darshan-stdio.c 14.5 KB
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/*
 * Copyright (C) 2015 University of Chicago.
 * See COPYRIGHT notice in top-level directory.
 *
 */

#define _XOPEN_SOURCE 500
#define _GNU_SOURCE

#include "darshan-runtime-config.h"
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/uio.h>
#include <sys/mman.h>
#include <search.h>
#include <assert.h>
#include <libgen.h>
#include <pthread.h>

#include "uthash.h"
#include "utlist.h"

#include "darshan.h"
#include "darshan-dynamic.h"

DARSHAN_FORWARD_DECL(fopen, FILE*, (const char *path, const char *mode));
DARSHAN_FORWARD_DECL(fopen64, FILE*, (const char *path, const char *mode));

/* The stdio_file_runtime structure maintains necessary runtime metadata
 * for the STDIO file record (darshan_stdio_file structure, defined in
 * darshan-stdio-log-format.h) pointed to by 'file_record'. This metadata
 * assists with the instrumenting of specific statistics in the file record.
 * 'hlink' is a hash table link structure used to add/remove this record
 * from the hash table of STDIO file records for this process. 
 *
 * RATIONALE: the STDIO module needs to track some stateful, volatile 
 * information about each open file (like the current file offset, most recent 
 * access time, etc.) to aid in instrumentation, but this information can't be
 * stored in the darshan_stdio_file struct because we don't want it to appear in
 * the final darshan log file.  We therefore associate a stdio_file_runtime
 * struct with each darshan_stdio_file struct in order to track this information.
  *
 * NOTE: There is a one-to-one mapping of stdio_file_runtime structs to
 * darshan_stdio_file structs.
 *
 * NOTE: The stdio_file_runtime struct contains a pointer to a darshan_stdio_file
 * struct (see the *file_record member) rather than simply embedding an entire
 * darshan_stdio_file struct.  This is done so that all of the darshan_stdio_file
 * structs can be kept contiguous in memory as a single array to simplify
 * reduction, compression, and storage.
 */
struct stdio_file_runtime
{
    /* TODO: make sure we need/want all of these fields */
    struct darshan_stdio_file* file_record;
    int64_t offset;
    int64_t last_byte_read;
    int64_t last_byte_written;
    enum darshan_io_type last_io_type;
    double last_meta_end;
    double last_read_end;
    double last_write_end;
    UT_hash_handle hlink;
};

/* The stdio_file_runtime_ref structure is used to associate a STDIO
 * stream with an already existing STDIO file record. This is
 * necessary as many STDIO I/O functions take only an input stream,
 * but STDIO file records are indexed by their full file paths (i.e., darshan
 * record identifiers for STDIO files are created by hashing the file path).
 * In other words, this structure is necessary as it allows us to look up a
 * file record either by a pathname (stdio_file_runtime) or by STDIO stream 
 * (stdio_file_runtime_ref), depending on which parameters are
 * available. This structure includes another hash table link, since separate
 * hashes are maintained for stdio_file_runtime structures and stdio_file_runtime_ref
 * structures.
 *
 * RATIONALE: In theory the FILE* information could be included in the
 * stdio_file_runtime struct rather than in a separate structure here.  The
 * reason we don't do that is because the same file could be opened multiple
 * times by a given process with different stream pointers and thus
 * simulataneously referenced using different stream pointers.  This practice is
 * not common, but we must support it.
 *
 * NOTE: there are potentially multiple stdio_file_runtime_ref structures
 * referring to a single stdio_file_runtime structure.  Most of the time there is
 * only one, however.
 */
struct stdio_file_runtime_ref
{
    struct stdio_file_runtime* file;
    FILE* stream;
    UT_hash_handle hlink;
};

