| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Profile PC and write result to FIFO. |
| 2 | Copyright (C) 1999-2015 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999. |
| 5 | |
| 6 | The GNU C Library is free software; you can redistribute it and/or |
| 7 | modify it under the terms of the GNU Lesser General Public |
| 8 | License as published by the Free Software Foundation; either |
| 9 | version 2.1 of the License, or (at your option) any later version. |
| 10 | |
| 11 | The GNU C Library is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | Lesser General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU Lesser General Public |
| 17 | License along with the GNU C Library; if not, see |
| 18 | <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include <errno.h> |
| 21 | #include <fcntl.h> |
| 22 | #include <stdint.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <unistd.h> |
| 25 | #include <libc-internal.h> |
| 26 | |
| 27 | /* Nonzero if we are actually doing something. */ |
| 28 | static int active; |
| 29 | |
| 30 | /* The file descriptor of the FIFO. */ |
| 31 | static int fd; |
| 32 | |
| 33 | |
| 34 | static void |
| 35 | __attribute__ ((constructor)) |
| 36 | install (void) |
| 37 | { |
| 38 | /* See whether the environment variable `PCPROFILE_OUTPUT' is defined. |
| 39 | If yes, it should name a FIFO. We open it and mark ourself as active. */ |
| 40 | const char *outfile = getenv ("PCPROFILE_OUTPUT"); |
| 41 | |
| 42 | if (outfile != NULL && *outfile != '\0') |
| 43 | { |
| 44 | fd = open (outfile, O_RDWR | O_CREAT, 0666); |
| 45 | |
| 46 | if (fd != -1) |
| 47 | { |
| 48 | uint32_t word; |
| 49 | |
| 50 | active = 1; |
| 51 | |
| 52 | /* Write a magic word which tells the reader about the byte |
| 53 | order and the size of the following entries. */ |
| 54 | word = 0xdeb00000 | sizeof (void *); |
| 55 | if (TEMP_FAILURE_RETRY (write (fd, &word, 4)) != 4) |
| 56 | { |
| 57 | /* If even this fails we shouldn't try further. */ |
| 58 | close (fd); |
| 59 | fd = -1; |
| 60 | active = 0; |
| 61 | } |
| 62 | } |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | |
| 67 | static void |
| 68 | __attribute__ ((destructor)) |
| 69 | uninstall (void) |
| 70 | { |
| 71 | if (active) |
| 72 | close (fd); |
| 73 | } |
| 74 | |
| 75 | |
| 76 | void |
| 77 | __cyg_profile_func_enter (void *this_fn, void *call_site) |
| 78 | { |
| 79 | void *buf[2]; |
| 80 | |
| 81 | if (! active) |
| 82 | return; |
| 83 | |
| 84 | /* Now write out the current position and that of the caller. We do |
| 85 | this now, and don't cache the because we want real-time output. */ |
| 86 | buf[0] = this_fn; |
| 87 | buf[1] = call_site; |
| 88 | |
| 89 | write (fd, buf, sizeof buf); |
| 90 | } |
| 91 | /* We don't handle entry and exit differently here. */ |
| 92 | strong_alias (__cyg_profile_func_enter, __cyg_profile_func_exit) |