git/read-cache.c
Linus Torvalds 5d1a5c02e8 [PATCH] Better error reporting for "git status"
Instead of "git status" ignoring (and hiding) potential errors from the
"git-update-index" call, make it exit if it fails, and show the error.

In order to do this, use the "-q" flag (to ignore not-up-to-date files)
and add a new "--unmerged" flag that allows unmerged entries in the index
without any errors.

This also avoids marking the index "changed" if an entry isn't actually
modified, and makes sure that we exit with an understandable error message
if the index is corrupt or unreadable. "read_cache()" no longer returns an
error for the caller to check.

Finally, make die() and usage() exit with recognizable error codes, if we
ever want to check the failure reason in scripts.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-10-01 23:55:47 -07:00

588 lines
14 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
struct cache_entry **active_cache = NULL;
unsigned int active_nr = 0, active_alloc = 0, active_cache_changed = 0;
/*
* This only updates the "non-critical" parts of the directory
* cache, ie the parts that aren't tracked by GIT, and only used
* to validate the cache.
*/
void fill_stat_cache_info(struct cache_entry *ce, struct stat *st)
{
ce->ce_ctime.sec = htonl(st->st_ctime);
ce->ce_mtime.sec = htonl(st->st_mtime);
#ifdef USE_NSEC
ce->ce_ctime.nsec = htonl(st->st_ctim.tv_nsec);
ce->ce_mtime.nsec = htonl(st->st_mtim.tv_nsec);
#endif
ce->ce_dev = htonl(st->st_dev);
ce->ce_ino = htonl(st->st_ino);
ce->ce_uid = htonl(st->st_uid);
ce->ce_gid = htonl(st->st_gid);
ce->ce_size = htonl(st->st_size);
}
int ce_match_stat(struct cache_entry *ce, struct stat *st)
{
unsigned int changed = 0;
switch (ntohl(ce->ce_mode) & S_IFMT) {
case S_IFREG:
changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0;
/* We consider only the owner x bit to be relevant for "mode changes" */
if (0100 & (ntohl(ce->ce_mode) ^ st->st_mode))
changed |= MODE_CHANGED;
break;
case S_IFLNK:
changed |= !S_ISLNK(st->st_mode) ? TYPE_CHANGED : 0;
break;
default:
die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
}
if (ce->ce_mtime.sec != htonl(st->st_mtime))
changed |= MTIME_CHANGED;
if (ce->ce_ctime.sec != htonl(st->st_ctime))
changed |= CTIME_CHANGED;
#ifdef USE_NSEC
/*
* nsec seems unreliable - not all filesystems support it, so
* as long as it is in the inode cache you get right nsec
* but after it gets flushed, you get zero nsec.
*/
if (ce->ce_mtime.nsec != htonl(st->st_mtim.tv_nsec))
changed |= MTIME_CHANGED;
if (ce->ce_ctime.nsec != htonl(st->st_ctim.tv_nsec))
changed |= CTIME_CHANGED;
#endif
if (ce->ce_uid != htonl(st->st_uid) ||
ce->ce_gid != htonl(st->st_gid))
changed |= OWNER_CHANGED;
if (ce->ce_ino != htonl(st->st_ino))
changed |= INODE_CHANGED;
#ifdef USE_STDEV
/*
* st_dev breaks on network filesystems where different
* clients will have different views of what "device"
* the filesystem is on
*/
if (ce->ce_dev != htonl(st->st_dev))
changed |= INODE_CHANGED;
#endif
if (ce->ce_size != htonl(st->st_size))
changed |= DATA_CHANGED;
return changed;
}
static int ce_compare_data(struct cache_entry *ce, struct stat *st)
{
int match = -1;
int fd = open(ce->name, O_RDONLY);
if (fd >= 0) {
unsigned char sha1[20];
if (!index_fd(sha1, fd, st, 0, NULL))
match = memcmp(sha1, ce->sha1, 20);
close(fd);
}
return match;
}
static int ce_compare_link(struct cache_entry *ce, unsigned long expected_size)
{
int match = -1;
char *target;
void *buffer;
unsigned long size;
char type[10];
int len;
target = xmalloc(expected_size);
len = readlink(ce->name, target, expected_size);
if (len != expected_size) {
free(target);
return -1;
}
buffer = read_sha1_file(ce->sha1, type, &size);
if (!buffer) {
free(target);
return -1;
}
if (size == expected_size)
match = memcmp(buffer, target, size);
free(buffer);
free(target);
return match;
}
int ce_modified(struct cache_entry *ce, struct stat *st)
{
int changed;
changed = ce_match_stat(ce, st);
if (!changed)
return 0;
/*
* If the mode or type has changed, there's no point in trying
* to refresh the entry - it's not going to match
*/
if (changed & (MODE_CHANGED | TYPE_CHANGED))
return changed;
/* Immediately after read-tree or update-index --cacheinfo,
* the length field is zero. For other cases the ce_size
* should match the SHA1 recorded in the index entry.
