git/entry.c
Jeff King 330c8e2670 entry.c: convert strcpy to xsnprintf
This particular conversion is non-obvious, because nobody
has passed our function the length of the destination
buffer. However, the interface to checkout_entry specifies
that the buffer must be at least TEMPORARY_FILENAME_LENGTH
bytes long, so we can check that (meaning the existing code
was not buggy, but merely worrisome to somebody reading it).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-09-25 10:18:18 -07:00

295 lines
7.4 KiB
C

#include "cache.h"
#include "blob.h"
#include "dir.h"
#include "streaming.h"
static void create_directories(const char *path, int path_len,
const struct checkout *state)
{
char *buf = xmalloc(path_len + 1);
int len = 0;
while (len < path_len) {
do {
buf[len] = path[len];
len++;
} while (len < path_len && path[len] != '/');
if (len >= path_len)
break;
buf[len] = 0;
/*
* For 'checkout-index --prefix=<dir>', <dir> is
* allowed to be a symlink to an existing directory,
* and we set 'state->base_dir_len' below, such that
* we test the path components of the prefix with the
* stat() function instead of the lstat() function.
*/
if (has_dirs_only_path(buf, len, state->base_dir_len))
continue; /* ok, it is already a directory. */
/*
* If this mkdir() would fail, it could be that there
* is already a symlink or something else exists
* there, therefore we then try to unlink it and try
* one more time to create the directory.
*/
if (mkdir(buf, 0777)) {
if (errno == EEXIST && state->force &&
!unlink_or_warn(buf) && !mkdir(buf, 0777))
continue;
die_errno("cannot create directory at '%s'", buf);
}
}
free(buf);
}
static void remove_subtree(struct strbuf *path)
{
DIR *dir = opendir(path->buf);
struct dirent *de;
int origlen = path->len;
if (!dir)
die_errno("cannot opendir '%s'", path->buf);
while ((de = readdir(dir)) != NULL) {
struct stat st;
if (is_dot_or_dotdot(de->d_name))
continue;
strbuf_addch(path, '/');
strbuf_addstr(path, de->d_name);
if (lstat(path->buf, &st))
die_errno("cannot lstat '%s'", path->buf);
if (S_ISDIR(st.st_mode))
remove_subtree(path);
else if (unlink(path->buf))
die_errno("cannot unlink '%s'", path->buf);
strbuf_setlen(path, origlen);
}
closedir(dir);
if (rmdir(path->buf))
die_errno("cannot rmdir '%s'", path->buf);
}
static int create_file(const char *path, unsigned int mode)
{
mode = (mode & 0100) ? 0777 : 0666;
return open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
}
static void *read_blob_entry(const struct cache_entry *ce, unsigned long *size)
{
enum object_type type;
void *new = read_sha1_file(ce->sha1, &type, size);
if (new) {
if (type == OBJ_BLOB)
return new;
free(new);
}
return NULL;
}
static int open_output_fd(char *path, const struct cache_entry *ce, int to_tempfile)
{
int symlink = (ce->ce_mode & S_IFMT) != S_IFREG;
if (to_tempfile) {
xsnprintf(path, TEMPORARY_FILENAME_LENGTH, "%s",
symlink ? ".merge_link_XXXXXX" : ".merge_file_XXXXXX");
return mkstemp(path);
} else {
return create_file(path, !symlink ? ce->ce_mode : 0666);
}
}
static int fstat_output(int fd, const struct checkout *state, struct stat *st)
{
/* use fstat() only when path == ce->name */
if (fstat_is_reliable() &&
state->refresh_cache && !state->base_dir_len) {
fstat(fd, st);
return 1;
}
return 0;
}
static int streaming_write_entry(const struct cache_entry *ce, char *path,
struct stream_filter *filter,
const struct checkout *state, int to_tempfile,
int *fstat_done, struct stat *statbuf)
{
int result = 0;
int fd;
fd = open_output_fd(path, ce, to_tempfile);
if (fd < 0)
return -1;
result |= stream_blob_to_fd(fd, ce->sha1, filter, 1);
*fstat_done = fstat_output(fd, state, statbuf);
result |= close(fd);
if (result)
unlink(path);
return result;
}
static int write_entry(struct cache_entry *ce,
