ueventd: replace char** links with std::vector<std::string>
Additionally replace the associated C string parsing with C++ and write
unit tests.
Bug: 33785894
Bug: 36250207
Test: Boot bullhead + unit tests
Change-Id: Iee1f72d248bca3bd2e1227045628935b3dd6195a
diff --git a/init/devices.cpp b/init/devices.cpp
index 760e0f5..a3467b9 100644
--- a/init/devices.cpp
+++ b/init/devices.cpp
@@ -32,12 +32,16 @@
#include <sys/wait.h>
#include <unistd.h>
+#include <algorithm>
#include <memory>
+#include <string>
#include <thread>
+#include <vector>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
+#include <android-base/strings.h>
#include <android-base/unique_fd.h>
#include <cutils/list.h>
#include <cutils/uevent.h>
@@ -178,9 +182,8 @@
}
}
-static mode_t get_device_perm(const char *path, const char **links,
- unsigned *uid, unsigned *gid)
-{
+static mode_t get_device_perm(const char* path, const std::vector<std::string>& links,
+ unsigned* uid, unsigned* gid) {
struct listnode *node;
struct perm_node *perm_node;
struct perms_ *dp;
@@ -189,26 +192,12 @@
* override ueventd.rc
*/
list_for_each_reverse(node, &dev_perms) {
- bool match = false;
-
perm_node = node_to_item(node, struct perm_node, plist);
dp = &perm_node->dp;
- if (perm_path_matches(path, dp)) {
- match = true;
- } else {
- if (links) {
- int i;
- for (i = 0; links[i]; i++) {
- if (perm_path_matches(links[i], dp)) {
- match = true;
- break;
- }
- }
- }
- }
-
- if (match) {
+ if (perm_path_matches(path, dp) ||
+ std::any_of(links.begin(), links.end(),
+ [dp](const auto& link) { return perm_path_matches(link.c_str(), dp); })) {
*uid = dp->uid;
*gid = dp->gid;
return dp->perm;
@@ -220,11 +209,8 @@
return 0600;
}
-static void make_device(const char *path,
- const char */*upath*/,
- int block, int major, int minor,
- const char **links)
-{
+static void make_device(const char* path, const char* /*upath*/, int block, int major, int minor,
+ const std::vector<std::string>& links) {
unsigned uid;
unsigned gid;
mode_t mode;
@@ -234,7 +220,12 @@
mode = get_device_perm(path, links, &uid, &gid) | (block ? S_IFBLK : S_IFCHR);
if (sehandle) {
- if (selabel_lookup_best_match(sehandle, &secontext, path, links, mode)) {
+ std::vector<const char*> c_links;
+ for (const auto& link : links) {
+ c_links.emplace_back(link.c_str());
+ }
+ c_links.emplace_back(nullptr);
+ if (selabel_lookup_best_match(sehandle, &secontext, path, &c_links[0], mode)) {
PLOG(ERROR) << "Device '" << path << "' not created; cannot find SELinux label";
return;
}
@@ -356,60 +347,55 @@
/* Given a path that may start with a PCI device, populate the supplied buffer
* with the PCI domain/bus number and the peripheral ID and return 0.
* If it doesn't start with a PCI device, or there is some error, return -1 */
-static int find_pci_device_prefix(const char *path, char *buf, ssize_t buf_sz)
-{
- const char *start, *end;
+static bool find_pci_device_prefix(const std::string& path, std::string* result) {
+ result->clear();
- if (strncmp(path, "/devices/pci", 12))
- return -1;
+ if (!android::base::StartsWith(path, "/devices/pci")) return false;
/* Beginning of the prefix is the initial "pci" after "/devices/" */
- start = path + 9;
+ std::string::size_type start = 9;
/* End of the prefix is two path '/' later, capturing the domain/bus number
* and the peripheral ID. Example: pci0000:00/0000:00:1f.2 */
- end = strchr(start, '/');
- if (!end)
- return -1;
- end = strchr(end + 1, '/');
- if (!end)
- return -1;
+ auto end = path.find('/', start);
+ if (end == std::string::npos) return false;
- /* Make sure we have enough room for the string plus null terminator */
- if (end - start + 1 > buf_sz)
- return -1;
+ end = path.find('/', end + 1);
+ if (end == std::string::npos) return false;
- strncpy(buf, start, end - start);
- buf[end - start] = '\0';
- return 0;
+ auto length = end - start;
+ if (length <= 4) {
+ // The minimum string that will get to this check is 'pci/', which is malformed,
+ // so return false
+ return false;
+ }
+
+ *result = path.substr(start, length);
+ return true;
}
/* Given a path that may start with a virtual block device, populate
* the supplied buffer with the virtual block device ID and return 0.
