Use kldsym(2) to lookup symbol values. This avoids the kvm_mkdb juggling
and is module aware. Yes, this means that kvm_nlist(3) will find symbols in loaded modules. The emulation of the nlist struct is pretty crude but seems to work well enough for all the users in the tree that I found.
This commit is contained in:
Peter Wemm
parent
c2696359ab
commit
c4a7cdb3b6
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=55127
133
lib/libkvm/kvm.c
133
lib/libkvm/kvm.c
@ -40,7 +40,7 @@
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static char sccsid[] = "@(#)kvm.c 8.2 (Berkeley) 2/13/94";
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#else
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static const char rcsid[] =
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"$FreeBSD$";
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"$FreeBSD$";
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#endif
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#endif /* LIBC_SCCS and not lint */
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@ -50,6 +50,7 @@ static const char rcsid[] =
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <sys/sysctl.h>
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#include <sys/linker.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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@ -58,7 +59,6 @@ static const char rcsid[] =
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#include <machine/vmparam.h>
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#include <ctype.h>
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#include <db.h>
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#include <fcntl.h>
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#include <kvm.h>
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#include <limits.h>
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@ -71,8 +71,6 @@ static const char rcsid[] =
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#include "kvm_private.h"
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static int kvm_dbopen __P((kvm_t *, const char *));
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char *
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kvm_geterr(kd)
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kvm_t *kd;
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@ -180,7 +178,6 @@ _kvm_open(kd, uf, mf, flag, errout)
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kd->pmfd = -1;
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kd->nlfd = -1;
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kd->vmst = 0;
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kd->db = 0;
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kd->procbase = 0;
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kd->argspc = 0;
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kd->argv = 0;
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@ -225,19 +222,6 @@ _kvm_open(kd, uf, mf, flag, errout)
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goto failed;
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}
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}
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/*
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* Open kvm nlist database. We go ahead and do this
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* here so that we don't have to hold on to the kernel
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* path name. Since a kvm application will surely do
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* a kvm_nlist(), this probably won't be a wasted effort.
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* If the database cannot be opened, open the namelist
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* argument so we revert to slow nlist() calls.
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*/
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if (kvm_dbopen(kd, uf) < 0 &&
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(kd->nlfd = open(uf, O_RDONLY, 0)) < 0) {
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_kvm_syserr(kd, kd->program, "%s", uf);
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goto failed;
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}
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} else {
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/*
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* This is a crash dump.
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@ -314,8 +298,6 @@ kvm_close(kd)
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error |= close(kd->vmfd);
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if (kd->nlfd >= 0)
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error |= close(kd->nlfd);
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if (kd->db != 0)
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error |= (kd->db->close)(kd->db);
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if (kd->vmst)
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_kvm_freevtop(kd);
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if (kd->procbase != 0)
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@ -327,72 +309,6 @@ kvm_close(kd)
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return (0);
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}
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/*
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* Set up state necessary to do queries on the kernel namelist
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* data base. If the data base is out-of-data/incompatible with
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* given executable, set up things so we revert to standard nlist call.
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* Only called for live kernels. Return 0 on success, -1 on failure.
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*/
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static int
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kvm_dbopen(kd, uf)
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kvm_t *kd;
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const char *uf;
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{
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char *cp;
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DBT rec;
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int dbversionlen;
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struct nlist nitem;
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char dbversion[_POSIX2_LINE_MAX];
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char kversion[_POSIX2_LINE_MAX];
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char dbname[MAXPATHLEN];
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if ((cp = rindex(uf, '/')) != 0)
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uf = cp + 1;
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(void)snprintf(dbname, sizeof(dbname), "%skvm_%s.db", _PATH_VARDB, uf);
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kd->db = dbopen(dbname, O_RDONLY, 0, DB_HASH, NULL);
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if (kd->db == 0)
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return (-1);
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/*
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* read version out of database
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*/
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rec.data = VRS_KEY;
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rec.size = sizeof(VRS_KEY) - 1;
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if ((kd->db->get)(kd->db, (DBT *)&rec, (DBT *)&rec, 0))
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goto close;
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if (rec.data == 0 || rec.size > sizeof(dbversion))
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goto close;
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bcopy(rec.data, dbversion, rec.size);
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dbversionlen = rec.size;
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/*
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* Read version string from kernel memory.
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* Since we are dealing with a live kernel, we can call kvm_read()
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* at this point.
