/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
#ident "$Id$"
/*======
This file is part of PerconaFT.


Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License, version 2,
    as published by the Free Software Foundation.

    PerconaFT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with PerconaFT.  If not, see <http://www.gnu.org/licenses/>.

----------------------------------------

    PerconaFT is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License, version 3,
    as published by the Free Software Foundation.

    PerconaFT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with PerconaFT.  If not, see <http://www.gnu.org/licenses/>.
======= */

#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."

#include <toku_portability.h>
#include <unistd.h>
#include <errno.h>
#include <toku_assert.h>
#include <stdio.h>
#include <string.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#include "memory.h"
#include "toku_time.h"
#include "toku_path.h"
#include <portability/toku_atomic.h>

static int toku_assert_on_write_enospc = 0;
static const int toku_write_enospc_sleep = 1;
static uint64_t toku_write_enospc_last_report;      // timestamp of most recent report to error log
static time_t   toku_write_enospc_last_time;        // timestamp of most recent ENOSPC
static uint32_t toku_write_enospc_current;          // number of threads currently blocked on ENOSPC
static uint64_t toku_write_enospc_total;            // total number of times ENOSPC was returned from an attempt to write

void toku_set_assert_on_write_enospc(int do_assert) {
    toku_assert_on_write_enospc = do_assert;
}

void toku_fs_get_write_info(time_t *enospc_last_time, uint64_t *enospc_current, uint64_t *enospc_total) {
    *enospc_last_time = toku_write_enospc_last_time;
    *enospc_current = toku_write_enospc_current;
    *enospc_total = toku_write_enospc_total;
}

//Print any necessary errors
//Return whether we should try the write again.
static void
try_again_after_handling_write_error(int fd, size_t len, ssize_t r_write) {
    int try_again = 0;

    assert(r_write < 0);
    int errno_write = get_error_errno();
    switch (errno_write) {
    case EINTR: { //The call was interrupted by a signal before any data was written; see signal(7).
	char err_msg[sizeof("Write of [] bytes to fd=[] interrupted.  Retrying.") + 20+10]; //64 bit is 20 chars, 32 bit is 10 chars
	snprintf(err_msg, sizeof(err_msg), "Write of [%" PRIu64 "] bytes to fd=[%d] interrupted.  Retrying.", (uint64_t)len, fd);
	perror(err_msg);
	fflush(stderr);
	try_again = 1;
	break;
    }
    case ENOSPC: {
        if (toku_assert_on_write_enospc) {
            char err_msg[sizeof("Failed write of [] bytes to fd=[].") + 20+10]; //64 bit is 20 chars, 32 bit is 10 chars
            snprintf(err_msg, sizeof(err_msg), "Failed write of [%" PRIu64 "] bytes to fd=[%d].", (uint64_t)len, fd);
            perror(err_msg);
            fflush(stderr);
            int out_of_disk_space = 1;
            assert(!out_of_disk_space); //Give an error message that might be useful if this is the only one that survives.
        } else {
            toku_sync_fetch_and_add(&toku_write_enospc_total, 1);
            toku_sync_fetch_and_add(&toku_write_enospc_current, 1);

            time_t tnow = time(0);
            toku_write_enospc_last_time = tnow;
            if (toku_write_enospc_last_report == 0 || tnow - toku_write_enospc_last_report >= 60) {
                toku_write_enospc_last_report = tnow;

                const int tstr_length = 26;
                char tstr[tstr_length];
                time_t t = time(0);
                ctime_r(&t, tstr);

                const int MY_MAX_PATH = 256;
                char fname[MY_MAX_PATH], symname[MY_MAX_PATH+1];
                sprintf(fname, "/proc/%d/fd/%d", getpid(), fd);
                ssize_t n = readlink(fname, symname, MY_MAX_PATH);

