[PATCH 05/13] linux-user: Use walk_memory_regions for open_self_maps

[Richard Henderson]

Replace the by-hand method of region identification with
the official user-exec interface.  Cross-check the region
provided to the callback with the interval tree from
read_self_maps().

Tested-by: Helge Deller <deller@gmx.de>
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/syscall.c | 192 ++++++++++++++++++++++++++-----------------
 1 file changed, 115 insertions(+), 77 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a562920a84..0b91f996b7 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8095,12 +8095,66 @@ static int open_self_cmdline(CPUArchState *cpu_env, int 
fd)
     return 0;
 }
 
-static void show_smaps(int fd, unsigned long size)
-{
-    unsigned long page_size_kb = TARGET_PAGE_SIZE >> 10;
-    unsigned long size_kb = size >> 10;
+struct open_self_maps_data {
+    TaskState *ts;
+    IntervalTreeRoot *host_maps;
+    int fd;
+    bool smaps;
+};
 
-    dprintf(fd, "Size:                  %lu kB\n"
+/*
+ * Subroutine to output one line of /proc/self/maps,
+ * or one region of /proc/self/smaps.
+ */
+
+#ifdef TARGET_HPPA
+# define test_stack(S, E, L)  (E == L)
+#else
+# define test_stack(S, E, L)  (S == L)
+#endif
+
+static void open_self_maps_4(const struct open_self_maps_data *d,
+                             const MapInfo *mi, abi_ptr start,
+                             abi_ptr end, unsigned flags)
+{
+    const struct image_info *info = d->ts->info;
+    const char *path = mi->path;
+    uint64_t offset;
+    int fd = d->fd;
+    int count;
+
+    if (test_stack(start, end, info->stack_limit)) {
+        path = "[stack]";
+    }
+
+    /* Except null device (MAP_ANON), adjust offset for this fragment. */
+    offset = mi->offset;
+    if (mi->dev) {
+        uintptr_t hstart = (uintptr_t)g2h_untagged(start);
+        offset += hstart - mi->itree.start;
+    }
+
+    count = dprintf(fd, TARGET_ABI_FMT_ptr "-" TARGET_ABI_FMT_ptr
+                    " %c%c%c%c %08" PRIx64 " %02x:%02x %"PRId64,
+                    start, end,
+                    (flags & PAGE_READ) ? 'r' : '-',
+                    (flags & PAGE_WRITE_ORG) ? 'w' : '-',
+                    (flags & PAGE_EXEC) ? 'x' : '-',
+                    mi->is_priv ? 'p' : 's',
+                    offset, major(mi->dev), minor(mi->dev),
+                    (uint64_t)mi->inode);
+    if (path) {
+        dprintf(fd, "%*s%s\n", 73 - count, "", path);
+    } else {
+        dprintf(fd, "\n");
+    }
+
+    if (d->smaps) {
+        unsigned long size = end - start;
+        unsigned long page_size_kb = TARGET_PAGE_SIZE >> 10;
+        unsigned long size_kb = size >> 10;
+
+        dprintf(fd, "Size:                  %lu kB\n"
                 "KernelPageSize:        %lu kB\n"
                 "MMUPageSize:           %lu kB\n"
                 "Rss:                   0 kB\n"
@@ -8121,91 +8175,75 @@ static void show_smaps(int fd, unsigned long size)
                 "Swap:                  0 kB\n"
                 "SwapPss:               0 kB\n"
                 "Locked:                0 kB\n"
-                "THPeligible:    0\n", size_kb, page_size_kb, page_size_kb);
+                "THPeligible:    0\n"
+                "VmFlags:%s%s%s%s%s%s%s%s\n",
+                size_kb, page_size_kb, page_size_kb,
+                (flags & PAGE_READ) ? " rd" : "",
+                (flags & PAGE_WRITE_ORG) ? " wr" : "",
+                (flags & PAGE_EXEC) ? " ex" : "",
+                mi->is_priv ? "" : " sh",
+                (flags & PAGE_READ) ? " mr" : "",
+                (flags & PAGE_WRITE_ORG) ? " mw" : "",
+                (flags & PAGE_EXEC) ? " me" : "",
+                mi->is_priv ? "" : " ms");
+    }
 }
 
-static int open_self_maps_1(CPUArchState *cpu_env, int fd, bool smaps)
+/*
+ * Callback for walk_memory_regions, when read_self_maps() fails.
+ * Proceed without the benefit of host /proc/self/maps cross-check.
+ */
+static int open_self_maps_3(void *opaque, target_ulong guest_start,
+                            target_ulong guest_end, unsigned long flags)
 {
-    CPUState *cpu = env_cpu(cpu_env);
-    TaskState *ts = cpu->opaque;
-    IntervalTreeRoot *map_info = read_self_maps();
-    IntervalTreeNode *s;
-    int count;
+    static const MapInfo mi = { .is_priv = true };
 