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*/
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rec.data = VRS_SYM;
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rec.size = sizeof(VRS_SYM) - 1;
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if ((kd->db->get)(kd->db, (DBT *)&rec, (DBT *)&rec, 0))
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goto close;
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if (rec.data == 0 || rec.size != sizeof(struct nlist))
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goto close;
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bcopy((char *)rec.data, (char *)&nitem, sizeof(nitem));
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if (kvm_read(kd, (u_long)nitem.n_value, kversion, dbversionlen) !=
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dbversionlen)
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goto close;
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/*
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* If they match, we win - otherwise clear out kd->db so
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* we revert to slow nlist().
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*/
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if (bcmp(dbversion, kversion, dbversionlen) == 0)
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return (0);
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close:
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(void)(kd->db->close)(kd->db);
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kd->db = 0;
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return (-1);
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}
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int
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kvm_nlist(kd, nl)
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kvm_t *kd;
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@ -400,44 +316,37 @@ kvm_nlist(kd, nl)
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{
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register struct nlist *p;
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register int nvalid;
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struct kld_sym_lookup lookup;
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/*
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* If we can't use the data base, revert to the
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* If we can't use the kld symbol lookup, revert to the
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* slow library call.
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*/
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if (kd->db == 0)
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if (!ISALIVE(kd))
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return (__fdnlist(kd->nlfd, nl));
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/*
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* We can use the kvm data base. Go through each nlist entry
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* and look it up with a db query.
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* We can use the kld lookup syscall. Go through each nlist entry
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* and look it up with a kldsym(2) syscall.
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*/
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nvalid = 0;
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for (p = nl; p->n_name && p->n_name[0]; ++p) {
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register int len;
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DBT rec;
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lookup.version = sizeof(lookup);
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lookup.symname = p->n_name;
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lookup.symvalue = 0;
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lookup.symsize = 0;
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if ((len = strlen(p->n_name)) > 4096) {
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/* sanity */
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_kvm_err(kd, kd->program, "symbol too large");
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return (-1);
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if (lookup.symname[0] == '_')
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lookup.symname++;
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if (kldsym(0, KLDSYM_LOOKUP, &lookup) != -1) {
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p->n_type = N_TEXT;
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p->n_other = 0;
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p->n_desc = 0;
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p->n_value = lookup.symvalue;
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++nvalid;
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/* lookup.symsize */
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}
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rec.data = p->n_name;
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rec.size = len;
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if ((kd->db->get)(kd->db, (DBT *)&rec, (DBT *)&rec, 0))
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continue;
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if (rec.data == 0 || rec.size != sizeof(struct nlist))
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continue;
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++nvalid;
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/*
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* Avoid alignment issues.
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*/
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bcopy((char *)&((struct nlist *)rec.data)->n_type,
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(char *)&p->n_type,
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sizeof(p->n_type));
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bcopy((char *)&((struct nlist *)rec.data)->n_value,
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(char *)&p->n_value,
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sizeof(p->n_value));
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}
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/*
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* Return the number of entries that weren't found.
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@ -42,7 +42,6 @@
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#include <vm/vm_param.h>
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#include <limits.h>
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#include <db.h>
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#include <stdlib.h>
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#include <machine/pmap.h>
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#include "kvm_private.h"
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@ -36,7 +36,12 @@
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)kvm_hp300.c 8.1 (Berkeley) 6/4/93";
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#else
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static const char rcsid[] =
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"$FreeBSD$";
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#endif
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#endif /* LIBC_SCCS and not lint */
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/*
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@ -57,7 +62,6 @@ static char sccsid[] = "@(#)kvm_hp300.c 8.1 (Berkeley) 6/4/93";
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#include <vm/vm_param.h>
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#include <limits.h>
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#include <db.h>
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#include "kvm_private.h"
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@ -32,7 +32,12 @@
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)kvm_file.c 8.1 (Berkeley) 6/4/93";
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#else
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static const char rcsid[] =
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"$FreeBSD$";
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#endif
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#endif /* LIBC_SCCS and not lint */
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/*
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@ -32,7 +32,12 @@
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)kvm_getloadavg.c 8.1 (Berkeley) 6/4/93";
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#else
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static const char rcsid[] =
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"$FreeBSD$";
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#endif
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#endif /* LIBC_SCCS and not lint */
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#include <sys/param.h>
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@ -43,7 +48,6 @@ static char sccsid[] = "@(#)kvm_getloadavg.c 8.1 (Berkeley) 6/4/93";
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#include <vm/vm_param.h>
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#include <stdlib.h>
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#include <db.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <nlist.h>
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@ -28,7 +28,6 @@ static const char rcsid[] =
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#include <err.h>
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#include <fcntl.h>
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#include <kvm.h>
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#include <limits.h>
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#include <nlist.h>
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#include <stdio.h>
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#include <stdlib.h>
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@ -36,7 +36,12 @@
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)kvm_hp300.c 8.1 (Berkeley) 6/4/93";
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#else
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static const char rcsid[] =
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"$FreeBSD$";
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#endif
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#endif /* LIBC_SCCS and not lint */
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/*
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@ -57,7 +62,6 @@ static char sccsid[] = "@(#)kvm_hp300.c 8.1 (Berkeley) 6/4/93";
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#include <vm/vm_param.h>
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#include <limits.h>
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#include <db.h>
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#include "kvm_private.h"
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@ -60,12 +60,10 @@ Each symbol is looked up using the n_name field, and if found, the
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corresponding n_type and n_value fields are filled in. These fields are set
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to 0 if the symbol is not found.