*/
if ((changed & DATA_CHANGED) && ce->ce_size != htonl(0))
return changed;
switch (st->st_mode & S_IFMT) {
case S_IFREG:
if (ce_compare_data(ce, st))
return changed | DATA_CHANGED;
break;
case S_IFLNK:
if (ce_compare_link(ce, st->st_size))
return changed | DATA_CHANGED;
break;
default:
return changed | TYPE_CHANGED;
}
return 0;
}
int base_name_compare(const char *name1, int len1, int mode1,
const char *name2, int len2, int mode2)
{
unsigned char c1, c2;
int len = len1 < len2 ? len1 : len2;
int cmp;
cmp = memcmp(name1, name2, len);
if (cmp)
return cmp;
c1 = name1[len];
c2 = name2[len];
if (!c1 && S_ISDIR(mode1))
c1 = '/';
if (!c2 && S_ISDIR(mode2))
c2 = '/';
return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
}
int cache_name_compare(const char *name1, int flags1, const char *name2, int flags2)
{
int len1 = flags1 & CE_NAMEMASK;
int len2 = flags2 & CE_NAMEMASK;
int len = len1 < len2 ? len1 : len2;
int cmp;
cmp = memcmp(name1, name2, len);
if (cmp)
return cmp;
if (len1 < len2)
return -1;
if (len1 > len2)
return 1;
if (flags1 < flags2)
return -1;
if (flags1 > flags2)
return 1;
return 0;
}
int cache_name_pos(const char *name, int namelen)
{
int first, last;
first = 0;
last = active_nr;
while (last > first) {
int next = (last + first) >> 1;
struct cache_entry *ce = active_cache[next];
int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
if (!cmp)
return next;
if (cmp < 0) {
last = next;
continue;
}
first = next+1;
}
return -first-1;
}
/* Remove entry, return true if there are more entries to go.. */
int remove_cache_entry_at(int pos)
{
active_cache_changed = 1;
active_nr--;
if (pos >= active_nr)
return 0;
memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
return 1;
}
int remove_file_from_cache(const char *path)
{
int pos = cache_name_pos(path, strlen(path));
if (pos < 0)
pos = -pos-1;
while (pos < active_nr && !strcmp(active_cache[pos]->name, path))
remove_cache_entry_at(pos);
return 0;
}
int ce_same_name(struct cache_entry *a, struct cache_entry *b)
{
int len = ce_namelen(a);
return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
}
int ce_path_match(const struct cache_entry *ce, const char **pathspec)
{
const char *match, *name;
int len;
if (!pathspec)
return 1;
len = ce_namelen(ce);
name = ce->name;
while ((match = *pathspec++) != NULL) {
int matchlen = strlen(match);
if (matchlen > len)
continue;
if (memcmp(name, match, matchlen))
continue;
if (matchlen && name[matchlen-1] == '/')
return 1;
if (name[matchlen] == '/' || !name[matchlen])
return 1;
if (!matchlen)
return 1;
}
return 0;
}
/*
* Do we have another file that has the beginning components being a
* proper superset of the name we're trying to add?
