#include "kill.h"

static double
uptime()
{
    char * savelocale;
    char buf[2048];
    FILE* file;
    if (!(file=fopen( PROC_BASE "/uptime", "r"))) {
        fprintf(stderr, "killall: error opening uptime file\n");    
        exit(1);
    }
    savelocale = setlocale(LC_NUMERIC,"C");
    if (fscanf(file, "%2047s", buf) == EOF) perror("uptime");
    fclose(file);
    setlocale(LC_NUMERIC,savelocale);
    return atof(buf);
}

/* process age from jiffies to seconds via uptime */
static double process_age(const unsigned long long jf)
{
    double age;
    double sc_clk_tck = sysconf(_SC_CLK_TCK);
    assert(sc_clk_tck > 0);
    age = uptime() - jf / sc_clk_tck;
    if (age < 0L)
        return 0L;
    return age;
}

typedef struct NAMEINFO {
    const char *name;
    int name_length;
    struct stat st;
} NAMEINFO;

static pid_t opt_ns_pid = 0;
static int verbose = 0, exact = 0, interactive = 0, reg = 0,
           quiet = 0, wait_until_dead = 0, process_group = 0,
           ignore_case = 0;
static long younger_than = 0, older_than = 0;

enum ns_type {
    IPCNS = 0,
    MNTNS,
    NETNS,
    PIDNS,
    USERNS,
    UTSNS
};

static const char *ns_names[] = {
    [IPCNS] = "ipc",
    [MNTNS] = "mnt",
    [NETNS] = "net",
    [PIDNS] = "pid",
    [USERNS] = "user",
    [UTSNS] = "uts",
};

static int
load_proc_cmdline(const pid_t pid, const char *comm, char **command, int *got_long)
{
    FILE *file;
    char *path, *p, *command_buf;
    int cmd_size = 128;
    int okay;

    if (asprintf (&path, PROC_BASE "/%d/cmdline", pid) < 0)
        return -1;
    if (!(file = fopen (path, "r")))
    {
        free (path);
        return -1;
    }
    free(path);

    if ( (command_buf = (char *)malloc (cmd_size)) == NULL)
        exit(1);

    while (1)
    {
        /* look for actual command so we skip over initial "sh" if any */

        /* 'cmdline' has arguments separated by nulls */
        for (p=command_buf; ; p++)
        {
            int c;
            if (p == (command_buf + cmd_size))
            {
                char *new_command_buf;
                int cur_size = cmd_size;
                cmd_size *= 2;
                new_command_buf = (char *)realloc(command_buf, cmd_size);
                if (!new_command_buf) {
                    if (command_buf)
                        free(command_buf);
                    exit (1);
                }
                command_buf = new_command_buf;
                p = command_buf + cur_size;
            }
            c = fgetc(file);
            if (c == EOF || c == '\0')
            {
                *p = '\0';
                break;
            } else {
                *p = c;
            }
        }
        if (strlen(command_buf) == 0) {
            okay = 0;
            break;
        }
        p = strrchr(command_buf,'/');
        p = p ? p+1 : command_buf;
        if (strncmp(p, comm, COMM_LEN-1) == 0) {
            okay = 1;
            if (!(*command = strdup(p))) {
                free(command_buf);
                exit(1);
            }
            break;
        }
    }
    (void) fclose(file);
    free(command_buf);
    command_buf = NULL;

    if (exact && !okay)
    {
        if (verbose)
            fprintf (stderr, _("killall: skipping partial match %s(%d)\n"),
                     comm, pid);
        *got_long = okay;
        return -1;
    }
    *got_long = okay;
    return 0;
}

static int
ask (char *name, pid_t pid, const int signal)
{
    int res;
    size_t len;
    char *line;

    line = NULL;
    len = 0;

    do {
        if (signal == SIGTERM)
            printf (_("Kill %s(%s%d) ? (y/N) "), name, process_group ? "pgid " : "",
                    pid);
        else
            printf (_("Signal %s(%s%d) ? (y/N) "), name, process_group ? "pgid " : "",
                    pid);

        fflush (stdout);

