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authorjkoshy <jkoshy@FreeBSD.org>2005-09-14 21:15:50 +0000
committerjkoshy <jkoshy@FreeBSD.org>2005-09-14 21:15:50 +0000
commite4de2de4329b31dda4eb1bea592e862571c817ff (patch)
treef8eb2c2f561281f4788d01846944e6bdc9cb3720 /usr.sbin
parent662afafc671db34e6c6e304b494c5b42661ca6fc (diff)
downloadFreeBSD-src-e4de2de4329b31dda4eb1bea592e862571c817ff.zip
FreeBSD-src-e4de2de4329b31dda4eb1bea592e862571c817ff.tar.gz
Determine where the runtime loader got mapped to when a dynamically
linked process was exec()'ed, and map samples in that address range into the appropriate buckets in the runtime loader's profile. Improve a few comments. MFC after: 3 days
Diffstat (limited to 'usr.sbin')
-rw-r--r--usr.sbin/pmcstat/pmcstat_log.c204
1 files changed, 119 insertions, 85 deletions
diff --git a/usr.sbin/pmcstat/pmcstat_log.c b/usr.sbin/pmcstat/pmcstat_log.c
index 7cfc841..d4def0e 100644
--- a/usr.sbin/pmcstat/pmcstat_log.c
+++ b/usr.sbin/pmcstat/pmcstat_log.c
@@ -78,11 +78,11 @@ __FBSDID("$FreeBSD$");
#define max(A,B) ((A) > (B) ? (A) : (B))
/*
- * A simple implementation to intern strings. Each interned string is
- * assigned a unique address, so that subsequent string compares can
- * be done by a simple pointer comparision.
+ * A simple implementation of interned strings. Each interned string
+ * is assigned a unique address, so that subsequent string compares
+ * can be done by a simple pointer comparision instead of with
+ * strcmp().
*/
-
struct pmcstat_string {
LIST_ENTRY(pmcstat_string) ps_next; /* hash link */
int ps_len;
@@ -143,12 +143,14 @@ struct pmcstat_image {
LIST_ENTRY(pmcstat_image) pi_next; /* hash link */
TAILQ_ENTRY(pmcstat_image) pi_lru; /* LRU list */
const char *pi_internedpath; /* cookie */
- const char *pi_samplename; /* sample file name */
+ const char *pi_samplename; /* sample path name */
enum pmcstat_image_type pi_type; /* executable type */
uintfptr_t pi_start; /* start address (inclusive) */
uintfptr_t pi_end; /* end address (exclusive) */
+ uintfptr_t pi_entry; /* entry address */
int pi_isdynamic; /* whether a dynamic object */
+ const char *pi_dynlinkerpath; /* path in .interp section */
LIST_HEAD(,pmcstat_gmonfile) pi_gmlist;
};
@@ -172,6 +174,7 @@ struct pmcstat_process {
LIST_ENTRY(pmcstat_process) pp_next; /* hash-next */
pid_t pp_pid; /* associated pid */
int pp_isactive; /* whether active */
+ uintfptr_t pp_entryaddr; /* entry address */
TAILQ_HEAD(,pmcstat_pcmap) pp_map; /* address range map */
};
@@ -192,8 +195,7 @@ static void pmcstat_gmon_unmap_file(struct pmcstat_gmonfile *_pgf);
static struct pmcstat_image *pmcstat_image_from_path(const char *_path);
static enum pmcstat_image_type pmcstat_image_get_type(const char *_p);
-static void pmcstat_image_get_elf_params(struct pmcstat_image *_image,
- uintfptr_t *_minp, uintfptr_t *_maxp, int *_isdyn);
+static void pmcstat_image_get_elf_params(struct pmcstat_image *_image);
static void pmcstat_image_increment_bucket(struct pmcstat_pcmap *_pcm,
uintfptr_t _pc, pmc_id_t _pmcid, struct pmcstat_args *_a);
static void pmcstat_image_link(struct pmcstat_process *_pp,
@@ -204,12 +206,12 @@ static void pmcstat_pmcid_add(pmc_id_t _pmcid, const char *_name,
static const char *pmcstat_pmcid_to_name(pmc_id_t _pmcid);
static void pmcstat_process_add_elf_image(struct pmcstat_process *_pp,
- const char *_path);
+ const char *_path, uintfptr_t _entryaddr);
+static void pmcstat_process_exec(struct pmcstat_process *_pp,
+ const char *_path, uintfptr_t _entryaddr);
static struct pmcstat_process *pmcstat_process_lookup(pid_t _pid, int _allocate);
static struct pmcstat_pcmap *pmcstat_process_find_map(
struct pmcstat_process *_p, uintfptr_t _pc);
-static void pmcstat_process_new_image(struct pmcstat_process *_pp,
- const char *_path);
static int pmcstat_string_compute_hash(const char *_string);
static const char *pmcstat_string_intern(const char *_s);
@@ -317,8 +319,7 @@ pmcstat_gmon_unmap_file(struct pmcstat_gmonfile *pgf)
}
static void
-pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
- uintfptr_t *maxp, int *is_dynamic)
+pmcstat_image_get_elf_params(struct pmcstat_image *image)
{
int fd, i;
struct stat st;
@@ -329,6 +330,8 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
const Elf_Shdr *sh;
const char *path;
+ assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN);
+
minva = ~(uintfptr_t) 0;
maxva = (uintfptr_t) 0;
path = image->pi_internedpath;
@@ -353,8 +356,8 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
if (h->e_type == ET_EXEC || h->e_type == ET_DYN) {
/*
- * Some kind of shared object: find the min,max va for
- * its executable sections.
