char *getenv(const char *name);
char *secure_getenv(const char *name);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
The getenv() function searches the environment list to find the envi-
ronment variable name, and returns a pointer to the corresponding value
The GNU-specific secure_getenv() function is just like getenv() except
that it returns NULL in cases where "secure execution" is required.
Secure execution is required if one of the following conditions was
true when the program run by the calling process was loaded:
* the process's effective user ID did not match its real user ID or
the process's effective group ID did not match its real group ID
(typically this is the result of executing a set-user-ID or set-
* the effective capability bit was set on the executable file; or
* the process has a nonempty permitted capability set.
Secure execution may also required if triggered by some Linux security
The secure_getenv() function is intended for use in general-purpose
libraries to avoid vulnerabilities that could occur if set-user-ID or
set-group-ID programs accidentally trusted the environment.
The getenv() function returns a pointer to the value in the environ-
ment, or NULL if there is no match.
secure_getenv() first appeared in glibc 2.17.
getenv(): SVr4, POSIX.1-2001, 4.3BSD, C89, C99.
secure_getenv() is a GNU extension.
The strings in the environment list are of the form name=value.
As typically implemented, getenv() returns a pointer to a string within
clearenv(3), getauxval(3), putenv(3), setenv(3), unsetenv(3), capabili-
This page is part of release 3.54 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2012-08-14 GETENV(3)
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