| GETENV(3C) | Standard C Library Functions | GETENV(3C) |
getenv,
secure_getenv — return value
for environment name
Standard C Library (libc, -lc)
#include
<stdlib.h>
char *
getenv(const char *name);
char *
secure_getenv(const char
*name);
The
getenv()
function searches the environment list (see
environ(7)) for a string of the form
name=Value
and, if the string is present, returns a pointer to the
value in the current environment.
The
secure_getenv()
function behaves similarly; however, evaluates the conditions that the
process was executed under. If the process was executed in a way that it is
considered setuid, setgid, or raised its privileges, that is the
issetugid(2) function would return
true, then the secure_getenv() function will always
return NULL. This is designed for programs that want
to ensure they do not trust potentially malicious user input while executed
with elevated capabilities. In all other respects, the
secure_getenv() function is identical to the
getenv() function.
If successful, the getenv() and
secure_getenv() functions return a pointer to the
value in the current environment; otherwise, they returns
a NULL pointer.
The getenv() function can be safely called
from a multithreaded application. Care must be exercised when using both
getenv() and
putenv(3C) in a multithreaded
application. These functions examine and modify the environment list, which
is shared by all threads in an application. The system prevents the list
from being accessed simultaneously by two different threads. It does not,
however, prevent two threads from successively accessing the environment
list using getenv() or
putenv(3C)
exec(2), issetugid(2), putenv(3C), attributes(7), environ(7), standards(7)
| January 19, 2025 | OmniOS |