Solved why does the execve always execute failed

[Raffeale]

int main() {
    int ret1 = execve("/bin/ls"," "," " );

    if(ret1<1){
        err(ret1,"execve failed");
    }
return 0;

}

When I run this code, I got execve failed: Bad address
It's my fault, it need pass the argv array pointer and envp array pointer.

 

[Raffeale]

When I change this code to this, I can run but the result is wrong. It output some environment variable.

    char *argv[1] = {'\0'};
    int ret1 = execv("/bin/ls",argv );

 

[vigole]

char *argv[] = { "ls", (char *)0 };
char *envp[] = { (char *)0 };
execve("/bin/ls", argv, envp);

 

[Raffeale]

char *argv[] = { "ls", (char *)0 };
char *envp[] = { (char *)0 };
execve("/bin/ls", argv, envp);

how to get evironment variables ? is there a function to get it? or run setenv with execv?

 

[Mjölnir]

apropos environment
man environ

 

[vigole]

how to get evironment variables ? is there a function to get it? or run setenv with execv?

execve(2)

The argument envp is also a pointer to a null-terminated array of character pointers to null-terminated strings.
A pointer to this array is normally stored in the global variable environ.

environ(7)

A process can query, update, and delete these strings using the getenv(3), setenv(3), and unsetenv(3) functions, respectively.

SEE ALSO
execve(2), getenv(3), setenv(3), unsetenv(3) and environ(7)

EXAMPLES

L145: src/contrib/nvi/common/util.c

freebsd-src

FreeBSD source tree

codeberg.org

L070: src/usr.sbin/pw/pw_log.c

freebsd-src

FreeBSD source tree

codeberg.org

L079: src/stand/efi/loader/bootinfo.c

freebsd-src

FreeBSD source tree

codeberg.org

L175: src/bin/ls/ls.c

freebsd-src

FreeBSD source tree

codeberg.org

L143: src/crypto/openssh/readpass.c

freebsd-src

FreeBSD source tree

codeberg.org

 

[Raffeale]

thanks a lot!