Page MenuHomeFreeBSD
Differential D38825 Diff 127670 cddl/contrib/opensolaris/lib/libdtrace/common/dt_sugar.c

Changeset View

Standalone View

View Options

cddl/contrib/opensolaris/lib/libdtrace/common/dt_sugar.c

Show All 9 Lines
* source. A copy of the CDDL is also available via the Internet at * source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL. * http://www.illumos.org/license/CDDL.
* *
* CDDL HEADER END * CDDL HEADER END
*/ */
/* /*
* Copyright (c) 2012, 2016 by Delphix. All rights reserved. * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
* Copyright (c) 2023 The FreeBSD Foundation
*
* Portions of this software were developed by Christos Margiolis
* <christos@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
*/ */
/* /*
* Syntactic sugar features are implemented by transforming the D parse tree * Syntactic sugar features are implemented by transforming the D parse tree
* such that it only uses the subset of D that is supported by the rest of the * such that it only uses the subset of D that is supported by the rest of the
* compiler / the kernel. A clause containing these language features is * compiler / the kernel. A clause containing these language features is
* referred to as a "super-clause", and its transformation typically entails * referred to as a "super-clause", and its transformation typically entails
* creating several "sub-clauses" to implement it. For diagnosability, the * creating several "sub-clauses" to implement it. For diagnosability, the
* sub-clauses will be printed if the "-xtree=8" flag is specified. * sub-clauses will be printed if the "-xtree=8" flag is specified.
* *
* Currently, the only syntactic sugar feature is "if/else" statements. Each * Currently, the only syntactic sugar feature is "if/else" statements. Each
* basic block (e.g. the body of the "if" and "else" statements, and the * basic block (e.g. the body of the "if" and "else" statements, and the
* statements before and after) is turned into its own sub-clause, with a * statements before and after) is turned into its own sub-clause, with a
* predicate that causes it to be executed only if the code flows to this point. * predicate that causes it to be executed only if the code flows to this point.
* Nested if/else statements are supported. * Nested if/else statements are supported.
* *
* This infrastructure is designed to accommodate other syntactic sugar features * This infrastructure is designed to accommodate other syntactic sugar features
* in the future. * in the future.
*/ */
#include <sys/types.h> #include <sys/types.h>
#include <sys/wait.h> #include <sys/wait.h>
#include <sys/sysmacros.h> #include <sys/sysmacros.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <assert.h> #include <assert.h>
#include <strings.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h> #include <ctype.h>
#include <dwarf.h>
#include <err.h>
#include <fcntl.h>
#include <gelf.h>
#include <libdwarf.h>
#include <libelf.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include <dt_module.h> #include <dt_module.h>
#include <dt_program.h> #include <dt_program.h>
#include <dt_provider.h> #include <dt_provider.h>
#include <dt_printf.h> #include <dt_printf.h>
#include <dt_pid.h> #include <dt_pid.h>
#include <dt_grammar.h> #include <dt_grammar.h>
#include <dt_ident.h> #include <dt_ident.h>
#include <dt_string.h> #include <dt_string.h>
#include <dt_impl.h> #include <dt_impl.h>
#include <zlib.h>
/* kinst-related */
struct elf_info {
Elf *elf;
struct section {
Elf_Scn *scn;
GElf_Shdr sh;
const char *name;
} *sl;
size_t shnum;
int fd;
};
struct entry {
struct off {
const char *func;
unsigned long val;
} *off;
int noff;
TAILQ_ENTRY(entry) next;
};
typedef struct dt_sugar_parse { typedef struct dt_sugar_parse {
dtrace_hdl_t *dtsp_dtp; /* dtrace handle */ dtrace_hdl_t *dtsp_dtp; /* dtrace handle */
dt_node_t *dtsp_pdescs; /* probe descriptions */ dt_node_t *dtsp_pdescs; /* probe descriptions */
int dtsp_num_conditions; /* number of condition variables */ int dtsp_num_conditions; /* number of condition variables */
int dtsp_num_ifs; /* number of "if" statements */ int dtsp_num_ifs; /* number of "if" statements */
dt_node_t *dtsp_clause_list; /* list of clauses */ dt_node_t *dtsp_clause_list; /* list of clauses */
struct elf_info dtsp_elf_mod; /* ELF info of the kernel executable */
struct elf_info dtsp_elf_dbg; /* ELF info of the kernel debug file */
dtrace_probedesc_t *dtsp_desc; /* kinst pdesc to duplicate contents */
Dwarf_Off dtsp_dieoff; /* DIE offset of kinst inline definition */
#define DF_EXISTS 0x01 /* function exists in module */
#define DF_REGULAR 0x02 /* function has regular definition */
#define DF_INLINE 0x04 /* function has inline definition */
#define DF_ENTRY 0x08 /* probe is entry */
#define DF_RETURN 0x10 /* probe is return */
#define DF_NEWPDESC 0x20 /* we're searching a new pdesc */
int dtsp_flags; /* kinst-related flags */
char dtsp_func[DTRACE_FUNCNAMELEN]; /* current function */
char dtsp_name[DTRACE_NAMELEN]; /* current probe name */
TAILQ_HEAD(, entry) dtsp_head; /* kinst inline copy entry TAILQ */
} dt_sugar_parse_t; } dt_sugar_parse_t;
enum {
F_SUBPROGRAM,
F_INLINE_COPY,
};
static void dt_sugar_visit_stmts(dt_sugar_parse_t *, dt_node_t *, int); static void dt_sugar_visit_stmts(dt_sugar_parse_t *, dt_node_t *, int);
/* /*
* Return a node for "self->%error". * Return a node for "self->%error".
* *
* Note that the "%" is part of the variable name, and is included so that * Note that the "%" is part of the variable name, and is included so that
* this variable name can not collide with any user-specified variable. * this variable name can not collide with any user-specified variable.
* *
Show All 12 Lines
* Append this clause to the clause list. * Append this clause to the clause list.
*/ */
static void static void
dt_sugar_append_clause(dt_sugar_parse_t *dp, dt_node_t *clause) dt_sugar_append_clause(dt_sugar_parse_t *dp, dt_node_t *clause)
{ {
dp->dtsp_clause_list = dt_node_link(dp->dtsp_clause_list, clause); dp->dtsp_clause_list = dt_node_link(dp->dtsp_clause_list, clause);
} }
/* /*
markjUnsubmitted
Done
Inline Actions