        if (getline (&line, &len, stdin) < 0)
            return 0;
        /* Check for default */
        if (line[0] == '\n') {
            free(line);
            return 0;
        }
        res = rpmatch(line);
        if (res >= 0) {
            free(line);
            return res;
        }
    } while(1);
    /* Never should get here */
}

const char *get_ns_name(int id) {
    if (id >= NUM_NS)
        return NULL;
    return ns_names[id];
}

static int get_ns(pid_t pid, int id) {
    struct stat st;
    char buff[50];
    snprintf(buff, sizeof(buff), "/proc/%i/ns/%s", pid, get_ns_name(id));
    if (stat(buff, &st))
        return 0;
    else
        return st.st_ino;
}


static void
free_regexp_list(regex_t *reglist, int names)
{
    int i;
    for (i = 0; i < names; i++)
        regfree(&reglist[i]);
    free(reglist);
}

static regex_t *
build_regexp_list(int names, char **namelist)
{
    int i;
    regex_t *reglist;
    int flag = REG_EXTENDED|REG_NOSUB;

    if (!(reglist = malloc (sizeof (regex_t) * names)))
    {
        perror ("malloc");
        exit (1);
    }

    if (ignore_case)
        flag |= REG_ICASE;

    for (i = 0; i < names; i++)
    {
        if (regcomp(&reglist[i], namelist[i], flag) != 0) 
        {
            fprintf(stderr, _("killall: Bad regular expression: %s\n"), namelist[i]);
            free_regexp_list(reglist, i);
            exit (1);
        }
    }
    return reglist;
}

static NAMEINFO *
build_nameinfo(const int names, char **namelist)
{
    int i;
    NAMEINFO *ni = NULL;
    if ( (ni = malloc(sizeof(NAMEINFO) * names)) == NULL)
        return NULL;

    for (i = 0; i < names; i++) 
    {
        ni[i].name = namelist[i];
        ni[i].st.st_dev = 0;
        if (!strchr (namelist[i], '/'))
        {
            ni[i].name_length = strlen (namelist[i]);
        }
        else if (stat (namelist[i], &(ni[i].st)) < 0)
        {
            perror (namelist[i]);
            free(ni);
            return NULL;
        }
    }
    return ni;
}

static pid_t *
create_pid_table(int *max_pids, int *pids)
{
    pid_t self, *pid_table;
    int pid;
    DIR *dir;
    struct dirent *de;

    self = getpid ();
    if (!(dir = opendir (PROC_BASE)))
    {
        perror (PROC_BASE);
        exit (1);
    }
    *max_pids = 256;
    pid_table = malloc (*max_pids * sizeof (pid_t));
    if (!pid_table)
    {
        perror ("malloc");
        exit (1);
    }
    *pids = 0;
    while ( (de = readdir (dir)) != NULL)
    {
        if (!(pid = (pid_t) atoi (de->d_name)) || pid == self)
            continue;
        if (*pids == *max_pids)
        {
            if (!(pid_table = realloc (pid_table, 2 * *pids * sizeof (pid_t))))
            {
                perror ("realloc");
                exit (1);
            }
            *max_pids *= 2;
        }
        pid_table[(*pids)++] = pid;
    }
    (void) closedir (dir);
    return pid_table;
}

static int
match_process_uid(pid_t pid, uid_t uid)
{
    char buf[128];
    uid_t puid;
    FILE *f;
    int re = -1;

    snprintf (buf, sizeof buf, PROC_BASE "/%d/status", pid);
    if (!(f = fopen (buf, "r")))
        return 0;

    while (fgets(buf, sizeof buf, f))
    {
        if (sscanf (buf, "Uid:\t%d", &puid))
        {
            re = uid==puid;
            break;
        }
    }
    fclose(f);
    if (re==-1)
    {
        fprintf(stderr, _("killall: Cannot get UID from process status\n"));
        exit(1);
    }
    return re;
}

static int
load_process_name_and_age(char *comm, double *process_age_sec,
                          const pid_t pid, int load_age)
{
    FILE *file;
    char *path;
    char buf[1024];
    char *startcomm, *endcomm;
    unsigned lencomm;
    *process_age_sec = 0;