+ * Some kind of executable object: find the min,max va
+ * for its executable sections.
*/
for (i = 0; i < h->e_shnum; i++)
if (sh[i].sh_flags & SHF_EXECINSTR) { /* code */
@@ -366,13 +369,25 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
err(EX_DATAERR, "ERROR: Unknown file type for \"%s\"",
image->pi_internedpath);
- *is_dynamic = 0;
+ image->pi_type = PMCSTAT_IMAGE_ELF;
+ image->pi_start = minva;
+ image->pi_entry = h->e_entry;
+ image->pi_end = maxva;
+ image->pi_isdynamic = 0;
+ image->pi_dynlinkerpath = NULL;
+
+
if (h->e_type == ET_EXEC) {
ph = (const Elf_Phdr *)((uintptr_t) mapbase + h->e_phoff);
for (i = 0; i < h->e_phnum; i++) {
switch (ph[i].p_type) {
case PT_DYNAMIC:
- *is_dynamic = 1;
+ image->pi_isdynamic = 1;
+ break;
+ case PT_INTERP:
+ image->pi_dynlinkerpath =
+ pmcstat_string_intern((char *) mapbase +
+ ph[i].p_offset);
break;
}
}
@@ -381,13 +396,12 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
if (munmap(mapbase, st.st_size) < 0)
err(EX_OSERR, "ERROR: Cannot unmap \"%s\"", path);
- *minp = minva;
- *maxp = maxva;
-
}
/*
- * Locate an image descriptor given an interned path.
+ * Locate an image descriptor given an interned path, adding a fresh
+ * descriptor to the cache if necessary. This function also finds a
+ * suitable name for this image's sample file.
*/
static struct pmcstat_image *
@@ -400,7 +414,7 @@ pmcstat_image_from_path(const char *internedpath)
hash = pmcstat_string_compute_hash(internedpath);
- /* look for an existing entry */
+ /* Look for an existing entry. */
LIST_FOREACH(pi, &pmcstat_image_hash[hash], pi_next)
if (pi->pi_internedpath == internedpath) {
/* move descriptor to the head of the lru list */
@@ -410,8 +424,8 @@ pmcstat_image_from_path(const char *internedpath)
}
/*
- * allocate a new entry and place at the head of the hash and
- * LRU lists
+ * Allocate a new entry and place at the head of the hash and
+ * LRU lists.
*/
pi = malloc(sizeof(*pi));
if (pi == NULL)
@@ -420,17 +434,23 @@ pmcstat_image_from_path(const char *internedpath)
pi->pi_type = PMCSTAT_IMAGE_UNKNOWN;
pi->pi_internedpath = internedpath;
pi->pi_start = ~0;
+ pi->pi_entry = ~0;
pi->pi_end = 0;
- /* look for a suitable name for the sample files */
+ /*
+ * Look for a suitable name for the sample files associated
+ * with this image: if `basename(path)`+".gmon" is available,
+ * we use that, otherwise we try iterating through
+ * `basename(path)`+ "~" + NNN + ".gmon" till we get a free
+ * entry.
+ */
if ((sn = basename(internedpath)) == NULL)
err(EX_OSERR, "ERROR: Cannot process \"%s\"", internedpath);
nlen = strlen(sn);
nlen = min(nlen, (int) sizeof(name) - 6); /* ".gmon\0" */
- snprintf(name, sizeof(name), "%.*s.gmon",
- nlen, sn);
+ snprintf(name, sizeof(name), "%.*s.gmon", nlen, sn);
if (pmcstat_string_lookup(name) == NULL)
pi->pi_samplename = pmcstat_string_intern(name);
@@ -532,6 +552,7 @@ pmcstat_image_increment_bucket(struct pmcstat_pcmap *map, uintfptr_t pc,
pgf->pgf_name = pmcstat_gmon_create_name(a->pa_samplesdir,
image, pmcid);
pgf->pgf_pmcid = pmcid;
+ assert(image->pi_end > image->pi_start);
pgf->pgf_nbuckets = (image->pi_end - image->pi_start) /
FUNCTION_ALIGNMENT; /* see <machine/profile.h> */
pgf->pgf_ndatabytes = sizeof(struct gmonhdr) +
@@ -659,41 +680,65 @@ pmcstat_pmcid_to_name(pmc_id_t pmcid)
*/
static void
-pmcstat_process_add_elf_image(struct pmcstat_process *pp, const char *path)
+pmcstat_process_add_elf_image(struct pmcstat_process *pp, const char *path,
+ uintfptr_t entryaddr)
{
- int isdynamic;
size_t linelen;
FILE *rf;
char *line;
- uintfptr_t minva, maxva;
uintmax_t libstart;
- struct pmcstat_image *image;
+ struct pmcstat_image *image, *rtldimage;
char libpath[PATH_MAX];
char command[PATH_MAX + sizeof(PMCSTAT_LDD_COMMAND) + 1];
- minva = ~ (uintfptr_t) 0;
- maxva = (uintfptr_t) 0;
- isdynamic = 0;
-
+ /* Look up path in the cache. */
if ((image = pmcstat_image_from_path(path)) == NULL)
return;
- if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) {
-
- pmcstat_image_get_elf_params(image, &minva, &maxva,
- &isdynamic);
-
- image->pi_type = PMCSTAT_IMAGE_ELF;
- image->pi_start = minva;
- image->pi_end = maxva;
- image->pi_isdynamic = isdynamic;
- }
+ if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
+ pmcstat_image_get_elf_params(image);
- /* create a map entry for the base executable */
- pmcstat_image_link(pp, image, minva, maxva);
+ /* Create a map entry for the base executable. */
+ pmcstat_image_link(pp, image, image->pi_start, image->pi_end);
+ /*
+ * For dynamically linked executables we need to:
+ * (a) find where the dynamic linker was mapped to for this
+ * process,
+ * (b) find all the executable objects that the dynamic linker
+ * brought in.
+ */
if (image->pi_isdynamic) {
+ /*
+ * The runtime loader gets loaded just after the maximum
+ * possible heap address. Like so:
+ *
+ * [ TEXT DATA BSS HEAP -->*RTLD SHLIBS <--STACK]
+ * ^ ^
+ * 0 VM_MAXUSER_ADDRESS
+ *
+ * The exact address where the loader gets mapped in
+ * will vary according to the size of the executable
+ * and the limits on the size of the process'es data
+ * segment at the time of exec(). The entry address
+ * recorded at process exec time corresponds to the
+ * 'start' address inside the dynamic linker. From
+ * this we can figure out the address where the
+ * runtime loader's file object had been mapped to.
