Home | History | Annotate | Download | only in daemon 
      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 
     26 void opd_create_pipe(void)
     27 {
     28 	mode_t orig_umask = umask(0111);
     29 	if (mkfifo(op_pipe_file, 0666) == -1) {
     30 		if (errno != EEXIST) {
     31 			perror("oprofiled: couldn't create pipe: ");
     32 			exit(EXIT_FAILURE);
     33 		}
     34 	}
     35 	umask(orig_umask);
     36 }
     37 
     38 
     39 void opd_open_pipe(void)
     40 {
     41 	fifo = open(op_pipe_file, O_RDONLY | O_NONBLOCK);
     42 	if (fifo == -1) {
     43 		perror("oprofiled: couldn't open pipe: ");
     44 		exit(EXIT_FAILURE);
     45 	}
     46 }
     47 
     48 
     49 void opd_close_pipe(void)
     50 {
     51 	close(fifo);
     52 }
     53 
     54 
     55 int is_jitconv_requested(void)
     56 {
     57 	/* number of dropped (unknown) requests */
     58 	static long nr_drops = 0;
     59 	/* modulus to output only a few warnings to avoid flooding oprofiled.log */
     60 	static int mod_cnt_drops = 1;
     61 	FILE * fd;
     62 	char line[256];
     63 	int i, ret = 0;
     64 
     65 	/* get a file descriptor to the pipe */
     66 	fd = fdopen(fifo, "r");
     67 
     68 	if (fd == NULL) {
     69 		perror("oprofiled: couldn't create file descriptor: ");
     70 		exit(EXIT_FAILURE);
     71 	}
     72 
     73 	/* read up to 99 lines to check for 'do_jitconv' */
     74 	for (i = 0; i < 99; i++) {
     75 		/* just break if no new line is found */
     76 		if (fgets(line, 256, fd) == NULL)
     77 			break;
     78 		line[strlen(line) - 1] = '\0';
     79 
     80 		if (strstr(line, "do_jitconv") != NULL) {
     81 			ret = 1;
     82 		} else {
     83 			nr_drops++;
     84 
     85 			if (nr_drops % mod_cnt_drops == 0) {
     86 				printf(
     87 				       "Warning: invalid pipe request received (dropped request(s): %ld)\n",
     88 				       nr_drops);
     89 				/* increase modulus to avoid flooding log file */
     90 				mod_cnt_drops *= 5;
     91 			}
     92 		}
     93 	}
     94 
     95 	return ret;
     96 }
     97