157 lines
3.6 KiB
C
157 lines
3.6 KiB
C
/*
|
|
* From: TCP Wrapper.
|
|
*
|
|
* Many systems have putenv() but no setenv(). Other systems have setenv() but
|
|
* no putenv() (MIPS). Still other systems have neither (NeXT). This is a
|
|
* re-implementation that hopefully ends all problems.
|
|
*
|
|
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
|
|
*/
|
|
#include "sys_defs.h"
|
|
|
|
#ifdef MISSING_SETENV_PUTENV
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <stdlib.h>
|
|
|
|
extern char **environ;
|
|
|
|
static int addenv(char *); /* append entry to environment */
|
|
static int allocated = 0; /* environ is, or is not, allocated */
|
|
|
|
#define DO_CLOBBER 1
|
|
|
|
/* namelength - determine length of name in "name=whatever" */
|
|
|
|
static int namelength(const char *name)
|
|
{
|
|
char *equal;
|
|
|
|
equal = strchr(name, '=');
|
|
return ((equal == 0) ? strlen(name) : (equal - name));
|
|
}
|
|
|
|
/* findenv - given name, locate name=value */
|
|
|
|
static char **findenv(const char *name, int len)
|
|
{
|
|
char **envp;
|
|
|
|
for (envp = environ; envp && *envp; envp++)
|
|
if (strncmp(name, *envp, len) == 0 && (*envp)[len] == '=')
|
|
return (envp);
|
|
return (0);
|
|
}
|
|
|
|
#if 0
|
|
|
|
/* getenv - given name, locate value */
|
|
|
|
char *getenv(const char *name)
|
|
{
|
|
int len = namelength(name);
|
|
char **envp = findenv(name, len);
|
|
|
|
return (envp ? *envp + len + 1 : 0);
|
|
}
|
|
|
|
/* putenv - update or append environment (name,value) pair */
|
|
|
|
int putenv(const char *nameval)
|
|
{
|
|
char *equal = strchr(nameval, '=');
|
|
char *value = (equal ? equal : "");
|
|
|
|
return (setenv(nameval, value, DO_CLOBBER));
|
|
}
|
|
|
|
/* unsetenv - remove variable from environment */
|
|
|
|
void unsetenv(const char *name)
|
|
{
|
|
char **envp;
|
|
|
|
while ((envp = findenv(name, namelength(name))) != 0)
|
|
while (envp[0] = envp[1])
|
|
envp++;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* setenv - update or append environment (name,value) pair */
|
|
|
|
int setenv(const char *name, const char *value, int clobber)
|
|
{
|
|
char *destination;
|
|
char **envp;
|
|
int l_name; /* length of name part */
|
|
unsigned int l_nameval; /* length of name=value */
|
|
|
|
/* Permit name= and =value. */
|
|
|
|
l_name = namelength(name);
|
|
envp = findenv(name, l_name);
|
|
if (envp != 0 && clobber == 0)
|
|
return (0);
|
|
if (*value == '=')
|
|
value++;
|
|
l_nameval = l_name + strlen(value) + 1;
|
|
|
|
/*
|
|
* Use available memory if the old value is long enough. Never free an
|
|
* old name=value entry because it may not be allocated.
|
|
*/
|
|
|
|
destination = (envp != 0 && strlen(*envp) >= l_nameval) ?
|
|
*envp : malloc(l_nameval + 1);
|
|
if (destination == 0)
|
|
return (-1);
|
|
strncpy(destination, name, l_name);
|
|
destination[l_name] = '=';
|
|
strcpy(destination + l_name + 1, value);
|
|
return ((envp == 0) ? addenv(destination) : (*envp = destination, 0));
|
|
}
|
|
|
|
/* cmalloc - malloc and copy block of memory */
|
|
|
|
static char *cmalloc(int new_len, char *old, int old_len)
|
|
{
|
|
char *new = malloc(new_len);
|
|
|
|
if (new != 0)
|
|
memcpy(new, old, old_len);
|
|
return (new);
|
|
}
|
|
|
|
/* addenv - append environment entry */
|
|
|
|
static int addenv(char *nameval)
|
|
{
|
|
char **envp;
|
|
int n_used; /* number of environment entries */
|
|
int l_used; /* bytes used excl. terminator */
|
|
int l_need; /* bytes needed incl. terminator */
|
|
|
|
for (envp = environ; envp && *envp; envp++)
|
|
/* void */ ;
|
|
n_used = envp - environ;
|
|
l_used = n_used * sizeof(*envp);
|
|
l_need = l_used + 2 * sizeof(*envp);
|
|
|
|
envp = allocated ?
|
|
(char **) realloc((char *) environ, l_need) :
|
|
(char **) cmalloc(l_need, (char *) environ, l_used);
|
|
if (envp == 0) {
|
|
return (-1);
|
|
} else {
|
|
allocated = 1;
|
|
environ = envp;
|
|
environ[n_used++] = nameval; /* add new entry */
|
|
environ[n_used] = 0; /* terminate list */
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
#endif
|