libdtrace: add support for lazyload mode.
Passing "-x lazyload" to dtrace -G during compilation causes dtrace(1) to not link drti.o into the output object file, so the USDT probes are not created during process startup. Instead, dtrace(1) will automatically discover and create probes on the process' behalf when attaching. Differential Revision: https://reviews.freebsd.org/D2203 Reviewed by: rpaulo MFC after: 1 month
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@ -147,6 +147,9 @@ dtrace_dof_init(void)
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dh.dofhp_dof = (uintptr_t)dof;
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dh.dofhp_addr = elf->e_type == ET_DYN ? (uintptr_t) lmp->l_addr : 0;
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#ifdef __FreeBSD__
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dh.dofhp_pid = getpid();
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#endif
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if (lmid == 0) {
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(void) snprintf(dh.dofhp_mod, sizeof (dh.dofhp_mod),
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@ -184,7 +187,7 @@ dtrace_dof_init(void)
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else {
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dprintf(1, "DTrace ioctl succeeded for DOF at %p\n", dof);
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#ifdef __FreeBSD__
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gen = dh.gen;
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gen = dh.dofhp_gen;
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#endif
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}
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@ -1785,11 +1785,17 @@ dtrace_program_link(dtrace_hdl_t *dtp, dtrace_prog_t *pgp, uint_t dflags,
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"failed to open %s: %s", file, strerror(errno)));
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}
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#else
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if (dtp->dt_lazyload) {
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if ((fd = open(file, O_RDWR | O_CREAT | O_TRUNC, 0666)) < 0)
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return (dt_link_error(dtp, NULL, -1, NULL,
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"failed to open %s: %s", file, strerror(errno)));
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} else {
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snprintf(tfile, sizeof(tfile), "%s.XXXXXX", file);
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if ((fd = mkstemp(tfile)) == -1)
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return (dt_link_error(dtp, NULL, -1, NULL,
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"failed to create temporary file %s: %s",
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tfile, strerror(errno)));
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}
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#endif
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/*
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@ -44,11 +44,16 @@
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#include <dt_program.h>
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#include <dt_pid.h>
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#include <dt_string.h>
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#ifndef illumos
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#include <libproc_compat.h>
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#endif
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#include <dt_module.h>
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#ifndef illumos
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#include <sys/sysctl.h>
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#include <unistd.h>
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#include <libproc_compat.h>
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#include <libelf.h>
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#include <gelf.h>
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#endif
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typedef struct dt_pid_probe {
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dtrace_hdl_t *dpp_dtp;
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dt_pcb_t *dpp_pcb;
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@ -566,6 +571,12 @@ dt_pid_usdt_mapping(void *data, const prmap_t *pmp, const char *oname)
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prsyminfo_t sip;
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dof_helper_t dh;
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GElf_Half e_type;
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#ifdef __FreeBSD__
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dof_hdr_t hdr;
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size_t sz;
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uint64_t dofmax;
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void *dof;
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#endif
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const char *mname;
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const char *syms[] = { "___SUNW_dof", "__SUNW_dof" };
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int i, fd = -1;
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@ -595,17 +606,61 @@ dt_pid_usdt_mapping(void *data, const prmap_t *pmp, const char *oname)
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continue;
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}
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#ifdef __FreeBSD__
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dh.dofhp_addr = (e_type == ET_EXEC) ? 0 : pmp->pr_vaddr;
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if (Pread(P, &hdr, sizeof (hdr), sym.st_value) !=
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sizeof (hdr)) {
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dt_dprintf("read of DOF header failed\n");
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continue;
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}
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sz = sizeof(dofmax);
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if (sysctlbyname("kern.dtrace.dof_maxsize", &dofmax, &sz,
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NULL, 0) != 0) {
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dt_dprintf("failed to read dof_maxsize: %s\n",
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strerror(errno));
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continue;
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}
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if (dofmax < hdr.dofh_loadsz) {
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dt_dprintf("DOF load size exceeds maximum\n");
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continue;
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}
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if ((dof = malloc(hdr.dofh_loadsz)) == NULL)
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return (-1);
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if (Pread(P, dof, hdr.dofh_loadsz, sym.st_value) !=
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hdr.dofh_loadsz) {
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free(dof);
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dt_dprintf("read of DOF section failed\n");
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continue;
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}
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dh.dofhp_dof = (uintptr_t)dof;
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dh.dofhp_pid = proc_getpid(P);
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dt_pid_objname(dh.dofhp_mod, sizeof (dh.dofhp_mod),
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sip.prs_lmid, mname);
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if (fd == -1 &&
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(fd = open("/dev/dtrace/helper", O_RDWR, 0)) < 0) {
