memzap

replay memory writes
git clone git://git.2f30.org/memzap.git
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commit 6c668ce4b667ea2dd1ffa6095f432a5238d6d4b5
parent 06ca031645eab753df49d17d83d38f276c88fae4
Author: sin <sin@2f30.org>
Date:   Mon Mar  4 14:27:56 +0000

memzap: Add some comments throughout the code

Diffstat:
memzap.c | 18++++++++++++++++++
1 file changed, 18 insertions(+), 0 deletions(-)
diff --git a/memzap.c b/memzap.c @@ -121,6 +121,7 @@ main(int argc, char *argv[]) if (!WIFSTOPPED(stat)) goto out_mmap; + /* Create .mdiff file and initialize the header */ snprintf(mdiff_path, sizeof(mdiff_path), "%s.mdiff", *argv); fd = create_mdiff(mdiff_path); @@ -130,20 +131,28 @@ main(int argc, char *argv[]) hdr.endianness = 0; hdr.version = 1; mdiff_start_diff(fd); + + /* Trace the child process and diff the memory regions + * per instruction */ do { + /* Read in the Nth generation of the traced region */ readmem(pid, buf, addr, len); if (!once) { dump_base_image(*argv, buf, len); once = true; } + /* Build a memory region that tracks this buffer */ mr_old = build_mem_region(buf, len); if (!mr_old) errx(1, "Failed to build memory region\n"); + /* Build an rbtree that tracks this memory region */ mt_old = build_mem_tree(mr_old); if (!mt_old) errx(1, "Failed to build memory tree\n"); + /* Single step the child in order to get the next + * generation */ single_step(pid); wait(&stat); if (!WIFSTOPPED(stat)) { @@ -152,23 +161,32 @@ main(int argc, char *argv[]) break; } + /* Read in the (N + 1)th generation of the traced + * region */ readmem(pid, buf_new, addr, len); + /* Build a memory region that tracks this buffer */ mr_new = build_mem_region(buf_new, len); if (!mr_new) errx(1, "Failed to build memory region\n"); + + /* Diff the original copy with the updated copy */ rdiff = diff_mem_region(mt_old, mr_new); if (rdiff->nmrdiffs) { + /* If we've found differences, then apply them on + * the Nth generation */ apply_diff(mr_old, rdiff); hdr.nregions += mdiff_append_rdiff(fd, rdiff); } + /* Free these and go up for another run */ free_mem_region(mr_old); free_mem_tree(mt_old); free_mem_region(mr_new); free_mem_region_diff(rdiff); } while(1); + /* Insert header at the start of the .mdiff file */ mdiff_insert_hdr(fd, &hdr); close_mdiff(fd); out_mmap: