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-rw-r--r--elf/dl-profile.c267
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diff --git a/elf/dl-profile.c b/elf/dl-profile.c
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+++ b/elf/dl-profile.c
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+/* Profiling of shared libraries.
+ Copyright (C) 1997 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <link.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/gmon.h>
+#include <sys/gmon_out.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+/* The LD_PROFILE feature has to be implemented different to the
+ normal profiling using the gmon/ functions. The problem is that an
+ arbitrary amount of processes simulataneously can be run using
+ profiling and all write the results in the same file. To provide
+ this mechanism one could implement a complicated mechanism to merge
+ the content of two profiling runs or one could extend the file
+ format to allow more than one data set. For the second solution we
+ would have the problem that the file can grow in size beyond any
+ limit and both solutions have the problem that the concurrency of
+ writing the results is a big problem.
+
+ Another much simpler method is to use mmap to map the same file in
+ all using programs and modify the data in the mmap'ed area and so
+ also automatically on the disk. Using the MAP_SHARED option of
+ mmap(2) this can be done without big problems in more than one
+ file.
+
+ This approach is very different from the normal profiling. We have
+ to use the profiling data in exactly the way they are expected to
+ be written to disk. */
+
+extern char *_strerror_internal __P ((int, char *buf, size_t));
+
+extern int __profile_frequency __P ((void));
+
+
+static struct gmonparam param;
+
+/* We define a special type to address the elements of the arc table.
+ This is basically the `gmon_cg_arc_record' format but it includes
+ the room for the tag and it uses real types. */
+struct here_cg_arc_record
+ {
+ char tag;
+ uintptr_t from_pc __attribute__ ((packed));
+ uintptr_t self_pc __attribute__ ((packed));
+ uint32_t count __attribute__ ((packed));
+ };
+
+static struct here_cg_arc_record *data;
+
+
+void
+_dl_start_profile (struct link_map *map, const char *output_dir)
+{
+ char *filename;
+ int fd;
+ struct stat st;
+ const ElfW(Phdr) *ph;
+ ElfW(Addr) mapstart = ~((ElfW(Addr)) 0);
+ ElfW(Addr) mapend = 0;
+ off_t expected_size;
+ struct gmon_hdr gmon_hdr;
+ struct gmon_hist_hdr hist_hdr;
+ struct gmon_hdr *addr;
+ char *hist;
+
+ /* Compute the size of the sections which contain program code. */
+ for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph)
+ if (ph->p_type == PT_LOAD && (ph->p_flags & PF_X))
+ {
+ ElfW(Addr) start = (ph->p_vaddr & ~(_dl_pagesize - 1));
+ ElfW(Addr) end = ((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
+ & ~(_dl_pagesize - 1));
+
+ if (start < mapstart)
+ mapstart = start;
+ if (end > mapend)
+ mapend = end;
+ }
+
+ /* Now we can compute the size of the profiling data. This is done
+ with the same formulars as in `monstartup' (see gmon.c). */
+ param.state = GMON_PROF_OFF;
+ param.lowpc = mapstart + map->l_addr;
+ param.highpc = mapend + map->l_addr;
+ param.textsize = mapend - mapstart;
+ param.kcountsize = param.textsize / HISTFRACTION;
+ param.hashfraction = HASHFRACTION;
+ param.log_hashfraction = -1;
+ if ((HASHFRACTION & (HASHFRACTION - 1)) == 0)
+ /* If HASHFRACTION is a power of two, mcount can use shifting
+ instead of integer division. Precompute shift amount. */
+ param.log_hashfraction = ffs (param.hashfraction
+ * sizeof (*param.froms)) - 1;
+ param.fromssize = param.textsize / HASHFRACTION;
+ param.tolimit = param.textsize * ARCDENSITY / 100;
+ if (param.tolimit < MINARCS)
+ param.tolimit = MINARCS;
+ if (param.tolimit > MAXARCS)
+ param.tolimit = MAXARCS;
+ param.tossize = param.tolimit * sizeof (struct tostruct);
+
+ expected_size = (sizeof (struct gmon_hdr)
+ + 1 + sizeof (struct gmon_hist_hdr)
+ + ((1 + sizeof (struct gmon_cg_arc_record))
+ * (param.fromssize / sizeof (*param.froms))));
+
+ /* Create the gmon_hdr we expect or write. */
+ memset (&gmon_hdr, '\0', sizeof (struct gmon_hdr));
+ memcpy (&gmon_hdr.cookie[0], GMON_MAGIC, sizeof (gmon_hdr.cookie));
+ *(int32_t *) gmon_hdr.version = GMON_VERSION;
+
+ /* Create the hist_hdr we expect or write. */
+ *(char **) hist_hdr.low_pc = (char *) mapstart;
+ *(char **) hist_hdr.high_pc = (char *) mapend;
+ *(int32_t *) hist_hdr.hist_size = param.kcountsize / sizeof (HISTCOUNTER);
+ *(int32_t *) hist_hdr.prof_rate = __profile_frequency ();
+ strncpy (hist_hdr.dimen, "seconds", sizeof (hist_hdr.dimen));
+ hist_hdr.dimen_abbrev = 's';
+
+ /* First determine the output name. We write in the directory
+ OUTPUT_DIR and the name is composed from the shared objects
+ soname (or the file name) and the ending ".profile". */
+ filename = (char *) alloca (strlen (output_dir) + 1 + strlen (_dl_profile)
+ + sizeof ".profile");
+ __stpcpy (__stpcpy (__stpcpy (__stpcpy (filename, output_dir), "/"),
+ _dl_profile),
+ ".profile");
+
+ fd = __open (filename, O_RDWR | O_CREAT, 0666);
+ if (fd == -1)
+ /* We cannot write the profiling data so don't do anthing. */
+ return;
+
+ if (fstat (fd, &st) < 0 || !S_ISREG (st.st_mode))
+ {
+ /* Not stat'able or not a regular file => don't use it. */
+ close (fd);
+ return;
+ }
+
+ /* Test the size. If it does not match what we expect from the size
+ values in the map MAP we don't use it and warn the user. */
+ if (st.st_size == 0)
+ {
+ /* We have to create the file. */
+ char buf[_dl_pagesize];
+
+ memset (buf, '\0', _dl_pagesize);
+
+ if (__lseek (fd, expected_size & ~(_dl_pagesize - 1), SEEK_SET) == -1)
+ {
+ char buf[400];
+ int errnum;
+ cannot_create:
+ errnum = errno;
+ __close (fd);
+ fprintf (stderr, "%s: cannot create file: %s\n", filename,
+ _strerror_internal (errnum, buf, sizeof buf));
+ return;
+ }
+
+ if (TEMP_FAILURE_RETRY (__write (fd, buf, (expected_size
+ & (_dl_pagesize - 1)))) < 0)
+ goto cannot_create;
+ }
+ else if (st.st_size != expected_size)
+ {
+ __close (fd);
+ wrong_format:
+ fprintf (stderr, "%s: file is no correct profile data file for `%s'\n",
+ filename, _dl_profile);
+ return;
+ }
+
+ addr = (void *) __mmap (NULL, expected_size, PROT_READ|PROT_WRITE,
+ MAP_SHARED|MAP_FILE, fd, 0);
+ if (addr == (void *) -1)
+ {
+ char buf[400];
+ int errnum = errno;
+ __close (fd);
+ fprintf (stderr, "%s: cannot map file: %s\n", filename,
+ _strerror_internal (errnum, buf, sizeof buf));
+ return;
+ }
+
+ /* We don't need the file desriptor anymore. */
+ __close (fd);
+
+ /* Pointer to data after the header. */
+ hist = (char *) (addr + 1);
+
+ /* Compute pointer to array of the arc information. */
+ data = (struct here_cg_arc_record *) (hist + 1
+ + sizeof (struct gmon_hist_hdr));
+
+ if (st.st_size == 0)
+ {
+ /* Create the signature. */
+ size_t cnt;
+
+ memcpy (addr, &gmon_hdr, sizeof (struct gmon_hdr));
+
+ *hist = GMON_TAG_TIME_HIST;
+ memcpy (hist + 1, &hist_hdr, sizeof (struct gmon_hist_hdr));
+
+ for (cnt = 0; cnt < param.fromssize / sizeof (*param.froms); ++cnt)
+ data[cnt].tag = GMON_TAG_CG_ARC;
+ }
+ else
+ {
+ /* Test the signature in the file. */
+ if (memcmp (addr, &gmon_hdr, sizeof (struct gmon_hdr)) != 0
+ || *hist != GMON_TAG_TIME_HIST
+ || memcmp (hist + 1, &hist_hdr, sizeof (struct gmon_hist_hdr)) != 0)
+ goto wrong_format;
+ }
+
+ /* Turn on profiling. */
+ param.state = GMON_PROF_ON;
+}
+
+
+void
+_dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
+{
+ if (param.state != GMON_PROF_ON)
+ return;
+ param.state = GMON_PROF_BUSY;
+
+ /* Compute relative addresses. The shared object can be loaded at
+ any address. The value of frompc could be anything. We cannot
+ restrict it in any way, just set to a fixed value (0) in case it
+ is outside the allowed range. These calls show up as calls from
+ <external> in the gprof output. */
+ frompc -= param.lowpc;
+ if (frompc >= param.textsize)
+ frompc = 0;
+ selfpc -= param.lowpc;
+
+ param.state = GMON_PROF_ON;
+}
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