Refactor _at functions, add symlink_at

Signed-off-by: Laurent Bercot <ska@appnovation.com>

7 files changed, 210 insertions, 104 deletions

diff --git a/src/libunixonacid/access_at.c b/src/libunixonacid/access_at.c
index e7f988c..f974fbe 100644
--- a/src/libunixonacid/access_at.c
+++ b/src/libunixonacid/access_at.c
@@ -27,30 +27,32 @@ int access_at (int dirfd, char const *file, int amode, unsigned int flag)
 
 #include <skalibs/djbunix.h>
 #include <skalibs/unix-transactional.h>
+#include "at-internal.h"
+
+struct access_s
+{
+  char const *file ;
+  int amode ;
+} ;
+
+static int do_access (void *p)
+{
+  struct access_s *b = p ;
+  return access(b->file, b->amode) ;
+}
+
+static void cancel_access (int r, void *p)
+{
+  (void)r ;
+  (void)p ;
+}
 
 int access_at (int dirfd, char const *file, int amode, unsigned int flag)
 {
-  int fdhere ;
-  if (getuid() != geteuid() || getgid() != getegid())
-    return (errno = ENOSYS, -1) ;
-  (void)flag ;
-  fdhere = openc_read(".") ;
-  if (fdhere < 0) return -1 ;
-  if (fd_chdir(dirfd) < 0)
-  {
-    fd_close(fdhere) ;
-    return -1 ;
-  }
-  if (access(file, amode) < 0)
-  {
-    int e = errno ;
-    fd_chdir(fdhere) ;
-    fd_close(fdhere) ;
-    return (errno = e, -1) ;
-  }
-  fd_chdir(fdhere) ;
-  fd_close(fdhere) ;
-  return 0 ;
+  struct access_s args = { .file = file, .amode = amode } ;
+  if (flag && (getuid() != geteuid() || getgid() != getegid()))
+    return (errno = ENOSYS, 1) ;
+  return emulate_at(dirfd, &do_access, &cancel_access, &args) ;
 }
 
 #endif
diff --git a/src/libunixonacid/at-internal.h b/src/libunixonacid/at-internal.h
new file mode 100644
index 0000000..e76d68a
--- /dev/null
+++ b/src/libunixonacid/at-internal.h
@@ -0,0 +1,10 @@
+/* ISC license. */
+
+#ifndef SKALIBS_AT_INTERNAL_H
+#define SKALIBS_AT_INTERNAL_H
+
+#include <skalibs/functypes.h>
+
+extern int emulate_at (int, init_func_ref, deinit_func_ref, void *) ;
+
+#endif
diff --git a/src/libunixonacid/emulate_at.c b/src/libunixonacid/emulate_at.c
new file mode 100644
index 0000000..0bb194a
--- /dev/null
+++ b/src/libunixonacid/emulate_at.c
@@ -0,0 +1,43 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#if !defined(SKALIBS_HASOPENAT) || !defined(SKALIBS_HASLINKAT)
+
+#include <skalibs/bsdsnowflake.h>
+
+#include <errno.h>
+
+#include <skalibs/functypes.h>
+#include <skalibs/djbunix.h>
+#include <skalibs/unix-transactional.h>
+#include "at-internal.h"
+
+int emulate_at (int dirfd, init_func_ref f, deinit_func_ref g, void *p)
+{
+  int r ;
+  int fdhere = open_read(".") ;
+  if (fdhere < 0) return -1 ;
+  if (fd_chdir(dirfd) < 0) goto errclose ;
+  r = (*f)(p) ;
+  if (r < 0)
+  {
+    int e = errno ;
+    fd_chdir(fdhere) ;
+    errno = e ;
+    goto errclose ;
+  }
+  if (fd_chdir(fdhere) < 0)
+  {
+    (*g)(r, p) ;
+    goto errclose ;
+  }
+  fd_close(fdhere) ;
+  return r ;
+
+ errclose:
+  fd_close(fdhere) ;
+  return -1 ;
+}
+
+#endif
diff --git a/src/libunixonacid/open2_at.c b/src/libunixonacid/open2_at.c
index d96c0b7..3afc4fb 100644
--- a/src/libunixonacid/open2_at.c
+++ b/src/libunixonacid/open2_at.c
@@ -12,6 +12,7 @@
 