/* The stdio_runtime structure maintains necessary state for storing
 * STDIO file records and for coordinating with darshan-core at 
 * shutdown time.
 */
struct stdio_runtime
{
    struct stdio_file_runtime* file_runtime_array;
    struct darshan_stdio_file* file_record_array;
    int file_array_size;
    int file_array_ndx;
    struct stdio_file_runtime* file_hash;
    struct stdio_file_runtime_ref* stream_hash;
};

static struct stdio_runtime *stdio_runtime = NULL;
static pthread_mutex_t stdio_runtime_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
static int instrumentation_disabled = 0;
static int darshan_mem_alignment = 1;
static int my_rank = -1;

static void stdio_runtime_initialize(void);
static struct stdio_file_runtime* stdio_file_by_name(const char *name);
static struct stdio_file_runtime* stdio_file_by_name_setstream(const char* name, FILE *stream);
static struct stdio_file_runtime* stdio_file_by_stream(FILE* stream);
static void stdio_file_close_stream(FILE *stream);

static void stdio_begin_shutdown(void);
static void stdio_get_output_data(MPI_Comm mod_comm, darshan_record_id *shared_recs,
    int shared_rec_count, void **stdio_buf, int *stdio_buf_sz);
static void stdio_shutdown(void);

#define STDIO_LOCK() pthread_mutex_lock(&stdio_runtime_mutex)
#define STDIO_UNLOCK() pthread_mutex_unlock(&stdio_runtime_mutex)

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/* TODO: remember to clean up stream_flag in posix module */
/* TODO: remember to update start_timestamp logic in other modules */

#define STDIO_RECORD_OPEN(__ret, __path, __tm1, __tm2) do { \
    struct stdio_file_runtime* file; \
    char* exclude; \
    int tmp_index = 0; \
    if(__ret == NULL) break; \
    while((exclude = darshan_path_exclusions[tmp_index])) { \
        if(!(strncmp(exclude, __path, strlen(exclude)))) \
            break; \
        tmp_index++; \
    } \
    if(exclude) break; \
    file = stdio_file_by_name_setstream(__path, __ret); \
    if(!file) break; \
    file->offset = 0; \
    file->last_byte_written = 0; \
    file->last_byte_read = 0; \
    file->file_record->counters[STDIO_FOPENS] += 1; \
    if(file->file_record->fcounters[STDIO_F_OPEN_START_TIMESTAMP] == 0 || \
     file->file_record->fcounters[STDIO_F_OPEN_START_TIMESTAMP] > __tm1) \
        file->file_record->fcounters[STDIO_F_OPEN_START_TIMESTAMP] = __tm1; \
    file->file_record->fcounters[STDIO_F_OPEN_END_TIMESTAMP] = __tm2; \
    DARSHAN_TIMER_INC_NO_OVERLAP(file->file_record->fcounters[STDIO_F_META_TIME], __tm1, __tm2, file->last_meta_end); \
} while(0)



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FILE* DARSHAN_DECL(fopen)(const char *path, const char *mode)
{
    FILE* ret;
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    double tm1, tm2;
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    fprintf(stderr, "FOO: HELLO WORLD (FOPEN)\n");

    MAP_OR_FAIL(fopen);

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    tm1 = darshan_core_wtime();
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    ret = __real_fopen(path, mode);
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    tm2 = darshan_core_wtime();

    STDIO_LOCK();
    stdio_runtime_initialize();
    STDIO_RECORD_OPEN(ret, path, tm1, tm2);
    STDIO_UNLOCK();
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    return(ret);
}

FILE* DARSHAN_DECL(fopen64)(const char *path, const char *mode)
{
    FILE* ret;

    fprintf(stderr, "FOO: HELLO WORLD (FOPEN64)\n");

    MAP_OR_FAIL(fopen64);

    ret = __real_fopen64(path, mode);

    return(ret);
}

/**********************************************************
 * Internal functions for manipulating STDIO module state *
 **********************************************************/

