From 933e986a9207d2b61c5119e18603b44b924e7226 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Thu, 7 Dec 2017 15:49:02 +0000
Subject:  Finally implement sarealpath() over realpath(). Prettier
 atomic_symlink().

---
 src/libstddjb/absolutepath.c       | 12 --------
 src/libstddjb/absolutepath_tmp.c   | 63 --------------------------------------
 src/libstddjb/sarealpath.c         | 26 ++++++++++++++++
 src/libstddjb/sarealpath_tmp.c     | 11 +++++++
 src/libunixonacid/atomic_symlink.c | 13 ++++++--
 5 files changed, 47 insertions(+), 78 deletions(-)
 delete mode 100644 src/libstddjb/absolutepath.c
 delete mode 100644 src/libstddjb/absolutepath_tmp.c
 create mode 100644 src/libstddjb/sarealpath.c
 create mode 100644 src/libstddjb/sarealpath_tmp.c

(limited to 'src')

diff --git a/src/libstddjb/absolutepath.c b/src/libstddjb/absolutepath.c
deleted file mode 100644
index 9a7a19f..0000000
--- a/src/libstddjb/absolutepath.c
+++ /dev/null
@@ -1,12 +0,0 @@
-/* ISC license. */
-
-/* MT-unsafe */
-
-#include <skalibs/stralloc.h>
-#include <skalibs/skamisc.h>
-#include <skalibs/djbunix.h>
-
-int sarealpath (stralloc *sa, char const *path)
-{
-  return sarealpath_tmp(sa, path, &satmp) ;
-}
diff --git a/src/libstddjb/absolutepath_tmp.c b/src/libstddjb/absolutepath_tmp.c
deleted file mode 100644
index 100a7e9..0000000
--- a/src/libstddjb/absolutepath_tmp.c
+++ /dev/null
@@ -1,63 +0,0 @@
-/* ISC license. */
-
-/* MT-unsafe (because of chdir) */
-
-#include <unistd.h>
-#include <errno.h>
-#include <skalibs/stralloc.h>
-#include <skalibs/djbunix.h>
-
-int sarealpath_tmp (stralloc *sa, char const *path, stralloc *tmp)
-{
-  size_t tmpbase = tmp->len ;
-  size_t base = sa->len ;
-  unsigned int loop = 48 ;
-  int fdhere ;
-  int wasnull = !sa->s ;
-
-  if (!path) return (errno = EINVAL, -1) ;
-  if (!stralloc_cats(sa, path)) return -1 ;
-  fdhere = open_read(".") ;
-  if (fdhere == -1)
-  {
-    if (wasnull) stralloc_free(sa) ; else sa->len = base ;
-    return -1 ;
-  }
-
-  do
-  {
-    tmp->len = tmpbase ;
-    if (!loop--) { errno = ELOOP ; goto err ; }
-    if (!sadirname(tmp, sa->s + base, sa->len - base)
-     || !stralloc_0(tmp)
-     || (chdir(tmp->s + tmpbase) == -1))
-      goto err ;
-    tmp->len = tmpbase ;
-    if (!sabasename(tmp, sa->s + base, sa->len - base)
-     || !stralloc_0(tmp)) goto err ;
-    sa->len = base ;
-  }
-  while (sareadlink(sa, tmp->s + tmpbase) >= 0) ;
-
-  if ((errno != EINVAL)
-   || (sagetcwd(sa) == -1)
-   || ((sa->len > base + 1) && !stralloc_catb(sa, "/", 1))
-   || ((--tmp->len > tmpbase) && (tmp->s[tmpbase] != '/') && !stralloc_catb(sa, tmp->s + tmpbase, tmp->len - tmpbase)))
-    goto err ;
-
-  tmp->len = tmpbase ;
-  fd_chdir(fdhere) ;
-  fd_close(fdhere) ;
-  return 0 ;
-
-err:
-  {
-    int e = errno ;
-    tmp->len = tmpbase ;
-    fd_chdir(fdhere) ;
-    fd_close(fdhere) ;
-    if (wasnull) stralloc_free(sa) ; else sa->len = base ;
-    errno = e ;
-  }
-  return -1 ;
-}
diff --git a/src/libstddjb/sarealpath.c b/src/libstddjb/sarealpath.c
new file mode 100644
index 0000000..0cf1825
--- /dev/null
+++ b/src/libstddjb/sarealpath.c
@@ -0,0 +1,26 @@
+/* ISC license. */
+
+#include <string.h>
+#include <limits.h>
+#include <stdlib.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+int sarealpath (stralloc *sa, char const *path)
+{
+  if (sa->s)
+  {
+    if (!stralloc_readyplus(sa, PATH_MAX)) return -1 ;
+    if (!realpath(path, sa->s + sa->len)) return -1 ;
+    sa->len += strlen(sa->s + sa->len) ;
+  }
+  else
+  {
+    char *p = realpath(path, 0) ;
+    if (!p) return -1 ;
+    sa->s = p ;
+    sa->len = strlen(p) ;
+    sa->a = sa->len + 1 ;
+  }
+  return 0 ;
+}
diff --git a/src/libstddjb/sarealpath_tmp.c b/src/libstddjb/sarealpath_tmp.c
new file mode 100644
index 0000000..31aeeb2
--- /dev/null
+++ b/src/libstddjb/sarealpath_tmp.c
@@ -0,0 +1,11 @@
+/* ISC license. */
+
+/* This function is now obsolete. */
+
+#include <skalibs/djbunix.h>
+
+int sarealpath_tmp (stralloc *sa, char const *path, stralloc *tmp)
+{
+  (void)tmp ;
+  return sarealpath(sa, path) ;
+}
diff --git a/src/libunixonacid/atomic_symlink.c b/src/libunixonacid/atomic_symlink.c
index 660e4d3..d438263 100644
--- a/src/libunixonacid/atomic_symlink.c
+++ b/src/libunixonacid/atomic_symlink.c
@@ -4,6 +4,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <stdio.h>
+#include <unistd.h>
 #include <skalibs/random.h>
 #include <skalibs/unix-transactional.h>
 
@@ -17,7 +18,7 @@ int atomic_symlink (char const *target, char const *name, char const *suffix)
   }
   {
     size_t namelen = strlen(name) ;
-    size_t suffixlen = suffix ? strlen(suffix) : 8 ;
+    size_t suffixlen = suffix ? strlen(suffix) : 25 ;
     char tmp[namelen + suffixlen + 2] ;
     memcpy(tmp, name, namelen) ;
     tmp[namelen] = ':' ;
@@ -25,8 +26,14 @@ int atomic_symlink (char const *target, char const *name, char const *suffix)
       memcpy(tmp + namelen + 1, suffix, suffixlen + 1) ;
     else
     {
-      random_name(tmp + namelen + 1, 8) ;
-      tmp[namelen + 9] = 0 ;
+      memcpy(tmp + namelen + 1, "atomic_symlink:", 15) ;
+      random_name(tmp + namelen + 16, 8) ;
+      tmp[namelen + 24] = 0 ;
+    }
+    {
+      int e = errno ;
+      if (unlink(tmp) < 0 && errno != ENOENT) return 0 ;
+      errno = e ;
     }
     if (symlink(target, tmp) < 0) return 0 ;
     if (rename(tmp, name) < 0)
-- 
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