 #include <errno.h>
 
+#include <skalibs/stat.h>
 #include <skalibs/fcntl.h>
 #include <skalibs/unix-transactional.h>
 
@@ -25,38 +26,33 @@ int open2_at (int dirfd, char const *file, int flags)
 
 #else
 
-#include <sys/stat.h>
-#include <errno.h>
-
 #include <skalibs/fcntl.h>
 #include <skalibs/djbunix.h>
 #include <skalibs/unix-transactional.h>
+#include "at-internal.h"
 
-int open2_at (int dirfd, char const *file, int flags)
+struct open2_s
 {
-  int fd ;
-  int fdhere = open_read(".") ;
-  if (fdhere < 0) return -1 ;
-  if (fd_chdir(dirfd) < 0) goto errclose ;
-  fd = open2(file, flags) ;
-  if (fd < 0)
-  {
-    int e = errno ;
-    fd_chdir(fdhere) ;
-    errno = e ;
-    goto errclose ;
-  }
-  if (fd_chdir(fdhere) < 0)
-  {
-    fd_close(fd) ;
-    goto errclose ;
-  }
-  fd_close(fdhere) ;
-  return fd ;
+  char const *file ;
+  int flags ;
+} ;
 
- errclose:
-  fd_close(fdhere) ;
-  return -1 ;
+static int do_open2 (void *p)
+{
+  struct open2_s *b = p ;
+  return open2(b->file, b->flags) ;
+}
+
+static void cancel_open2 (int fd, void *p)
+{
+  (void)p ;
+  fd_close(fd) ;
+}
+
+int open2_at (int dirfd, char const *file, int flags)
+{
+  struct open2_s args = { .file = file, .flags = flags } ;
+  return emulate_at(dirfd, &do_open2, &cancel_open2, &args) ;
 }
 
 #endif
diff --git a/src/libunixonacid/open3_at.c b/src/libunixonacid/open3_at.c
index 742a579..a960339 100644
--- a/src/libunixonacid/open3_at.c
+++ b/src/libunixonacid/open3_at.c
@@ -25,38 +25,34 @@ int open3_at (int dirfd, char const *file, int flags, unsigned int mode)
 
 #else
 
-#include <sys/stat.h>
-#include <errno.h>
-
 #include <skalibs/fcntl.h>
 #include <skalibs/djbunix.h>
 #include <skalibs/unix-transactional.h>
+#include "at-internal.h"
 
-int open3_at (int dirfd, char const *file, int flags, unsigned int mode)
+struct open3_s
 {
-  int fd ;
-  int fdhere = open_read(".") ;
-  if (fdhere < 0) return -1 ;
-  if (fd_chdir(dirfd) < 0) goto errclose ;
-  fd = open3(file, flags, mode) ;
-  if (fd < 0)
-  {
-    int e = errno ;
-    fd_chdir(fdhere) ;
-    errno = e ;
-    goto errclose ;
-  }
-  if (fd_chdir(fdhere) < 0)
-  {
-    fd_close(fd) ;
-    goto errclose ;
-  }
-  fd_close(fdhere) ;
-  return fd ;
+  char const *file ;
+  int flags ;
+  unsigned int mode ;
+} ;
 
- errclose:
-  fd_close(fdhere) ;
-  return -1 ;
+static int do_open3 (void *p)
+{
+  struct open3_s *b = p ;
+  return open3(b->file, b->flags, b->mode) ;
+}
+
+static void cancel_open3 (int fd, void *p)
+{
+  (void)p ;
+  fd_close(fd) ;
+}
+
+int open3_at (int dirfd, char const *file, int flags, unsigned int mode)
+{
+  struct open3_s args = { .file = file, .flags = flags, .mode = mode } ;
+  return emulate_at(dirfd, &do_open3, &cancel_open3, &args) ;
 }
 
 #endif
diff --git a/src/libunixonacid/stat_at.c b/src/libunixonacid/stat_at.c
index e4040d5..57aa8dd 100644
--- a/src/libunixonacid/stat_at.c
+++ b/src/libunixonacid/stat_at.c
@@ -8,10 +8,11 @@
 #define _ATFILE_SOURCE
 #endif
 
