Getting and printing command-line arguments

Question

(char *)curpsinfo->pr_psargs will give me the "first part of the command line",
but that has two deficiencies:
1. If the command line is long, it might get truncated.
2. If the command line contains white space, I have no way to know whether the
spaces in the string are part of an argument ot separation. That is, I can't tell
"ls 'foo bar' baz" from "ls foo bar baz"
I want to get the individual arguments, so that I can print them as run-length encoded strings:
cmd=7:/bin/ls
a1=7:foo bar
a2=3:baz

Answer 1

I've reworked your script:
inline int TGT_PID = $1;
BEGIN { /* 1 */
        printf("BEGIN\n");
        mypids[TGT_PID]++;
syscall::exece:entry /* 2 */
/mypids[curpsinfo->pr_ppid] != 0/ {
        self->follow = 1;
syscall::exece:entry
/(self->follow != 0) &&
(this->argp = (uintptr_t)(curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?
    *(uint32_t *)copyin(arg1 + 0 * 4, 4) :
    *(uint64_t *)copyin(arg1 + 0 * 4, 8))) != NULL/
        a1 = copyinstr(this->argp);
        a1_l = strlen(a1);
        printf("a1=%d:%s\n", a1_l, a1);
        this->last = 1;
syscall::exece:entry
/(self->follow != 0) && this->last == 1 &&
(this->argp = (uintptr_t)(curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?
    *(uint32_t *)copyin(arg1 + 1 * 4, 4) :
    *(uint64_t *)copyin(arg1 + 1 * 4, 8))) != NULL/
        a1 = copyinstr(this->argp);
        a1_l = strlen(a1);
        printf("a1=%d:%s\n", a1_l, a1);
        this->last = 2;
syscall::exece:entry
/(self->follow != 0) && this->last == 2 &&
(this->argp = (uintptr_t)(curpsinfo->pr_dmodel == PR_MODEL_ILP32 ?
    *(uint32_t *)copyin(arg1 + 2 * 4, 4) :
    *(uint64_t *)copyin(arg1 + 2 * 4, 8))) != NULL/
        a1 = copyinstr(this->argp);
        a1_l = strlen(a1);
        printf("a1=%d:%s\n", a1_l, a1);
}The way I debugged this was by figuring out the action that was causing the error by removing actions and then examining its arguments. In this case, you were using the curpsinfo which had the arguments before exece(). You actually wanted to use arg1 as you had before which a char ** NULL-terminated array of arguments.
Since it's a NULL-terminated list, I added the this->list stuff so I didn't walk off the end of the list.