compat/fsmonitor/fsm-path-utils-darwin.c

   1 #include "git-compat-util.h"
   2 #include "fsmonitor-ll.h"
   3 #include "fsmonitor-path-utils.h"
   4 #include "gettext.h"
   5 #include "trace.h"
   6 #include <dirent.h>
   7 #include <errno.h>
   8 #include <fcntl.h>
   9 #include <sys/param.h>
  10 #include <sys/mount.h>
  11
  12 int fsmonitor__get_fs_info(const char *path, struct fs_info *fs_info)
  13 {
  14         struct statfs fs;
  15         if (statfs(path, &fs) == -1) {
  16                 int saved_errno = errno;
  17                 trace_printf_key(&trace_fsmonitor, "statfs('%s') failed: %s",
  18                                  path, strerror(saved_errno));
  19                 errno = saved_errno;
  20                 return -1;
  21         }
  22
  23         trace_printf_key(&trace_fsmonitor,
  24                          "statfs('%s') [type 0x%08x][flags 0x%08x] '%s'",
  25                          path, fs.f_type, fs.f_flags, fs.f_fstypename);
  26
  27         if (!(fs.f_flags & MNT_LOCAL))
  28                 fs_info->is_remote = 1;
  29         else
  30                 fs_info->is_remote = 0;
  31
  32         fs_info->typename = xstrdup(fs.f_fstypename);
  33
  34         trace_printf_key(&trace_fsmonitor,
  35                                 "'%s' is_remote: %d",
  36                                 path, fs_info->is_remote);
  37         return 0;
  38 }
  39
  40 int fsmonitor__is_fs_remote(const char *path)
  41 {
  42         struct fs_info fs;
  43         if (fsmonitor__get_fs_info(path, &fs))
  44                 return -1;
  45
  46         free(fs.typename);
  47
  48         return fs.is_remote;
  49 }
  50
  51 /*
  52  * Scan the root directory for synthetic firmlinks that when resolved
  53  * are a prefix of the path, stopping at the first one found.
  54  *
  55  * Some information about firmlinks and synthetic firmlinks:
  56  * https://eclecticlight.co/2020/01/23/catalina-boot-volumes/
  57  *
  58  * macOS no longer allows symlinks in the root directory; any link found
  59  * there is therefore a synthetic firmlink.
  60  *
  61  * If this function gets called often, will want to cache all the firmlink
  62  * information, but for now there is only one caller of this function.
  63  *
  64  * If there is more than one alias for the path, that is another
  65  * matter altogether.
  66  */
  67 int fsmonitor__get_alias(const char *path, struct alias_info *info)
  68 {
  69         DIR *dir;
  70         int retval = -1;
  71         const char *const root = "/";
  72         struct stat st;
  73         struct dirent *de;
  74         struct strbuf alias;
  75         struct strbuf points_to = STRBUF_INIT;
  76
  77         dir = opendir(root);
  78         if (!dir)
  79                 return error_errno(_("opendir('%s') failed"), root);
  80
  81         strbuf_init(&alias, 256);
  82
  83         while ((de = readdir(dir)) != NULL) {
  84                 strbuf_reset(&alias);
  85                 strbuf_addf(&alias, "%s%s", root, de->d_name);
  86
  87                 if (lstat(alias.buf, &st) < 0) {
  88                         error_errno(_("lstat('%s') failed"), alias.buf);
  89                         goto done;
  90                 }
  91
  92                 if (!S_ISLNK(st.st_mode))
  93                         continue;
  94
  95                 if (strbuf_readlink(&points_to, alias.buf, st.st_size) < 0) {
  96                         error_errno(_("strbuf_readlink('%s') failed"), alias.buf);
  97                         goto done;
  98                 }
  99
 100                 if (!strncmp(points_to.buf, path, points_to.len) &&
 101                         (path[points_to.len] == '/')) {
 102                         strbuf_addbuf(&info->alias, &alias);
 103                         strbuf_addbuf(&info->points_to, &points_to);
 104                         trace_printf_key(&trace_fsmonitor,
 105                                 "Found alias for '%s' : '%s' -> '%s'",
 106                                 path, info->alias.buf, info->points_to.buf);
 107                         retval = 0;
 108                         goto done;
 109                 }
 110         }
 111         retval = 0; /* no alias */
 112
 113 done:
 114         strbuf_release(&alias);
 115         strbuf_release(&points_to);
 116         if (closedir(dir) < 0)
 117                 return error_errno(_("closedir('%s') failed"), root);
 118         return retval;
 119 }
 120
 121 char *fsmonitor__resolve_alias(const char *path,
 122         const struct alias_info *info)
 123 {
 124         if (!info->alias.len)
 125                 return NULL;
 126
 127         if ((!strncmp(info->alias.buf, path, info->alias.len))
 128                 && path[info->alias.len] == '/') {
 129                 struct strbuf tmp = STRBUF_INIT;
 130                 const char *remainder = path + info->alias.len;
 131
 132                 strbuf_addbuf(&tmp, &info->points_to);
 133                 strbuf_add(&tmp, remainder, strlen(remainder));
 134                 return strbuf_detach(&tmp, NULL);
 135         }
 136
 137         return NULL;
 138 }