+#include <skalibs/bsdsnowflake.h>
 #include <skalibs/nonposix.h>
 
-#include <sys/stat.h>
 
+#include <skalibs/stat.h>
 #include <skalibs/fcntl.h>
 #include <skalibs/unix-transactional.h>
 
@@ -27,52 +28,50 @@ int lstat_at (int dirfd, char const *file, struct stat *st)
 
 #else
 
- /* OpenBSD plz. lstat() is POSIX. */
+#include <skalibs/bsdsnowflake.h>
 #include <skalibs/nonposix.h>
 
-#include <sys/stat.h>
 #include <errno.h>
 
+#include <skalibs/stat.h>
 #include <skalibs/fcntl.h>
-#include <skalibs/djbunix.h>
 #include <skalibs/unix-transactional.h>
+#include "at-internal.h"
 
-static int fstat_at (int dirfd, char const *file, struct stat *st, int (*dostat)(char const *, struct stat *))
+struct stat_s
 {
-  int r ;
-  int fdhere = open_read(".") ;
-  if (fdhere < 0) return -1 ;
-  if (fd_chdir(dirfd) < 0)
-  {
-    fd_close(fdhere) ;
-    return -1 ;
-  }
-  r = (*dostat)(file, st) ;
-  if (r < 0)
-  {
-    int e = errno ;
-    fd_chdir(fdhere) ;
-    fd_close(fdhere) ;
-    errno = e ;
-    return -1 ;
-  }
-  if (fd_chdir(fdhere) < 0)
-  {
-    fd_close(fdhere) ;
-    return -1 ;
-  }
-  fd_close(fdhere) ;
-  return r ;
+  char const *file ;
+  struct stat *st ;
+} ;
+
+static int do_stat (void *p)
+{
+  struct stat_s *b = p ;
+  return stat(b->file, b->st) ;
+}
+
+static int do_lstat (void *p)
+{
+  struct stat_s *b = p ;
+  return lstat(b->file, b->st) ;
+}
+
+static void cancel_stat (int r, void *p)
+{
+  (void)r ;
+  (void)p ;
 }
 
 int stat_at (int dirfd, char const *file, struct stat *st)
 {
-  return fstat_at(dirfd, file, st, &stat) ;
+  struct stat_s args = { .file = file, .st = st } ;
+  return emulate_at(dirfd, &do_stat, &cancel_stat, &args) ;
 }
 
 int lstat_at (int dirfd, char const *file, struct stat *st)
 {
-  return fstat_at(dirfd, file, st, &lstat) ;
+  struct stat_s args = { .file = file, .st = st } ;
+  return emulate_at(dirfd, &do_lstat, &cancel_stat, &args) ;
 }
 
 #endif
diff --git a/src/libunixonacid/symlink_at.c b/src/libunixonacid/symlink_at.c
new file mode 100644
index 0000000..4d63120
--- /dev/null
+++ b/src/libunixonacid/symlink_at.c
@@ -0,0 +1,60 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#ifdef SKALIBS_HASLINKAT
+
+#ifndef _ATFILE_SOURCE
+#define _ATFILE_SOURCE
+#endif
+
+#include <skalibs/nonposix.h>
+
+#include <unistd.h>
+#include <errno.h>
+
+#include <skalibs/fcntl.h>
+#include <skalibs/unix-transactional.h>
+
+int symlink_at (char const *src, int dirfd, char const *dst)
+{
+  int r ;
+  do r = symlinkat(src, dirfd, dst) ;
+  while (r == -1 && errno == EINTR) ;
+  return r ;
+}
+
+#else
+
+#include <unistd.h>
+#include <errno.h>
+
+#include <skalibs/posixplz.h>
+#include <skalibs/unix-transactional.h>
+
+struct symlink_s
+{
+  char const *src ;
+  char const *dst ;
+} ;
+
+static int do_symlink (void *p)
+{
+  struct symlink_s *b = p ;
+  return symlink(b->src, b->dst) ;
+}
+
+static void cancel_symlink (int r, void *p)
+{
+  struct symlink_s *b = p ;
+  (void)r ;
+  unlink_void(b->dst) ;
+}
+
+int symlink_at (char const *src, int dirfd, char const *dst)
+{
+  struct symlink_s args = { .src = src, .dst = dst } ;
+  return emulate_at(dirfd, &do_symlink, &cancel_symlink, &args) ;
+}
+
+#endif