    if (asprintf (&path, PROC_BASE "/%d/stat", pid) < 0)
        return -1;
    if (!(file = fopen (path, "r")))
    {
        free(path);
        return -1;
    }
    free (path);
    if (fgets(buf, 1024, file) == NULL)
    {
        fclose(file);
        return -1;
    }
    fclose(file);
    startcomm = strchr(buf, '(') + 1;
    endcomm = strrchr(startcomm, ')');
    lencomm = endcomm - startcomm;
    if (lencomm < 0)
        lencomm = 0;
    if (lencomm > COMM_LEN -1)
        lencomm = COMM_LEN -1;
    strncpy(comm, startcomm, lencomm);
    comm[lencomm] = '\0';

    endcomm += 2; // skip ") "
    if (load_age)
    {
        unsigned long long proc_stt_jf = 0;
        if (sscanf(endcomm, "%*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %*s %Lu",
                   &proc_stt_jf) != 1)
        {
            return -1;
        }
        *process_age_sec = process_age(proc_stt_jf);
    }
    return lencomm;
}

#ifdef WITH_SELINUX
int
kill_all(int signal, int name_count, char **namelist, struct passwd *pwent, 
         regex_t *scontext )
#else  /*WITH_SELINUX*/
int
kill_all (int signal, int name_count, char **namelist, struct passwd *pwent)
#endif /*WITH_SELINUX*/
{
    struct stat st;
    NAMEINFO *name_info = NULL;
    char *path, comm[COMM_LEN];
    char *command = NULL;
    pid_t *pid_table, *pid_killed;
    pid_t *pgids = NULL;
    int i, j, length, got_long, error;
    int pids, max_pids, pids_killed;
    unsigned long found;
    regex_t *reglist = NULL;
    long ns_ino = 0;
#ifdef WITH_SELINUX
    security_context_t lcontext=NULL;
#endif /*WITH_SELINUX*/

    if (opt_ns_pid)
        ns_ino = get_ns(opt_ns_pid, PIDNS);

    if (name_count && reg)
        reglist = build_regexp_list(name_count, namelist);
    else
        if ( (name_info = build_nameinfo(name_count, namelist)) == NULL)
            exit(1);

    pid_table = create_pid_table(&max_pids, &pids);
    found = 0;
    pids_killed = 0;
    pid_killed = malloc (max_pids * sizeof (pid_t));
    if (!pid_killed)
    {
        perror ("malloc");
        exit (1);
    }
    if (process_group)
    {
        pgids = calloc (pids, sizeof (pid_t));
        if (!pgids)
        {
            perror ("malloc");
            exit (1);
        }
    }
    got_long = 0;
    for (i = 0; i < pids; i++)
    {
        pid_t id;
        int found_name = -1;
        double process_age_sec = 0;
        /* match by UID */
        if (pwent && match_process_uid(pid_table[i], pwent->pw_uid)==0)
            continue;
        if (opt_ns_pid && ns_ino && ns_ino != get_ns(pid_table[i], PIDNS))
            continue;

#ifdef WITH_SELINUX
        /* match by SELinux context */
        if (scontext) 
        {
            if (getpidcon(pid_table[i], &lcontext) < 0)
                continue;
            if (regexec(scontext, lcontext, 0, NULL, 0) != 0) {
                freecon(lcontext);
                continue;
            }
            freecon(lcontext);
        }
#endif /*WITH_SELINUX*/
        length = load_process_name_and_age(comm, &process_age_sec, pid_table[i], (younger_than||older_than));
        if (length < 0)
            continue;

        /* test for process age, if required */
        if ( younger_than && (process_age_sec > younger_than ) )
            continue;
        if ( older_than   && (process_age_sec < older_than ) )
            continue;

        got_long = 0;
        if (command) {
            free(command);
            command = NULL;
        }
        if (length == COMM_LEN - 1)
            if (load_proc_cmdline(pid_table[i], comm, &command, &got_long) < 0)
                continue;

