So I am reversing an ELF binary, now from my knowledge in C the main function has two argument, argc and argv
but some linux binaries that i am reversing have 3 when i decompile them! one int and the other two are char**, i assume the second is the argv but what is the last one?
one example is this binary for a CTF:
The third one is an array to environment variables that this program has access to. If you read the documentation of execve it reads as follows:
The argument vector and environment can be accessed by the called program's main function, when it is defined as:
int main(int argc, char *argv[], char *envp[])Note, however, that the use of a third argument to the main function is not specified in POSIX.1; according to POSIX.1, the environment should be accessed via the external variable environ(7).
