From 6cf9052e88e23902a6fd1e6dcb8f07145383501c Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pali=20Roh=C3=A1r?= Date: Fri, 18 Nov 2022 22:57:11 +0100 Subject: [PATCH] libpci: windows: Fix path returned by GetModuleFileName() GetModuleFileName() on Windows 10 has bugs and returns bogus path. Implement fixups to make path usable for later fopen() call. --- lib/init.c | 39 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 36 insertions(+), 3 deletions(-) diff --git a/lib/init.c b/lib/init.c index 8c8f973..a310cc5 100644 --- a/lib/init.c +++ b/lib/init.c @@ -300,11 +300,11 @@ pci_init_name_list_path(struct pci_access *a) * buffer is too small and does not signal any error. In this case retry * again with larger buffer. */ - size = 256; /* initial buffer size (more than sizeof(PCI_IDS)) */ + size = 256; /* initial buffer size (more than sizeof(PCI_IDS)-4) */ retry: path = pci_malloc(a, size); - len = GetModuleFileName(module, path, size-sizeof(PCI_IDS)); - if (len >= size-sizeof(PCI_IDS)) + len = GetModuleFileName(module, path, size-sizeof(PCI_IDS)-4); /* 4 for "\\\\?\\" */ + if (len >= size-sizeof(PCI_IDS)-4) { free(path); size *= 2; @@ -313,6 +313,39 @@ retry: else if (len == 0) path[0] = '\0'; + /* + * GetModuleFileName() has bugs. On Windows 10 it prepends current drive + * letter if path is just pure NT namespace (with "\\??\\" prefix). Such + * extra drive letter makes path fully invalid and unusable. So remove + * extra drive letter to make path valid again. + * Reproduce: CreateProcessW("\\??\\C:\\lspci.exe", ...) + */ + if (((path[0] >= 'a' && path[0] <= 'z') || + (path[0] >= 'A' && path[0] <= 'Z')) && + strncmp(path+1, ":\\??\\", 5) == 0) + { + memmove(path, path+2, len-2); + len -= 2; + path[len] = '\0'; + } + + /* + * GetModuleFileName() has bugs. On Windows 10 it does not add "\\\\?\\" + * prefix when path is in native NT UNC namespace. Such path is treated by + * WinAPI/DOS functions as standard DOS path relative to the current + * directory, hence something completely different. So prepend missing + * "\\\\?\\" prefix to make path valid again. + * Reproduce: CreateProcessW("\\??\\UNC\\10.0.2.4\\qemu\\lspci.exe", ...) + */ + if (strncmp(path, "\\UNC\\", 5) == 0 || + strncmp(path, "UNC\\", 4) == 0) + { + memmove(path+4, path, len); + memcpy(path, "\\\\?\\", 4); + len += 4; + path[len] = '\0'; + } + #elif defined(PCI_OS_DJGPP) || defined(PCI_OS_WINDOWS) const char *exe_path; -- 2.39.2