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87843f15 | 1 | /* Profile PC and write result to FIFO. |
6d7e8eda | 2 | Copyright (C) 1999-2023 Free Software Foundation, Inc. |
87843f15 | 3 | This file is part of the GNU C Library. |
87843f15 UD |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
87843f15 UD |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 13 | Lesser General Public License for more details. |
87843f15 | 14 | |
41bdb6e2 | 15 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
87843f15 | 18 | |
cab30d75 | 19 | #include <errno.h> |
87843f15 | 20 | #include <fcntl.h> |
cab30d75 | 21 | #include <stdint.h> |
87843f15 UD |
22 | #include <stdlib.h> |
23 | #include <unistd.h> | |
24 | ||
25 | /* Nonzero if we are actually doing something. */ | |
26 | static int active; | |
27 | ||
28 | /* The file descriptor of the FIFO. */ | |
29 | static int fd; | |
30 | ||
31 | ||
32 | static void | |
33 | __attribute__ ((constructor)) | |
34 | install (void) | |
35 | { | |
36 | /* See whether the environment variable `PCPROFILE_OUTPUT' is defined. | |
37 | If yes, it should name a FIFO. We open it and mark ourself as active. */ | |
38 | const char *outfile = getenv ("PCPROFILE_OUTPUT"); | |
39 | ||
40 | if (outfile != NULL && *outfile != '\0') | |
41 | { | |
cab30d75 | 42 | fd = open (outfile, O_RDWR | O_CREAT, 0666); |
87843f15 UD |
43 | |
44 | if (fd != -1) | |
cab30d75 UD |
45 | { |
46 | uint32_t word; | |
47 | ||
48 | active = 1; | |
49 | ||
50 | /* Write a magic word which tells the reader about the byte | |
51 | order and the size of the following entries. */ | |
52 | word = 0xdeb00000 | sizeof (void *); | |
53 | if (TEMP_FAILURE_RETRY (write (fd, &word, 4)) != 4) | |
54 | { | |
55 | /* If even this fails we shouldn't try further. */ | |
56 | close (fd); | |
57 | fd = -1; | |
58 | active = 0; | |
59 | } | |
60 | } | |
87843f15 UD |
61 | } |
62 | } | |
63 | ||
64 | ||
65 | static void | |
66 | __attribute__ ((destructor)) | |
67 | uninstall (void) | |
68 | { | |
69 | if (active) | |
70 | close (fd); | |
71 | } | |
72 | ||
73 | ||
74 | void | |
75 | __cyg_profile_func_enter (void *this_fn, void *call_site) | |
76 | { | |
77 | void *buf[2]; | |
78 | ||
79 | if (! active) | |
80 | return; | |
81 | ||
82 | /* Now write out the current position and that of the caller. We do | |
83 | this now, and don't cache the because we want real-time output. */ | |
84 | buf[0] = this_fn; | |
85 | buf[1] = call_site; | |
86 | ||
87 | write (fd, buf, sizeof buf); | |
88 | } | |
89 | /* We don't handle entry and exit differently here. */ | |
90 | strong_alias (__cyg_profile_func_enter, __cyg_profile_func_exit) |