        /* match by process name */
        for (j = 0; j < name_count; j++)
        {
            if (reg)
            {
                if (regexec (&reglist[j], got_long ? command : comm, 0, NULL, 0) != 0)
                    continue;
            }
            else /* non-regex */
            {
                if (!name_info[j].st.st_dev)
                {
                    if (length != COMM_LEN - 1 || name_info[j].name_length < COMM_LEN - 1)
                    {
                        if (ignore_case == 1)
                        {
                            if (strcasecmp (namelist[j], comm))
                                continue;
                        } else {
                            if (strcmp(namelist[j], comm))
                                continue;
                        }
                    } else {
                        if (ignore_case == 1)
                        {
                            if (got_long ? strcasecmp (namelist[j], command) :
                                strncasecmp (namelist[j], comm, COMM_LEN - 1))
                                continue;
                        } else {
                            if (got_long ? strcmp (namelist[j], command) :
                                strncmp (namelist[j], comm, COMM_LEN - 1))
                                continue;
                        }
                    }
                } else {
                    int ok = 1; 
                    if (asprintf (&path, PROC_BASE "/%d/exe", pid_table[i]) < 0)
                        continue;
                    if (stat (path, &st) < 0) 
                        ok = 0;
                    else if (name_info[j].st.st_dev != st.st_dev ||
                             name_info[j].st.st_ino != st.st_ino)
                    {
                        /* maybe the binary has been modified and std[j].st_ino
                         * is not reliable anymore. We need to compare paths.
                         */
                        size_t len = strlen(namelist[j]);
                        char *linkbuf = malloc(len + 1);

                        if (!linkbuf ||
                            readlink(path, linkbuf, len + 1) != (ssize_t)len ||
                            memcmp(namelist[j], linkbuf, len))
                            ok = 0;
                        free(linkbuf);
                    }
                    free(path);
                    if (!ok)
                        continue;
                }
            } /* non-regex */
            found_name = j;
            break;
        }  
        if (name_count && found_name==-1)
            continue;  /* match by process name faild */

        /* check for process group */
        if (!process_group)
            id = pid_table[i];
        else
        {
            int j;

            id = getpgid (pid_table[i]);
            pgids[i] = id;
            if (id < 0)
            {
                fprintf (stderr, "killall: getpgid(%d): %s\n",
                         pid_table[i], strerror (errno));
            }
            for (j = 0; j < i; j++)
                if (pgids[j] == id)
                    break;
            if (j < i)
                continue;
        }    
        if (interactive && !ask (comm, id, signal))
            continue;
        if (kill (process_group ? -id : id, signal) >= 0)
        {
            if (verbose)
                fprintf (stderr, _("Killed %s(%s%d) with signal %d\n"), got_long ? command :
                         comm, process_group ? "pgid " : "", id, signal);
            if (found_name >= 0)
                /* mark item of namelist */
                found |= 1UL << found_name;
            pid_killed[pids_killed++] = id;
        }
        else if (errno != ESRCH || interactive)
            fprintf (stderr, "%s(%d): %s\n", got_long ? command :
                     comm, id, strerror (errno));
    }
    if (command)
        free(command);
    if (reglist)
        free_regexp_list(reglist, name_count);
    free(pgids);
    if (!quiet)
        for (i = 0; i < name_count; i++)
            if (!(found & (1UL << i)))
                fprintf (stderr, _("%s: no process found\n"), namelist[i]);
    if (name_count)
        /* killall returns a zero return code if at least one process has 
         * been killed for each listed command. */
        error = found == ((1UL << (name_count - 1)) | ((1UL << (name_count - 1)) - 1)) ? 0 : 1;
    else
        /* in nameless mode killall returns a zero return code if at least 
         * one process has killed */
        error = pids_killed ? 0 : 1;
    /*
     * We scan all (supposedly) killed processes every second to detect dead
     * processes as soon as possible in order to limit problems of race with
     * PID re-use.
     */
    while (pids_killed && wait_until_dead)
    {
        for (i = 0; i < pids_killed;)
        {
            if (kill (process_group ? -pid_killed[i] : pid_killed[i], 0) < 0 &&
                errno == ESRCH)
            {
                pid_killed[i] = pid_killed[--pids_killed];
                continue;
            }
            i++;
        }
        sleep (1);        /* wait a bit longer */
    }
    free(pid_killed);
    free(pid_table);
    free(name_info);
    return error;
}