You should avoid adding global variables to libdtrace, all state should be accessed via the dtrace_hdl_t structure.

markj: You should avoid adding global variables to libdtrace, all state should be accessed via the…
christosAuthorUnsubmitted
Done
Inline Actions

Since this is dt_sugar-only code, do you think I could embed those globals
in dt_sugar_parse_t instead?

christos: Since this is dt_sugar-only code, do you think I could embed those globals in…
* Prepend this clause to the clause list. * Prepend this clause to the clause list.
*/ */
static void static void
dt_sugar_prepend_clause(dt_sugar_parse_t *dp, dt_node_t *clause) dt_sugar_prepend_clause(dt_sugar_parse_t *dp, dt_node_t *clause)
{ {
dp->dtsp_clause_list = dt_node_link(clause, dp->dtsp_clause_list); dp->dtsp_clause_list = dt_node_link(clause, dp->dtsp_clause_list);
} }
▲ Show 20 Lines • Show All 79 Lines • ▼ Show 20 Lines
{ {
dp->dtsp_num_conditions++; dp->dtsp_num_conditions++;
dt_sugar_append_clause(dp, dt_sugar_new_condition_impl(dp, dt_sugar_append_clause(dp, dt_sugar_new_condition_impl(dp,
pred, condid, dp->dtsp_num_conditions)); pred, condid, dp->dtsp_num_conditions));
return (dp->dtsp_num_conditions); return (dp->dtsp_num_conditions);
} }
/* /*
* Visit the specified node and all of its descendants. Currently this is only * kinst-related
* used to count the number of "if" statements (dtsp_num_ifs).
*/ */
static int
dt_sugar_elf_init(dtrace_hdl_t *dtp, struct elf_info *ei, const char *file)
markjUnsubmitted
Done
Inline Actions

Any reason not to use dt_alloc()?

markj: Any reason not to use `dt_alloc()`?
{
Elf_Scn *scn;
GElf_Shdr sh;
struct section *s;
const char *name;
size_t shstrndx, ndx;
if (elf_version(EV_CURRENT) == EV_NONE) {
warnx("dt_sugar: elf_version(): %s", elf_errmsg(-1));
return (-1);
}
if ((ei->fd = open(file, O_RDONLY)) < 0) {
dt_dprintf("dt_sugar: open(%s)", file);
return (-1);
}
if ((ei->elf = elf_begin(ei->fd, ELF_C_READ, NULL)) == NULL) {
warnx("dt_sugar: elf_begin(): %s", elf_errmsg(-1));
return (-1);
}
if (elf_kind(ei->elf) == ELF_K_NONE) {
warnx("dt_sugar: not an ELF file: %s", file);
return (-1);
}
/* Load ELF sections */
if (!elf_getshnum(ei->elf, &ei->shnum)) {
warnx("dt_sugar: elf_getshnum(): %s", elf_errmsg(-1));
return (-1);
}
ei->sl = dt_alloc(dtp, ei->shnum * sizeof(struct section));
if (ei->sl == NULL)
longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
if (!elf_getshstrndx(ei->elf, &shstrndx)) {
warnx("dt_sugar: elf_getshstrndx(): %s", elf_errmsg(-1));
return (-1);
}
if ((scn = elf_getscn(ei->elf, 0)) == NULL) {
warnx("dt_sugar: elf_getscn(): %s", elf_errmsg(-1));
return (-1);
}
(void) elf_errno();
do {
if (gelf_getshdr(scn, &sh) == NULL) {
warnx("dt_sugar: gelf_getshdr(): %s", elf_errmsg(-1));
(void) elf_errno();
continue;
}
if ((name = elf_strptr(ei->elf, shstrndx, sh.sh_name)) == NULL)
(void) elf_errno();
if ((ndx = elf_ndxscn(scn)) == SHN_UNDEF && elf_errno() != 0) {
warnx("dt_sugar: elf_ndxscn(): %s", elf_errmsg(-1));
continue;
}
if (ndx >= ei->shnum)
continue;
s = &ei->sl[ndx];
s->scn = scn;
s->sh = sh;
s->name = name;
markjUnsubmitted
Done
Inline Actions

