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authorTom Lane2004-05-05 21:18:29 +0000
committerTom Lane2004-05-05 21:18:29 +0000
commit74f641fe2c6e0101e54ff6a4cc9e5b7bdfc3ed15 (patch)
treee705cf14bfa7aad925476de8decb69c4202eb4bb
parenta10ffced96ed461e78ecf9370cafa183008a512b (diff)
Second try at a portable unsetenv().
-rwxr-xr-xconfigure3
-rw-r--r--configure.in2
-rw-r--r--src/bin/initdb/initdb.c22
-rw-r--r--src/include/c.h4
-rw-r--r--src/include/pg_config.h.in3
-rw-r--r--src/port/unsetenv.c56
6 files changed, 68 insertions, 22 deletions
diff --git a/configure b/configure
index 74b98bee63..3490b9a695 100755
--- a/configure
+++ b/configure
@@ -11744,7 +11744,8 @@ fi
-for ac_func in crypt fseeko getopt getrusage inet_aton random rint srandom strcasecmp strdup strerror strtol strtoul
+
+for ac_func in crypt fseeko getopt getrusage inet_aton random rint srandom strcasecmp strdup strerror strtol strtoul unsetenv
do
as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
echo "$as_me:$LINENO: checking for $ac_func" >&5
diff --git a/configure.in b/configure.in
index e284230b3c..e815c758d1 100644
--- a/configure.in
+++ b/configure.in
@@ -858,7 +858,7 @@ else
AC_CHECK_FUNCS([fpclass fp_class fp_class_d class], [break])
fi
-AC_REPLACE_FUNCS([crypt fseeko getopt getrusage inet_aton random rint srandom strcasecmp strdup strerror strtol strtoul])
+AC_REPLACE_FUNCS([crypt fseeko getopt getrusage inet_aton random rint srandom strcasecmp strdup strerror strtol strtoul unsetenv])
# system's version of getaddrinfo(), if any, may be used only if we found
# a definition for struct addrinfo; see notes in src/include/getaddrinfo.h
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index ecf615ac4c..8135ded17e 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -264,24 +264,6 @@ xstrdup(const char *s)
}
/*
- * unsetenv() doesn't exist everywhere, so emulate it with this ugly
- * but well-tested technique (borrowed from backend's variable.c).
- */
-static void
-pg_unsetenv(const char *varname)
-{
- char *envstr = xmalloc(strlen(varname) + 2);
-
- /* First, override any existing setting by forcibly defining the var */
- sprintf(envstr, "%s=", varname);
- putenv(envstr);
-
- /* Now we can clobber the variable definition this way: */
- strcpy(envstr, "=");
- putenv(envstr);
-}
-
-/*
* delete a directory tree recursively
* assumes path points to a valid directory
* deletes everything under path
@@ -1260,10 +1242,10 @@ bootstrap_template1(char *short_version)
snprintf(cmd, sizeof(cmd), "LC_CTYPE=%s", lc_ctype);
putenv(xstrdup(cmd));
- pg_unsetenv("LC_ALL");
+ unsetenv("LC_ALL");
/* Also ensure backend isn't confused by this environment var: */
- pg_unsetenv("PGCLIENTENCODING");
+ unsetenv("PGCLIENTENCODING");
snprintf(cmd, sizeof(cmd),
"\"%s/postgres\" -boot -x1 %s %s template1",
diff --git a/src/include/c.h b/src/include/c.h
index 74815317cb..971c933e72 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -720,6 +720,10 @@ extern int vsnprintf(char *str, size_t count, const char *fmt, va_list args);
#define memmove(d, s, c) bcopy(s, d, c)
#endif
+#ifndef HAVE_UNSETENV
+extern void unsetenv(const char *name);
+#endif
+
#ifndef DLLIMPORT
#define DLLIMPORT /* no special DLL markers on most ports */
#endif
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 7722087da0..aea533ad83 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -530,6 +530,9 @@
/* Define to 1 if you have unix sockets. */
#undef HAVE_UNIX_SOCKETS
+/* Define to 1 if you have the `unsetenv' function. */
+#undef HAVE_UNSETENV
+
/* Define to 1 if you have the `utime' function. */
#undef HAVE_UTIME
diff --git a/src/port/unsetenv.c b/src/port/unsetenv.c
new file mode 100644
index 0000000000..71be033b1b
--- /dev/null
+++ b/src/port/unsetenv.c
@@ -0,0 +1,56 @@
+/*-------------------------------------------------------------------------
+ *
+ * unsetenv.c
+ * unsetenv() emulation for machines without it
+ *
+ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * $PostgreSQL$
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "c.h"
+
+
+void
+unsetenv(const char *name)
+{
+ char *envstr;
+
+ if (getenv(name) == NULL)
+ return; /* no work */
+
+ /*
+ * The technique embodied here works if libc follows the Single Unix Spec
+ * and actually uses the storage passed to putenv() to hold the environ
+ * entry. When we clobber the entry in the second step we are ensuring
+ * that we zap the actual environ member. However, there are some libc
+ * implementations (notably recent BSDs) that do not obey SUS but copy
+ * the presented string. This method fails on such platforms. Hopefully
+ * all such platforms have unsetenv() and thus won't be using this hack.
+ *
+ * Note that repeatedly setting and unsetting a var using this code
+ * will leak memory.
+ */
+
+ envstr = (char *) malloc(strlen(name) + 2);
+ if (!envstr) /* not much we can do if no memory */
+ return;
+
+ /* Override the existing setting by forcibly defining the var */
+ sprintf(envstr, "%s=", name);
+ putenv(envstr);
+
+ /* Now we can clobber the variable definition this way: */
+ strcpy(envstr, "=");
+
+ /*
+ * This last putenv cleans up if we have multiple zero-length names
+ * as a result of unsetting multiple things.
+ */
+ putenv(envstr);
+}