                if ((int)n == -1)
                    fprintf(stderr, "%.24s PerconaFT No space when writing %" PRIu64 " bytes to fd=%d ", tstr, (uint64_t) len, fd);
                else {
		    tstr[n] = 0; // readlink doesn't append a NUL to the end of the buffer.
                    fprintf(stderr, "%.24s PerconaFT No space when writing %" PRIu64 " bytes to %*s ", tstr, (uint64_t) len, (int) n, symname);
		}
                fprintf(stderr, "retry in %d second%s\n", toku_write_enospc_sleep, toku_write_enospc_sleep > 1 ? "s" : "");
                fflush(stderr);
            }
            sleep(toku_write_enospc_sleep);
            try_again = 1;
            toku_sync_fetch_and_sub(&toku_write_enospc_current, 1);
            break;
        }
    }
    default:
	break;
    }
    assert(try_again);
    errno = errno_write;
}

static ssize_t (*t_write)(int, const void *, size_t);
static ssize_t (*t_full_write)(int, const void *, size_t);
static ssize_t (*t_pwrite)(int, const void *, size_t, off_t);
static ssize_t (*t_full_pwrite)(int, const void *, size_t, off_t);
static FILE *  (*t_fdopen)(int, const char *);
static FILE *  (*t_fopen)(const char *, const char *);
static int     (*t_open)(const char *, int, int);
static int     (*t_fclose)(FILE *);
static ssize_t (*t_read)(int, void *, size_t);
static ssize_t (*t_pread)(int, void *, size_t, off_t);

void toku_set_func_write (ssize_t (*write_fun)(int, const void *, size_t)) {
    t_write = write_fun;
}

void toku_set_func_full_write (ssize_t (*write_fun)(int, const void *, size_t)) {
    t_full_write = write_fun;
}

void toku_set_func_pwrite (ssize_t (*pwrite_fun)(int, const void *, size_t, off_t)) {
    t_pwrite = pwrite_fun;
}

void toku_set_func_full_pwrite (ssize_t (*pwrite_fun)(int, const void *, size_t, off_t)) {
    t_full_pwrite = pwrite_fun;
}

void toku_set_func_fdopen(FILE * (*fdopen_fun)(int, const char *)) {
    t_fdopen = fdopen_fun;
}

void toku_set_func_fopen(FILE * (*fopen_fun)(const char *, const char *)) {
    t_fopen = fopen_fun;
}

void toku_set_func_open(int (*open_fun)(const char *, int, int)) {
    t_open = open_fun;
}

void toku_set_func_fclose(int (*fclose_fun)(FILE*)) {
    t_fclose = fclose_fun;
}

void toku_set_func_read (ssize_t (*read_fun)(int, void *, size_t)) {
    t_read = read_fun;
}

void toku_set_func_pread (ssize_t (*pread_fun)(int, void *, size_t, off_t)) {
    t_pread = pread_fun;
}

void
toku_os_full_write (int fd, const void *buf, size_t len) {
    const char *bp = (const char *) buf;
    while (len > 0) {
        ssize_t r;
        if (t_full_write) {
            r = t_full_write(fd, bp, len);
        } else {
            r = write(fd, bp, len);
        }
        if (r > 0) {
            len           -= r;
            bp            += r;
        }
        else {
            try_again_after_handling_write_error(fd, len, r);
        }
    }
    assert(len == 0);
}

int
toku_os_write (int fd, const void *buf, size_t len) {
    const char *bp = (const char *) buf;
    int result = 0;
    while (len > 0) {
        ssize_t r;
        if (t_write) {
            r = t_write(fd, bp, len);
        } else {
            r = write(fd, bp, len);
        }
        if (r < 0) {
            result = errno;
            break;
        }
        len           -= r;
        bp            += r;
    }
    return result;
}

void
toku_os_full_pwrite (int fd, const void *buf, size_t len, toku_off_t off) {
    assert(0==((long long)buf)%512);
    assert((len%512 == 0) && (off%512)==0); // to make pwrite work.
    const char *bp = (const char *) buf;
    while (len > 0) {
        ssize_t r;
        if (t_full_pwrite) {
            r = t_full_pwrite(fd, bp, len, off);
        } else {
            r = pwrite(fd, bp, len, off);
        }
        if (r > 0) {
            len           -= r;
            bp            += r;
            off           += r;
        }
        else {
            try_again_after_handling_write_error(fd, len, r);
        }
    }
    assert(len == 0);
}

