;
const char *path = rr->items[i].path;
const char *name = (const char *)rr->items[i].util;
if (!stat(rr_path(name, "preimage"), &st) &&
!stat(rr_path(name, "postimage"), &st)) {
if (!merge(name, path)) {
fprintf(stderr, "Resolved '%s' using "
"previous resolution.\n", path);
goto tail_optimization;
}
}
/* Let's see if we have resolved it. */
ret = handle_file(path, NULL, NULL);
if (ret)
continue;
fprintf(stderr, "Recorded resolution for '%s'.\n", path);
copy_file(path, rr_path(name, "postimage"));
tail_optimization:
if (i < rr->nr - 1)
memmove(rr->items + i,
rr->items + i + 1,
sizeof(rr->items[0]) * (rr->nr - i - 1));
rr->nr--;
i--;
}
return write_rr(rr, fd);
}
static int git_rerere_config(const char *var, const char *value)
{
if (!strcmp(var, "gc.rerereresolved"))
cutoff_resolve = git_config_int(var, value);
else if (!strcmp(var, "gc.rerereunresolved"))
cutoff_noresolve = git_config_int(var, value);
else
return git_default_config(var, value);
return 0;
}
int cmd_rerere(int argc, const char **argv, const char *prefix)
{
struct path_list merge_rr = { NULL, 0, 0, 1 };
int i, fd = -1;
struct stat st;
if (stat(git_path("rr-cache"), &st) || !S_ISDIR(st.st_mode))
return 0;
git_config(git_rerere_config);
merge_rr_path = xstrdup(git_path("rr-cache/MERGE_RR"));
fd = hold_lock_file_for_update(&write_lock, merge_rr_path, 1);
read_rr(&merge_rr);
if (argc < 2)
return do_plain_rerere(&merge_rr, fd);
else if (!strcmp(argv[1], "clear")) {
for (i = 0; i < merge_rr.nr; i++) {
const char *name = (const char *)merge_rr.items[i].util;
if (!stat(git_path("rr-cache/%s", name), &st) &&
S_ISDIR(st.st_mode) &&
stat(rr_path(name, "postimage"), &st))
unlink_rr_item(name);
}
unlink(merge_rr_path);
} else if (!strcmp(argv[1], "gc"))
garbage_collect(&merge_rr);
else if (!strcmp(argv[1], "status"))
for (i = 0; i < merge_rr.nr; i++)
printf("%s\n", merge_rr.items[i].path);
else if (!strcmp(argv[1], "diff"))
for (i = 0; i < merge_rr.nr; i++) {
const char *path = merge_rr.items[i].path;
const char *name = (const char *)merge_rr.items[i].util;
diff_two(rr_path(name, "preimage"), path, path, path);
}
else
usage(git_rerere_usage);
path_list_clear(&merge_rr, 1);
return 0;
}