[patch] automatic device finding on Mac and Linux

[RJVB]

Currently hfsinspect will find the device a file is on automatically only on BSD. The author seems to have missed the fact that Apple's Darwin is a BSD variant, and indeed the code works just fine there (on 10.9 at least). Fortunately, because for me the manual specification didn't work.

Linux doesn't have a single syscall that returns the required information, but one can parse the output from df -h.

Here's a patch (corrected):

diff --git a/src/hfsinspect.c b/src/hfsinspect.c
index fb380bf..019724a 100644
--- a/src/hfsinspect.c
+++ b/src/hfsinspect.c
@@ -14,6 +14,9 @@
 #if defined(BSD)
     #include <sys/mount.h>     //statfs
 #endif
+#ifdef __linux__
+    #include <ctype.h>
+#endif
 
 #include "logging/logging.h"   // console printing routines
 #include "volumes/volumes.h"
@@ -69,13 +72,13 @@ char* deviceAtPath(char* path)
 
 bool resolveDeviceAndPath(char* path_in, char* device_out, char* path_out)
 {
-#if defined(__BSD__)
     char* path = realpath(path_in, NULL);
     if (path == NULL) {
         die(1, path_in);
         return false;
     }
 
+#if defined(__BSD__) || defined(__APPLE__)
     struct statfs stats;
     int           result = statfs(path_in, &stats);
     if (result < 0) {
@@ -110,6 +113,60 @@ bool resolveDeviceAndPath(char* path_in, char* device_out, char* path_out)
     debug("Path out: %s", path_out);
 
     return true;
+#elif defined(__linux__)
+    bool ret = false;
+    char *command = NULL;
+    int comlen = asprintf(&command, "df -h \"%s\" | tail --lines=1", path_in);
+    FILE *fp = comlen > 0 ? popen(command, "r") : NULL;
+    if (fp) {
+        char buf[PATH_MAX * 3], *s = buf;
+        if (fgets(buf, sizeof(buf), fp) == buf) {
+            char *d = device_out;
+            s = buf;
+            while (*s && !isspace(*s)) {
+                *d++ = *s++;
+            }
+            if (isspace(*s)) {
+                *d = '\0';
+            } else {
+                warning("%s: failure reading mount device from \"%s\"", __FUNCTION__, buf);
+                device_out[0] = '\0';
+            }
+            s = strstr(buf, "% /");
+            if (s) {
+                char* mountPoint = &s[2];
+                size_t len = strlen(mountPoint);
+                if (len > 0 && mountPoint[len-1] == '\n') {
+                    mountPoint[len-1] = '\0';
+                    len -= 1;
+                }
+                if (strncmp(mountPoint, "/", PATH_MAX) != 0) {
+                    // Remove mount point from path name (rather blindly, yes)
+                    d = &path[len];
+                    (void)strlcpy(path_out, &path[len], PATH_MAX);
+                } else {
+                    (void)strlcpy(path_out, path, PATH_MAX);
+                }
+                free(path);
+                ret = true;
+            } else {
+                warning("%s: failure reading mountPoint from \"%s\"", __FUNCTION__, buf);
+                path_out[0] = '\0';
+            }
+        } else {
+            perror(command);
+        }
+        pclose(fp);
+        debug("Path in: %s", path_in);
+        debug("Device out: %s", device_out);
+        debug("Path out: %s", path_out);
+    } else {
+        perror(command ? command : path_in);
+    }
+    if (comlen) {
+        free(command);
+    }
+    return ret;
 #else
     warning("%s: not supported on this platform", __FUNCTION__);
     return false;

[RJVB]

my bad, I had read the code too quickly. Patch fixed.

Here's the output on a decmpfs (HFS) compressed file mounted under linux (where its size shows up as 0 because all content is in the resource fork):

# HFSX Volume Format (v5)
  volume name            = VMs
  case sensitivity       = case sensitive
  bootable               = no

# Record ID 0 (1/22) (length: 304) (Node 45171)
  Catalog Key
  +-----------------------------------------------------------------------------------+
  | length | parentID   | length | nodeName                                           |
  | 54     | 1605764    | 24     | qdockarealayout.cpp.orig                           |
  +-----------------------------------------------------------------------------------+

  recordType             = kHFSPlusFileRecord
  flags                  = 000000001000011
  record->flags          = kHFSThreadExistsMask (2)
  record->flags          = kHFSHasAttributesMask (4)
  record->flags          = kHFSHasDateAddedMask (128)
  reserved1              = 0
  fileID                 = 18239046
  createDate             = Mon 13 Aug 2018 21:43:41 GMT
  contentModDate         = Mon 13 Aug 2018 21:43:41 GMT
  attributeModDate       = Mon 13 Aug 2018 22:09:19 GMT
  accessDate             = Fri 07 Sep 2018 21:15:40 GMT
  backupDate             = Thu 01 Jan 1970 00:00:00 GMT
  ownerID                = 505
  groupID                = 80
  adminFlags             = 0000000 (0)
  ownerFlags             = 0000040 (32)
                         . 00040 compressed
  fileMode               = -rw-r--r--
  fileMode               = 0100644 (33188)
  mode & S_IFMT          = 0100000 (S_IFREG)
  mode                   = 0000400 (S_IRUSR)
  mode                   = 0000200 (S_IWUSR)
  mode                   = 0000040 (S_IRGRP)
  mode                   = 0000004 (S_IROTH)
  special.linkCount      = 1
  
  # Finder Info
    fdType                 = 0x00000000 ()
    fdCreator              = 0x00000000 ()
    fdFlags                = 000000000000000
    fdLocation             = (0, 0)
    opaque                 = 0
  textEncoding           = 0
  reserved2              = 0
  
  # Data Fork
    fork                   = data
    logicalSize            = (empty)
  
  # Resource Fork
    fork                   = resource
    logicalSize            = 19.25 KiB (19716 bytes)
    clumpSize              = 0.00 bytes
    totalBlocks            = 20.00 KiB (5 blocks)
    extents                =   startBlock   blockCount    % of file
                           =     13833415            5       100.00
                           = --------------------------------------
                           =    1 extents            5       100.00
                           = 5.00 blocks per extent on average.