+ */
+ rtldimage = pmcstat_image_from_path(image->pi_dynlinkerpath);
+ if (rtldimage == NULL)
+ err(EX_OSERR, "ERROR: Cannot find image for "
+ "\"%s\"", image->pi_dynlinkerpath);
+ if (rtldimage->pi_type == PMCSTAT_IMAGE_UNKNOWN)
+ pmcstat_image_get_elf_params(rtldimage);
+
+ libstart = entryaddr - rtldimage->pi_entry;
+ pmcstat_image_link(pp, rtldimage, libstart,
+ libstart + rtldimage->pi_end - rtldimage->pi_start);
+
+ /* Process all other objects loaded by this executable. */
(void) snprintf(command, sizeof(command), "%s %s",
PMCSTAT_LDD_COMMAND, path);
@@ -718,16 +763,8 @@ pmcstat_process_add_elf_image(struct pmcstat_process *pp, const char *path)
err(EX_OSERR, "ERROR: Cannot process "
"\"%s\"", libpath);
- if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) {
-
- pmcstat_image_get_elf_params(image,
- &minva, &maxva, &isdynamic);
-
- image->pi_type = PMCSTAT_IMAGE_ELF;
- image->pi_start = minva;
- image->pi_end = maxva;
- image->pi_isdynamic = isdynamic;
- }
+ if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
+ pmcstat_image_get_elf_params(image);
pmcstat_image_link(pp, image, libstart + image->pi_start,
libstart + image->pi_end);
@@ -790,27 +827,12 @@ pmcstat_process_lookup(pid_t pid, int allocate)
}
/*
- * Find the map entry associated with process 'p' at PC value 'pc'.
- */
-
-static struct pmcstat_pcmap *
-pmcstat_process_find_map(struct pmcstat_process *p, uintfptr_t pc)
-{
- struct pmcstat_pcmap *ppm;
-
- TAILQ_FOREACH(ppm, &p->pp_map, ppm_next)
- if (pc >= ppm->ppm_lowpc && pc < ppm->ppm_highpc)
- return ppm;
-
- return NULL;
-}
-
-/*
* Associate an image and a process.
*/
static void
-pmcstat_process_new_image(struct pmcstat_process *pp, const char *path)
+pmcstat_process_exec(struct pmcstat_process *pp, const char *path,
+ uintfptr_t entryaddr)
{
enum pmcstat_image_type filetype;
struct pmcstat_image *image;
@@ -825,19 +847,35 @@ pmcstat_process_new_image(struct pmcstat_process *pp, const char *path)
switch (filetype) {
case PMCSTAT_IMAGE_ELF:
- pmcstat_process_add_elf_image(pp, path);
+ pmcstat_process_add_elf_image(pp, path, entryaddr);
break;
case PMCSTAT_IMAGE_AOUT:
break;
default:
- err(EX_SOFTWARE, "ERROR: Unsupported executable type \"%s\"",
- path);
+ err(EX_SOFTWARE, "ERROR: Unsupported executable type for "
+ "\"%s\"", path);
}
}
+/*
+ * Find the map entry associated with process 'p' at PC value 'pc'.
+ */
+
+static struct pmcstat_pcmap *
+pmcstat_process_find_map(struct pmcstat_process *p, uintfptr_t pc)
+{
+ struct pmcstat_pcmap *ppm;
+
+ TAILQ_FOREACH(ppm, &p->pp_map, ppm_next)
+ if (pc >= ppm->ppm_lowpc && pc < ppm->ppm_highpc)
+ return ppm;
+
+ return NULL;
+}
+
/*
* Compute a 'hash' value for a string.
@@ -983,7 +1021,8 @@ pmcstat_convert_log(struct pmcstat_args *a)
ev.pl_u.pl_x.pl_pathname);
/* link to the new image */
- pmcstat_process_new_image(pp, image_path);
+ pmcstat_process_exec(pp, image_path,
+ ev.pl_u.pl_x.pl_entryaddr);
break;
case PMCLOG_TYPE_PROCEXIT:
@@ -1198,10 +1237,9 @@ pmcstat_process_log(struct pmcstat_args *a)
void
pmcstat_initialize_logging(struct pmcstat_args *a)
{
- int i, isdynamic;
+ int i;
const char *kernpath;
struct pmcstat_image *img;
- uintfptr_t minva, maxva;
/* use a convenient format for 'ldd' output */
if (setenv("LD_TRACE_LOADED_OBJECTS_FMT1","%p %x\n",1) != 0)
@@ -1223,12 +1261,8 @@ pmcstat_initialize_logging(struct pmcstat_args *a)
img = pmcstat_image_from_path(kernpath);
- pmcstat_image_get_elf_params(img, &minva, &maxva, &isdynamic);
- img->pi_type = PMCSTAT_IMAGE_ELF;
- img->pi_start = minva;
- img->pi_end = maxva;
-
- pmcstat_image_link(pmcstat_kernproc, img, minva, maxva);
+ pmcstat_image_get_elf_params(img);
+ pmcstat_image_link(pmcstat_kernproc, img, img->pi_start, img->pi_end);
return;
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