Instead of duplicating all of these fields, why not embed the GElf_Shdr directly into the section structure?

markj: Instead of duplicating all of these fields, why not embed the GElf_Shdr directly into the…
} while ((scn = elf_nextscn(ei->elf, scn)) != NULL);
if (elf_errno() != 0)
warnx("dt_sugar: elf_nextscn(): %s", elf_errmsg(-1));
return (0);
}
static void static void
dt_sugar_elf_deinit(dtrace_hdl_t *dtp, struct elf_info *ei)
{
dt_free(dtp, ei->sl);
close(ei->fd);
elf_end(ei->elf);
}
/*
* Verify the checksum in the .gnu_debuglink section to make sure the debug
* file is up to date.
*/
static int
dt_sugar_elf_verify_debuglink(struct elf_info *ei, int dbgfd)
{
Elf_Data *d;
struct section *s;
char buf[MAXPHYS];
ssize_t nr;
uint32_t crc, compcrc;
int i;
for (i = 1; i < ei->shnum; i++) {
s = &ei->sl[i];
if (strcmp(s->name, ".gnu_debuglink") == 0)
break;
}
if ((d = elf_getdata(s->scn, NULL)) == NULL) {
if (elf_errno() != 0)
warnx("dt_sugar: elf_getdata(): %s", elf_errmsg(-1));
return (-1);
}
if (d->d_size < sizeof(crc) + 1 || d->d_buf == NULL)
return (-1);
if (strnlen(d->d_buf, d->d_size) >= d->d_size - sizeof(crc))
return (-1);
memcpy(&crc, (uint8_t *)d->d_buf + d->d_size - sizeof(crc),
sizeof(crc));
compcrc = crc32(0L, Z_NULL, 0);
while ((nr = read(dbgfd, buf, sizeof(buf))) > 0)
compcrc = crc32(compcrc, (char *)buf, nr);
if (nr != 0 || crc != compcrc)
return (-1);
return (0);
}
/*
* Find the caller function and offset of an inline copy. Since we know the
* inline copy's boundaries (`addr_lo` and `addr_hi` arguments), the caller
* function is going to be the ELF symbol that the inline copy's boundaries are
* inside of.
*/
static void
dt_sugar_kinst_find_caller_func(dt_sugar_parse_t *dp, struct off *off,
uint64_t addr_lo, uint64_t addr_hi, int last)
{
Elf_Data *d;
GElf_Sym sym;
struct section *s;
uint8_t *buf;
uint64_t addr, lo, hi;
uint32_t stab;
int len, i, j;
markjUnsubmitted
Done
Inline Actions

What's the purpose of the else-if?

markj: What's the purpose of the else-if?
christosAuthorUnsubmitted
Done
Inline Actions

No real use other than to make it obvious that I'm handling both entry
and return probes.

