stdlib: Tune down fork arc4random tests

[thirdparty/glibc.git] / stdlib / setenv.c

diff --git a/stdlib/setenv.c b/stdlib/setenv.c
index b60c4f0151a623669b5cdb738528cac4e0a15643..ba5257d3bfafd5227ac03e09f96de5acb551f685 100644 (file)
--- a/stdlib/setenv.c
+++ b/stdlib/setenv.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1992-2015 Free Software Foundation, Inc.
+/* Copyright (C) 1992-2023 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -13,12 +13,19 @@
 
    You should have received a copy of the GNU Lesser General Public
    License along with the GNU C Library; if not, see
-   <http://www.gnu.org/licenses/>.  */
+   <https://www.gnu.org/licenses/>.  */
 
 #if HAVE_CONFIG_H
 # include <config.h>
 #endif
 
+/* Pacify GCC; see the commentary about VALLEN below.  This is needed
+   at least through GCC 4.9.2.  Pacify GCC for the entire file, as
+   there seems to be no way to pacify GCC selectively, only for the
+   place where it's needed.  Do not use DIAG_IGNORE_NEEDS_COMMENT
+   here, as it's not defined yet.  */
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+
 #include <errno.h>
 #if !_LIBC
 # if !defined errno && !defined HAVE_ERRNO_DECL
@@ -46,7 +53,7 @@ extern char **environ;
 
 #if _LIBC
 /* This lock protects against simultaneous modifications of `environ'.  */
-# include <bits/libc-lock.h>
+# include <libc-lock.h>
 __libc_lock_define_initialized (static, envlock)
 # define LOCK  __libc_lock_lock (envlock)
 # define UNLOCK        __libc_lock_unlock (envlock)
@@ -106,16 +113,22 @@ static char **last_environ;
    to reuse values once generated for a `setenv' call since we can never
    free the strings.  */
 int
-__add_to_environ (name, value, combined, replace)
-     const char *name;
-     const char *value;
-     const char *combined;
-     int replace;
+__add_to_environ (const char *name, const char *value, const char *combined,
+                 int replace)
 {
   char **ep;
   size_t size;
+
+  /* Compute lengths before locking, so that the critical section is
+     less of a performance bottleneck.  VALLEN is needed only if
+     COMBINED is null (unfortunately GCC is not smart enough to deduce
+     this; see the #pragma at the start of this file).  Testing
+     COMBINED instead of VALUE causes setenv (..., NULL, ...)  to dump
+     core now instead of corrupting memory later.  */
   const size_t namelen = strlen (name);
-  const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
+  size_t vallen;
+  if (combined == NULL)
+    vallen = strlen (value) + 1;
 
   LOCK;
 
@@ -137,7 +150,9 @@ __add_to_environ (name, value, combined, replace)
     {
       char **new_environ;
 
-      /* We allocated this space; we can extend it.  */
+      /* We allocated this space; we can extend it.  Avoid using the raw
+        reallocated pointer to avoid GCC -Wuse-after-free.  */
+      uintptr_t ip_last_environ = (uintptr_t)last_environ;
       new_environ = (char **) realloc (last_environ,
                                       (size + 2) * sizeof (char *));
       if (new_environ == NULL)
@@ -146,7 +161,7 @@ __add_to_environ (name, value, combined, replace)
          return -1;
        }
 
-      if (__environ != last_environ)
+      if ((uintptr_t)__environ != ip_last_environ)
        memcpy ((char *) new_environ, (char *) __environ,
                size * sizeof (char *));
 
@@ -235,10 +250,7 @@ __add_to_environ (name, value, combined, replace)
 }
 
 int
-setenv (name, value, replace)
-     const char *name;
-     const char *value;
-     int replace;
+setenv (const char *name, const char *value, int replace)
 {
   if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
     {
@@ -250,8 +262,7 @@ setenv (name, value, replace)
 }
 
 int
-unsetenv (name)
-     const char *name;
+unsetenv (const char *name)
 {
   size_t len;
   char **ep;
@@ -269,18 +280,20 @@ unsetenv (name)
   ep = __environ;
   if (ep != NULL)
     while (*ep != NULL)
-      if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
-       {
-         /* Found it.  Remove this pointer by moving later ones back.  */
-         char **dp = ep;
-
-         do
-           dp[0] = dp[1];
-         while (*dp++);
-         /* Continue the loop in case NAME appears again.  */
-       }
-      else
-       ++ep;
+      {
+       if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
+         {
+           /* Found it.  Remove this pointer by moving later ones back.  */
+           char **dp = ep;
+
+           do
+               dp[0] = dp[1];
+           while (*dp++);
+           /* Continue the loop in case NAME appears again.  */
+         }
+       else
+         ++ep;
+      }
 
   UNLOCK;
 
@@ -310,7 +323,8 @@ clearenv (void)
   return 0;
 }
 #ifdef _LIBC
-libc_freeres_fn (free_mem)
+void
+__libc_setenv_freemem (void)
 {
   /* Remove all traces.  */
   clearenv ();