ssize_t
toku_os_pwrite (int fd, const void *buf, size_t len, toku_off_t off) {
    assert(0==((long long)buf)%512); // these asserts are to ensure that direct I/O will work.
    assert(0==len             %512);
    assert(0==off             %512);
    const char *bp = (const char *) buf;
    ssize_t result = 0;
    while (len > 0) {
        ssize_t r;
        if (t_pwrite) {
            r = t_pwrite(fd, bp, len, off);
        } else {
            r = pwrite(fd, bp, len, off);
        }
        if (r < 0) {
            result = errno;
            break;
        }
        len           -= r;
        bp            += r;
        off           += r;
    }
    return result;
}

FILE * 
toku_os_fdopen(int fildes, const char *mode) {
    FILE * rval;
    if (t_fdopen)
	rval = t_fdopen(fildes, mode);
    else 
	rval = fdopen(fildes, mode);
    return rval;
}
    

FILE *
toku_os_fopen(const char *filename, const char *mode){
    FILE * rval;
    if (t_fopen)
	rval = t_fopen(filename, mode);
    else
	rval = fopen(filename, mode);
    return rval;
}

int 
toku_os_open(const char *path, int oflag, int mode) {
    int rval;
    if (t_open)
	rval = t_open(path, oflag, mode);
    else
	rval = open(path, oflag, mode);
    return rval;
}

int
toku_os_open_direct(const char *path, int oflag, int mode) {
    int rval;
#if defined(HAVE_O_DIRECT)
    rval = toku_os_open(path, oflag | O_DIRECT, mode);
#elif defined(HAVE_F_NOCACHE)
    rval = toku_os_open(path, oflag, mode);
    if (rval >= 0) {
        int r = fcntl(rval, F_NOCACHE, 1);
        if (r == -1) {
            perror("setting F_NOCACHE");
        }
    }
#else
# error "No direct I/O implementation found."
#endif
    return rval;
}

int
toku_os_fclose(FILE * stream) {  
    int rval = -1;
    if (t_fclose)
	rval = t_fclose(stream);
    else {                      // if EINTR, retry until success
	while (rval != 0) {
	    rval = fclose(stream);
	    if (rval && (errno != EINTR))
		break;
	}
    }
    return rval;
}

int 
toku_os_close(int fd) {  // if EINTR, retry until success
    int r = -1;
    while (r != 0) {
	r = close(fd);
	if (r) {
	    int rr = errno;
	    if (rr!=EINTR) printf("rr=%d (%s)\n", rr, strerror(rr));
	    assert(rr==EINTR);
	}
    }
    return r;
}

int toku_os_rename(const char *old_name, const char *new_name) {
    return rename(old_name, new_name);
}

int toku_os_unlink(const char *path) { return unlink(path); }

ssize_t 
toku_os_read(int fd, void *buf, size_t count) {
    ssize_t r;
    if (t_read)
        r = t_read(fd, buf, count);
    else
        r = read(fd, buf, count);
    return r;
}

ssize_t
toku_os_pread (int fd, void *buf, size_t count, off_t offset) {
    assert(0==((long long)buf)%512);
    assert(0==count%512);
    assert(0==offset%512);
    ssize_t r;
    if (t_pread) {
	r = t_pread(fd, buf, count, offset);
    } else {
	r = pread(fd, buf, count, offset);
    }
    return r;
}

void toku_os_recursive_delete(const char *path) {
    char buf[TOKU_PATH_MAX + sizeof("rm -rf ")];
    strcpy(buf, "rm -rf ");
    strncat(buf, path, TOKU_PATH_MAX);
    int r = system(buf);
    assert_zero(r);
}

// fsync logic:

// t_fsync exists for testing purposes only
static int (*t_fsync)(int) = 0;
static uint64_t toku_fsync_count;
static uint64_t toku_fsync_time;
static uint64_t toku_long_fsync_threshold = 1000000;
static uint64_t toku_long_fsync_count;
static uint64_t toku_long_fsync_time;
static uint64_t toku_long_fsync_eintr_count;
static int toku_fsync_debug = 0;

void toku_set_func_fsync(int (*fsync_function)(int)) {
    t_fsync = fsync_function;
}

