gcore command to coredump a process

commands/Makefile

@@ -12,7 +12,7 @@ SUBDIR=	aal add_route arp ash at autil awk \
 	dhrystone diff dirname  dis386 dis88 diskctl du dumpcore \
 	ed eject elle elvis env expand factor file \
 	find finger fingerd fix fold format fortune fsck.mfs \
-	ftp101 gcov-pull getty grep head hexdump host \
+	ftp101 gcore gcov-pull getty grep head hexdump host \
 	hostaddr id ifconfig ifdef install \
 	intr ipcrm ipcs irdpd isoread join kill last leave \
 	less lex loadkeys loadramdisk logger login look lp \

commands/gcore/Makefile

@@ -0,0 +1,4 @@
+PROG=  gcore
+MAN=
+
+.include <bsd.prog.mk>

commands/gcore/gcore.c

@@ -0,0 +1,66 @@
+/* gcore - create core file of running process */
+
+#include <fcntl.h>
+#include <unistd.h>	
+#include <minix/config.h>
+#include <minix/type.h>
+#include <minix/ipc.h>
+#include <minix/const.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <timers.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+int main(int argc, char *argv[])
+{
+  pid_t pid;
+  int r, status;
+
+  if(argc != 2) {
+	printf("usage: %s <pid>\n", argv[0]);
+	return 1;
+  }
+
+  pid = atoi(argv[1]);
+
+  if (ptrace(T_ATTACH, pid, 0, 0) != 0) {
+	perror("ptrace(T_ATTACH)");
+	return 1;
+  }
+
+  if (waitpid(pid, &status, 0) != pid) {
+	perror("waitpid");
+	return 1;
+  }
+
+  while (WIFSTOPPED(status) && WSTOPSIG(status) != SIGSTOP) {
+	/* whatever happens here is fine */
+	ptrace(T_RESUME, pid, 0, WSTOPSIG(status));
+
+	if (waitpid(pid, &status, 0) != pid) {
+		perror("waitpid");
+		return 1;
+	}
+  }
+
+  if (!WIFSTOPPED(status)) {
+	fprintf(stderr, "process died while attaching\n");
+	return 1;
+  }
+
+  if (ptrace(T_DUMPCORE, pid, 0, 0)) {
+	fprintf(stderr, "warning, dumpcore failed (%s)\n",
+	strerror(errno));
+  }
+
+  if (ptrace(T_DETACH, pid, 0, 0)) {
+	fprintf(stderr, "warning, detaching failed (%s)\n",
+	strerror(errno));
+  }
+
+  return r;
+}

common/include/minix/com.h

@@ -794,6 +794,7 @@
 
 /* Additional parameters for PM_DUMPCORE */
 #  define PM_TERM_SIG		m1_i2	/* process's termination signal */
+#  define PM_TRACED_PROC	m1_i3	/* required for T_DUMPCORE */
 
 /* Parameters for the EXEC_NEWMEM call */
 #define EXC_NM_PROC	m1_i1		/* process that needs new map */

include/sys/ptrace.h

@@ -23,6 +23,7 @@
 #define T_SETOPT	13	/* set trace options */
 #define T_GETRANGE	14	/* get range of values */
 #define T_SETRANGE	15	/* set range of values */
+#define T_DUMPCORE      16      /* dumps the core for the process with the given pid */
 
 #define T_READB_INS	100	/* Read a byte from the text segment of an
 				 * untraced process (only for root)

nbsd_include/sys/ptrace.h

@@ -23,6 +23,7 @@
 #define T_SETOPT	13	/* set trace options */
 #define T_GETRANGE	14	/* get range of values */
 #define T_SETRANGE	15	/* set range of values */
+#define T_DUMPCORE      16      /* dumps the core for the process with the given pid */
 