char *path, const struct checkout *state, int to_tempfile)
{
unsigned int ce_mode_s_ifmt = ce->ce_mode & S_IFMT;
int fd, ret, fstat_done = 0;
char *new;
struct strbuf buf = STRBUF_INIT;
unsigned long size;
size_t wrote, newsize = 0;
struct stat st;
if (ce_mode_s_ifmt == S_IFREG) {
struct stream_filter *filter = get_stream_filter(ce->name, ce->sha1);
if (filter &&
!streaming_write_entry(ce, path, filter,
state, to_tempfile,
&fstat_done, &st))
goto finish;
}
switch (ce_mode_s_ifmt) {
case S_IFREG:
case S_IFLNK:
new = read_blob_entry(ce, &size);
if (!new)
return error("unable to read sha1 file of %s (%s)",
path, sha1_to_hex(ce->sha1));
if (ce_mode_s_ifmt == S_IFLNK && has_symlinks && !to_tempfile) {
ret = symlink(new, path);
free(new);
if (ret)
return error("unable to create symlink %s (%s)",
path, strerror(errno));
break;
}
/*
* Convert from git internal format to working tree format
*/
if (ce_mode_s_ifmt == S_IFREG &&
convert_to_working_tree(ce->name, new, size, &buf)) {
free(new);
new = strbuf_detach(&buf, &newsize);
size = newsize;
}
fd = open_output_fd(path, ce, to_tempfile);
if (fd < 0) {
free(new);
return error("unable to create file %s (%s)",
path, strerror(errno));
}
wrote = write_in_full(fd, new, size);
if (!to_tempfile)
fstat_done = fstat_output(fd, state, &st);
close(fd);
free(new);
if (wrote != size)
return error("unable to write file %s", path);
break;
case S_IFGITLINK:
if (to_tempfile)
return error("cannot create temporary submodule %s", path);
if (mkdir(path, 0777) < 0)
return error("cannot create submodule directory %s", path);
break;
default:
return error("unknown file mode for %s in index", path);
}
finish:
if (state->refresh_cache) {
assert(state->istate);
if (!fstat_done)
lstat(ce->name, &st);
fill_stat_cache_info(ce, &st);
ce->ce_flags |= CE_UPDATE_IN_BASE;
state->istate->cache_changed |= CE_ENTRY_CHANGED;
}
return 0;
}
/*
* This is like 'lstat()', except it refuses to follow symlinks
* in the path, after skipping "skiplen".
*/
static int check_path(const char *path, int len, struct stat *st, int skiplen)
{
const char *slash = path + len;
while (path < slash && *slash != '/')
slash--;
if (!has_dirs_only_path(path, slash - path, skiplen)) {
errno = ENOENT;
return -1;
}
return lstat(path, st);
}
/*
* Write the contents from ce out to the working tree.
*
* When topath[] is not NULL, instead of writing to the working tree
* file named by ce, a temporary file is created by this function and
* its name is returned in topath[], which must be able to hold at
* least TEMPORARY_FILENAME_LENGTH bytes long.
*/
int checkout_entry(struct cache_entry *ce,
const struct checkout *state, char *topath)
{
static struct strbuf path = STRBUF_INIT;
struct stat st;
if (topath)
return write_entry(ce, topath, state, 1);
strbuf_reset(&path);
strbuf_add(&path, state->base_dir, state->base_dir_len);
strbuf_add(&path, ce->name, ce_namelen(ce));
if (!check_path(path.buf, path.len, &st, state->base_dir_len)) {
unsigned changed = ce_match_stat(ce, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
if (!changed)
return 0;
if (!state->force) {
if (!state->quiet)
fprintf(stderr,
"%s already exists, no checkout\n",
path.buf);
return -1;
}
/*
* We unlink the old file, to get the new one with the
* right permissions (including umask, which is nasty
* to emulate by hand - much easier to let the system
* just do the right thing)
*/
if (S_ISDIR(st.st_mode)) {
/* If it is a gitlink, leave it alone! */
if (S_ISGITLINK(ce->ce_mode))
return 0;
if (!state->force)
return error("%s is a directory", path.buf);
remove_subtree(&path);
} else if (unlink(path.buf))
return error("unable to unlink old '%s' (%s)",
path.buf, strerror(errno));
} else if (state->not_new)
return 0;
create_directories(path.buf, path.len, state);
return write_entry(ce, path.buf, state, 0);
}