MFC r316286:

  Add support for capturing 'struct ptrace_lwpinfo' for signals resulting in a
  process dumping core in the corefile.

  Direct stable changed: Padding added to struct thread and td_si added to end
  with explicit bzeroing when forking/initializing a thread to preserve KBI.

5 files changed, 149 insertions, 46 deletions

diff --git a/lib/libprocstat/Symbol.map b/lib/libprocstat/Symbol.map
index 1495bfc..75a8916 100644
--- a/lib/libprocstat/Symbol.map
+++ b/lib/libprocstat/Symbol.map
@@ -36,3 +36,8 @@ FBSD_1.3 {
 	procstat_getvmmap;
 	procstat_open_core;
 };
+
+FBSD_1.5 {
+	procstat_freeptlwpinfo;
+	procstat_getptlwpinfo;
+};
diff --git a/lib/libprocstat/core.c b/lib/libprocstat/core.c
index 70ab86d..9baa0cd 100644
--- a/lib/libprocstat/core.c
+++ b/lib/libprocstat/core.c
@@ -1,5 +1,6 @@
 /*-
  * Copyright (c) 2013 Mikolaj Golub <trociny@FreeBSD.org>
+ * Copyright (c) 2017 Dell EMC
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -30,6 +31,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/param.h>
 #include <sys/elf.h>
 #include <sys/exec.h>
+#include <sys/ptrace.h>
 #include <sys/user.h>
 
 #include <assert.h>
@@ -56,6 +58,24 @@ struct procstat_core
 	GElf_Phdr	pc_phdr;
 };
 
+static struct psc_type_info {
+	unsigned int	n_type;
+	int		structsize;
+} psc_type_info[PSC_TYPE_MAX] = {
+	{ .n_type  = NT_PROCSTAT_PROC, .structsize = sizeof(struct kinfo_proc) },
+	{ .n_type = NT_PROCSTAT_FILES, .structsize = sizeof(struct kinfo_file) },
+	{ .n_type = NT_PROCSTAT_VMMAP, .structsize = sizeof(struct kinfo_vmentry) },
+	{ .n_type = NT_PROCSTAT_GROUPS, .structsize = sizeof(gid_t) },
+	{ .n_type = NT_PROCSTAT_UMASK, .structsize = sizeof(u_short) },
+	{ .n_type = NT_PROCSTAT_RLIMIT, .structsize = sizeof(struct rlimit) * RLIM_NLIMITS },
+	{ .n_type = NT_PROCSTAT_OSREL, .structsize = sizeof(int) },
+	{ .n_type = NT_PROCSTAT_PSSTRINGS, .structsize = sizeof(vm_offset_t) },
+	{ .n_type = NT_PROCSTAT_PSSTRINGS, .structsize = sizeof(vm_offset_t) },
+	{ .n_type = NT_PROCSTAT_PSSTRINGS, .structsize = sizeof(vm_offset_t) },
+	{ .n_type = NT_PROCSTAT_AUXV, .structsize = sizeof(Elf_Auxinfo) },
+	{ .n_type = NT_PTLWPINFO, .structsize = sizeof(struct ptrace_lwpinfo) },
+};
+
 static bool	core_offset(struct procstat_core *core, off_t offset);
 static bool	core_read(struct procstat_core *core, void *buf, size_t len);
 static ssize_t	core_read_mem(struct procstat_core *core, void *buf,
@@ -154,59 +174,20 @@ procstat_core_get(struct procstat_core *core, enum psc_type type, void *buf,
 	off_t offset, eoffset;
 	vm_offset_t psstrings;
 	void *freebuf;
-	size_t len;
-	u_int32_t n_type;
-	int cstructsize, structsize;
+	size_t len, curlen;
+	int cstructsize;
 	char nbuf[8];
 
 	assert(core->pc_magic == PROCSTAT_CORE_MAGIC);
 
-	switch(type) {
-	case PSC_TYPE_PROC:
-		n_type = NT_PROCSTAT_PROC;
-		structsize = sizeof(struct kinfo_proc);
-		break;
-	case PSC_TYPE_FILES:
-		n_type = NT_PROCSTAT_FILES;
-		structsize = sizeof(struct kinfo_file);
-		break;
-	case PSC_TYPE_VMMAP:
-		n_type = NT_PROCSTAT_VMMAP;
-		structsize = sizeof(struct kinfo_vmentry);
-		break;
-	case PSC_TYPE_GROUPS:
-		n_type = NT_PROCSTAT_GROUPS;
-		structsize = sizeof(gid_t);
-		break;
-	case PSC_TYPE_UMASK:
-		n_type = NT_PROCSTAT_UMASK;
-		structsize = sizeof(u_short);
-		break;
-	case PSC_TYPE_RLIMIT:
-		n_type = NT_PROCSTAT_RLIMIT;
-		structsize = sizeof(struct rlimit) * RLIM_NLIMITS;
-		break;
-	case PSC_TYPE_OSREL:
-		n_type = NT_PROCSTAT_OSREL;
-		structsize = sizeof(int);
-		break;
-	case PSC_TYPE_PSSTRINGS:
-	case PSC_TYPE_ARGV:
-	case PSC_TYPE_ENVV:
-		n_type = NT_PROCSTAT_PSSTRINGS;
-		structsize = sizeof(vm_offset_t);
-		break;
-	case PSC_TYPE_AUXV:
-		n_type = NT_PROCSTAT_AUXV;
-		structsize = sizeof(Elf_Auxinfo);
-		break;
-	default:
+	if (type >= PSC_TYPE_MAX) {
 		warnx("unknown core stat type: %d", type);
 		return (NULL);
 	}
 