// keep trying if fsync fails because of EINTR
static void file_fsync_internal (int fd) {
    uint64_t tstart = toku_current_time_microsec();
    int r = -1;
    uint64_t eintr_count = 0;
    while (r != 0) {
	if (t_fsync) {
	    r = t_fsync(fd);
        } else {
	    r = fsync(fd);
        }
	if (r) {
            assert(get_error_errno() == EINTR);
            eintr_count++;
	}
    }
    toku_sync_fetch_and_add(&toku_fsync_count, 1);
    uint64_t duration = toku_current_time_microsec() - tstart;
    toku_sync_fetch_and_add(&toku_fsync_time, duration);
    if (duration >= toku_long_fsync_threshold) {
        toku_sync_fetch_and_add(&toku_long_fsync_count, 1);
        toku_sync_fetch_and_add(&toku_long_fsync_time, duration);
        toku_sync_fetch_and_add(&toku_long_fsync_eintr_count, eintr_count);
        if (toku_fsync_debug) {
            const int tstr_length = 26;
            char tstr[tstr_length];
            time_t t = time(0);
#if __linux__
            char fdname[256];
            snprintf(fdname, sizeof fdname, "/proc/%d/fd/%d", getpid(), fd);
            char lname[256];
            ssize_t s = readlink(fdname, lname, sizeof lname);
            if (0 < s && s < (ssize_t) sizeof lname)
                lname[s] = 0;
            fprintf(stderr, "%.24s toku_file_fsync %s fd=%d %s duration=%" PRIu64 " usec eintr=%" PRIu64 "\n", 
                    ctime_r(&t, tstr), __FUNCTION__, fd, s > 0 ? lname : "?", duration, eintr_count);
#else
            fprintf(stderr, "%.24s toku_file_fsync  %s fd=%d duration=%" PRIu64 " usec eintr=%" PRIu64 "\n", 
                    ctime_r(&t, tstr), __FUNCTION__, fd, duration, eintr_count);
#endif
            fflush(stderr);
        }
    }
}

void toku_file_fsync_without_accounting(int fd) {
    file_fsync_internal(fd);
}

void toku_fsync_dirfd_without_accounting(DIR *dir) {
    int fd = dirfd(dir);
    toku_file_fsync_without_accounting(fd);
}

int toku_fsync_dir_by_name_without_accounting(const char *dir_name) {
    int r = 0;
    DIR * dir = opendir(dir_name);
    if (!dir) {
        r = get_error_errno();
    } else {
        toku_fsync_dirfd_without_accounting(dir);
        r = closedir(dir);
        if (r != 0) {
            r = get_error_errno();
        }
    }
    return r;
}

// include fsync in scheduling accounting
void toku_file_fsync(int fd) {
    file_fsync_internal (fd);
}

// for real accounting
void toku_get_fsync_times(uint64_t *fsync_count, uint64_t *fsync_time, uint64_t *long_fsync_threshold, uint64_t *long_fsync_count, uint64_t *long_fsync_time) {
    *fsync_count = toku_fsync_count;
    *fsync_time = toku_fsync_time;
    *long_fsync_threshold = toku_long_fsync_threshold;
    *long_fsync_count = toku_long_fsync_count;
    *long_fsync_time = toku_long_fsync_time;
}

int toku_fsync_directory(const char *fname) {
    int result = 0;
    
    // extract dirname from fname
    const char *sp = strrchr(fname, '/');
    size_t len;
    char *dirname = NULL;
    if (sp) {
        resource_assert(sp >= fname);
        len = sp - fname + 1;
        MALLOC_N(len+1, dirname);
        if (dirname == NULL) {
            result = get_error_errno();
        } else {
            strncpy(dirname, fname, len);
            dirname[len] = 0;
        }
    } else {
        dirname = toku_strdup(".");
        if (dirname == NULL) {
            result = get_error_errno();
        }
    }

    if (result == 0) {
        result = toku_fsync_dir_by_name_without_accounting(dirname);
    }
    toku_free(dirname);
    return result;
}
