jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
linux-user: factor out reading of /proc/self/maps
Unfortunately reading /proc/self/maps is still considered the gold
standard for a process finding out about it's own memory layout. As we
will want this data in other contexts soon factor out the code to read
and parse the data. Rather than just blindly copying the existing
sscanf based code we use a more modern glib version of the parsing
code to make a more general purpose map structure.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200403191150.863-9-alex.bennee@linaro.org>
+151
-30
+44
include/qemu/selfmap.h
+44
include/qemu/selfmap.h
···
1
+
/*
2
+
* Utility functions to read our own memory map
3
+
*
4
+
* Copyright (c) 2020 Linaro Ltd
5
+
*
6
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* SPDX-License-Identifier: GPL-2.0-or-later
7
+
*/
8
+
9
+
#ifndef _SELFMAP_H_
10
+
#define _SELFMAP_H_
11
+
12
+
typedef struct {
13
+
unsigned long start;
14
+
unsigned long end;
15
+
16
+
/* flags */
17
+
bool is_read;
18
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bool is_write;
19
+
bool is_exec;
20
+
bool is_priv;
21
+
22
+
unsigned long offset;
23
+
gchar *dev;
24
+
uint64_t inode;
25
+
gchar *path;
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+
} MapInfo;
27
+
28
+
29
+
/**
30
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* read_self_maps:
31
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*
32
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* Read /proc/self/maps and return a list of MapInfo structures.
33
+
*/
34
+
GSList *read_self_maps(void);
35
+
36
+
/**
37
+
* free_self_maps:
38
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* @info: a GSlist
39
+
*
40
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* Free a list of MapInfo structures.
41
+
*/
42
+
void free_self_maps(GSList *info);
43
+
44
+
#endif /* _SELFMAP_H_ */
+28
-30
linux-user/syscall.c
+28
-30
linux-user/syscall.c
···
117
117
118
118
#include "qemu.h"
119
119
#include "qemu/guest-random.h"
120
+
#include "qemu/selfmap.h"
120
121
#include "user/syscall-trace.h"
121
122
#include "qapi/error.h"
122
123
#include "fd-trans.h"
···
7232
7233
{
7233
7234
CPUState *cpu = env_cpu((CPUArchState *)cpu_env);
7234
7235
TaskState *ts = cpu->opaque;
7235
-
FILE *fp;
7236
-
char *line = NULL;
7237
-
size_t len = 0;
7238
-
ssize_t read;
7236
+
GSList *map_info = read_self_maps();
7237
+
GSList *s;
7238
+
7239
+
for (s = map_info; s; s = g_slist_next(s)) {
7240
+
MapInfo *e = (MapInfo *) s->data;
7239
7241
7240
-
fp = fopen("/proc/self/maps", "r");
7241
-
if (fp == NULL) {
7242
-
return -1;
7243
-
}
7242
+
if (h2g_valid(e->start)) {
7243
+
unsigned long min = e->start;
7244
+
unsigned long max = e->end;
7245
+
int flags = page_get_flags(h2g(min));
7246
+
const char *path;
7244
7247
7245
-
while ((read = getline(&line, &len, fp)) != -1) {
7246
-
int fields, dev_maj, dev_min, inode;
7247
-
uint64_t min, max, offset;
7248
-
char flag_r, flag_w, flag_x, flag_p;
7249
-
char path[512] = "";
7250
-
fields = sscanf(line, "%"PRIx64"-%"PRIx64" %c%c%c%c %"PRIx64" %x:%x %d"
7251
-
" %512s", &min, &max, &flag_r, &flag_w, &flag_x,
7252
-
&flag_p, &offset, &dev_maj, &dev_min, &inode, path);
7248
+
max = h2g_valid(max - 1) ?
