1 files changed, 156 insertions, 0 deletions
diff --git a/Compat.c b/Compat.c
new file mode 100644
index 0000000..d0ad2cc
--- /dev/null
+++ b/Compat.c
@@ -0,0 +1,156 @@
+/*
+htop - Compat.c
+(C) 2020 htop dev team
+Released under the GNU GPLv2+, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "config.h" // IWYU pragma: keep
+
+#include "Compat.h"
+
+#include <errno.h>
+#include <fcntl.h> // IWYU pragma: keep
+#include <limits.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h> // IWYU pragma: keep
+
+#include "XUtils.h" // IWYU pragma: keep
+
+
+/* GNU/Hurd does not have PATH_MAX in limits.h */
+#ifndef PATH_MAX
+# define PATH_MAX 4096
+#endif
+
+
+int Compat_faccessat(int dirfd,
+                     const char* pathname,
+                     int mode,
+                     int flags) {
+   int ret;
+
+#ifdef HAVE_FACCESSAT
+
+   // Implementation note: AT_SYMLINK_NOFOLLOW unsupported on FreeBSD, fallback to lstat in that case
+
+   errno = 0;
+
+   ret = faccessat(dirfd, pathname, mode, flags);
+   if (!ret || errno != EINVAL)
+      return ret;
+
+#endif
+
+   // Error out on unsupported configurations
+   if (dirfd != (int)AT_FDCWD || mode != F_OK) {
+      errno = EINVAL;
+      return -1;
+   }
+
+   // Fallback to stat(2)/lstat(2) depending on flags
+   struct stat statinfo;
+   if (flags) {
+      ret = lstat(pathname, &statinfo);
+   } else {
+      ret = stat(pathname, &statinfo);
+   }
+
+   return ret;
+}
+
+int Compat_fstatat(int dirfd,
+                   const char* dirpath,
+                   const char* pathname,
+                   struct stat* statbuf,
+                   int flags) {
+
+#ifdef HAVE_FSTATAT
+
+   (void)dirpath;
+
+   return fstatat(dirfd, pathname, statbuf, flags);
+
+#else
+
+   (void)dirfd;
+
+   char path[4096];
+   xSnprintf(path, sizeof(path), "%s/%s", dirpath, pathname);
+
+   if (flags & AT_SYMLINK_NOFOLLOW)
+      return lstat(path, statbuf);
+
+   return stat(path, statbuf);
+
+#endif
+}
+
+#ifndef HAVE_OPENAT
+
+int Compat_openat(const char* dirpath,
+                  const char* pathname,
+                  int flags) {
+
+   char path[4096];
+   xSnprintf(path, sizeof(path), "%s/%s", dirpath, pathname);
+
+   return open(path, flags);
+}
+
+#endif /* !HAVE_OPENAT */
+
+ssize_t Compat_readlinkat(int dirfd,
+                          const char* dirpath,
+                          const char* pathname,
+                          char* buf,
+                          size_t bufsize) {
+
+#ifdef HAVE_READLINKAT
+
+   (void)dirpath;
+
+   return readlinkat(dirfd, pathname, buf, bufsize);
+
+#else
+
+   (void)dirfd;
+
+   char path[4096];
+   xSnprintf(path, sizeof(path), "%s/%s", dirpath, pathname);
+
+   return readlink(path, buf, bufsize);
+
+#endif
+}
+
+ssize_t Compat_readlink(openat_arg_t dirfd,
+                        const char* pathname,
+                        char* buf,
+                        size_t bufsize) {
+
+#ifdef HAVE_OPENAT
+
+   char fdPath[32];
+   xSnprintf(fdPath, sizeof(fdPath), "/proc/self/fd/%d", dirfd);
+
+   char dirPath[PATH_MAX + 1];
+   ssize_t r = readlink(fdPath, dirPath, sizeof(dirPath) - 1);
+   if (r < 0)
+      return r;
+
+   dirPath[r] = '\0';
+
+   char linkPath[PATH_MAX + 1];
+   xSnprintf(linkPath, sizeof(linkPath), "%s/%s", dirPath, pathname);
+
+#else
+
+   char linkPath[PATH_MAX + 1];
+   xSnprintf(linkPath, sizeof(linkPath), "%s/%s", dirfd, pathname);
+
+#endif /* HAVE_OPENAT */
+
+   return readlink(linkPath, buf, bufsize);
+}