christos: No real use other than to make it obvious that I'm handling both `entry` and `return` probes.
/* Find the caller function's boundaries and name. */
off->func = NULL;
for (i = 1; i < dp->dtsp_elf_mod.shnum; i++) {
s = &dp->dtsp_elf_mod.sl[i];
if (s->sh.sh_type != SHT_SYMTAB && s->sh.sh_type != SHT_DYNSYM)
continue;
if (s->sh.sh_link >= dp->dtsp_elf_mod.shnum)
continue;
stab = s->sh.sh_link;
len = (int)(s->sh.sh_size / s->sh.sh_entsize);
(void) elf_errno();
if ((d = elf_getdata(s->scn, NULL)) == NULL) {
if (elf_errno() != 0)
warnx("dt_sugar: elf_getdata(): %s",
elf_errmsg(-1));
continue;
}
if (d->d_size <= 0)
continue;
if (s->sh.sh_entsize == 0)
continue;
else if (len > INT_MAX)
continue;
for (j = 0; j < len; j++) {
if (gelf_getsym(d, j, &sym) != &sym) {
warnx("dt_sugar: gelf_getsym(): %s",
elf_errmsg(-1));
continue;
}
if (GELF_ST_TYPE(sym.st_info) != STT_FUNC)
continue;
lo = sym.st_value;
hi = sym.st_value + sym.st_size;
if (addr_lo < lo || addr_hi > hi)
continue;
if ((off->func = elf_strptr(dp->dtsp_elf_mod.elf, stab,
sym.st_name)) != NULL)
break;
}
}
/* Find inline copy's return offset. */
for (i = 1; i < dp->dtsp_elf_mod.shnum; i++) {
s = &dp->dtsp_elf_mod.sl[i];
if (strcmp(s->name, ".text") != 0 ||
s->sh.sh_type != SHT_PROGBITS)
continue;
(void) elf_errno();
if ((d = elf_getdata(s->scn, NULL)) == NULL) {
if (elf_errno() != 0)
warnx("dt_sugar: elf_getdata(): %s",
elf_errmsg(-1));
continue;
}
if (d->d_size <= 0 || d->d_buf == NULL)
continue;
buf = d->d_buf;
addr = s->sh.sh_addr + d->d_off;
while (addr != lo) {
addr++;
buf++;
}
if (dp->dtsp_flags & DF_ENTRY) {
off->val = addr_lo - lo;
} else if (dp->dtsp_flags & DF_RETURN) {
if (addr_hi == hi || last) {
/*
* In this case the offset is one instruction
* *outside* the inline or the caller function,
* so we have to go back one instruction to
* stay within bounds.
*/
/*
* Get to the inline copy's start manually to
* avoid potential dtrace_disx86() failures.
*/
while (addr != addr_lo) {
addr++;
buf++;
}
len = 0;
while (addr != addr_hi) {
len = dtrace_instr_size(buf);
addr += len;
buf += len;
}
addr -= len;
off->val = addr - lo;
} else
off->val = addr_hi - lo;
}
break;
}
}
/*
* Parse DWARF info recursively and create a TAILQ of entries that correspond
* to inline copies of the probe function.
*/
static void
dt_sugar_kinst_parse_die(dt_sugar_parse_t *dp, Dwarf_Debug dbg, Dwarf_Die die,
int level, int flag)
{
static Dwarf_Die die_root;
Dwarf_Die die_next;
Dwarf_Ranges *ranges, *rp;
Dwarf_Attribute attp;
Dwarf_Addr base0, lowpc, highpc;
Dwarf_Off dieoff, cuoff, culen, v_off;
Dwarf_Unsigned nbytes, v_udata;
Dwarf_Signed nranges;
Dwarf_Half attr, tag;
Dwarf_Bool v_flag;
Dwarf_Error error;
struct entry *e;
struct off *off;
char *v_str;
int res, noff, i, found = 0;
if (level == 0)
die_root = die;
if (dwarf_dieoffset(die, &dieoff, &error) != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (dwarf_die_CU_offset_range(die, &cuoff, &culen, &error) != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
cuoff = 0;
}
if (dwarf_tag(die, &tag, &error) != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (tag != DW_TAG_subprogram && tag != DW_TAG_inlined_subroutine)
goto cont;
if (flag == F_SUBPROGRAM && tag == DW_TAG_subprogram) {
/* Find if the function exists in the current module. */
if (dwarf_hasattr(die, DW_AT_name, &v_flag, &error) !=
DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (!v_flag)
goto cont;
if (dwarf_diename(die, &v_str, &error) != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (strcmp(v_str, dp->dtsp_func) == 0)
dp->dtsp_flags |= DF_EXISTS;
else
goto cont;
if (dwarf_hasattr(die, DW_AT_inline, &v_flag, &error) !=
DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (v_flag) {
dp->dtsp_flags |= DF_INLINE;
found = 1;
} else
dp->dtsp_flags |= DF_REGULAR;
goto cont;
} else if (flag == F_INLINE_COPY) {
res = dwarf_attr(die, DW_AT_abstract_origin, &attp, &error);
if (res != DW_DLV_OK) {
if (res == DW_DLV_ERROR)
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (dwarf_formref(attp, &v_off, &error) != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
v_off += cuoff;
/* Doesn't point to the definition's DIE offset. */
if (v_off != dp->dtsp_dieoff)
goto cont;
if (dwarf_hasattr(die, DW_AT_ranges, &v_flag, &error) !=
DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (v_flag) {
/* DIE has ranges */
res = dwarf_attr(die, DW_AT_ranges, &attp, &error);
if (res != DW_DLV_OK) {
if (res == DW_DLV_ERROR)
warnx("dt_sugar: %s",
dwarf_errmsg(error));
goto cont;
}
if (dwarf_global_formref(attp, &v_off, &error) !=
DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
if (dwarf_get_ranges(dbg, v_off, &ranges, &nranges,
&nbytes, &error) != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
res = dwarf_lowpc(die_root, &lowpc, &error);
if (res != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
base0 = lowpc;
if (dp->dtsp_flags & DF_ENTRY) {
/*
* Trace the first instruction of the first
* range since this is the beginning of the
* inline copy.
*/
noff = 1;
} else if (dp->dtsp_flags & DF_RETURN) {
/*
* Trace the last instruction of every range in
* case the inline copy is split into multiple
* ranges (e.g if it has early `return`s).
*/
noff = nranges - 1;
}
off = dt_alloc(dp->dtsp_dtp, noff * sizeof(struct off));
if (off == NULL)
longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
for (i = 0; i < noff; i++) {
rp = &ranges[i];
if (rp->dwr_type == DW_RANGES_ADDRESS_SELECTION)
base0 = rp->dwr_addr2;
dt_sugar_kinst_find_caller_func(dp, &off[i],
rp->dwr_addr1 + base0,
rp->dwr_addr2 + base0,
(dp->dtsp_flags & DF_RETURN) &&
i == noff - 1);
}
dwarf_ranges_dealloc(dbg, ranges, nranges);
} else {
/* DIE has high/low PC boundaries */
res = dwarf_lowpc(die, &lowpc, &error);
if (res != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
res = dwarf_highpc(die, &highpc, &error);
if (res != DW_DLV_OK) {
warnx("dt_sugar: %s", dwarf_errmsg(error));
goto cont;
}
noff = 1;
off = dt_alloc(dp->dtsp_dtp, noff * sizeof(struct off));
if (off == NULL)
longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
dt_sugar_kinst_find_caller_func(dp, off, lowpc,
lowpc + highpc,
dp->dtsp_flags & DF_RETURN);
}
} else
goto cont;
e = dt_alloc(dp->dtsp_dtp, sizeof(struct entry));
if (e == NULL)
longjmp(yypcb->pcb_jmpbuf, EDT_NOMEM);
e->noff = noff;
e->off = off;
TAILQ_INSERT_TAIL(&dp->dtsp_head, e, next);
cont:
/*
* Inline copies might appear before the declaration, so we need to
* re-parse the CU.
*
* The rationale for choosing to re-parse the CU instead of using a
* hash table of DIEs is that, because we re-parse only when an inline
* definition of the function we want is found, statistically, we won't
* have to re-parse many times at all considering that only a handful
* of CUs will define the same function, whereas if we have used a hash
* table, we would first need to parse the whole CU at once and store
* all DW_TAG_inlined_subroutine DIEs (so that we can match them
* afterwards). In this case, we always have to "parse" twice -- first
* the CU, then the DIE table -- and also, the program would use much
* more memory since we would have allocated DIEs, which most of them
* would never be used.
*/
if (found) {
die = die_root;
level = 0;
/*
* We'll be checking against the DIE offset of the definition
* to determine if the inline copy's DW_AT_abstract_origin
* points to it.
*/
dp->dtsp_dieoff = dieoff;
flag = F_INLINE_COPY;
}
res = dwarf_child(die, &die_next, &error);
if (res == DW_DLV_ERROR)
warnx("dt_sugar: %s", dwarf_errmsg(error));
else if (res == DW_DLV_OK)
dt_sugar_kinst_parse_die(dp, dbg, die_next, level + 1, flag);
res = dwarf_siblingof(dbg, die, &die_next, &error);
if (res == DW_DLV_ERROR)
warnx("dt_sugar: %s", dwarf_errmsg(error));
else if (res == DW_DLV_OK)
dt_sugar_kinst_parse_die(dp, dbg, die_next, level, flag);
/*
* Deallocating on level 0 will attempt to double-free, since die_root
* points to the first DIE. We'll deallocate the root DIE in main().
*/
if (level > 0)
dwarf_dealloc(dbg, die, DW_DLA_DIE);
}
/*
* Append new clauses for each inline copy to the parse tree.
*
* If foo() is an inline function, and is called from functions bar() and baz()
* at offsets 10 and 20 respectively, we'll transform the parse tree from:
*
* kinst::foo:<entry|return>
* /<pred>/
* {
* <acts>
* }
*
* To:
*
* kinst::bar:10,
* kinst::baz:20
* /<pred>/
* {
* <acts>
* }
*/
static void
dt_sugar_kinst_create_probes(dt_sugar_parse_t *dp)
{
dt_node_t *dnp, *pdesc;
struct entry *e;
char buf[DTRACE_FULLNAMELEN];
int i, n;
dnp = dp->dtsp_clause_list->dn_pdescs;
n = dp->dtsp_flags & DF_NEWPDESC;
/* We have found inline copies. Clean up as well */
while (!TAILQ_EMPTY(&dp->dtsp_head)) {
e = TAILQ_FIRST(&dp->dtsp_head);
TAILQ_REMOVE(&dp->dtsp_head, e, next);
for (i = 0; i < e->noff; i++) {
if (dp->dtsp_flags & DF_NEWPDESC) {
/* We want to get here only once per-pdesc. */
dp->dtsp_flags &= ~DF_NEWPDESC;
/*
* Since we're trying to trace inline copies of
* a given function by requesting a probe of
* the form
* `kinst::<inline_func_name>:<entry|return>`,
* the requested probe, by definition cannot be
* traced, and as a result DTrace will exit
markjUnsubmitted
Done
Inline Actions

