git/update-cache.c

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/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
/*
* Default to not allowing changes to the list of files. The
* tool doesn't actually care, but this makes it harder to add
* files to the revision control by mistake by doing something
* like "git-update-cache *" and suddenly having all the object
* files be revision controlled.
*/
static int allow_add = 0, allow_remove = 0, allow_replace = 0, not_new = 0, quiet = 0, info_only = 0;
static int force_remove;
/* Three functions to allow overloaded pointer return; see linux/err.h */
static inline void *ERR_PTR(long error)
{
return (void *) error;
}
static inline long PTR_ERR(const void *ptr)
{
return (long) ptr;
}
static inline long IS_ERR(const void *ptr)
{
return (unsigned long)ptr > (unsigned long)-1000L;
}
static int add_file_to_cache(char *path)
{
int size, namelen, option, status;
struct cache_entry *ce;
struct stat st;
int fd;
char *target;
status = lstat(path, &st);
if (status < 0 || S_ISDIR(st.st_mode)) {
/* When we used to have "path" and now we want to add
* "path/file", we need a way to remove "path" before
* being able to add "path/file". However,
* "git-update-cache --remove path" would not work.
* --force-remove can be used but this is more user
* friendly, especially since we can do the opposite
* case just fine without --force-remove.
*/
if (status == 0 || (errno == ENOENT || errno == ENOTDIR)) {
if (allow_remove)
return remove_file_from_cache(path);
}
return error("open(\"%s\"): %s", path, strerror(errno));
}
namelen = strlen(path);
size = cache_entry_size(namelen);
ce = xmalloc(size);
memset(ce, 0, size);
memcpy(ce->name, path, namelen);
fill_stat_cache_info(ce, &st);
ce->ce_mode = create_ce_mode(st.st_mode);
ce->ce_flags = htons(namelen);
switch (st.st_mode & S_IFMT) {
case S_IFREG:
fd = open(path, O_RDONLY);
if (fd < 0)
return -1;
if (index_fd(ce->sha1, fd, &st, !info_only, NULL) < 0)
return -1;
break;
case S_IFLNK:
target = xmalloc(st.st_size+1);
if (readlink(path, target, st.st_size+1) != st.st_size) {
free(target);
return -1;
}
if (info_only) {
unsigned char hdr[50];
int hdrlen;
write_sha1_file_prepare(target, st.st_size, "blob",
ce->sha1, hdr, &hdrlen);
} else if (write_sha1_file(target, st.st_size, "blob", ce->sha1))
return -1;
free(target);
break;
default:
return -1;
}
option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
return add_cache_entry(ce, option);
}
static int 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 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;
}
/*
* "refresh" does not calculate a new sha1 file or bring the
* cache up-to-date for mode/content changes. But what it
* _does_ do is to "re-match" the stat information of a file
* with the cache, so that you can refresh the cache for a
* file that hasn't been changed but where the stat entry is
* out of date.
*
* For example, you'd want to do this after doing a "git-read-tree",
* to link up the stat cache details with the proper files.
*/
static struct cache_entry *refresh_entry(struct cache_entry *ce)
{
struct stat st;
struct cache_entry *updated;
int changed, size;
if (lstat(ce->name, &st) < 0)
return ERR_PTR(-errno);
changed = ce_match_stat(ce, &st);
if (!changed)
return ce;
/*
* 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 ERR_PTR(-EINVAL);
switch (st.st_mode & S_IFMT) {
case S_IFREG:
if (compare_data(ce, &st))
return ERR_PTR(-EINVAL);
break;
case S_IFLNK:
if (compare_link(ce, st.st_size))
return ERR_PTR(-EINVAL);
break;
default:
return ERR_PTR(-EINVAL);
}
size = ce_size(ce);
updated = xmalloc(size);
memcpy(updated, ce, size);
fill_stat_cache_info(updated, &st);
return updated;
}
static int refresh_cache(void)
{
int i;
int has_errors = 0;
for (i = 0; i < active_nr; i++) {
struct cache_entry *ce, *new;
ce = active_cache[i];
if (ce_stage(ce)) {
printf("%s: needs merge\n", ce->name);
has_errors = 1;
while ((i < active_nr) &&
! strcmp(active_cache[i]->name, ce->name))
i++;
i--;
continue;
}
new = refresh_entry(ce);
if (IS_ERR(new)) {
if (not_new && PTR_ERR(new) == -ENOENT)
continue;
if (quiet)
continue;
printf("%s: needs update\n", ce->name);
has_errors = 1;
continue;
}
active_cache_changed = 1;
/* You can NOT just free active_cache[i] here, since it
* might not be necessarily malloc()ed but can also come
* from mmap(). */
active_cache[i] = new;
}
return has_errors;
}
/*
* We fundamentally don't like some paths: we don't want
* dot or dot-dot anywhere, and for obvious reasons don't
* want to recurse into ".git" either.
