/*
* prb_child_create() - this routine instantiates and rendevous with the
* target child process. This routine returns an opaque handle for the
* childs /proc entry.
*/
prb_status_t
prb_child_create(const char *cmdname, char * const *cmdargs,
const char *loption, const char *libtnfprobe_path,
char * const *envp, prb_proc_ctl_t **ret_val)
{
prb_status_t prbstat;
pid_t childpid;
char executable_name[PATH_MAX + 2];
extern char **environ;
char * const * env_to_use;
size_t loptlen, probepathlen;
volatile shmem_msg_t *smp;
/* initialize shmem communication buffer to cause child to wait */
prbstat = prb_shmem_init(&smp);
if (prbstat)
return (prbstat);
/* fork to create the child process */
childpid = fork();
if (childpid == (pid_t) - 1) {
DBG(perror("prb_child_create: fork failed"));
return (prb_status_map(errno));
}
if (childpid == 0) {
char *oldenv;
char *newenv;
/* ---- CHILD PROCESS ---- */
DBG_TNF_PROBE_1(prb_child_create_1, "libtnfctl",
"sunw%verbosity 1; sunw%debug 'child process created'",
tnf_long, pid, getpid());
if (envp) {
env_to_use = envp;
goto ContChild;
}
/* append libtnfprobe.so to the LD_PRELOAD environment */
loptlen = (loption) ? strlen(loption) : 0;
/* probepathlen has a "/" added in ("+ 1") */
probepathlen = (libtnfprobe_path) ?
(strlen(libtnfprobe_path) + 1) : 0;
oldenv = getenv(PRELOAD);
if (oldenv) {
newenv = (char *) malloc(strlen(PRELOAD) +
1 + /* "=" */
strlen(oldenv) +
1 + /* " " */
probepathlen +
strlen(LIBPROBE) +
1 + /* " " */
loptlen +
1); /* NULL */
if (!newenv)
goto ContChild;
(void) strcpy(newenv, PRELOAD);
(void) strcat(newenv, "=");
(void) strcat(newenv, oldenv);
(void) strcat(newenv, " ");
if (probepathlen) {
(void) strcat(newenv, libtnfprobe_path);
(void) strcat(newenv, "/");
}
(void) strcat(newenv, LIBPROBE);
if (loptlen) {
(void) strcat(newenv, " ");
(void) strcat(newenv, loption);
}
} else {
newenv = (char *) malloc(strlen(PRELOAD) +
1 + /* "=" */
probepathlen +
strlen(LIBPROBE) +
1 + /* " " */
loptlen +
1); /* NULL */
if (!newenv)
goto ContChild;
(void) strcpy(newenv, PRELOAD);
(void) strcat(newenv, "=");
if (probepathlen) {
(void) strcat(newenv, libtnfprobe_path);
(void) strcat(newenv, "/");
}
(void) strcat(newenv, LIBPROBE);
if (loptlen) {
(void) strcat(newenv, " ");
(void) strcat(newenv, loption);
}
}
(void) putenv((char *) newenv);
env_to_use = environ;
/*
* We don't check the return value of putenv because the
* desired libraries might already be in the target, even
* if our effort to change the environment fails. We
* should continue either way ...
*/
ContChild:
/* wait until the parent releases us */
(void) prb_shmem_wait(smp);
DBG_TNF_PROBE_1(prb_child_create_2, "libtnfctl",
"sunw%verbosity 2; "
"sunw%debug 'child process about to exec'",
tnf_string, cmdname, cmdname);
/*
* make the child it's own process group.
* This is so that signals delivered to parent are not
* also delivered to child.
*/
(void) setpgrp();
prbstat = find_executable(cmdname, executable_name);
if (prbstat) {
DBG((void) fprintf(stderr, "prb_child_create: %s\n",
prb_status_str(prbstat)));
/* parent waits for exit */
_exit(1);
}
if (execve(executable_name, cmdargs, env_to_use) == -1) {
DBG(perror("prb_child_create: exec failed"));
_exit(1);
}
/* Never reached */
_exit(1);
}
/* ---- PARENT PROCESS ---- */
/* child is waiting for us */
prbstat = sync_child(childpid, smp, ret_val);
if (prbstat) {
return (prbstat);
}
return (PRB_STATUS_OK);
}
/*
* prb_rtld_wait() - waits on target to execute getpid()
*/
static prb_status_t
prb_rtld_wait(prb_proc_ctl_t *proc_p)
{
prb_proc_state_t pstate;
prb_status_t prbstat;
DBG_TNF_PROBE_0(prb_rtld_wait_1, "libtnfctl", "sunw%verbosity 2");
/* stop on exit of getpid() */
prbstat = prb_proc_exit(proc_p, SYS_getpid, PRB_SYS_ADD);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't set up child to stop on "
"exit of getpid(): %s\n", prb_status_str(prbstat)));
return (prbstat);
}
/* stop on entry of exit() - i.e. exec failed */
prbstat = prb_proc_entry(proc_p, SYS_exit, PRB_SYS_ADD);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't set up child to stop on "
"entry of exit(): %s\n", prb_status_str(prbstat)));
return (prbstat);
}
/* continue target and wait for it to stop */
prbstat = prb_proc_cont(proc_p);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't continue target process: %s\n",
prb_status_str(prbstat)));
return (prbstat);
}
/* wait for target to stop */
prbstat = prb_proc_wait(proc_p, B_FALSE, NULL);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't wait on target process: %s\n",
prb_status_str(prbstat)));
return (prbstat);
}
/* make sure it did stop on getpid() */
prbstat = prb_proc_state(proc_p, &pstate);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't get state of target: %s\n",
prb_status_str(prbstat)));
return (prbstat);
}
if (pstate.ps_issysentry && (pstate.ps_syscallnum == SYS_exit)) {
DBG((void) fprintf(stderr, "prb_rtld_wait: target exited\n"));
return (prb_status_map(EACCES));
}
/* catch any other errors */
if (!(pstate.ps_issysexit && (pstate.ps_syscallnum == SYS_getpid))) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: target didn't stop on getpid\n"));
return (PRB_STATUS_BADSYNC);
}
/* clear wait on getpid */
prbstat = prb_proc_exit(proc_p, SYS_getpid, PRB_SYS_DEL);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't clear child to stop on "
"exit of getpid(): %s\n", prb_status_str(prbstat)));
return (prbstat);
}
/* clear wait on exit */
prbstat = prb_proc_entry(proc_p, SYS_exit, PRB_SYS_DEL);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't clear child to stop on "
"entry of exit(): %s\n", prb_status_str(prbstat)));
return (prbstat);
}
/* start-stop the process to clear it out of the system call */
prbstat = prb_proc_prstop(proc_p);
if (prbstat) {
DBG((void) fprintf(stderr,
"prb_rtld_wait: couldn't prstop child: %s\n",
prb_status_str(prbstat)));
return (prbstat);
}
return (PRB_STATUS_OK);
}
