dumpcore: use ptrace function to trigger a coredump

. dumpcore currently relies on minix segments
	. also ptrace dumpcore fix
This commit is contained in:
Ben Gras 2012-06-15 02:38:00 +02:00
parent 5e38c802d8
commit 85ff5a947e
3 changed files with 19 additions and 170 deletions

View file

@ -20,172 +20,6 @@
#define CLICK_WORDS (CLICK_SIZE / sizeof(unsigned long))
int adjust_stack(pid_t pid, struct mem_map *seg)
{
static unsigned long buf[CLICK_WORDS];
struct ptrace_range pr;
size_t off, top, bottom;
int i;
/* FIXME: kernel/VM strangeness */
seg->mem_vir -= seg->mem_len - 1;
/* Scan the stack, top to bottom, to find the lowest accessible region.
* In practice that will be at 64MB, so we also scan for the lowest non-zero
* region in order to keep the core file size managable.
* Portability note: this code assumes that the stack grows down.
*/
top = seg->mem_vir + seg->mem_len;
pr.pr_space = TS_DATA;
pr.pr_addr = (top - 1) << CLICK_SHIFT;
pr.pr_size = sizeof(buf);
pr.pr_ptr = buf;
for (off = top - 1; off >= seg->mem_vir; off--) {
if (ptrace(T_GETRANGE, pid, (long) &pr, 0)) {
if (errno == EFAULT)
break;
perror("ptrace(T_GETRANGE)");
return 1;
}
for (i = 0; i < CLICK_WORDS; i += sizeof(buf[0]))
if (buf[i] != 0)
bottom = off;
pr.pr_addr -= sizeof(buf);
}
/* Add one extra zero page as margin. */
if (bottom > off && bottom > seg->mem_vir)
bottom--;
seg->mem_len -= bottom - seg->mem_vir;
seg->mem_vir = bottom;
return 0;
}
int write_seg(int fd, pid_t pid, int seg, off_t seg_off, phys_bytes seg_bytes)
{
ssize_t w;
static char buf[CLICK_SIZE];
struct ptrace_range pr;
pr.pr_space = (seg == T) ? TS_INS : TS_DATA;
pr.pr_addr = seg_off;
pr.pr_size = sizeof(buf);
pr.pr_ptr = buf;
for ( ; pr.pr_addr < seg_off + seg_bytes; pr.pr_addr += sizeof(buf))
{
/* Copy a chunk from user space to the block buffer. */
if (ptrace(T_GETRANGE, pid, (long) &pr, 0)) {
/* Create holes for inaccessible areas. */
if (errno == EFAULT) {
lseek(fd, sizeof(buf), SEEK_CUR);
continue;
}
perror("ptrace(T_GETRANGE)");
return 1;
}
if((w=write(fd, buf, sizeof(buf))) != sizeof(buf)) {
if(w < 0) printf("write error: %s\n", strerror(errno));
printf("write_seg: write failed: %d/%d\n", w, sizeof(buf));
return 1;
}
}
return 0;
}
int dumpcore(pid_t pid)
{
int r, seg, fd;
vir_bytes len;
off_t off, seg_off;
long data;
struct mem_map segs[NR_LOCAL_SEGS];
struct proc procentry;
ssize_t w;
char core_name[PATH_MAX];
/* Get the process table entry for this process. */
len = sizeof(struct proc) / sizeof(long);
for (off = 0; off < len; off++)
{
errno = 0;
data = ptrace(T_GETUSER, pid, off * sizeof(long), 0);
if (data == -1 && errno != 0)
{
perror("ptrace(T_GETUSER)");
return 1;
}
((long *) &procentry)[off] = data;
}
memcpy(segs, procentry.p_memmap, sizeof(segs));
/* Correct and reduce the stack segment. */
r = adjust_stack(pid, &segs[S]);
if (r != 0)
goto error;
/* Create a core file with a temporary, unique name. */
sprintf(core_name, "core.%d", pid);
if((fd = open(core_name, O_CREAT|O_EXCL|O_WRONLY, 0600)) < 0) {
fprintf(stderr, "couldn't open %s (%s)\n", core_name,
strerror(errno));
return 1;
}
/* Write out the process's segments. */
if((w=write(fd, segs, sizeof(segs))) != sizeof(segs)) {
if(w < 0) printf("write error: %s\n", strerror(errno));
printf( "segs write failed: %d/%d\n", w, sizeof(segs));
goto error;
}
/* Write out the whole kernel process table entry to get the regs. */
if((w=write(fd, &procentry, sizeof(procentry))) != sizeof(procentry)) {
if(w < 0) printf("write error: %s\n", strerror(errno));
printf( "proc write failed: %d/%d\n", w, sizeof(procentry));
goto error;
}
/* Loop through segments and write the segments themselves out. */
for (seg = 0; seg < NR_LOCAL_SEGS; seg++) {
len= segs[seg].mem_len << CLICK_SHIFT;
seg_off= segs[seg].mem_vir << CLICK_SHIFT;
r= write_seg(fd, pid, seg, seg_off, len);
if (r != 0)
goto error;
}
/* Give the core file its final name. */
if (rename(core_name, "core")) {
perror("rename");
goto error;
}
close(fd);
return 0;
error:
close(fd);
unlink(core_name);
return 1;
}
int main(int argc, char *argv[])
{
pid_t pid;
@ -223,7 +57,10 @@ int main(int argc, char *argv[])
return 1;
}
r = dumpcore(pid);
if (ptrace(T_DUMPCORE, pid, 0, 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",

View file

@ -839,7 +839,13 @@ static void service_pm_postponed(void)
proc_e = job_m_in.PM_PROC;
traced_proc_e = job_m_in.PM_TRACED_PROC;
term_signal = job_m_in.PM_TERM_SIG;
if(job_m_in.PM_PROC != job_m_in.PM_TRACED_PROC) {
/* dumpcore request */
term_signal = 0;
} else {
/* dumpcore on exit */
term_signal = job_m_in.PM_TERM_SIG;
}
core_path = (vir_bytes) job_m_in.PM_PATH;
r = pm_dumpcore(proc_e, term_signal, core_path);
@ -918,7 +924,12 @@ static void service_pm()
case PM_DUMPCORE:
{
endpoint_t proc_e = job_m_in.PM_PROC;
okendpt(proc_e, &slot);
if(isokendpt(proc_e, &slot) != OK) {
printf("VFS: proc ep %d not ok\n", proc_e);
return;
}
fp = &fproc[slot];
if (fp->fp_flags & FP_PENDING) {

View file

@ -717,7 +717,8 @@ int pm_dumpcore(endpoint_t proc_e, int csig, vir_bytes exe_name)
unlock_filp(f);
(void) close_fd(fp, core_fd); /* ignore failure, we're exiting anyway */
free_proc(fp, FP_EXITING);
if(csig)
free_proc(fp, FP_EXITING);
return(OK);
}