This should use the kern.bootfile sysctl instead of hard-coding the path. Then we have three cases: debug info is embedded in the kernel executable itself (should be rare), kernel.debug is in the same directory as the kernel, or kernel.debug is in /usr/lib/debug/$(dirname $(sysctl -n kern.bootfile)).

It might make sense to keep the bootfile path in the dtrace_hdl_t since there's some other code in libdtrace that uses it.

(Since the current code should work fine, you could postpone fixing this until later, just be sure to add a TODO comment or so.)

markj: This should use the `kern.bootfile` sysctl instead of hard-coding the path. Then we have three…
* with an error because it cannot create a
* probe for this function. In order to get
* around this, we're overriding the requested
* probe's <function> and <offset> fields with
* the very first inline copy's information.
*/
snprintf(buf, sizeof(buf), "%lu", e->off[i].val);
strlcpy(dp->dtsp_desc->dtpd_func, e->off[i].func,
sizeof(dp->dtsp_desc->dtpd_func));
strlcpy(dp->dtsp_desc->dtpd_name, buf,
sizeof(dp->dtsp_desc->dtpd_name));
} else {
/*
* Create a new probe description for each
* inline copy and append it to the main pdesc
* list.
*/
snprintf(buf, sizeof(buf), "%s:%s:%s:%lu",
dp->dtsp_desc->dtpd_provider,
dp->dtsp_desc->dtpd_mod,
e->off[i].func, e->off[i].val);
pdesc = dt_node_pdesc_by_name(strdup(buf));
dnp = dt_node_link(dnp, pdesc);
}
}
dt_free(dp->dtsp_dtp, e->off);
dt_free(dp->dtsp_dtp, e);
}
if (!(dp->dtsp_flags & DF_INLINE)) {
/*
* Delegate non-inline function probes to FBT so that we don't
* duplicate FBT code in kinst. Regular kinst probes are not
* affected by this.
*/
strlcpy(dp->dtsp_desc->dtpd_provider, "fbt",
sizeof(dp->dtsp_desc->dtpd_provider));
} else if ((~dp->dtsp_flags & (DF_REGULAR | DF_INLINE)) == 0 && n) {
/*
* If we have found a regular definition along with an inline
* one, create an FBT probe for the non-inline definition as
* well.
*/
snprintf(buf, sizeof(buf), "fbt:%s:%s:%s",
dp->dtsp_desc->dtpd_mod, dp->dtsp_func, dp->dtsp_name);
pdesc = dt_node_pdesc_by_name(strdup(buf));
dnp = dt_node_link(dnp, pdesc);
}
}
/*
* Initialize libelf and libdwarf and parse kernel.debug's DWARF info.
*/
static void
dt_sugar_do_kinst_inline(dt_sugar_parse_t *dp)
{
dt_module_t *dmp;
Dwarf_Debug dbg;
Dwarf_Die die;
Dwarf_Error error;
char dbgfile[MAXPATHLEN];
int res = DW_DLV_OK;
strlcpy(dp->dtsp_func, dp->dtsp_desc->dtpd_func, sizeof(dp->dtsp_func));
strlcpy(dp->dtsp_name, dp->dtsp_desc->dtpd_name, sizeof(dp->dtsp_func));
dp->dtsp_flags = 0;
/* We only make entry and return probes for inline functions. */
if (strcmp(dp->dtsp_name, "entry") == 0)
dp->dtsp_flags |= DF_ENTRY;
else if (strcmp(dp->dtsp_name, "return") == 0)
dp->dtsp_flags |= DF_RETURN;
else
return;
dp->dtsp_flags |= DF_NEWPDESC;
for (dmp = dt_list_next(&dp->dtsp_dtp->dt_modlist); dmp != NULL;
dmp = dt_list_next(dmp)) {
if (strcmp(dmp->dm_name, "C") == 0 ||
strcmp(dmp->dm_name, "D") == 0)
continue;
(void) snprintf(dbgfile, sizeof(dbgfile),
"/usr/lib/debug/%s.debug", dmp->dm_file);
if (dt_sugar_elf_init(dp->dtsp_dtp, &dp->dtsp_elf_mod,
dmp->dm_file) < 0)
continue;
if (dt_sugar_elf_init(dp->dtsp_dtp, &dp->dtsp_elf_dbg,
dbgfile) < 0) {
dt_sugar_elf_deinit(dp->dtsp_dtp, &dp->dtsp_elf_mod);
continue;
}
if (dt_sugar_elf_verify_debuglink(&dp->dtsp_elf_mod,
dp->dtsp_elf_dbg.fd) < 0) {
warnx("dt_sugar: debug link mismatch: "
"make sure '%s' is up to date", dbgfile);
dt_sugar_elf_deinit(dp->dtsp_dtp, &dp->dtsp_elf_mod);
dt_sugar_elf_deinit(dp->dtsp_dtp, &dp->dtsp_elf_dbg);
continue;
}
if (dwarf_elf_init(dp->dtsp_elf_dbg.elf, DW_DLC_READ, NULL,
NULL, &dbg, &error) != DW_DLV_OK) {
warnx("dt_sugar: dwarf_elf_init(): %s",
dwarf_errmsg(error));
continue;
}
TAILQ_INIT(&dp->dtsp_head);
dp->dtsp_flags &= ~(DF_INLINE | DF_REGULAR | DF_EXISTS);
while ((res = dwarf_next_cu_header(dbg, NULL, NULL, NULL, NULL,
NULL, &error)) == DW_DLV_OK) {
die = NULL;
while (dwarf_siblingof(dbg, die, &die, &error) ==
DW_DLV_OK) {
dt_sugar_kinst_parse_die(dp, dbg, die, 0,
F_SUBPROGRAM);
}
dwarf_dealloc(dbg, die, DW_DLA_DIE);
}
if (res == DW_DLV_ERROR)
warnx("dt_sugar: %s", dwarf_errmsg(error));
if (!(dp->dtsp_flags & DF_EXISTS))
goto cont;
domagoj.stolfa_gmail.comUnsubmitted
Done
Inline Actions

