Author: trociny
Date: Tue Apr 16 19:19:14 2013
New Revision: 249558
URL: http://svnweb.freebsd.org/changeset/base/249558

Log:
  Add a new set of notes to a process core dump to store procstat data.
  
  The notes format is a header of sizeof(int), which stores the size of
  the corresponding data structure to provide some versioning, and data
  in the format as it is returned by a related sysctl call.
  
  The userland tools (procstat(1)) will be taught to extract this data,
  providing additional info for postmortem analysis.
  
  PR:           kern/173723
  Suggested by: jhb
  Discussed with:       jhb, kib
  Reviewed by:  jhb (initial version), kib
  MFC after:    1 month

Modified:
  head/sys/kern/imgact_elf.c
  head/sys/sys/elf_common.h

Modified: head/sys/kern/imgact_elf.c
==============================================================================
--- head/sys/kern/imgact_elf.c  Tue Apr 16 17:50:20 2013        (r249557)
+++ head/sys/kern/imgact_elf.c  Tue Apr 16 19:19:14 2013        (r249558)
@@ -66,6 +66,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/vnode.h>
 #include <sys/syslog.h>
 #include <sys/eventhandler.h>
+#include <sys/user.h>
 
 #include <net/zlib.h>
 
@@ -1062,12 +1063,22 @@ static void __elfN(puthdr)(struct thread
 static void __elfN(putnote)(struct note_info *, struct sbuf *);
 static size_t register_note(struct note_info_list *, int, outfunc_t, void *);
 static int sbuf_drain_core_output(void *, const char *, int);
+static int sbuf_drain_count(void *arg, const char *data, int len);
 
 static void __elfN(note_fpregset)(void *, struct sbuf *, size_t *);
 static void __elfN(note_prpsinfo)(void *, struct sbuf *, size_t *);
 static void __elfN(note_prstatus)(void *, struct sbuf *, size_t *);
 static void __elfN(note_threadmd)(void *, struct sbuf *, size_t *);
 static void __elfN(note_thrmisc)(void *, struct sbuf *, size_t *);
+static void __elfN(note_procstat_auxv)(void *, struct sbuf *, size_t *);
+static void __elfN(note_procstat_proc)(void *, struct sbuf *, size_t *);
+static void __elfN(note_procstat_psstrings)(void *, struct sbuf *, size_t *);
+static void note_procstat_files(void *, struct sbuf *, size_t *);
+static void note_procstat_groups(void *, struct sbuf *, size_t *);
+static void note_procstat_osrel(void *, struct sbuf *, size_t *);
+static void note_procstat_rlimit(void *, struct sbuf *, size_t *);
+static void note_procstat_umask(void *, struct sbuf *, size_t *);
+static void note_procstat_vmmap(void *, struct sbuf *, size_t *);
 
 #ifdef COMPRESS_USER_CORES
 extern int compress_user_cores;
@@ -1113,9 +1124,21 @@ static int
 sbuf_drain_core_output(void *arg, const char *data, int len)
 {
        struct sbuf_drain_core_params *p;
-       int error;
+       int error, locked;
 
        p = (struct sbuf_drain_core_params *)arg;
+
+       /*
+        * Some kern_proc out routines that print to this sbuf may
+        * call us with the process lock held. Draining with the
+        * non-sleepable lock held is unsafe. The lock is needed for
+        * those routines when dumping a live process. In our case we
+        * can safely release the lock before draining and acquire
+        * again after.
+        */
+       locked = PROC_LOCKED(p->td->td_proc);
+       if (locked)
+               PROC_UNLOCK(p->td->td_proc);
 #ifdef COMPRESS_USER_CORES
        if (p->gzfile != Z_NULL)
                error = compress_core(p->gzfile, NULL, __DECONST(char *, data),
@@ -1126,12 +1149,27 @@ sbuf_drain_core_output(void *arg, const 
                    __DECONST(void *, data), len, p->offset, UIO_SYSSPACE,
                    IO_UNIT | IO_DIRECT, p->active_cred, p->file_cred, NULL,
                    p->td);
+       if (locked)
+               PROC_LOCK(p->td->td_proc);
        if (error != 0)
                return (-error);
        p->offset += len;
        return (len);
 }
 
+/*
+ * Drain into a counter.
+ */
+static int
+sbuf_drain_count(void *arg, const char *data __unused, int len)
+{
+       size_t *sizep;
+
+       sizep = (size_t *)arg;
+       *sizep += len;
+       return (len);
+}
+
 int
 __elfN(coredump)(struct thread *td, struct vnode *vp, off_t limit, int flags)
 {
@@ -1436,6 +1474,25 @@ __elfN(prepare_notes)(struct thread *td,
                        thr = TAILQ_NEXT(thr, td_plist);
        }
 
