From 9e16195f3f7f3cf7815200869be936bfcecfa333 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 5 May 2004 21:18:29 +0000 Subject: [PATCH] Second try at a portable unsetenv(). --- configure | 3 +- configure.in | 4 +-- src/bin/initdb/initdb.c | 24 ++-------------- src/include/c.h | 6 +++- src/include/pg_config.h.in | 3 ++ src/port/unsetenv.c | 56 ++++++++++++++++++++++++++++++++++++++ 6 files changed, 71 insertions(+), 25 deletions(-) create mode 100644 src/port/unsetenv.c 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 74e31f73fd..8ddb6b7372 100644 --- a/configure.in +++ b/configure.in @@ -1,5 +1,5 @@ dnl Process this file with autoconf to produce a configure script. -dnl $PostgreSQL: pgsql/configure.in,v 1.343 2004/04/30 16:08:01 momjian Exp $ +dnl $PostgreSQL: pgsql/configure.in,v 1.344 2004/05/05 21:18:29 tgl Exp $ dnl dnl Developers, please strive to achieve this order: dnl @@ -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 1d39cbb89e..f3b2f30fd5 100644 --- a/src/bin/initdb/initdb.c +++ b/src/bin/initdb/initdb.c @@ -43,7 +43,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * Portions taken from FreeBSD. * - * $PostgreSQL: pgsql/src/bin/initdb/initdb.c,v 1.24 2004/05/05 16:09:31 tgl Exp $ + * $PostgreSQL: pgsql/src/bin/initdb/initdb.c,v 1.25 2004/05/05 21:18:29 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -263,24 +263,6 @@ xstrdup(const char *s) return result; } -/* - * 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 @@ -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 129634f5bb..b3ee88968d 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -12,7 +12,7 @@ * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/c.h,v 1.162 2004/04/30 20:47:33 momjian Exp $ + * $PostgreSQL: pgsql/src/include/c.h,v 1.163 2004/05/05 21:18:29 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -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..122fb3f9ea --- /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: pgsql/src/port/unsetenv.c,v 1.1 2004/05/05 21:18:29 tgl Exp $ + * + *------------------------------------------------------------------------- + */ + +#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); +}