/* initialize internal STDIO module data structures and register with darshan-core */
static void stdio_runtime_initialize()
{
    int mem_limit;
    struct darshan_module_funcs stdio_mod_fns =
    {
        .begin_shutdown = &stdio_begin_shutdown,
        .get_output_data = &stdio_get_output_data,
        .shutdown = &stdio_shutdown
    };

    /* don't do anything if already initialized or instrumenation is disabled */
    if(stdio_runtime || instrumentation_disabled)
        return;

    /* register the stdio module with darshan core */
    darshan_core_register_module(
        DARSHAN_STDIO_MOD,
        &stdio_mod_fns,
        &my_rank,
        &mem_limit,
        &darshan_mem_alignment);

    /* return if no memory assigned by darshan core */
    if(mem_limit == 0)
        return;

    stdio_runtime = malloc(sizeof(*stdio_runtime));
    if(!stdio_runtime)
        return;
    memset(stdio_runtime, 0, sizeof(*stdio_runtime));

    /* set maximum number of file records according to max memory limit */
    /* NOTE: maximum number of records is based on the size of a stdio file record */
    /* TODO: should we base memory usage off file record or total runtime structure sizes? */
    stdio_runtime->file_array_size = mem_limit / sizeof(struct darshan_stdio_file);
    stdio_runtime->file_array_ndx = 0;

    /* allocate array of runtime file records */
    stdio_runtime->file_runtime_array = malloc(stdio_runtime->file_array_size *
                                               sizeof(struct stdio_file_runtime));
    stdio_runtime->file_record_array = malloc(stdio_runtime->file_array_size *
                                              sizeof(struct darshan_stdio_file));
    if(!stdio_runtime->file_runtime_array || !stdio_runtime->file_record_array)
    {
        stdio_runtime->file_array_size = 0;
        return;
    }
    memset(stdio_runtime->file_runtime_array, 0, stdio_runtime->file_array_size *
           sizeof(struct stdio_file_runtime));
    memset(stdio_runtime->file_record_array, 0, stdio_runtime->file_array_size *
           sizeof(struct darshan_stdio_file));

    return;
}

/* get a STDIO file record for the given file path */
static struct stdio_file_runtime* stdio_file_by_name(const char *name)
{
    struct stdio_file_runtime *file = NULL;
    char *newname = NULL;
    darshan_record_id file_id;
    int file_alignment;
    int limit_flag;

    if(!stdio_runtime || instrumentation_disabled)
        return(NULL);

    newname = darshan_clean_file_path(name);
    if(!newname)
        newname = (char*)name;

    limit_flag = (stdio_runtime->file_array_ndx >= stdio_runtime->file_array_size);

    /* get a unique id for this file from darshan core */
    darshan_core_register_record(
        (void*)newname,
        strlen(newname),
        DARSHAN_STDIO_MOD,
        1,
        limit_flag,
        &file_id,
        &file_alignment);

    /* the file record id is set to 0 if no memory is available for tracking
     * new records -- just fall through and ignore this record
     */
    if(file_id == 0)
    {
        if(newname != name)
            free(newname);
        return(NULL);
    }

    /* search the hash table for this file record, and return if found */
    HASH_FIND(hlink, stdio_runtime->file_hash, &file_id, sizeof(darshan_record_id), file);
    if(file)
    {
        if(newname != name)
            free(newname);
        return(file);
    }

    /* no existing record, assign a new file record from the global array */
    file = &(stdio_runtime->file_runtime_array[stdio_runtime->file_array_ndx]);
    file->file_record = &(stdio_runtime->file_record_array[stdio_runtime->file_array_ndx]);
    file->file_record->f_id = file_id;
    file->file_record->rank = my_rank;