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.Pp
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The program
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.Xr kvm_mkdb 8
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builds a database from the running kernel's namelist.
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If the database matches the opened kernel,
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.Fn kvm_nlist
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uses it to speed lookups.
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.Xr kldsym 2
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is used to locate the symbol. This is a less than perfect emulation
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of the nlist values but has the advantage of being aware of kernel modules
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and is reasonably fast.
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.Sh RETURN VALUES
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The
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.Fn kvm_nlist
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@ -76,6 +74,7 @@ If the kernel symbol table was unreadable, -1 is returned.
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.It Pa /var/db/kvm_kernel.db
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.El
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.Sh SEE ALSO
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.Xr kldsym 2 ,
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.Xr kvm 3 ,
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.Xr kvm_close 3 ,
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.Xr kvm_getargv 3 ,
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@ -85,5 +84,4 @@ If the kernel symbol table was unreadable, -1 is returned.
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.Xr kvm_open 3 ,
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.Xr kvm_openfiles 3 ,
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.Xr kvm_read 3 ,
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.Xr kvm_write 3 ,
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.Xr kvm_mkdb 8
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.Xr kvm_write 3
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@ -35,6 +35,7 @@
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* SUCH DAMAGE.
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*
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* @(#)kvm_private.h 8.1 (Berkeley) 6/4/93
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* $FreeBSD$
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*/
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struct __kvm {
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@ -46,7 +47,6 @@ struct __kvm {
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const char *program;
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char *errp; /* XXX this can probably go away */
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char errbuf[_POSIX2_LINE_MAX];
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DB *db;
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#define ISALIVE(kd) ((kd)->vmfd >= 0)
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int pmfd; /* physical memory file (or crashdump) */
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int vmfd; /* virtual memory file (-1 if crashdump) */
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@ -70,7 +70,6 @@ static char sccsid[] = "@(#)kvm_proc.c 8.3 (Berkeley) 9/23/93";
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#include <limits.h>
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#include <memory.h>
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#include <db.h>
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#include <paths.h>
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#include "kvm_private.h"
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@ -675,6 +674,12 @@ kvm_getargv(kd, kp, nchr)
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static char **bufp;
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static int argc;
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if (!ISALIVE(kd)) {
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_kvm_err(kd, kd->program,
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"cannot read user space from dead kernel");
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return (0);
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}
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if (!buflen) {
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l = sizeof(buflen);
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i = sysctlbyname("kern.ps_arg_cache_limit",
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@ -36,7 +36,12 @@
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*/
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#if defined(LIBC_SCCS) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)kvm_sparc.c 8.1 (Berkeley) 6/4/93";
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#else
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static const char rcsid[] =
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"$FreeBSD$";
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#endif
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#endif /* LIBC_SCCS and not lint */
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/*
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@ -56,7 +61,6 @@ static char sccsid[] = "@(#)kvm_sparc.c 8.1 (Berkeley) 6/4/93";
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#include <vm/vm_param.h>
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#include <limits.h>
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#include <db.h>
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#include "kvm_private.h"
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|
||||
|
||||
Loading…
Reference in New Issue
Block a user