git

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#include "git-compat-util.h"
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#include "fsmonitor-ll.h"
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#include "fsmonitor-path-utils.h"
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#include "gettext.h"
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#include "trace.h"
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/param.h>
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#include <sys/mount.h>
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int fsmonitor__get_fs_info(const char *path, struct fs_info *fs_info)
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{
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	struct statfs fs;
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	if (statfs(path, &fs) == -1) {
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		int saved_errno = errno;
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		trace_printf_key(&trace_fsmonitor, "statfs('%s') failed: %s",
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				 path, strerror(saved_errno));
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		errno = saved_errno;
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		return -1;
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	}
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	trace_printf_key(&trace_fsmonitor,
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			 "statfs('%s') [type 0x%08x][flags 0x%08x] '%s'",
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			 path, fs.f_type, fs.f_flags, fs.f_fstypename);
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	if (!(fs.f_flags & MNT_LOCAL))
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		fs_info->is_remote = 1;
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	else
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		fs_info->is_remote = 0;
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	fs_info->typename = xstrdup(fs.f_fstypename);
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	trace_printf_key(&trace_fsmonitor,
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				"'%s' is_remote: %d",
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				path, fs_info->is_remote);
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	return 0;
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}
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int fsmonitor__is_fs_remote(const char *path)
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{
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	struct fs_info fs;
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	if (fsmonitor__get_fs_info(path, &fs))
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		return -1;
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	free(fs.typename);
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	return fs.is_remote;
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}
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/*
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 * Scan the root directory for synthetic firmlinks that when resolved
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 * are a prefix of the path, stopping at the first one found.
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 *
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 * Some information about firmlinks and synthetic firmlinks:
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 * https://eclecticlight.co/2020/01/23/catalina-boot-volumes/
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 *
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 * macOS no longer allows symlinks in the root directory; any link found
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 * there is therefore a synthetic firmlink.
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 *
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 * If this function gets called often, will want to cache all the firmlink
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 * information, but for now there is only one caller of this function.
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 *
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 * If there is more than one alias for the path, that is another
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 * matter altogether.
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 */
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int fsmonitor__get_alias(const char *path, struct alias_info *info)
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{
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	DIR *dir;
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	int retval = -1;
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	const char *const root = "/";
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	struct stat st;
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	struct dirent *de;
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	struct strbuf alias;
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	struct strbuf points_to = STRBUF_INIT;
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	dir = opendir(root);
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	if (!dir)
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		return error_errno(_("opendir('%s') failed"), root);
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	strbuf_init(&alias, 256);
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	while ((de = readdir(dir)) != NULL) {
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		strbuf_reset(&alias);
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		strbuf_addf(&alias, "%s%s", root, de->d_name);
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		if (lstat(alias.buf, &st) < 0) {
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			error_errno(_("lstat('%s') failed"), alias.buf);
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			goto done;
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		}
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		if (!S_ISLNK(st.st_mode))
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			continue;
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		if (strbuf_readlink(&points_to, alias.buf, st.st_size) < 0) {
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			error_errno(_("strbuf_readlink('%s') failed"), alias.buf);
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			goto done;
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		}
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		if (!strncmp(points_to.buf, path, points_to.len) &&
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			(path[points_to.len] == '/')) {
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			strbuf_addbuf(&info->alias, &alias);
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			strbuf_addbuf(&info->points_to, &points_to);
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			trace_printf_key(&trace_fsmonitor,
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				"Found alias for '%s' : '%s' -> '%s'",
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				path, info->alias.buf, info->points_to.buf);
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			retval = 0;
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			goto done;
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		}
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	}
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	retval = 0; /* no alias */
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done:
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	strbuf_release(&alias);
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	strbuf_release(&points_to);
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	if (closedir(dir) < 0)
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		return error_errno(_("closedir('%s') failed"), root);
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	return retval;
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}
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char *fsmonitor__resolve_alias(const char *path,
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	const struct alias_info *info)
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{
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	if (!info->alias.len)
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		return NULL;
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	if ((!strncmp(info->alias.buf, path, info->alias.len))
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		&& path[info->alias.len] == '/') {
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		struct strbuf tmp = STRBUF_INIT;
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		const char *remainder = path + info->alias.len;
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		strbuf_addbuf(&tmp, &info->points_to);
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		strbuf_add(&tmp, remainder, strlen(remainder));
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		return strbuf_detach(&tmp, NULL);
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	}
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	return NULL;
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}
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