I don't see any other uses of cont, perhaps this can be done without using a goto?

domagoj.stolfa_gmail.com: I don't see any other uses of `cont`, perhaps this can be done without using a goto?
dt_sugar_kinst_create_probes(dp);
cont:
christosAuthorUnsubmitted
Done
Inline Actions
warnx("dt_sugar: %s", dwarf_errmsg(error));
- if (!(dp->dtsp_flags & DF_EXISTS))
- goto cont;
-
- dt_sugar_kinst_create_probes(dp);
- cont:
+ if (dp->dtsp_flags & DF_EXISTS)
+ dt_sugar_kinst_create_probes(dp);
+
dwarf_finish(dbg, &error);

I don't see any other uses of cont, perhaps this can be done without using a goto?

I guess it could be rewritten like this.

christos: > I don't see any other uses of cont, perhaps this can be done without using a goto? I guess it…
dwarf_finish(dbg, &error);
dt_sugar_elf_deinit(dp->dtsp_dtp, &dp->dtsp_elf_mod);
dt_sugar_elf_deinit(dp->dtsp_dtp, &dp->dtsp_elf_dbg);
}
}
/*
* Visit the specified node and all of its descendants.
*/
static void
dt_sugar_visit_all(dt_sugar_parse_t *dp, dt_node_t *dnp) dt_sugar_visit_all(dt_sugar_parse_t *dp, dt_node_t *dnp)
{ {
dt_node_t *arg; dt_node_t *arg;
switch (dnp->dn_kind) { switch (dnp->dn_kind) {
case DT_NODE_FREE: case DT_NODE_FREE:
case DT_NODE_INT: case DT_NODE_INT:
case DT_NODE_STRING: case DT_NODE_STRING:
case DT_NODE_SYM: case DT_NODE_SYM:
case DT_NODE_TYPE: case DT_NODE_TYPE:
case DT_NODE_PROBE: case DT_NODE_PROBE:
case DT_NODE_PDESC: case DT_NODE_PDESC:
case DT_NODE_IDENT: case DT_NODE_IDENT:
markjUnsubmitted
Done
Inline Actions

Don't we want to check the probe name as well? This code shouldn't modify regular kinst::<func>:<offset> probes.

markj: Don't we want to check the probe name as well? This code shouldn't modify regular kinst::<func>…
christosAuthorUnsubmitted
Done
Inline Actions