*
* Also, we don't want double slashes or slashes at the
* end that can make pathnames ambiguous.
*/
static int verify_dotfile(const char *rest)
{
/*
* The first character was '.', but that
* has already been discarded, we now test
* the rest.
*/
switch (*rest) {
/* "." is not allowed */
case '\0': case '/':
return 0;
/*
* ".git" followed by NUL or slash is bad. This
* shares the path end test with the ".." case.
*/
case 'g':
if (rest[1] != 'i')
break;
if (rest[2] != 't')
break;
rest += 2;
/* fallthrough */
case '.':
if (rest[1] == '\0' || rest[1] == '/')
return 0;
}
return 1;
}
static int verify_path(char *path)
{
char c;
goto inside;
for (;;) {
if (!c)
return 1;
if (c == '/') {
inside:
c = *path++;
switch (c) {
default:
continue;
case '/': case '\0':
break;
case '.':
if (verify_dotfile(path))
continue;
}
return 0;
}
c = *path++;
}
}
static int add_cacheinfo(char *arg1, char *arg2, char *arg3)
{
int size, len, option;
unsigned int mode;
unsigned char sha1[20];
struct cache_entry *ce;
if (sscanf(arg1, "%o", &mode) != 1)
return -1;
if (get_sha1_hex(arg2, sha1))
return -1;
if (!verify_path(arg3))
return -1;
len = strlen(arg3);
size = cache_entry_size(len);
ce = xmalloc(size);
memset(ce, 0, size);
memcpy(ce->sha1, sha1, 20);
memcpy(ce->name, arg3, len);
ce->ce_flags = htons(len);
ce->ce_mode = create_ce_mode(mode);
option = allow_add ? ADD_CACHE_OK_TO_ADD : 0;
option |= allow_replace ? ADD_CACHE_OK_TO_REPLACE : 0;
return add_cache_entry(ce, option);
}
static struct cache_file cache_file;
int main(int argc, char **argv)
{
int i, newfd, entries, has_errors = 0;
int allow_options = 1;
newfd = hold_index_file_for_update(&cache_file, get_index_file());
if (newfd < 0)
die("unable to create new cachefile");
entries = read_cache();
if (entries < 0)
die("cache corrupted");
for (i = 1 ; i < argc; i++) {
char *path = argv[i];
if (allow_options && *path == '-') {
if (!strcmp(path, "--")) {
allow_options = 0;
continue;
}
if (!strcmp(path, "-q")) {
quiet = 1;
continue;
}
if (!strcmp(path, "--add")) {
allow_add = 1;
continue;
}
if (!strcmp(path, "--replace")) {
allow_replace = 1;
continue;
}
if (!strcmp(path, "--remove")) {
allow_remove = 1;
continue;
}
if (!strcmp(path, "--refresh")) {
has_errors |= refresh_cache();
continue;
}
if (!strcmp(path, "--cacheinfo")) {
if (i+3 >= argc)
die("git-update-cache: --cacheinfo <mode> <sha1> <path>");
if (add_cacheinfo(argv[i+1], argv[i+2], argv[i+3]))
die("git-update-cache: --cacheinfo cannot add %s", argv[i+3]);
i += 3;
continue;
}
if (!strcmp(path, "--info-only")) {
info_only = 1;
continue;
}
if (!strcmp(path, "--force-remove")) {
force_remove = 1;
continue;
}
if (!strcmp(path, "--ignore-missing")) {
not_new = 1;
continue;
}
die("unknown option %s", path);
}
if (!verify_path(path)) {
fprintf(stderr, "Ignoring path %s\n", argv[i]);
continue;
}
if (force_remove) {
if (remove_file_from_cache(path))
die("git-update-cache: --force-remove cannot remove %s", path);
continue;
}
if (add_file_to_cache(path))
die("Unable to add %s to database", path);
}
if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
die("Unable to write new cachefile");
return has_errors ? 1 : 0;
}