 #define T_READB_INS	100	/* Read a byte from the text segment of an
 				 * untraced process (only for root)

servers/pm/forkexit.c

@@ -317,6 +317,7 @@ int dump_core;			/* flag indicating whether to dump core */
   /* Tell VFS about the exiting process. */
   m.m_type = dump_core ? PM_DUMPCORE : PM_EXIT;
   m.PM_PROC = rmp->mp_endpoint;
+  m.PM_TRACED_PROC = rmp->mp_endpoint;
 
   if (dump_core) {
     m.PM_TERM_SIG = rmp->mp_sigstatus;

servers/pm/main.c

@@ -477,7 +477,15 @@ PRIVATE void handle_vfs_reply()
 	if (m_in.PM_STATUS == OK)
 		rmp->mp_sigstatus |= DUMPED;
 
+	if (m_in.PM_PROC == m_in.PM_TRACED_PROC)
+		/* The reply is to a core dump request
+		 * for a killed process */
 		exit_restart(rmp, TRUE /*dump_core*/);
+	else
+		/* The reply is to a core dump request
+		 * for a traced process (T_DUMPCORE) */
+		/* Wake up the original caller */
+		setreply(rmp-mproc, rmp->mp_procgrp);
 
 	break;
 

servers/pm/trace.c

@@ -42,6 +42,7 @@ PUBLIC int do_trace()
   register struct mproc *child;
   struct ptrace_range pr;
   int i, r, seg, req;
+  message m;
 
   req = m_in.request;
 
@@ -90,6 +91,27 @@ PUBLIC int do_trace()
 	mp->mp_reply.reply_trace = 0;
 	return(OK);
 
+  case T_DUMPCORE:
+	if ((child = find_proc(m_in.pid)) == NULL) return(ESRCH);
+
+	/* Allow dumpcore only if traced! */
+	if (child->mp_tracer != who_p) return(EPERM);
+
+	/* Tell VFS to dump the core. */
+	m.m_type = PM_DUMPCORE;
+	m.PM_PROC = mp->mp_endpoint;
+	m.PM_TRACED_PROC = child->mp_endpoint;
+	/* Note that m.PM_PROC != m.PM_TRACED_PROC
+	 * (we use this to differentiate between a VFS core dump reply for a
+	 * an exiting process and the one for a traced process) */
+
+	m.PM_TERM_SIG = child->mp_sigstatus;
+	m.PM_PATH = child->mp_name;
+
+	tell_vfs(mp, &m);
+
+	return(SUSPEND); /* Suspend the process until we receive reply from VFS */
+
   case T_STOP:		/* stop the process */
 	/* This call is not exposed to user programs, because its effect can be
 	 * achieved better by sending the traced process a signal with kill(2).

servers/vfs/main.c

@@ -558,6 +558,7 @@ PRIVATE void service_pm()
 	/* Reply status to PM */
 	m_out.m_type = PM_CORE_REPLY;
 	m_out.PM_PROC = m_in.PM_PROC;
+	m_out.PM_TRACED_PROC = m_in.PM_TRACED_PROC;
 	m_out.PM_STATUS = r;
 	
 	break;

servers/vfs/misc.c

@@ -581,8 +581,9 @@ int csig;
 char *exe_name;
 {
   int proc_s, r, old_who_e;
+  int traced_proc_e = m_in.PM_TRACED_PROC;
 
-  okendpt(proc_e, &proc_s);
+  okendpt(traced_proc_e, &proc_s);
   fp = &fproc[proc_s];
 
   /* Open the core file */
@@ -603,10 +604,12 @@ char *exe_name;
   close_fd(fp, r);
 
   /* Terminate the process */
+  if (traced_proc_e == proc_e)
 	free_proc(&fproc[proc_s], FP_EXITING);
 
   /* Restore the important variables that have been overwritten */
   m_in.PM_PROC = proc_e;
+  m_in.PM_TRACED_PROC = traced_proc_e;
   who_e = old_who_e;
 
   return OK;