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parasite: Code grouping in parasite_infect_seized

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- mmap_seized returns only NULL on error, drop
   redumdant test
 - setup control block in one group
 - no need for err_free label, xfree handles NULL easily
 - prepare registers for munmap_seized call on error path

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
This commit is contained in:
Cyrill Gorcunov
2012-02-13 23:17:51 +04:00
parent a349f1f137
commit 293d999e4f
1 changed files with 18 additions and 19 deletions
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37
parasite-syscall.c
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@@ -551,35 +551,29 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, int pid_dir, struct list_
goto err; goto err;
} }
/* Setup control block */
ctl->pid = pid;
if (ptrace(PTRACE_GETREGS, pid, NULL, &regs)) if (ptrace(PTRACE_GETREGS, pid, NULL, &regs))
pr_err_jmp(err_free); pr_err_jmp(err);
vma_area = get_vma_by_ip(vma_area_list, regs.ip); vma_area = get_vma_by_ip(vma_area_list, regs.ip);
if (!vma_area) { if (!vma_area) {
pr_err("No suitable VMA found to run parasite " pr_err("No suitable VMA found to run parasite "
"bootstrap code (pid: %d)\n", pid); "bootstrap code (pid: %d)\n", pid);
goto err_free; goto err;
} }
regs_orig = regs; regs_orig = regs;
parasite_setup_regs(vma_area->vma.start, &regs); parasite_setup_regs(vma_area->vma.start, &regs);
ctl->remote_map = mmap_seized(pid, &regs, NULL, (size_t)parasite_size, ctl->remote_map = mmap_seized(pid, &regs, NULL, (size_t)parasite_size,
PROT_READ | PROT_WRITE | PROT_EXEC, PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_SHARED, -1, 0); MAP_ANONYMOUS | MAP_SHARED, -1, 0);
if (!ctl->remote_map) {
if (!ctl->remote_map || (long)ctl->remote_map < 0) {
pr_err("Can't allocate memory for parasite blob (pid: %d)\n", pid); pr_err("Can't allocate memory for parasite blob (pid: %d)\n", pid);
goto err_restore_regs; goto err_restore_regs;
} }
ctl->map_length = round_up(parasite_size, PAGE_SIZE); ctl->map_length = round_up(parasite_size, PAGE_SIZE);
ctl->parasite_ip = PARASITE_HEAD_ADDR((unsigned long)ctl->remote_map);
snprintf(fname, sizeof(fname), "map_files/%p-%p", snprintf(fname, sizeof(fname), "map_files/%p-%p",
ctl->remote_map, ctl->remote_map + ctl->map_length); ctl->remote_map, ctl->remote_map + ctl->map_length);
fd = openat(pid_dir, fname, O_RDWR); fd = openat(pid_dir, fname, O_RDWR);
@@ -589,7 +583,7 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, int pid_dir, struct list_
} }
ctl->local_map = mmap(NULL, parasite_size, PROT_READ | PROT_WRITE, ctl->local_map = mmap(NULL, parasite_size, PROT_READ | PROT_WRITE,
MAP_SHARED | MAP_FILE, fd, 0); MAP_SHARED | MAP_FILE, fd, 0);
close(fd); close(fd);
if (ctl->local_map == MAP_FAILED) { if (ctl->local_map == MAP_FAILED) {
@@ -602,8 +596,11 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, int pid_dir, struct list_
jerr(ptrace(PTRACE_SETREGS, pid, NULL, &regs_orig), err_munmap_restore); jerr(ptrace(PTRACE_SETREGS, pid, NULL, &regs_orig), err_munmap_restore);
ctl->addr_cmd = (void *)PARASITE_CMD_ADDR((unsigned long)ctl->local_map); /* Setup control block */
ctl->addr_args = (void *)PARASITE_ARGS_ADDR((unsigned long)ctl->local_map); ctl->pid = pid;
ctl->parasite_ip = PARASITE_HEAD_ADDR((unsigned long)ctl->remote_map);
ctl->addr_cmd = (void *)PARASITE_CMD_ADDR((unsigned long)ctl->local_map);
ctl->addr_args = (void *)PARASITE_ARGS_ADDR((unsigned long)ctl->local_map);
ret = parasite_init(ctl, pid); ret = parasite_init(ctl, pid);
if (ret) { if (ret) {
@@ -614,7 +611,7 @@ struct parasite_ctl *parasite_infect_seized(pid_t pid, int pid_dir, struct list_
ret = parasite_set_logfd(ctl, pid); ret = parasite_set_logfd(ctl, pid);
if (ret) { if (ret) {
pr_err("%d: Can't set a logging descriptor\n", pid); pr_err("%d: Can't set a logging descriptor\n", pid);
goto err_munmap_restore; goto err_fini;
} }
return ctl; return ctl;
@@ -624,17 +621,19 @@ err_fini:
&args, sizeof(args)); &args, sizeof(args));
if (ret) if (ret)
pr_panic("Can't finalize parasite (pid: %d) task\n", ctl->pid); pr_panic("Can't finalize parasite (pid: %d) task\n", ctl->pid);
err_munmap_restore: err_munmap_restore:
regs = regs_orig, regs.ip = vma_area->vma.start; regs = regs_orig;
parasite_setup_regs(vma_area->vma.start, &regs);
if (munmap_seized(pid, &regs, ctl->remote_map, ctl->map_length)) if (munmap_seized(pid, &regs, ctl->remote_map, ctl->map_length))
pr_panic("mmap_seized failed (pid: %d)\n", pid); pr_panic("mmap_seized failed (pid: %d)\n", pid);
err_restore_regs: err_restore_regs:
if (ptrace(PTRACE_SETREGS, pid, NULL, &regs_orig)) if (ptrace(PTRACE_SETREGS, pid, NULL, &regs_orig))
pr_panic("PTRACE_SETREGS failed (pid: %d)\n", pid); pr_panic("PTRACE_SETREGS failed (pid: %d)\n", pid);
err_free:
if (ctl)
free(ctl);
err: err:
xfree(ctl);
return NULL; return NULL;
} }