opd_pipe.c

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#include "opd_pipe.h"
#include "opd_printf.h"
#include "op_config.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>

static int fifo;
static FILE * fifo_fd = NULL;

void opd_create_pipe(void)
{
    mode_t orig_umask = umask(0111);
    if (mkfifo(op_pipe_file, 0666) == -1) {
        if (errno != EEXIST) {
            perror("oprofiled: couldn't create pipe: ");
            exit(EXIT_FAILURE);
        }
    }
    umask(orig_umask);
}


void opd_open_pipe(void)
{
    fifo = open(op_pipe_file, O_RDONLY | O_NONBLOCK);
    if (fifo == -1) {
        perror("oprofiled: couldn't open pipe: ");
        exit(EXIT_FAILURE);
    }
}


void opd_close_pipe(void)
{
    if (fifo_fd)
        fclose(fifo_fd);
    close(fifo);
}


int is_jitconv_requested(void)
{
    /* number of dropped (unknown) requests */
    static long nr_drops = 0;
    /* modulus to output only a few warnings to avoid flooding oprofiled.log */
    static int mod_cnt_drops = 1;
    char line[256];
    int i, ret = 0;

    /* get a file descriptor to the pipe */
    if (!fifo_fd)
        fifo_fd = fdopen(fifo, "r");

    if (fifo_fd == NULL) {
        perror("oprofiled: couldn't create file descriptor: ");
        exit(EXIT_FAILURE);
    }

    /* read up to 99 lines to check for 'do_jitconv' */
    for (i = 0; i < 99; i++) {
        /* just break if no new line is found */
        if (fgets(line, 256, fifo_fd) == NULL)
            break;
        line[strlen(line) - 1] = '\0';

        if (strstr(line, "do_jitconv") != NULL) {
            ret = 1;
        } else {
            nr_drops++;

            if (nr_drops % mod_cnt_drops == 0) {
                printf(
                       "Warning: invalid pipe request received (dropped request(s): %ld)\n",
                       nr_drops);
                /* increase modulus to avoid flooding log file */
                mod_cnt_drops *= 5;
            }
        }
    }

    return ret;
}