 	offset = core->pc_phdr.p_offset;
 	eoffset = offset + core->pc_phdr.p_filesz;
+	curlen = 0;
 
 	while (offset < eoffset) {
 		if (!core_offset(core, offset))
@@ -220,7 +201,7 @@ procstat_core_get(struct procstat_core *core, enum psc_type type, void *buf,
 
 		if (nhdr.n_namesz == 0 && nhdr.n_descsz == 0)
 			break;
-		if (nhdr.n_type != n_type)
+		if (nhdr.n_type != psc_type_info[type].n_type)
 			continue;
 		if (nhdr.n_namesz != 8)
 			continue;
@@ -234,7 +215,7 @@ procstat_core_get(struct procstat_core *core, enum psc_type type, void *buf,
 		}
 		if (!core_read(core, &cstructsize, sizeof(cstructsize)))
 			return (NULL);
-		if (cstructsize != structsize) {
+		if (cstructsize != psc_type_info[type].structsize) {
 			warnx("version mismatch");
 			return (NULL);
 		}
@@ -251,7 +232,7 @@ procstat_core_get(struct procstat_core *core, enum psc_type type, void *buf,
 				return (NULL);
 			}
 		}
-		if (!core_read(core, buf, len)) {
+		if (!core_read(core, (char *)buf + curlen, len)) {
 			free(freebuf);
 			return (NULL);
 		}
@@ -267,11 +248,20 @@ procstat_core_get(struct procstat_core *core, enum psc_type type, void *buf,
 				buf = NULL;
 			free(freebuf);
 			buf = get_args(core, psstrings, type, buf, &len);
+		} else if (type == PSC_TYPE_PTLWPINFO) {
+			*lenp -= len;
+			curlen += len;
+			continue;
 		}
 		*lenp = len;
 		return (buf);
         }
 
+	if (curlen != 0) {
+		*lenp = curlen;
+		return (buf);
+	}
+
 	return (NULL);
 }
 
@@ -431,3 +421,57 @@ done:
 	free(argv);
 	return (args);
 }
+
+int
+procstat_core_note_count(struct procstat_core *core, enum psc_type type)
+{
+	Elf_Note nhdr;
+	off_t offset, eoffset;
+	int cstructsize;
+	char nbuf[8];
+	int n;
+
+	if (type >= PSC_TYPE_MAX) {
+		warnx("unknown core stat type: %d", type);
+		return (0);
+	}
+
+	offset = core->pc_phdr.p_offset;
+	eoffset = offset + core->pc_phdr.p_filesz;
+
+	for (n = 0; offset < eoffset; n++) {
+		if (!core_offset(core, offset))
+			return (0);
+		if (!core_read(core, &nhdr, sizeof(nhdr)))
+			return (0);
+
+		offset += sizeof(nhdr) +
+		    roundup2(nhdr.n_namesz, sizeof(Elf32_Size)) +
+		    roundup2(nhdr.n_descsz, sizeof(Elf32_Size));
+
+		if (nhdr.n_namesz == 0 && nhdr.n_descsz == 0)
+			break;
+		if (nhdr.n_type != psc_type_info[type].n_type)
+			continue;
+		if (nhdr.n_namesz != 8)
+			continue;
+		if (!core_read(core, nbuf, sizeof(nbuf)))
+			return (0);
+		if (strcmp(nbuf, "FreeBSD") != 0)
+			continue;
+		if (nhdr.n_descsz < sizeof(cstructsize)) {
+			warnx("corrupted core file");
+			return (0);
+		}
+		if (!core_read(core, &cstructsize, sizeof(cstructsize)))
+			return (0);
+		if (cstructsize != psc_type_info[type].structsize) {
+			warnx("version mismatch");
+			return (0);
+		}
+		if (nhdr.n_descsz - sizeof(cstructsize) == 0)
+			return (0);
+	}
+
+	return (n);
+}
diff --git a/lib/libprocstat/core.h b/lib/libprocstat/core.h
index 6639abc..701697b 100644
--- a/lib/libprocstat/core.h
+++ b/lib/libprocstat/core.h
@@ -1,5 +1,6 @@
 /*-
  * Copyright (c) 2013 Mikolaj Golub <trociny@FreeBSD.org>
+ * Copyright (c) 2017 Dell EMC
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -41,6 +42,8 @@ enum psc_type {
 	PSC_TYPE_ARGV,
 	PSC_TYPE_ENVV,
 	PSC_TYPE_AUXV,
+	PSC_TYPE_PTLWPINFO,
+	PSC_TYPE_MAX
 };
 
 struct procstat_core;
@@ -48,6 +51,7 @@ struct procstat_core;
 void procstat_core_close(struct procstat_core *core);
 void *procstat_core_get(struct procstat_core *core, enum psc_type type,
     void * buf, size_t *lenp);
+int procstat_core_note_count(struct procstat_core *core, enum psc_type type);
 struct procstat_core *procstat_core_open(const char *filename);
 