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dt_dprintf("open of helper device failed: %s\n",
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strerror(errno));
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free(dof);
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return (-1); /* errno is set for us */
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}
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if (ioctl(fd, DTRACEHIOC_ADDDOF, &dh, sizeof (dh)) < 0)
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dt_dprintf("DOF was rejected for %s\n", dh.dofhp_mod);
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free(dof);
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#else
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dh.dofhp_dof = sym.st_value;
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dh.dofhp_addr = (e_type == ET_EXEC) ? 0 : pmp->pr_vaddr;
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dt_pid_objname(dh.dofhp_mod, sizeof (dh.dofhp_mod),
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#ifdef illumos
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sip.prs_lmid, mname);
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#else
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0, mname);
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#endif
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#ifdef illumos
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if (fd == -1 &&
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(fd = pr_open(P, "/dev/dtrace/helper", O_RDWR, 0)) < 0) {
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dt_dprintf("pr_open of helper device failed: %s\n",
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@ -618,8 +673,10 @@ dt_pid_usdt_mapping(void *data, const prmap_t *pmp, const char *oname)
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#endif
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}
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#ifdef illumos
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if (fd != -1)
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#ifdef __FreeBSD__
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(void) close(fd);
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#else
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(void) pr_close(P, fd);
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#endif
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@ -634,7 +691,6 @@ dt_pid_create_usdt_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
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int ret = 0;
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assert(DT_MUTEX_HELD(&dpr->dpr_lock));
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#ifdef illumos
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(void) Pupdate_maps(P);
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if (Pobject_iter(P, dt_pid_usdt_mapping, P) != 0) {
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ret = -1;
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@ -646,9 +702,6 @@ dt_pid_create_usdt_probes(dtrace_probedesc_t *pdp, dtrace_hdl_t *dtp,
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(int)proc_getpid(P), strerror(errno));
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#endif
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}
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#else
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ret = 0;
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#endif
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/*
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* Put the module name in its canonical form.
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@ -59,6 +59,6 @@
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#define Pstate proc_state
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#define Psymbol_iter_by_addr proc_iter_symbyaddr
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#define Punsetflags proc_clearflags
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#define Pupdate_maps(p) do { } while (0)
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#define Pupdate_maps proc_rdagent
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#define Pupdate_syms proc_updatesyms
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#define Pxecbkpt proc_bkptexec
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@ -15374,13 +15374,15 @@ dtrace_helper_action_destroy(dtrace_helper_action_t *helper,
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}
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static int
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dtrace_helper_destroygen(int gen)
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dtrace_helper_destroygen(dtrace_helpers_t *help, int gen)
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{
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proc_t *p = curproc;
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dtrace_helpers_t *help = p->p_dtrace_helpers;
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dtrace_vstate_t *vstate;
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int i;
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if (help == NULL)
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help = p->p_dtrace_helpers;
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ASSERT(MUTEX_HELD(&dtrace_lock));
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if (help == NULL || gen > help->dthps_generation)
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@ -15478,9 +15480,9 @@ dtrace_helper_validate(dtrace_helper_action_t *helper)
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}
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static int
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dtrace_helper_action_add(int which, dtrace_ecbdesc_t *ep)
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dtrace_helper_action_add(int which, dtrace_ecbdesc_t *ep,
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dtrace_helpers_t *help)
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{
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dtrace_helpers_t *help;
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dtrace_helper_action_t *helper, *last;
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dtrace_actdesc_t *act;
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dtrace_vstate_t *vstate;
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@ -15490,7 +15492,6 @@ dtrace_helper_action_add(int which, dtrace_ecbdesc_t *ep)
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if (which < 0 || which >= DTRACE_NHELPER_ACTIONS)
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return (EINVAL);
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help = curproc->p_dtrace_helpers;
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last = help->dthps_actions[which];
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vstate = &help->dthps_vstate;
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@ -15614,15 +15615,12 @@ dtrace_helper_provider_register(proc_t *p, dtrace_helpers_t *help,
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}
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static int
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dtrace_helper_provider_add(dof_helper_t *dofhp, int gen)
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dtrace_helper_provider_add(dof_helper_t *dofhp, dtrace_helpers_t *help, int gen)
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{
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dtrace_helpers_t *help;
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dtrace_helper_provider_t *hprov, **tmp_provs;
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uint_t tmp_maxprovs, i;
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ASSERT(MUTEX_HELD(&dtrace_lock));
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help = curproc->p_dtrace_helpers;
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ASSERT(help != NULL);
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/*
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@ -15914,13 +15912,28 @@ dtrace_helper_slurp(dof_hdr_t *dof, dof_helper_t *dhp)