+       size += register_note(list, NT_PROCSTAT_PROC,
+           __elfN(note_procstat_proc), p);
+       size += register_note(list, NT_PROCSTAT_FILES,
+           note_procstat_files, p);
+       size += register_note(list, NT_PROCSTAT_VMMAP,
+           note_procstat_vmmap, p);
+       size += register_note(list, NT_PROCSTAT_GROUPS,
+           note_procstat_groups, p);
+       size += register_note(list, NT_PROCSTAT_UMASK,
+           note_procstat_umask, p);
+       size += register_note(list, NT_PROCSTAT_RLIMIT,
+           note_procstat_rlimit, p);
+       size += register_note(list, NT_PROCSTAT_OSREL,
+           note_procstat_osrel, p);
+       size += register_note(list, NT_PROCSTAT_PSSTRINGS,
+           __elfN(note_procstat_psstrings), p);
+       size += register_note(list, NT_PROCSTAT_AUXV,
+           __elfN(note_procstat_auxv), p);
+
        *sizep = size;
 }
 
@@ -1562,6 +1619,9 @@ typedef struct fpreg32 elf_prfpregset_t;
 typedef struct fpreg32 elf_fpregset_t;
 typedef struct reg32 elf_gregset_t;
 typedef struct thrmisc32 elf_thrmisc_t;
+#define ELF_KERN_PROC_MASK     KERN_PROC_MASK32
+typedef struct kinfo_proc32 elf_kinfo_proc_t;
+typedef uint32_t elf_ps_strings_t;
 #else
 typedef prstatus_t elf_prstatus_t;
 typedef prpsinfo_t elf_prpsinfo_t;
@@ -1569,6 +1629,9 @@ typedef prfpregset_t elf_prfpregset_t;
 typedef prfpregset_t elf_fpregset_t;
 typedef gregset_t elf_gregset_t;
 typedef thrmisc_t elf_thrmisc_t;
+#define ELF_KERN_PROC_MASK     0
+typedef struct kinfo_proc elf_kinfo_proc_t;
+typedef vm_offset_t elf_ps_strings_t;
 #endif
 
 static void
@@ -1686,6 +1749,221 @@ __elfN(note_threadmd)(void *arg, struct 
        *sizep = size;
 }
 