-    for (s = interval_tree_iter_first(map_info, 0, -1); s;
-         s = interval_tree_iter_next(s, 0, -1)) {
-        MapInfo *e = container_of(s, MapInfo, itree);
+    open_self_maps_4(opaque, &mi, guest_start, guest_end, flags);
+    return 0;
+}
 
-        if (h2g_valid(e->itree.start)) {
-            unsigned long min = e->itree.start;
-            unsigned long max = e->itree.last + 1;
-            int flags = page_get_flags(h2g(min));
-            const char *path;
+/*
+ * Callback for walk_memory_regions, when read_self_maps() succeeds.
+ */
+static int open_self_maps_2(void *opaque, target_ulong guest_start,
+                            target_ulong guest_end, unsigned long flags)
+{
+    const struct open_self_maps_data *d = opaque;
+    uintptr_t host_start = (uintptr_t)g2h_untagged(guest_start);
+    uintptr_t host_last = (uintptr_t)g2h_untagged(guest_end - 1);
 
-            max = h2g_valid(max - 1) ?
-                max : (uintptr_t) g2h_untagged(GUEST_ADDR_MAX) + 1;
+    while (1) {
+        IntervalTreeNode *n =
+            interval_tree_iter_first(d->host_maps, host_start, host_start);
+        MapInfo *mi = container_of(n, MapInfo, itree);
+        uintptr_t this_hlast = MIN(host_last, n->last);
+        target_ulong this_gend = h2g(this_hlast) + 1;
 
-            if (!page_check_range(h2g(min), max - min, flags)) {
-                continue;
-            }
+        open_self_maps_4(d, mi, guest_start, this_gend, flags);
 
-#ifdef TARGET_HPPA
-            if (h2g(max) == ts->info->stack_limit) {
-#else
-            if (h2g(min) == ts->info->stack_limit) {
-#endif
-                path = "[stack]";
-            } else {
-                path = e->path;
-            }
-
-            count = dprintf(fd, TARGET_ABI_FMT_ptr "-" TARGET_ABI_FMT_ptr
-                            " %c%c%c%c %08" PRIx64 " %02x:%02x %"PRId64,
-                            h2g(min), h2g(max - 1) + 1,
-                            (flags & PAGE_READ) ? 'r' : '-',
-                            (flags & PAGE_WRITE_ORG) ? 'w' : '-',
-                            (flags & PAGE_EXEC) ? 'x' : '-',
-                            e->is_priv ? 'p' : 's',
-                            (uint64_t)e->offset,
-                            major(e->dev), minor(e->dev),
-                            (uint64_t)e->inode);
-            if (path) {
-                dprintf(fd, "%*s%s\n", 73 - count, "", path);
-            } else {
-                dprintf(fd, "\n");
-            }
-            if (smaps) {
-                show_smaps(fd, max - min);
-                dprintf(fd, "VmFlags:%s%s%s%s%s%s%s%s\n",
-                        (flags & PAGE_READ) ? " rd" : "",
-                        (flags & PAGE_WRITE_ORG) ? " wr" : "",
-                        (flags & PAGE_EXEC) ? " ex" : "",
-                        e->is_priv ? "" : " sh",
-                        (flags & PAGE_READ) ? " mr" : "",
-                        (flags & PAGE_WRITE_ORG) ? " mw" : "",
-                        (flags & PAGE_EXEC) ? " me" : "",
-                        e->is_priv ? "" : " ms");
-            }
+        if (this_hlast == host_last) {
+            return 0;
         }
+        host_start = this_hlast + 1;
+        guest_start = h2g(host_start);
     }
+}
 
-    free_self_maps(map_info);
+static int open_self_maps_1(CPUArchState *env, int fd, bool smaps)
+{
+    struct open_self_maps_data d = {
+        .ts = env_cpu(env)->opaque,
+        .host_maps = read_self_maps(),
+        .fd = fd,
+        .smaps = smaps
+    };
 
-#ifdef TARGET_VSYSCALL_PAGE
-    /*
-     * We only support execution from the vsyscall page.
-     * This is as if CONFIG_LEGACY_VSYSCALL_XONLY=y from v5.3.
-     */
-    count = dprintf(fd, TARGET_FMT_lx "-" TARGET_FMT_lx
-                    " --xp 00000000 00:00 0",
-                    TARGET_VSYSCALL_PAGE, TARGET_VSYSCALL_PAGE + 
TARGET_PAGE_SIZE);
-    dprintf(fd, "%*s%s\n", 73 - count, "",  "[vsyscall]");
-    if (smaps) {
-        show_smaps(fd, TARGET_PAGE_SIZE);
-        dprintf(fd, "VmFlags: ex\n");
+    if (d.host_maps) {
+        walk_memory_regions(&d, open_self_maps_2);
+        free_self_maps(d.host_maps);
+    } else {
+        walk_memory_regions(&d, open_self_maps_3);
     }
-#endif
-
     return 0;
 }
 
-- 
2.34.1