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
parent
5e38c802d8
commit
85ff5a947e
3 changed files with 19 additions and 170 deletions
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@ -20,172 +20,6 @@
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#define CLICK_WORDS (CLICK_SIZE / sizeof(unsigned long))
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int adjust_stack(pid_t pid, struct mem_map *seg)
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{
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static unsigned long buf[CLICK_WORDS];
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struct ptrace_range pr;
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size_t off, top, bottom;
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int i;
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/* FIXME: kernel/VM strangeness */
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seg->mem_vir -= seg->mem_len - 1;
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/* Scan the stack, top to bottom, to find the lowest accessible region.
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* In practice that will be at 64MB, so we also scan for the lowest non-zero
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* region in order to keep the core file size managable.
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* Portability note: this code assumes that the stack grows down.
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*/
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top = seg->mem_vir + seg->mem_len;
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pr.pr_space = TS_DATA;
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pr.pr_addr = (top - 1) << CLICK_SHIFT;
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pr.pr_size = sizeof(buf);
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pr.pr_ptr = buf;
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for (off = top - 1; off >= seg->mem_vir; off--) {
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if (ptrace(T_GETRANGE, pid, (long) &pr, 0)) {
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if (errno == EFAULT)
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break;
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perror("ptrace(T_GETRANGE)");
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return 1;
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}
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for (i = 0; i < CLICK_WORDS; i += sizeof(buf[0]))
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if (buf[i] != 0)
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bottom = off;
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pr.pr_addr -= sizeof(buf);
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}
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/* Add one extra zero page as margin. */
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if (bottom > off && bottom > seg->mem_vir)
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bottom--;
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seg->mem_len -= bottom - seg->mem_vir;
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seg->mem_vir = bottom;
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return 0;
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}
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int write_seg(int fd, pid_t pid, int seg, off_t seg_off, phys_bytes seg_bytes)
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{
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ssize_t w;
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static char buf[CLICK_SIZE];
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struct ptrace_range pr;
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pr.pr_space = (seg == T) ? TS_INS : TS_DATA;
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pr.pr_addr = seg_off;
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pr.pr_size = sizeof(buf);
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pr.pr_ptr = buf;
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for ( ; pr.pr_addr < seg_off + seg_bytes; pr.pr_addr += sizeof(buf))
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{
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/* Copy a chunk from user space to the block buffer. */
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if (ptrace(T_GETRANGE, pid, (long) &pr, 0)) {
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/* Create holes for inaccessible areas. */
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if (errno == EFAULT) {
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lseek(fd, sizeof(buf), SEEK_CUR);
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continue;
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}
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perror("ptrace(T_GETRANGE)");
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return 1;
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}
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if((w=write(fd, buf, sizeof(buf))) != sizeof(buf)) {
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if(w < 0) printf("write error: %s\n", strerror(errno));
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printf("write_seg: write failed: %d/%d\n", w, sizeof(buf));
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return 1;
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}
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}
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return 0;
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}
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int dumpcore(pid_t pid)
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{
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int r, seg, fd;
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vir_bytes len;
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off_t off, seg_off;
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long data;
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struct mem_map segs[NR_LOCAL_SEGS];
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struct proc procentry;
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ssize_t w;
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char core_name[PATH_MAX];
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/* Get the process table entry for this process. */
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len = sizeof(struct proc) / sizeof(long);
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for (off = 0; off < len; off++)
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{
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errno = 0;
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data = ptrace(T_GETUSER, pid, off * sizeof(long), 0);
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if (data == -1 && errno != 0)
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{
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perror("ptrace(T_GETUSER)");
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return 1;
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}
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((long *) &procentry)[off] = data;
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}
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memcpy(segs, procentry.p_memmap, sizeof(segs));
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/* Correct and reduce the stack segment. */
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r = adjust_stack(pid, &segs[S]);
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if (r != 0)
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goto error;
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/* Create a core file with a temporary, unique name. */
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sprintf(core_name, "core.%d", pid);
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if((fd = open(core_name, O_CREAT|O_EXCL|O_WRONLY, 0600)) < 0) {
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fprintf(stderr, "couldn't open %s (%s)\n", core_name,
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strerror(errno));
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return 1;
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}
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/* Write out the process's segments. */
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if((w=write(fd, segs, sizeof(segs))) != sizeof(segs)) {
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if(w < 0) printf("write error: %s\n", strerror(errno));
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printf( "segs write failed: %d/%d\n", w, sizeof(segs));
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goto error;
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}
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/* Write out the whole kernel process table entry to get the regs. */
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if((w=write(fd, &procentry, sizeof(procentry))) != sizeof(procentry)) {
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if(w < 0) printf("write error: %s\n", strerror(errno));
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printf( "proc write failed: %d/%d\n", w, sizeof(procentry));
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goto error;
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}
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/* Loop through segments and write the segments themselves out. */
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for (seg = 0; seg < NR_LOCAL_SEGS; seg++) {
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len= segs[seg].mem_len << CLICK_SHIFT;
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seg_off= segs[seg].mem_vir << CLICK_SHIFT;
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r= write_seg(fd, pid, seg, seg_off, len);
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if (r != 0)
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goto error;
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}
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/* Give the core file its final name. */
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if (rename(core_name, "core")) {
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perror("rename");
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goto error;
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}
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close(fd);
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return 0;
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error:
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close(fd);
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unlink(core_name);
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return 1;
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}
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int main(int argc, char *argv[])
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{
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pid_t pid;
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@ -223,7 +57,10 @@ int main(int argc, char *argv[])
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return 1;
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}
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r = dumpcore(pid);
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if (ptrace(T_DUMPCORE, pid, 0, 0) != 0) {
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fprintf(stderr, "warning, dumpcore failed (%s)\n",
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strerror(errno));
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}
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if (ptrace(T_DETACH, pid, 0, 0)) {
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fprintf(stderr, "warning, detaching failed (%s)\n",
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@ -839,7 +839,13 @@ static void service_pm_postponed(void)
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proc_e = job_m_in.PM_PROC;
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traced_proc_e = job_m_in.PM_TRACED_PROC;
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term_signal = job_m_in.PM_TERM_SIG;
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if(job_m_in.PM_PROC != job_m_in.PM_TRACED_PROC) {
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/* dumpcore request */
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term_signal = 0;
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} else {
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/* dumpcore on exit */
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term_signal = job_m_in.PM_TERM_SIG;
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}
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core_path = (vir_bytes) job_m_in.PM_PATH;
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r = pm_dumpcore(proc_e, term_signal, core_path);
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@ -918,7 +924,12 @@ static void service_pm()
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case PM_DUMPCORE:
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{
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endpoint_t proc_e = job_m_in.PM_PROC;
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okendpt(proc_e, &slot);
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if(isokendpt(proc_e, &slot) != OK) {
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printf("VFS: proc ep %d not ok\n", proc_e);
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return;
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}
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fp = &fproc[slot];
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if (fp->fp_flags & FP_PENDING) {
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@ -717,7 +717,8 @@ int pm_dumpcore(endpoint_t proc_e, int csig, vir_bytes exe_name)
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unlock_filp(f);
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(void) close_fd(fp, core_fd); /* ignore failure, we're exiting anyway */
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free_proc(fp, FP_EXITING);
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if(csig)
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free_proc(fp, FP_EXITING);
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return(OK);
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}
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