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dtrace_helpers_t *help;
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dtrace_vstate_t *vstate;
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dtrace_enabling_t *enab = NULL;
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proc_t *p = curproc;
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int i, gen, rv, nhelpers = 0, nprovs = 0, destroy = 1;
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uintptr_t daddr = (uintptr_t)dof;
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ASSERT(MUTEX_HELD(&dtrace_lock));
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if ((help = curproc->p_dtrace_helpers) == NULL)
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help = dtrace_helpers_create(curproc);
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#ifdef __FreeBSD__
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if (dhp->dofhp_pid != p->p_pid) {
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if ((p = pfind(dhp->dofhp_pid)) == NULL)
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return (-1);
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if (!P_SHOULDSTOP(p) ||
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(p->p_flag & P_TRACED) == 0 ||
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p->p_pptr->p_pid != curproc->p_pid) {
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PROC_UNLOCK(p);
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return (-1);
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}
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PROC_UNLOCK(p);
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}
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#endif
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if ((help = p->p_dtrace_helpers) == NULL)
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help = dtrace_helpers_create(p);
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vstate = &help->dthps_vstate;
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@ -15968,12 +15981,13 @@ dtrace_helper_slurp(dof_hdr_t *dof, dof_helper_t *dhp)
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continue;
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if ((rv = dtrace_helper_action_add(DTRACE_HELPER_ACTION_USTACK,
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ep)) != 0) {
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ep, help)) != 0) {
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/*
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* Adding this helper action failed -- we are now going
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* to rip out the entire generation and return failure.
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*/
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(void) dtrace_helper_destroygen(help->dthps_generation);
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(void) dtrace_helper_destroygen(help,
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help->dthps_generation);
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dtrace_enabling_destroy(enab);
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dtrace_dof_destroy(dof);
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return (-1);
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@ -15990,9 +16004,9 @@ dtrace_helper_slurp(dof_hdr_t *dof, dof_helper_t *dhp)
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if (dhp != NULL && nprovs > 0) {
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dhp->dofhp_dof = (uint64_t)(uintptr_t)dof;
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if (dtrace_helper_provider_add(dhp, gen) == 0) {
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if (dtrace_helper_provider_add(dhp, help, gen) == 0) {
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mutex_exit(&dtrace_lock);
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dtrace_helper_provider_register(curproc, help, dhp);
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dtrace_helper_provider_register(p, help, dhp);
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mutex_enter(&dtrace_lock);
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destroy = 0;
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@ -16956,7 +16970,7 @@ dtrace_ioctl_helper(int cmd, intptr_t arg, int *rv)
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case DTRACEHIOC_REMOVE: {
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mutex_enter(&dtrace_lock);
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rval = dtrace_helper_destroygen(arg);
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rval = dtrace_helper_destroygen(NULL, arg);
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mutex_exit(&dtrace_lock);
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return (rval);
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@ -1423,8 +1423,9 @@ typedef struct dof_helper {
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char dofhp_mod[DTRACE_MODNAMELEN]; /* executable or library name */
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uint64_t dofhp_addr; /* base address of object */
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uint64_t dofhp_dof; /* address of helper DOF */
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#ifndef illumos
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int gen;
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#ifdef __FreeBSD__
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pid_t dofhp_pid; /* target process ID */
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int dofhp_gen;
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#endif
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} dof_helper_t;
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@ -32,9 +32,9 @@ static int
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dtrace_ioctl_helper(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
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struct thread *td)
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{
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int rval;
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dof_helper_t *dhp = NULL;
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dof_hdr_t *dof = NULL;
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int rval;
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switch (cmd) {
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case DTRACEHIOC_ADDDOF:
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@ -51,7 +51,7 @@ dtrace_ioctl_helper(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
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mutex_enter(&dtrace_lock);
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if ((rval = dtrace_helper_slurp((dof_hdr_t *)dof, dhp)) != -1) {
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if (dhp) {
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dhp->gen = rval;
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dhp->dofhp_gen = rval;
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copyout(dhp, addr, sizeof(*dhp));
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}
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rval = 0;
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@ -59,10 +59,11 @@ dtrace_ioctl_helper(struct cdev *dev, u_long cmd, caddr_t addr, int flags,
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rval = EINVAL;
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}
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mutex_exit(&dtrace_lock);
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return (rval);
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case DTRACEHIOC_REMOVE:
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mutex_enter(&dtrace_lock);
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rval = dtrace_helper_destroygen((int)*addr);
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rval = dtrace_helper_destroygen(NULL, (int)*addr);
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mutex_exit(&dtrace_lock);
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return (rval);
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