target.c

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/*
 * Helper functions for handling target threads/cpus
 *
 * Copyright (C) 2012, LG Electronics, Namhyung Kim <namhyung.kim@lge.com>
 *
 * Released under the GPL v2.
 */

#include "target.h"
#include "util.h"
#include "debug.h"

#include <pwd.h>
#include <string.h>


enum target_errno target__validate(struct target *target)
{
    enum target_errno ret = TARGET_ERRNO__SUCCESS;

    if (target->pid)
        target->tid = target->pid;

    /* CPU and PID are mutually exclusive */
    if (target->tid && target->cpu_list) {
        target->cpu_list = NULL;
        if (ret == TARGET_ERRNO__SUCCESS)
            ret = TARGET_ERRNO__PID_OVERRIDE_CPU;
    }

    /* UID and PID are mutually exclusive */
    if (target->tid && target->uid_str) {
        target->uid_str = NULL;
        if (ret == TARGET_ERRNO__SUCCESS)
            ret = TARGET_ERRNO__PID_OVERRIDE_UID;
    }

    /* UID and CPU are mutually exclusive */
    if (target->uid_str && target->cpu_list) {
        target->cpu_list = NULL;
        if (ret == TARGET_ERRNO__SUCCESS)
            ret = TARGET_ERRNO__UID_OVERRIDE_CPU;
    }

    /* PID and SYSTEM are mutually exclusive */
    if (target->tid && target->system_wide) {
        target->system_wide = false;
        if (ret == TARGET_ERRNO__SUCCESS)
            ret = TARGET_ERRNO__PID_OVERRIDE_SYSTEM;
    }

    /* UID and SYSTEM are mutually exclusive */
    if (target->uid_str && target->system_wide) {
        target->system_wide = false;
        if (ret == TARGET_ERRNO__SUCCESS)
            ret = TARGET_ERRNO__UID_OVERRIDE_SYSTEM;
    }

    /* THREAD and SYSTEM/CPU are mutually exclusive */
    if (target->per_thread && (target->system_wide || target->cpu_list)) {
        target->per_thread = false;
        if (ret == TARGET_ERRNO__SUCCESS)
            ret = TARGET_ERRNO__SYSTEM_OVERRIDE_THREAD;
    }

    return ret;
}

enum target_errno target__parse_uid(struct target *target)
{
    struct passwd pwd, *result;
    char buf[1024];
    const char *str = target->uid_str;

    target->uid = UINT_MAX;
    if (str == NULL)
        return TARGET_ERRNO__SUCCESS;

    /* Try user name first */
    getpwnam_r(str, &pwd, buf, sizeof(buf), &result);

    if (result == NULL) {
        /*
         * The user name not found. Maybe it's a UID number.
         */
        char *endptr;
        int uid = strtol(str, &endptr, 10);

        if (*endptr != '\0')
            return TARGET_ERRNO__INVALID_UID;

        getpwuid_r(uid, &pwd, buf, sizeof(buf), &result);

        if (result == NULL)
            return TARGET_ERRNO__USER_NOT_FOUND;
    }

    target->uid = result->pw_uid;
    return TARGET_ERRNO__SUCCESS;
}

/*
 * This must have a same ordering as the enum target_errno.
 */
static const char *target__error_str[] = {
    "PID/TID switch overriding CPU",
    "PID/TID switch overriding UID",
    "UID switch overriding CPU",
    "PID/TID switch overriding SYSTEM",
    "UID switch overriding SYSTEM",
    "SYSTEM/CPU switch overriding PER-THREAD",
    "Invalid User: %s",
    "Problems obtaining information for user %s",
};

int target__strerror(struct target *target, int errnum,
              char *buf, size_t buflen)
{
    int idx;
    const char *msg;

    BUG_ON(buflen == 0);

    if (errnum >= 0) {
        str_error_r(errnum, buf, buflen);
        return 0;
    }

    if (errnum <  __TARGET_ERRNO__START || errnum >= __TARGET_ERRNO__END)
        return -1;

    idx = errnum - __TARGET_ERRNO__START;
    msg = target__error_str[idx];

    switch (errnum) {
    case TARGET_ERRNO__PID_OVERRIDE_CPU ...
         TARGET_ERRNO__SYSTEM_OVERRIDE_THREAD:
        snprintf(buf, buflen, "%s", msg);
        break;

    case TARGET_ERRNO__INVALID_UID:
    case TARGET_ERRNO__USER_NOT_FOUND:
        snprintf(buf, buflen, msg, target->uid_str);
        break;

    default:
        /* cannot reach here */
        break;
    }

    return 0;
}