opd_pipe.c revision 10e23eebca4175a8dfe3a788b2bebacb1fcfce54 
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
24static int fifo;
25
26void 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
39void 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
49void opd_close_pipe(void)
50{
51	close(fifo);
52}
53
54
55int 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