KVM_GETU(3K)

NAME
kvm_getu, kvm_getcmd - get the u-area or invocation arguments for a process

SYNOPSIS

#include <kvm.h>
#include <sys/param.h>
#include <sys/user.h>
#include <sys/proc.h>

struct user *kvm_getu(kd, proc)
kvm_t *kd;
struct proc *proc;

int kvm_getcmd(kd, proc, u, arg, env)
kvm_t *kd;
struct proc *proc;
struct user *u;
char ***arg;
char ***env;

DESCRIPTION

kvm_getu() reads the u-area of the process specified by proc to an area of static storage associated with kd and returns a pointer to it. Subsequent calls to kvm_getu() will overwrite this static area.

kd is a pointer to a kernel identifier returned by kvm_open(3K). proc is a pointer to a copy (in the current process' address space) of a proc structure (obtained, for instance, by a prior kvm_nextproc(3K) call). As a side effect, kvm_getu() sets the address space used to resolve user addresses in subsequent kvm_read() and kvm_write() calls to be the space belonging to proc.

kvm_getcmd() constructs a list of string pointers that represent the command arguments and environment that were used to initiate the process specified by proc.

kd is a pointer to a kernel identifier returned by kvm_open(3K). u is a pointer to a copy (in the current process' address space) of a user structure (obtained, for instance, by a prior kvm_getu() call). If arg is not NULL, then the command line arguments are formed into a null-terminated array of string pointers. The address of the first such pointer is returned in arg. If env is not NULL, then the environment is formed into a null-terminated array of string pointers. The address of the first of these is returned in env.

The pointers returned in arg and env refer to data allocated by malloc(3V) and should be freed (by a call to free (see malloc(3V)) when no longer needed. Both the string pointers and the strings themselves are deallocated when freed.

Since the environment and command line arguments may have been modified by the user process, there is no guarantee that it will be possible to reconstruct the original command at all. Thus, kvm_getcmd() will make the best attempt possible, returning -1 if the user process data is unrecognizable.

RETURN VALUES

On success, kvm_getu() returns a pointer to a copy of the u-area of the process specified by proc. On failure, it returns NULL.

kvm_getcmd() returns:

0   on success.

-1  on failure.

SEE ALSO
execve(2V), kvm_nextproc(3K), kvm_open(3K), kvm_read(3K), malloc(3V)

NOTES

If kvm_getcmd() returns -1, the caller still has the option of using the command line fragment that is stored in the u-area.