From ae76d2d032de474280c4d336c31d0f8ae4347828 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=8E=E9=80=9A=E6=B4=B2?= <carter.li@eoitek.com>
Date: Tue, 15 Oct 2024 19:40:03 +0800
Subject: [PATCH] IO (Linux): improve performance of `ffPathExists`

---
 src/common/io/io.h              | 26 ++++++++++++++++----------
 src/detection/bios/bios_bsd.c   |  2 +-
 src/detection/bios/bios_linux.c |  2 +-
 src/detection/tpm/tpm_linux.c   |  4 ++--
 src/detection/wifi/wifi_linux.c |  2 +-
 5 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/src/common/io/io.h b/src/common/io/io.h
index 908169985..06ab29106 100644
--- a/src/common/io/io.h
+++ b/src/common/io/io.h
@@ -13,6 +13,7 @@
     #include <unistd.h>
     #include <dirent.h>
     #include <sys/stat.h>
+    #include <errno.h>
     typedef int FFNativeFD;
     #define FF_INVALID_FD (-1)
     // procfs's file can be changed between read calls such as /proc/meminfo and /proc/uptime.
@@ -116,17 +117,22 @@ static inline bool ffPathExists(const char* path, FFPathType pathType)
     }
     else
     {
-        struct stat fileStat;
-        if(stat(path, &fileStat) != 0)
-            return false;
+        size_t len = strlen(path);
+        assert(len < PATH_MAX);
+        if (len == 0) return false;
 
-        unsigned int mode = fileStat.st_mode & S_IFMT;
-
-        if(pathType & FF_PATHTYPE_FILE && mode != S_IFDIR)
-            return true;
-
-        if(pathType & FF_PATHTYPE_DIRECTORY && mode == S_IFDIR)
-            return true;
+        int ret;
+        if (path[len - 1] != '/')
+        {
+            char buf[PATH_MAX + 1];
+            memcpy(buf, path, len);
+            buf[len] = '/';
+            buf[len + 1] = 0;
+            ret = access(buf, F_OK);
+        }
+        else
+            ret = access(path, F_OK);
+        return pathType == FF_PATHTYPE_DIRECTORY ? ret == 0 : ret == -1 && errno == ENOTDIR;
     }
 
     #endif
diff --git a/src/detection/bios/bios_bsd.c b/src/detection/bios/bios_bsd.c
index aa115de21..11f762099 100644
--- a/src/detection/bios/bios_bsd.c
+++ b/src/detection/bios/bios_bsd.c
@@ -25,7 +25,7 @@ const char* ffDetectBios(FFBiosResult* result)
         {
             ffStrbufSetStatic(&result->type,
                 ffPathExists("/dev/efi" /*efidev*/, FF_PATHTYPE_FILE) ||
-                ffPathExists("/boot/efi/efi" /*efi partition*/, FF_PATHTYPE_DIRECTORY)
+                ffPathExists("/boot/efi/efi/" /*efi partition*/, FF_PATHTYPE_DIRECTORY)
                     ? "UEFI" : "BIOS");
         }
     }
diff --git a/src/detection/bios/bios_linux.c b/src/detection/bios/bios_linux.c
index 86342c159..98bb40c38 100644
--- a/src/detection/bios/bios_linux.c
+++ b/src/detection/bios/bios_linux.c
@@ -10,7 +10,7 @@ const char *ffDetectBios(FFBiosResult *bios)
     ffGetSmbiosValue("/sys/devices/virtual/dmi/id/bios_release", "/sys/class/dmi/id/bios_release", &bios->release);
     ffGetSmbiosValue("/sys/devices/virtual/dmi/id/bios_vendor", "/sys/class/dmi/id/bios_vendor", &bios->vendor);
     ffGetSmbiosValue("/sys/devices/virtual/dmi/id/bios_version", "/sys/class/dmi/id/bios_version", &bios->version);
-    if (ffPathExists("/sys/firmware/efi", FF_PATHTYPE_DIRECTORY) || ffPathExists("/sys/firmware/acpi/tables/UEFI", FF_PATHTYPE_FILE))
+    if (ffPathExists("/sys/firmware/efi/", FF_PATHTYPE_DIRECTORY) || ffPathExists("/sys/firmware/acpi/tables/UEFI", FF_PATHTYPE_FILE))
         ffStrbufSetStatic(&bios->type, "UEFI");
     else
         ffStrbufSetStatic(&bios->type, "BIOS");
diff --git a/src/detection/tpm/tpm_linux.c b/src/detection/tpm/tpm_linux.c
index 2547339c6..90c7cf7c1 100644
--- a/src/detection/tpm/tpm_linux.c
+++ b/src/detection/tpm/tpm_linux.c
@@ -3,9 +3,9 @@
 
 const char* ffDetectTPM(FFTPMResult* result)
 {
-    if (!ffPathExists("/sys/class/tpm/tpm0", FF_PATHTYPE_DIRECTORY))
+    if (!ffPathExists("/sys/class/tpm/tpm0/", FF_PATHTYPE_DIRECTORY))
     {
-        if (!ffPathExists("/sys/class/tpm", FF_PATHTYPE_DIRECTORY))
+        if (!ffPathExists("/sys/class/tpm/", FF_PATHTYPE_DIRECTORY))
             return "TPM is not supported by kernel";
         return "TPM device is not found";
     }
diff --git a/src/detection/wifi/wifi_linux.c b/src/detection/wifi/wifi_linux.c
index b2e6e464f..2e6b90f20 100644
--- a/src/detection/wifi/wifi_linux.c
+++ b/src/detection/wifi/wifi_linux.c
@@ -274,7 +274,7 @@ const char* ffDetectWifi(FF_MAYBE_UNUSED FFlist* result)
 
     for(struct if_nameindex* i = infs; !(i->if_index == 0 && i->if_name == NULL); ++i)
     {
-        ffStrbufSetF(&buffer, "/sys/class/net/%s/phy80211", i->if_name);
+        ffStrbufSetF(&buffer, "/sys/class/net/%s/phy80211/", i->if_name);
         if(!ffPathExists(buffer.chars, FF_PATHTYPE_DIRECTORY))
             continue;