7249
+
max : (uintptr_t) g2h(GUEST_ADDR_MAX) + 1;
7253
7250
7254
-
if ((fields < 10) || (fields > 11)) {
7255
-
continue;
7256
-
}
7257
-
if (h2g_valid(min)) {
7258
-
int flags = page_get_flags(h2g(min));
7259
-
max = h2g_valid(max - 1) ? max : (uintptr_t)g2h(GUEST_ADDR_MAX) + 1;
7260
7251
if (page_check_range(h2g(min), max - min, flags) == -1) {
7261
7252
continue;
7262
7253
}
7254
+
7263
7255
if (h2g(min) == ts->info->stack_limit) {
7264
-
pstrcpy(path, sizeof(path), " [stack]");
7256
+
path = " [stack]";
7257
+
} else {
7258
+
path = e->path;
7265
7259
}
7260
+
7266
7261
dprintf(fd, TARGET_ABI_FMT_ptr "-" TARGET_ABI_FMT_ptr
7267
-
" %c%c%c%c %08" PRIx64 " %02x:%02x %d %s%s\n",
7268
-
h2g(min), h2g(max - 1) + 1, flag_r, flag_w,
7269
-
flag_x, flag_p, offset, dev_maj, dev_min, inode,
7270
-
path[0] ? " " : "", path);
7262
+
" %c%c%c%c %08" PRIx64 " %s %"PRId64" %s%s\n",
7263
+
h2g(min), h2g(max - 1) + 1,
7264
+
e->is_read ? 'r' : '-',
7265
+
e->is_write ? 'w' : '-',
7266
+
e->is_exec ? 'x' : '-',
7267
+
e->is_priv ? 'p' : '-',
7268
+
(uint64_t) e->offset, e->dev, e->inode,
7269
+
path ? " " : "", path ? path : "");
7271
7270
}
7272
7271
}
7272
+
7273
+
free_self_maps(map_info);
7273
7274
7274
7275
#ifdef TARGET_VSYSCALL_PAGE
7275
7276
/*
···
7280
7281
" --xp 00000000 00:00 0 [vsyscall]\n",
7281
7282
TARGET_VSYSCALL_PAGE, TARGET_VSYSCALL_PAGE + TARGET_PAGE_SIZE);
7282
7283
#endif
7283
-
7284
-
free(line);
7285
-
fclose(fp);
7286
7284
7287
7285
return 0;
7288
7286
}
+1
util/Makefile.objs
+1
util/Makefile.objs
+78
util/selfmap.c
+78
util/selfmap.c
···
1
+
/*
2
+
* Utility function to get QEMU's own process map
3
+
*
4
+
* Copyright (c) 2020 Linaro Ltd
5
+
*
6
+
* SPDX-License-Identifier: GPL-2.0-or-later
7
+
*/
8
+
9
+
#include "qemu/osdep.h"
10
+
#include "qemu/cutils.h"
11
+
#include "qemu/selfmap.h"
12
+
13
+
GSList *read_self_maps(void)
14
+
{
15
+
gchar *maps;
16
+
GSList *map_info = NULL;
17
+
18
+
if (g_file_get_contents("/proc/self/maps", &maps, NULL, NULL)) {
19
+
gchar **lines = g_strsplit(maps, "\n", 0);
20
+
int i, entries = g_strv_length(lines);
21
+
22
+
for (i = 0; i < entries; i++) {
23
+
gchar **fields = g_strsplit(lines[i], " ", 6);
24
+
if (g_strv_length(fields) > 4) {
25
+
MapInfo *e = g_new0(MapInfo, 1);
26
+
int errors;
27
+
const char *end;
28
+
29
+
errors = qemu_strtoul(fields[0], &end, 16, &e->start);
30
+
errors += qemu_strtoul(end + 1, NULL, 16, &e->end);
31
+
32
+
e->is_read = fields[1][0] == 'r';
33
+
e->is_write = fields[1][1] == 'w';
34
+
e->is_exec = fields[1][2] == 'x';
35
+
e->is_priv = fields[1][3] == 'p';
36
+
37
+
errors += qemu_strtoul(fields[2], NULL, 16, &e->offset);
38
+
e->dev = g_strdup(fields[3]);
39
+
errors += qemu_strtou64(fields[4], NULL, 10, &e->inode);
40
+
41
+
/*
42
+
* The last field may have leading spaces which we
43
+
* need to strip.
44
+
*/
45
+
if (g_strv_length(fields) == 6) {
46
+
e->path = g_strdup(g_strchug(fields[5]));
47
+
}
48
+
map_info = g_slist_prepend(map_info, e);
49
+
}
50
+
51
+
g_strfreev(fields);
52
+
}
53
+
g_strfreev(lines);
54
+
g_free(maps);
55
+
}
56
+
57
+
/* ensure the map data is in the same order we collected it */
58
+
return g_slist_reverse(map_info);
59
+
}
60
+
61
+
/**
62
+
* free_self_maps:
63
+
* @info: a GSlist
64
+
*
65
+
* Free a list of MapInfo structures.
66
+
*/
67
+
static void free_info(gpointer data)
68
+
{
69
+
MapInfo *e = (MapInfo *) data;
70
+
g_free(e->dev);
71
+
g_free(e->path);
72
+
g_free(e);
73
+
}
74
+
75
+
void free_self_maps(GSList *info)
76
+
{
77
+
g_slist_free_full(info, &free_info);
78
+
}