varun-r-mallya/sysprof
1
0
Fork 0
mirror of https://github.com/varun-r-mallya/sysprof.git synced 2025-12-31 20:36:25 +00:00
Code Issues Packages Projects Releases Wiki Activity

libsysprof: use mountinfo helper for path translations

Browse Source
This commit is contained in:
Christian Hergert
2019-08-02 13:10:28 -07:00
parent 96dbd07c82
commit ba725d1599
1 changed files with 21 additions and 193 deletions
Download Patch File Download Diff File Expand all files Collapse all files

214
src/libsysprof/sysprof-proc-source.c
View File

@ -44,6 +44,7 @@
#include <string.h>
#include "sysprof-helpers.h"
#include "sysprof-mountinfo.h"
#include "sysprof-proc-source.h"
struct _SysprofProcSource
@ -51,38 +52,14 @@ struct _SysprofProcSource
GObject parent_instance;
SysprofCaptureWriter *writer;
GArray *pids;
SysprofMountinfo *mountinfo;
};
static void source_iface_init (SysprofSourceInterface *iface);
static gchar **proc_readlines (const gchar *format,
...)
G_GNUC_PRINTF (1, 2);
static void source_iface_init (SysprofSourceInterface *iface);
G_DEFINE_TYPE_EXTENDED (SysprofProcSource, sysprof_proc_source, G_TYPE_OBJECT, 0,
G_IMPLEMENT_INTERFACE (SYSPROF_TYPE_SOURCE, source_iface_init))
static gchar **
proc_readlines (const gchar *format,
...)
{
SysprofHelpers *helpers = sysprof_helpers_get_default ();
g_autofree gchar *filename = NULL;
g_autofree gchar *contents = NULL;
gchar **ret = NULL;
va_list args;
g_assert (format != NULL);
va_start (args, format);
filename = g_strdup_vprintf (format, args);
va_end (args);
if (sysprof_helpers_get_proc_file (helpers, filename, NULL, &contents, NULL))
ret = g_strsplit (contents, "\n", 0);
return g_steal_pointer (&ret);
}
static void
sysprof_proc_source_populate_process (SysprofProcSource *self,
GPid pid,
@ -98,151 +75,9 @@ sysprof_proc_source_populate_process (SysprofProcSource *self,
cmdline);
}
static gboolean
strv_at_least_len (GStrv strv,
guint len)
{
for (guint i = 0; i < len; i++)
{
if (strv[i] == NULL)
return FALSE;
}
return TRUE;
}
static gchar *
find_mount (GStrv mounts,
const gchar *mount)
{
gsize len = strlen (mount);
for (guint i = 0; mounts[i]; i++)
{
const gchar *endptr;
const gchar *begin;
if (!g_str_has_prefix (mounts[i], mount))
continue;
if (mounts[i][len] != ' ')
continue;
begin = &mounts[i][len + 1];
endptr = strchr (begin, ' ');
if (endptr == NULL)
continue;
return g_strndup (begin, endptr - begin);
}
return NULL;
}
/**
* sysprof_proc_source_translate_path:
* @file: the path to the file inside target mount namespace
* @mountinfo: mount info to locate translated path
* @out_file: (out): location for the translated path
* @out_file_len: length of @out_file
*
* This function will use @mountinfo to locate the longest common prefix
* to determine which mount contains @file. That will be used to translate
* the path pointed to by @file into the host namespace.
*
* The result is stored in @out_file and will always be NULL terminated.
*/
static void
sysprof_proc_source_translate_path (const gchar *file,
GStrv mountinfo,
GStrv mounts,
gchar *out_file,
gsize out_file_len)
{
g_autofree gchar *closest_host = NULL;
g_autofree gchar *closest_guest = NULL;
g_autofree gchar *closest_mount = NULL;
gsize closest_len = 0;
g_assert (file != NULL);
g_assert (g_str_has_prefix (file, "/newroot/"));
g_assert (mountinfo != NULL);
g_assert (out_file != NULL);
if (!g_str_has_prefix (file, "/newroot/"))
goto failure;
file += strlen ("/newroot");
for (guint i = 0; mountinfo[i] != NULL; i++)
{
g_auto(GStrv) parts = g_strsplit (mountinfo[i], " ", 11);
const gchar *host;
const gchar *guest;
const gchar *mount;
/*
* Not ideal to do the string split here, but it is much easier
* to just do that until we get this right, and then improve
* things later when a strok()/etc parser.
*/
if (!strv_at_least_len (parts, 10))
continue;
host = parts[3];
guest = parts[4];
mount = parts[9];
if (g_str_has_prefix (file, guest))
{
gsize len = strlen (guest);
if (len > closest_len && (file[len] == '\0' || file[len] == '/'))
{