    /* add new record to file hash table */
    HASH_ADD(hlink, stdio_runtime->file_hash, file_record->f_id, sizeof(darshan_record_id), file);
    stdio_runtime->file_array_ndx++;

    if(newname != name)
        free(newname);
    return(file);
}

/* get a STDIO file record for the given file path, and also create a
 * reference structure using the returned stream
 */
static struct stdio_file_runtime* stdio_file_by_name_setstream(const char* name, FILE *stream)
{
    struct stdio_file_runtime* file;
    struct stdio_file_runtime_ref* ref;

    if(!stdio_runtime || instrumentation_disabled)
        return(NULL);

    /* find file record by name first */
    file = stdio_file_by_name(name);

    if(!file)
        return(NULL);

    /* search hash table for existing file ref for this stream */
    HASH_FIND(hlink, stdio_runtime->stream_hash, &stream, sizeof(FILE*), ref);
    if(ref)
    {
        /* we have a reference.  Make sure it points to the correct file
         * and return it
         */
        ref->file = file;
        return(file);
    }

    /* if we hit this point, then we don't have a reference for this stream 
     * in the table yet.  Add it.
     */
    ref = malloc(sizeof(*ref));
    if(!ref)
        return(NULL);
    memset(ref, 0, sizeof(*ref));

    ref->file = file;
    ref->stream = stream;    
    HASH_ADD(hlink, stdio_runtime->stream_hash, stream, sizeof(FILE*), ref);

    return(file);
}

/* get a STDIO file record for the given stream */
static struct stdio_file_runtime* stdio_file_by_stream(FILE *stream)
{
    struct stdio_file_runtime_ref* ref;

    if(!stdio_runtime || instrumentation_disabled)
        return(NULL);

    /* search hash table for existing file ref for this stream */
    HASH_FIND(hlink, stdio_runtime->stream_hash, &stream, sizeof(FILE*), ref);
    if(ref)
        return(ref->file);

    return(NULL);
}

/* free up reference data structures for the given stream */
static void stdio_file_close_stream(FILE *stream)
{
    struct stdio_file_runtime_ref* ref;

    if(!stdio_runtime || instrumentation_disabled)
        return;

    /* search hash table for this stream */
    HASH_FIND(hlink, stdio_runtime->stream_hash, &stream, sizeof(FILE*), ref);
    if(ref)
    {
        /* we have a reference, delete it */
        HASH_DELETE(hlink, stdio_runtime->stream_hash, ref);
        free(ref);
    }

    return;
}

/************************************************************************
 * Functions exported by this module for coordinating with darshan-core *
 ************************************************************************/

static void stdio_begin_shutdown()
{
    assert(stdio_runtime);

    STDIO_LOCK();
    /* disable further instrumentation while Darshan shuts down */
    instrumentation_disabled = 1;
    STDIO_UNLOCK();

    return;
}

static void stdio_get_output_data(
    MPI_Comm mod_comm,
    darshan_record_id *shared_recs,
    int shared_rec_count,
    void **stdio_buf,
    int *stdio_buf_sz)
{

    assert(stdio_runtime);

    *stdio_buf = (void *)(stdio_runtime->file_record_array);
    *stdio_buf_sz = stdio_runtime->file_array_ndx * sizeof(struct darshan_stdio_file);

    return;
}

static void stdio_shutdown()
{
    struct stdio_file_runtime_ref *ref, *tmp;

    assert(stdio_runtime);

    HASH_ITER(hlink, stdio_runtime->stream_hash, ref, tmp)
    {
        HASH_DELETE(hlink, stdio_runtime->stream_hash, ref);
        free(ref);
    }

    HASH_CLEAR(hlink, stdio_runtime->file_hash); /* these entries are freed all at once below */

    free(stdio_runtime->file_runtime_array);
    free(stdio_runtime->file_record_array);
    free(stdio_runtime);
    stdio_runtime = NULL;
    instrumentation_disabled = 0;
    
    return;
}

/*
 * Local variables:
 *  c-indent-level: 4
 *  c-basic-offset: 4
 * End:
 *
 * vim: ts=8 sts=4 sw=4 expandtab
 */