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      1 /**
      2  * @file daemon/opd_pipe.c
      3  * Functions handling the $SESSIONDIR/opd_pipe FIFO special file.
      4  * NOTE: This code is dealing with potentially insecure input.
      5  *
      6  * @remark Copyright 2008 OProfile authors
      7  * @remark Read the file COPYING
      8  *
      9  * @author Daniel Hansel
     10  */
     11 
     12 #include "opd_pipe.h"
     13 #include "opd_printf.h"
     14 #include "op_config.h"
     15 
     16 #include <stdio.h>
     17 #include <stdlib.h>
     18 #include <string.h>
     19 #include <fcntl.h>
     20 #include <unistd.h>
     21 #include <errno.h>
     22 #include <sys/stat.h>
     23 
     24 static int fifo;
     25 static FILE * fifo_fd = NULL;
     26 
     27 void opd_create_pipe(void)
     28 {
     29 	mode_t orig_umask = umask(0111);
     30 	if (mkfifo(op_pipe_file, 0666) == -1) {
     31 		if (errno != EEXIST) {
     32 			perror("oprofiled: couldn't create pipe: ");
     33 			exit(EXIT_FAILURE);
     34 		}
     35 	}
     36 	umask(orig_umask);
     37 }
     38 
     39 
     40 void opd_open_pipe(void)
     41 {
     42 	fifo = open(op_pipe_file, O_RDONLY | O_NONBLOCK);
     43 	if (fifo == -1) {
     44 		perror("oprofiled: couldn't open pipe: ");
     45 		exit(EXIT_FAILURE);
     46 	}
     47 }
     48 
     49 
     50 void opd_close_pipe(void)
     51 {
     52 	if (fifo_fd)
     53 		fclose(fifo_fd);
     54 	close(fifo);
     55 }
     56 
     57 
     58 int is_jitconv_requested(void)
     59 {
     60 	/* number of dropped (unknown) requests */
     61 	static long nr_drops = 0;
     62 	/* modulus to output only a few warnings to avoid flooding oprofiled.log */
     63 	static int mod_cnt_drops = 1;
     64 	char line[256];
     65 	int i, ret = 0;
     66 
     67 	/* get a file descriptor to the pipe */
     68 	if (!fifo_fd)
     69 		fifo_fd = fdopen(fifo, "r");
     70 
     71 	if (fifo_fd == NULL) {
     72 		perror("oprofiled: couldn't create file descriptor: ");
     73 		exit(EXIT_FAILURE);
     74 	}
     75 
     76 	/* read up to 99 lines to check for 'do_jitconv' */
     77 	for (i = 0; i < 99; i++) {
     78 		/* just break if no new line is found */
     79 		if (fgets(line, 256, fifo_fd) == NULL)
     80 			break;
     81 		line[strlen(line) - 1] = '\0';
     82 
     83 		if (strstr(line, "do_jitconv") != NULL) {
     84 			ret = 1;
     85 		} else {
     86 			nr_drops++;
     87 
     88 			if (nr_drops % mod_cnt_drops == 0) {
     89 				printf(
     90 				       "Warning: invalid pipe request received (dropped request(s): %ld)\n",
     91 				       nr_drops);
     92 				/* increase modulus to avoid flooding log file */
     93 				mod_cnt_drops *= 5;
     94 			}
     95 		}
     96 	}
     97 
     98 	return ret;
     99 }
    100