This doesn't affect kinst::<func>:<offset> probes at all. The
flag is tested in dt_sugar_do_kinst_inline() and will exit right away
if the probe is neither entry nor return.

christos: This doesn't affect `kinst::<func>:<offset>` probes at all. The flag is tested in…
break; break;
case DT_NODE_FUNC: case DT_NODE_FUNC:
for (arg = dnp->dn_args; arg != NULL; arg = arg->dn_list) for (arg = dnp->dn_args; arg != NULL; arg = arg->dn_list)
dt_sugar_visit_all(dp, arg); dt_sugar_visit_all(dp, arg);
break; break;
case DT_NODE_OP1: case DT_NODE_OP1:
▲ Show 20 Lines • Show All 242 Lines • ▼ Show 20 Lines
/* /*
* Transform the super-clause into straight-D, returning the new list of * Transform the super-clause into straight-D, returning the new list of
* sub-clauses. * sub-clauses.
*/ */
dt_node_t * dt_node_t *
dt_compile_sugar(dtrace_hdl_t *dtp, dt_node_t *clause) dt_compile_sugar(dtrace_hdl_t *dtp, dt_node_t *clause)
{ {
dt_sugar_parse_t dp = { 0 }; dt_sugar_parse_t dp = { 0 };
dt_node_t *dnp;
int condid = 0; int condid = 0;
dp.dtsp_dtp = dtp; dp.dtsp_dtp = dtp;
dp.dtsp_pdescs = clause->dn_pdescs; dp.dtsp_pdescs = clause->dn_pdescs;
/* make dt_node_int() generate an "int"-typed integer */ /* make dt_node_int() generate an "int"-typed integer */
yyintdecimal = B_TRUE; yyintdecimal = B_TRUE;
yyintsuffix[0] = '\0'; yyintsuffix[0] = '\0';
Show All 30 Lines if (dp.dtsp_num_ifs == 0 && dp.dtsp_num_conditions == 0) {
} }
} }
if (dp.dtsp_num_conditions != 0) { if (dp.dtsp_num_conditions != 0) {
dt_sugar_prepend_clause(&dp, dt_sugar_prepend_clause(&dp,
dt_sugar_new_clearerror_clause(&dp)); dt_sugar_new_clearerror_clause(&dp));
} }
/*
* This loop is a bit of a hack. What it does is iterate through all
* probe descriptions and handle kinst entry/return probes, but you
* will notice that in case we handle inline function probes,
* dt_sugar_kinst_create_probes() appends new elements to the list
* we're looping through, yet it works just fine!
*
* Consider the following initial `dn_pdescs` list:
*
* dn_pdescs = kinst::inlinefunc1:entry
* dn_pdescs->dn_list = kinst::inlinefunc2:return
* dn_pdescs->dn_list->dn_list = kinst::normalfunc1:0
* dn_pdescs->dn_list->dn_list->dn_list = kinst::normalfunc2:entry
*
* The final list will look like this (read the comments in
* dt_sugar_kinst_create_probes()):
*
* dn_pdescs = kinst::callerfunc1:<x>
* dn_pdescs->dn_list = kinst::callerfunc2:<y>
* dn_pdescs->dn_list->dn_list = kinst::normalfunc1:0
* dn_pdescs->dn_list->dn_list->dn_list = fbt::normalfunc2:entry
* ... = new probes are appended here
*
* Because it is guaranteed that any new probes appended to the list by
* dt_sugar_kinst_create_probes() will be regular kinst probes, the
* loop below *does* loop through them as well, but does nothing since
* regular kinst probes are skipped.
*/
for (dnp = dp.dtsp_clause_list->dn_pdescs; dnp != NULL;
dnp = dnp->dn_list) {
int fd;
if (strcmp(dnp->dn_desc->dtpd_provider, "kinst") != 0)
continue;
/*
* Make sure kinst exists to avoid spending time parsing DWARF
* in case it doesn't.
*/
fd = open("/dev/dtrace/kinst", O_RDONLY);
if (fd < 0) {
close(fd);
continue;
}
close(fd);
dp.dtsp_desc = dnp->dn_desc;
dt_sugar_do_kinst_inline(&dp);
}
if (dp.dtsp_clause_list != NULL && if (dp.dtsp_clause_list != NULL &&
dp.dtsp_clause_list->dn_list != NULL && !dtp->dt_has_sugar) { dp.dtsp_clause_list->dn_list != NULL && !dtp->dt_has_sugar) {
dtp->dt_has_sugar = B_TRUE; dtp->dt_has_sugar = B_TRUE;
dt_sugar_prepend_clause(&dp, dt_sugar_makeerrorclause()); dt_sugar_prepend_clause(&dp, dt_sugar_makeerrorclause());
} }
return (dp.dtsp_clause_list); return (dp.dtsp_clause_list);
} }