*/
static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replace)
{
int retval = 0;
int len = ce_namelen(ce);
int stage = ce_stage(ce);
const char *name = ce->name;
while (pos < active_nr) {
struct cache_entry *p = active_cache[pos++];
if (len >= ce_namelen(p))
break;
if (memcmp(name, p->name, len))
break;
if (ce_stage(p) != stage)
continue;
if (p->name[len] != '/')
continue;
retval = -1;
if (!ok_to_replace)
break;
remove_cache_entry_at(--pos);
}
return retval;
}
/*
* Do we have another file with a pathname that is a proper
* subset of the name we're trying to add?
*/
static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace)
{
int retval = 0;
int stage = ce_stage(ce);
const char *name = ce->name;
const char *slash = name + ce_namelen(ce);
for (;;) {
int len;
for (;;) {
if (*--slash == '/')
break;
if (slash <= ce->name)
return retval;
}
len = slash - name;
pos = cache_name_pos(name, ntohs(create_ce_flags(len, stage)));
if (pos >= 0) {
retval = -1;
if (ok_to_replace)
break;
remove_cache_entry_at(pos);
continue;
}
/*
* Trivial optimization: if we find an entry that
* already matches the sub-directory, then we know
* we're ok, and we can exit.
*/
pos = -pos-1;
while (pos < active_nr) {
struct cache_entry *p = active_cache[pos];
if ((ce_namelen(p) <= len) ||
(p->name[len] != '/') ||
memcmp(p->name, name, len))
break; /* not our subdirectory */
if (ce_stage(p) == stage)
/* p is at the same stage as our entry, and
* is a subdirectory of what we are looking
* at, so we cannot have conflicts at our
* level or anything shorter.
*/
return retval;
pos++;
}
}
return retval;
}
/* We may be in a situation where we already have path/file and path
* is being added, or we already have path and path/file is being
* added. Either one would result in a nonsense tree that has path
* twice when git-write-tree tries to write it out. Prevent it.
*
* If ok-to-replace is specified, we remove the conflicting entries
* from the cache so the caller should recompute the insert position.
* When this happens, we return non-zero.
*/
static int check_file_directory_conflict(const struct cache_entry *ce, int pos, int ok_to_replace)
{
/*
* We check if the path is a sub-path of a subsequent pathname
* first, since removing those will not change the position
* in the array
*/
int retval = has_file_name(ce, pos, ok_to_replace);
/*
* Then check if the path might have a clashing sub-directory
* before it.
*/
return retval + has_dir_name(ce, pos, ok_to_replace);
}
int add_cache_entry(struct cache_entry *ce, int option)
{
int pos;
int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
/* existing match? Just replace it */
if (pos >= 0) {
active_cache_changed = 1;
active_cache[pos] = ce;
return 0;
}
pos = -pos-1;
/*
* Inserting a merged entry ("stage 0") into the index
* will always replace all non-merged entries..