g_free (closest_host);
g_free (closest_guest);
g_free (closest_mount);
closest_guest = g_strdup (guest);
closest_host = g_strdup (host);
closest_mount = g_strdup (mount);
closest_len = len;
}
}
}
if (closest_len > 0)
{
/*
* The translated path is relative to the mount. So we need to add that
* prefix to this as well, based on matching it from the closest_mount.
*/
g_autofree gchar *mount = NULL;
mount = find_mount (mounts, closest_mount);
if (mount != NULL)
{
g_autofree gchar *path = NULL;
path = g_build_filename (mount, closest_host, file + strlen (closest_guest), NULL);
g_strlcpy (out_file, path, out_file_len);
return;
}
}
failure:
/* Fallback to just copying the source */
g_strlcpy (out_file, file, out_file_len);
}
static void
sysprof_proc_source_populate_maps (SysprofProcSource *self,
GPid pid,
GStrv mounts,
const gchar *mapsstr,
const gchar *mountinfostr)
{
@ -255,13 +90,15 @@ sysprof_proc_source_populate_maps (SysprofProcSource *self,
g_assert (mountinfostr != NULL);
g_assert (pid > 0);
sysprof_mountinfo_reset (self->mountinfo);
sysprof_mountinfo_parse_mountinfo (self->mountinfo, mountinfostr);
maps = g_strsplit (mapsstr, "\n", 0);
mountinfo = g_strsplit (mountinfostr, "\n", 0);
for (i = 0; maps [i] != NULL; i++)
{
gchar file[256];
gchar translated[256];
g_autofree gchar *translated = NULL;
gchar file[512];
const gchar *fileptr = file;
gulong start;
gulong end;
@ -270,9 +107,8 @@ sysprof_proc_source_populate_maps (SysprofProcSource *self,
gint r;
r = sscanf (maps [i],
"%lx-%lx %*15s %lx %*x:%*x %lu %255s",
"%lx-%lx %*15s %lx %*x:%*x %lu %512s",
&start, &end, &offset, &inode, file);
file [sizeof file - 1] = '\0';
if (r != 5)
@ -293,23 +129,9 @@ sysprof_proc_source_populate_maps (SysprofProcSource *self,
inode = 0;
}
if (g_str_has_prefix (file, "/newroot/"))
{
/*
* If this file starts with /newroot/, then it is in a different
* mount-namespace from our profiler process. This means that we need
* to translate the filename to the real path on disk inside our
* (hopefully the default) mount-namespace. To do this, we have to
* look at /proc/$pid/mountinfo to locate the longest-common-prefix
* for the path.
*/
sysprof_proc_source_translate_path (file,
mountinfo,
mounts,
translated,
sizeof translated);
fileptr = translated;
}
/* Possibly translate the path based on mounts/mountinfo data */
if ((translated = sysprof_mountinfo_translate (self->mountinfo, file)))
fileptr = translated;
sysprof_capture_writer_add_map (self->writer,
SYSPROF_CAPTURE_CURRENT_TIME,
@ -343,7 +165,8 @@ static void
sysprof_proc_source_populate (SysprofProcSource *self,
GVariant *info)
{
g_auto(GStrv) mounts = NULL;
g_autofree gchar *mounts = NULL;
SysprofHelpers *helpers;
gsize n_pids = 0;
g_assert (SYSPROF_IS_PROC_SOURCE (self));
@ -353,9 +176,12 @@ sysprof_proc_source_populate (SysprofProcSource *self,
if (self->writer == NULL)
return;
if (!(mounts = proc_readlines ("/proc/mounts")))
helpers = sysprof_helpers_get_default ();
if (!sysprof_helpers_get_proc_file (helpers, "/proc/mounts", NULL, &mounts, NULL))
return;
sysprof_mountinfo_parse_mounts (self->mountinfo, mounts);
n_pids = g_variant_n_children (info);
for (gsize i = 0; i < n_pids; i++)
{
@ -386,7 +212,7 @@ sysprof_proc_source_populate (SysprofProcSource *self,
maps = "";
sysprof_proc_source_populate_process (self, pid, *cmdline ? cmdline : comm);
sysprof_proc_source_populate_maps (self, pid, mounts, maps, mountinfo);
sysprof_proc_source_populate_maps (self, pid, maps, mountinfo);
skip:
g_variant_dict_clear (&dict);
@ -492,6 +318,7 @@ sysprof_proc_source_finalize (GObject *object)
g_clear_pointer (&self->writer, sysprof_capture_writer_unref);
g_clear_pointer (&self->pids, g_array_unref);
g_clear_pointer (&self->mountinfo, sysprof_mountinfo_free);
G_OBJECT_CLASS (sysprof_proc_source_parent_class)->finalize (object);
}
@ -508,6 +335,7 @@ static void
sysprof_proc_source_init (SysprofProcSource *self)
{
self->pids = g_array_new (FALSE, FALSE, sizeof (GPid));
self->mountinfo = sysprof_mountinfo_new ();
}
SysprofSource *