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![Junio C Hamano](/assets/img/avatar_default.png)
When "git checkout-index" checks out path A/B/C, it makes sure A and A/B are truly directories; if there is a regular file or symlink at A, we prefer to remove it. We used to do this by catching an error return from mkdir(2), and on EEXIST did unlink(2), and when it succeeded, tried another mkdir(2). Thomas Glanzmann found out the above does not work on Solaris for a root user, as unlink(2) was so old fashioned there that it allowed to unlink a directory. As pointed out, this still doesn't guarantee that git won't call "unlink()" on a directory (race conditions etc), but that's fundamentally true (there is no "funlink()" like there is "fstat()"), and besides, that is in no way git-specific (ie it's true of any application that gets run as root). Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
231 lines
5.7 KiB
C
231 lines
5.7 KiB
C
#include "cache.h"
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#include "blob.h"
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static void create_directories(const char *path, const struct checkout *state)
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{
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int len = strlen(path);
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char *buf = xmalloc(len + 1);
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const char *slash = path;
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while ((slash = strchr(slash+1, '/')) != NULL) {
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struct stat st;
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int stat_status;
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len = slash - path;
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memcpy(buf, path, len);
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buf[len] = 0;
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if (len <= state->base_dir_len)
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/*
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* checkout-index --prefix=<dir>; <dir> is
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* allowed to be a symlink to an existing
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* directory.
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*/
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stat_status = stat(buf, &st);
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else
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/*
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* if there currently is a symlink, we would
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* want to replace it with a real directory.
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*/
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stat_status = lstat(buf, &st);
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if (!stat_status && S_ISDIR(st.st_mode))
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continue; /* ok, it is already a directory. */
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/*
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* We know stat_status == 0 means something exists
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* there and this mkdir would fail, but that is an
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* error codepath; we do not care, as we unlink and
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* mkdir again in such a case.
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*/
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if (mkdir(buf, 0777)) {
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if (errno == EEXIST && state->force &&
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!unlink(buf) && !mkdir(buf, 0777))
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continue;
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die("cannot create directory at %s", buf);
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}
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}
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free(buf);
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}
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static void remove_subtree(const char *path)
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{
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DIR *dir = opendir(path);
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struct dirent *de;
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char pathbuf[PATH_MAX];
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char *name;
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if (!dir)
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die("cannot opendir %s (%s)", path, strerror(errno));
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strcpy(pathbuf, path);
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name = pathbuf + strlen(path);
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*name++ = '/';
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while ((de = readdir(dir)) != NULL) {
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struct stat st;
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if ((de->d_name[0] == '.') &&
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((de->d_name[1] == 0) ||
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((de->d_name[1] == '.') && de->d_name[2] == 0)))
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continue;
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strcpy(name, de->d_name);
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if (lstat(pathbuf, &st))
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die("cannot lstat %s (%s)", pathbuf, strerror(errno));
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if (S_ISDIR(st.st_mode))
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remove_subtree(pathbuf);
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else if (unlink(pathbuf))
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die("cannot unlink %s (%s)", pathbuf, strerror(errno));
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}
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closedir(dir);
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if (rmdir(path))
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die("cannot rmdir %s (%s)", path, strerror(errno));
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}
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static int create_file(const char *path, unsigned int mode)
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{
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mode = (mode & 0100) ? 0777 : 0666;
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return open(path, O_WRONLY | O_CREAT | O_EXCL, mode);
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}
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static void *read_blob_entry(struct cache_entry *ce, const char *path, unsigned long *size)
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{
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enum object_type type;
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void *new = read_sha1_file(ce->sha1, &type, size);
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if (new) {
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if (type == OBJ_BLOB)
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return new;
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free(new);
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}
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return NULL;
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}
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static int write_entry(struct cache_entry *ce, char *path, const struct checkout *state, int to_tempfile)
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{
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int fd;
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long wrote;
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switch (ntohl(ce->ce_mode) & S_IFMT) {
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char *buf, *new;
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unsigned long size;
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case S_IFREG:
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new = read_blob_entry(ce, path, &size);
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if (!new)
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return error("git-checkout-index: unable to read sha1 file of %s (%s)",
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path, sha1_to_hex(ce->sha1));
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if (to_tempfile) {
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strcpy(path, ".merge_file_XXXXXX");
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fd = mkstemp(path);
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} else
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fd = create_file(path, ntohl(ce->ce_mode));
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if (fd < 0) {
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free(new);
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return error("git-checkout-index: unable to create file %s (%s)",
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path, strerror(errno));
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}
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/*
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* Convert from git internal format to working tree format
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*/
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buf = convert_to_working_tree(ce->name, new, &size);
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if (buf) {
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free(new);
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new = buf;
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}
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wrote = write_in_full(fd, new, size);
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close(fd);
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free(new);
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if (wrote != size)
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return error("git-checkout-index: unable to write file %s", path);
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break;
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case S_IFLNK:
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new = read_blob_entry(ce, path, &size);
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if (!new)
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return error("git-checkout-index: unable to read sha1 file of %s (%s)",
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path, sha1_to_hex(ce->sha1));
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if (to_tempfile || !has_symlinks) {
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if (to_tempfile) {
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strcpy(path, ".merge_link_XXXXXX");
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fd = mkstemp(path);
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} else
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fd = create_file(path, 0666);
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if (fd < 0) {
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free(new);
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return error("git-checkout-index: unable to create "
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"file %s (%s)", path, strerror(errno));
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}
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wrote = write_in_full(fd, new, size);
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close(fd);
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free(new);
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if (wrote != size)
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return error("git-checkout-index: unable to write file %s",
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path);
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} else {
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wrote = symlink(new, path);
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free(new);
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if (wrote)
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return error("git-checkout-index: unable to create "
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"symlink %s (%s)", path, strerror(errno));
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}
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break;
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case S_IFDIRLNK:
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if (to_tempfile)
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return error("git-checkout-index: cannot create temporary subproject %s", path);
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if (mkdir(path, 0777) < 0)
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return error("git-checkout-index: cannot create subproject directory %s", path);
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break;
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default:
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return error("git-checkout-index: unknown file mode for %s", path);
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}
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if (state->refresh_cache) {
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struct stat st;
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lstat(ce->name, &st);
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fill_stat_cache_info(ce, &st);
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}
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return 0;
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}
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int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath)
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{
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static char path[PATH_MAX + 1];
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struct stat st;
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int len = state->base_dir_len;
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if (topath)
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return write_entry(ce, topath, state, 1);
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memcpy(path, state->base_dir, len);
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strcpy(path + len, ce->name);
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if (!lstat(path, &st)) {
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unsigned changed = ce_match_stat(ce, &st, 1);
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if (!changed)
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return 0;
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if (!state->force) {
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if (!state->quiet)
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fprintf(stderr, "git-checkout-index: %s already exists\n", path);
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return -1;
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}
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/*
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* We unlink the old file, to get the new one with the
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* right permissions (including umask, which is nasty
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* to emulate by hand - much easier to let the system
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* just do the right thing)
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*/
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unlink(path);
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if (S_ISDIR(st.st_mode)) {
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/* If it is a gitlink, leave it alone! */
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if (S_ISDIRLNK(ntohl(ce->ce_mode)))
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return 0;
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if (!state->force)
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return error("%s is a directory", path);
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remove_subtree(path);
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}
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} else if (state->not_new)
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return 0;
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create_directories(path, state);
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return write_entry(ce, path, state, 0);
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}
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