+#ifdef KINFO_PROC_SIZE
+CTASSERT(sizeof(struct kinfo_proc) == KINFO_PROC_SIZE);
+#endif
+
+static void
+__elfN(note_procstat_proc)(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       size = sizeof(structsize) + p->p_numthreads *
+           sizeof(elf_kinfo_proc_t);
+
+       if (sb != NULL) {
+               KASSERT(*sizep == size, ("invalid size"));
+               structsize = sizeof(elf_kinfo_proc_t);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PROC_LOCK(p);
+               kern_proc_out(p, sb, ELF_KERN_PROC_MASK);
+       }
+       *sizep = size;
+}
+
+#ifdef KINFO_FILE_SIZE
+CTASSERT(sizeof(struct kinfo_file) == KINFO_FILE_SIZE);
+#endif
+
+static void
+note_procstat_files(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       if (sb == NULL) {
+               size = 0;
+               sb = sbuf_new(NULL, NULL, 128, SBUF_FIXEDLEN);
+               sbuf_set_drain(sb, sbuf_drain_count, &size);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PROC_LOCK(p);
+               kern_proc_filedesc_out(p, sb, -1);
+               sbuf_finish(sb);
+               sbuf_delete(sb);
+               *sizep = size;
+       } else {
+               structsize = sizeof(struct kinfo_file);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PROC_LOCK(p);
+               kern_proc_filedesc_out(p, sb, -1);
+       }
+}
+
+#ifdef KINFO_VMENTRY_SIZE
+CTASSERT(sizeof(struct kinfo_vmentry) == KINFO_VMENTRY_SIZE);
+#endif
+
+static void
+note_procstat_vmmap(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       if (sb == NULL) {
+               size = 0;
+               sb = sbuf_new(NULL, NULL, 128, SBUF_FIXEDLEN);
+               sbuf_set_drain(sb, sbuf_drain_count, &size);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PROC_LOCK(p);
+               kern_proc_vmmap_out(p, sb);
+               sbuf_finish(sb);
+               sbuf_delete(sb);
+               *sizep = size;
+       } else {
+               structsize = sizeof(struct kinfo_vmentry);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PROC_LOCK(p);
+               kern_proc_vmmap_out(p, sb);
+       }
+}
+
+static void
+note_procstat_groups(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       size = sizeof(structsize) + p->p_ucred->cr_ngroups * sizeof(gid_t);
+       if (sb != NULL) {
+               KASSERT(*sizep == size, ("invalid size"));
+               structsize = sizeof(gid_t);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               sbuf_bcat(sb, p->p_ucred->cr_groups, p->p_ucred->cr_ngroups *
+                   sizeof(gid_t));
+       }
+       *sizep = size;
+}
+
+static void
+note_procstat_umask(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       size = sizeof(structsize) + sizeof(p->p_fd->fd_cmask);
+       if (sb != NULL) {
+               KASSERT(*sizep == size, ("invalid size"));
+               structsize = sizeof(p->p_fd->fd_cmask);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               sbuf_bcat(sb, &p->p_fd->fd_cmask, sizeof(p->p_fd->fd_cmask));
+       }
+       *sizep = size;
+}
+
+static void
+note_procstat_rlimit(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       struct rlimit rlim[RLIM_NLIMITS];
+       size_t size;
+       int structsize, i;
+
+       p = (struct proc *)arg;
+       size = sizeof(structsize) + sizeof(rlim);
+       if (sb != NULL) {
+               KASSERT(*sizep == size, ("invalid size"));
+               structsize = sizeof(rlim);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PROC_LOCK(p);
+               for (i = 0; i < RLIM_NLIMITS; i++)
+                       lim_rlimit(p, i, &rlim[i]);
+               PROC_UNLOCK(p);
+               sbuf_bcat(sb, rlim, sizeof(rlim));
+       }
+       *sizep = size;
+}
+
+static void
+note_procstat_osrel(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       size = sizeof(structsize) + sizeof(p->p_osrel);
+       if (sb != NULL) {
+               KASSERT(*sizep == size, ("invalid size"));
+               structsize = sizeof(p->p_osrel);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               sbuf_bcat(sb, &p->p_osrel, sizeof(p->p_osrel));
+       }
+       *sizep = size;
+}
+
+static void
+__elfN(note_procstat_psstrings)(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       elf_ps_strings_t ps_strings;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       size = sizeof(structsize) + sizeof(ps_strings);
+       if (sb != NULL) {
+               KASSERT(*sizep == size, ("invalid size"));
+               structsize = sizeof(ps_strings);
+#if defined(COMPAT_FREEBSD32) && __ELF_WORD_SIZE == 32
+               ps_strings = PTROUT(p->p_sysent->sv_psstrings);
+#else
+               ps_strings = p->p_sysent->sv_psstrings;
+#endif
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               sbuf_bcat(sb, &ps_strings, sizeof(ps_strings));
+       }
+       *sizep = size;
+}
+
+static void
+__elfN(note_procstat_auxv)(void *arg, struct sbuf *sb, size_t *sizep)
+{
+       struct proc *p;
+       size_t size;
+       int structsize;
+
+       p = (struct proc *)arg;
+       if (sb == NULL) {
+               size = 0;
+               sb = sbuf_new(NULL, NULL, 128, SBUF_FIXEDLEN);
+               sbuf_set_drain(sb, sbuf_drain_count, &size);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PHOLD(p);
+               proc_getauxv(curthread, p, sb);
+               PRELE(p);
+               sbuf_finish(sb);
+               sbuf_delete(sb);
+               *sizep = size;
+       } else {
+               structsize = sizeof(Elf_Auxinfo);
+               sbuf_bcat(sb, &structsize, sizeof(structsize));
+               PHOLD(p);
+               proc_getauxv(curthread, p, sb);
+               PRELE(p);
+       }
+}
+
 static boolean_t
 __elfN(parse_notes)(struct image_params *imgp, Elf_Brandnote *checknote,
     int32_t *osrel, const Elf_Phdr *pnote)

Modified: head/sys/sys/elf_common.h
==============================================================================
--- head/sys/sys/elf_common.h   Tue Apr 16 17:50:20 2013        (r249557)
+++ head/sys/sys/elf_common.h   Tue Apr 16 19:19:14 2013        (r249558)
@@ -487,6 +487,15 @@ typedef struct {
 #define        NT_FPREGSET     2       /* Floating point registers. */
 #define        NT_PRPSINFO     3       /* Process state info. */
 #define        NT_THRMISC      7       /* Thread miscellaneous info. */
+#define        NT_PROCSTAT_PROC        8       /* Procstat proc data. */
+#define        NT_PROCSTAT_FILES       9       /* Procstat files data. */
+#define        NT_PROCSTAT_VMMAP       10      /* Procstat vmmap data. */
+#define        NT_PROCSTAT_GROUPS      11      /* Procstat groups data. */
+#define        NT_PROCSTAT_UMASK       12      /* Procstat umask data. */
+#define        NT_PROCSTAT_RLIMIT      13      /* Procstat rlimit data. */
+#define        NT_PROCSTAT_OSREL       14      /* Procstat osreldate data. */
+#define        NT_PROCSTAT_PSSTRINGS   15      /* Procstat ps_strings data. */
+#define        NT_PROCSTAT_AUXV        16      /* Procstat auxv data. */
 
 /* Symbol Binding - ELFNN_ST_BIND - st_info */
 #define        STB_LOCAL       0       /* Local symbol */
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