*/
if (pos < active_nr && ce_stage(ce) == 0) {
while (ce_same_name(active_cache[pos], ce)) {
ok_to_add = 1;
if (!remove_cache_entry_at(pos))
break;
}
}
if (!ok_to_add)
return -1;
if (!skip_df_check && check_file_directory_conflict(ce, pos, ok_to_replace)) {
if (!ok_to_replace)
return -1;
pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
pos = -pos-1;
}
/* Make sure the array is big enough .. */
if (active_nr == active_alloc) {
active_alloc = alloc_nr(active_alloc);
active_cache = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
}
/* Add it in.. */
active_nr++;
if (active_nr > pos)
memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
active_cache[pos] = ce;
active_cache_changed = 1;
return 0;
}
static int verify_hdr(struct cache_header *hdr, unsigned long size)
{
SHA_CTX c;
unsigned char sha1[20];
if (hdr->hdr_signature != htonl(CACHE_SIGNATURE))
return error("bad signature");
if (hdr->hdr_version != htonl(2))
return error("bad index version");
SHA1_Init(&c);
SHA1_Update(&c, hdr, size - 20);
SHA1_Final(sha1, &c);
if (memcmp(sha1, (void *)hdr + size - 20, 20))
return error("bad index file sha1 signature");
return 0;
}
int read_cache(void)
{
int fd, i;
struct stat st;
unsigned long size, offset;
void *map;
struct cache_header *hdr;
errno = EBUSY;
if (active_cache)
return active_nr;
errno = ENOENT;
fd = open(get_index_file(), O_RDONLY);
if (fd < 0) {
if (errno == ENOENT)
return 0;
die("index file open failed (%s)", strerror(errno));
}
size = 0; // avoid gcc warning
map = MAP_FAILED;
if (!fstat(fd, &st)) {
size = st.st_size;
errno = EINVAL;
if (size >= sizeof(struct cache_header) + 20)
map = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
}
close(fd);
if (map == MAP_FAILED)
die("index file mmap failed (%s)", strerror(errno));
hdr = map;
if (verify_hdr(hdr, size) < 0)
goto unmap;
active_nr = ntohl(hdr->hdr_entries);
active_alloc = alloc_nr(active_nr);
active_cache = calloc(active_alloc, sizeof(struct cache_entry *));
offset = sizeof(*hdr);
for (i = 0; i < active_nr; i++) {
struct cache_entry *ce = map + offset;
offset = offset + ce_size(ce);
active_cache[i] = ce;
}
return active_nr;
unmap:
munmap(map, size);
errno = EINVAL;
die("index file corrupt");
}
#define WRITE_BUFFER_SIZE 8192
static unsigned char write_buffer[WRITE_BUFFER_SIZE];
static unsigned long write_buffer_len;
static int ce_write(SHA_CTX *context, int fd, void *data, unsigned int len)
{
while (len) {
unsigned int buffered = write_buffer_len;
unsigned int partial = WRITE_BUFFER_SIZE - buffered;
if (partial > len)
partial = len;
memcpy(write_buffer + buffered, data, partial);
buffered += partial;
if (buffered == WRITE_BUFFER_SIZE) {
SHA1_Update(context, write_buffer, WRITE_BUFFER_SIZE);
if (write(fd, write_buffer, WRITE_BUFFER_SIZE) != WRITE_BUFFER_SIZE)
return -1;
buffered = 0;
}
write_buffer_len = buffered;
len -= partial;
data += partial;
}
return 0;
}
static int ce_flush(SHA_CTX *context, int fd)
{
unsigned int left = write_buffer_len;
if (left) {
write_buffer_len = 0;
SHA1_Update(context, write_buffer, left);
}
/* Flush first if not enough space for SHA1 signature */
if (left + 20 > WRITE_BUFFER_SIZE) {
if (write(fd, write_buffer, left) != left)
return -1;
left = 0;
}
/* Append the SHA1 signature at the end */
SHA1_Final(write_buffer + left, context);
left += 20;
if (write(fd, write_buffer, left) != left)
return -1;
return 0;
}
int write_cache(int newfd, struct cache_entry **cache, int entries)
{
SHA_CTX c;
struct cache_header hdr;
int i, removed;
for (i = removed = 0; i < entries; i++)
if (!cache[i]->ce_mode)
removed++;
hdr.hdr_signature = htonl(CACHE_SIGNATURE);
hdr.hdr_version = htonl(2);
hdr.hdr_entries = htonl(entries - removed);
SHA1_Init(&c);
if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
return -1;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
if (!ce->ce_mode)
continue;
if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
return -1;
}
return ce_flush(&c, newfd);
}