 #endif 	/* !_CORE_H_ */
diff --git a/lib/libprocstat/libprocstat.c b/lib/libprocstat/libprocstat.c
index 9dc9800..9c6877c 100644
--- a/lib/libprocstat/libprocstat.c
+++ b/lib/libprocstat/libprocstat.c
@@ -1,4 +1,5 @@
 /*-
+ * Copyright (c) 2017 Dell EMC
  * Copyright (c) 2009 Stanislav Sedov <stas@FreeBSD.org>
  * Copyright (c) 1988, 1993
  *      The Regents of the University of California.  All rights reserved.
@@ -65,6 +66,7 @@ __FBSDID("$FreeBSD$");
 #define	_KERNEL
 #include <sys/mount.h>
 #include <sys/pipe.h>
+#include <sys/ptrace.h>
 #include <ufs/ufs/quota.h>
 #include <ufs/ufs/inode.h>
 #include <fs/devfs/devfs.h>
@@ -2469,6 +2471,48 @@ procstat_freeauxv(struct procstat *procstat __unused, Elf_Auxinfo *auxv)
 	free(auxv);
 }
 
+static struct ptrace_lwpinfo *
+procstat_getptlwpinfo_core(struct procstat_core *core, unsigned int *cntp)
+{
+	void *buf;
+	struct ptrace_lwpinfo *pl;
+	unsigned int cnt;
+	size_t len;
+
+	cnt = procstat_core_note_count(core, PSC_TYPE_PTLWPINFO);
+	if (cnt == 0)
+		return (NULL);
+
+	len = cnt * sizeof(*pl);
+	buf = calloc(1, len);
+	pl = procstat_core_get(core, PSC_TYPE_PTLWPINFO, buf, &len);
+	if (pl == NULL) {
+		free(buf);
+		return (NULL);
+	}
+	*cntp = len / sizeof(*pl);
+	return (pl);
+}
+
+struct ptrace_lwpinfo *
+procstat_getptlwpinfo(struct procstat *procstat, unsigned int *cntp)
+{
+	switch (procstat->type) {
+	case PROCSTAT_CORE:
+	 	return (procstat_getptlwpinfo_core(procstat->core, cntp));
+	default:
+		warnx("unknown access method: %d", procstat->type);
+		return (NULL);
+	}
+}
+
+void
+procstat_freeptlwpinfo(struct procstat *procstat __unused,
+    struct ptrace_lwpinfo *pl)
+{
+	free(pl);
+}
+
 static struct kinfo_kstack *
 procstat_getkstack_sysctl(pid_t pid, int *cntp)
 {
diff --git a/lib/libprocstat/libprocstat.h b/lib/libprocstat/libprocstat.h
index 7af6ccb..00b6f1c 100644
--- a/lib/libprocstat/libprocstat.h
+++ b/lib/libprocstat/libprocstat.h
@@ -1,5 +1,6 @@
 /*-
  * Copyright (c) 2009 Stanislav Sedov <stas@FreeBSD.org>
+ * Copyright (c) 2017 Dell EMC
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -101,6 +102,7 @@
 struct kinfo_kstack;
 struct kinfo_vmentry;
 struct procstat;
+struct ptrace_lwpinfo;
 struct rlimit;
 struct filestat {
 	int	fs_type;	/* Descriptor type. */
@@ -172,6 +174,8 @@ void	procstat_freekstack(struct procstat *procstat,
 void	procstat_freeprocs(struct procstat *procstat, struct kinfo_proc *p);
 void	procstat_freefiles(struct procstat *procstat,
     struct filestat_list *head);
+void	procstat_freeptlwpinfo(struct procstat *procstat,
+    struct ptrace_lwpinfo *pl);
 void	procstat_freevmmap(struct procstat *procstat,
     struct kinfo_vmentry *vmmap);
 struct filestat_list	*procstat_getfiles(struct procstat *procstat,
@@ -196,6 +200,8 @@ char	**procstat_getargv(struct procstat *procstat, struct kinfo_proc *p,
 Elf_Auxinfo	*procstat_getauxv(struct procstat *procstat,
     struct kinfo_proc *kp, unsigned int *cntp);
 #endif
+struct ptrace_lwpinfo	*procstat_getptlwpinfo(struct procstat *procstat,
+    unsigned int *cntp);
 char	**procstat_getenvv(struct procstat *procstat, struct kinfo_proc *p,
     size_t nchr);
 gid_t	*procstat_getgroups(struct procstat *procstat, struct kinfo_proc *kp,