* If it doesn't start with a virtual block device, or there is some
* error, return -1 */
-static int find_vbd_device_prefix(const char *path, char *buf, ssize_t buf_sz)
-{
- const char *start, *end;
+static bool find_vbd_device_prefix(const std::string& path, std::string* result) {
+ result->clear();
+
+ if (!android::base::StartsWith(path, "/devices/vbd-")) return false;
/* Beginning of the prefix is the initial "vbd-" after "/devices/" */
- if (strncmp(path, "/devices/vbd-", 13))
- return -1;
+ std::string::size_type start = 13;
/* End of the prefix is one path '/' later, capturing the
virtual block device ID. Example: 768 */
- start = path + 13;
- end = strchr(start, '/');
- if (!end)
- return -1;
+ auto end = path.find('/', start);
+ if (end == std::string::npos) return false;
- /* Make sure we have enough room for the string plus null terminator */
- if (end - start + 1 > buf_sz)
- return -1;
+ auto length = end - start;
+ if (length == 0) return false;
- strncpy(buf, start, end - start);
- buf[end - start] = '\0';
- return 0;
+ *result = path.substr(start, length);
+ return true;
}
static void parse_event(const char *msg, struct uevent *uevent)
@@ -467,133 +453,108 @@
}
}
-char** get_character_device_symlinks(struct uevent* uevent) {
- const char *parent;
- const char *slash;
- char **links;
- int link_num = 0;
- int width;
- struct platform_node *pdev;
-
- pdev = find_platform_device(uevent->path);
- if (!pdev)
- return NULL;
-
- links = (char**) malloc(sizeof(char *) * 2);
- if (!links)
- return NULL;
- memset(links, 0, sizeof(char *) * 2);
+std::vector<std::string> get_character_device_symlinks(uevent* uevent) {
+ platform_node* pdev = find_platform_device(uevent->path);
+ if (!pdev) return {};
/* skip "/devices/platform/<driver>" */
- parent = strchr(uevent->path + pdev->path_len, '/');
- if (!parent)
- goto err;
+ std::string parent = std::string(uevent->path);
+ auto parent_start = parent.find('/', pdev->path_len);
+ if (parent_start == std::string::npos) return {};
- if (!strncmp(parent, "/usb", 4)) {
- /* skip root hub name and device. use device interface */
- while (*++parent && *parent != '/');
- if (*parent)
- while (*++parent && *parent != '/');
- if (!*parent)
- goto err;
- slash = strchr(++parent, '/');
- if (!slash)
- goto err;
- width = slash - parent;
- if (width <= 0)
- goto err;
+ parent.erase(0, parent_start);
- if (asprintf(&links[link_num], "/dev/usb/%s%.*s", uevent->subsystem, width, parent) > 0)
- link_num++;
- else
- links[link_num] = NULL;
- mkdir("/dev/usb", 0755);
- }
- else {
- goto err;
- }
+ if (!android::base::StartsWith(parent, "/usb")) return {};
+
+ // skip root hub name and device. use device interface
+ // skip 3 slashes, including the first / by starting the search at the 1st character, not 0th.
+ // then extract what comes between the 3rd and 4th slash
+ // e.g. "/usb/usb_device/name/tty2-1:1.0" -> "name"
+
+ std::string::size_type start = 0;
+ start = parent.find('/', start + 1);
+ if (start == std::string::npos) return {};
+
+ start = parent.find('/', start + 1);
+ if (start == std::string::npos) return {};
+
+ auto end = parent.find('/', start + 1);
+ if (end == std::string::npos) return {};
+
+ start++; // Skip the first '/'
+
+ auto length = end - start;
+ if (length == 0) return {};
+
+ auto name_string = parent.substr(start, length);
+
+ // TODO: remove std::string() when uevent->subsystem is an std::string
+ std::vector<std::string> links;
+ links.emplace_back("/dev/usb/" + std::string(uevent->subsystem) + name_string);
+
+ mkdir("/dev/usb", 0755);
return links;
-err:
- free(links);
- return NULL;
}
// replaces any unacceptable characters with '_', the
// length of the resulting string is equal to the input string
-void sanitize_partition_name(char* s) {
+void sanitize_partition_name(std::string* string) {
const char* accept =
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"0123456789"
"_-.";
- if (!s) return;
+ if (!string) return;
- while (*s) {
- s += strspn(s, accept);
- if (*s) *s++ = '_';
+ std::string::size_type pos = 0;
+ while ((pos = string->find_first_not_of(accept, pos)) != std::string::npos) {
+ (*string)[pos] = '_';
}
}
-char** get_block_device_symlinks(struct uevent* uevent) {
- const char *device;
- struct platform_node *pdev;
- const char *slash;
- const char *type;
- char buf[256];
- char link_path[256];
- int link_num = 0;
- char *p;
+std::vector<std::string> get_block_device_symlinks(uevent* uevent) {
+ std::string device;
+ struct platform_node* pdev;
+ std::string type;
pdev = find_platform_device(uevent->path);
if (pdev) {
device = pdev->name;
type = "platform";
- } else if (!find_pci_device_prefix(uevent->path, buf, sizeof(buf))) {
- device = buf;
+ } else if (find_pci_device_prefix(uevent->path, &device)) {
type = "pci";
- } else if (!find_vbd_device_prefix(uevent->path, buf, sizeof(buf))) {
- device = buf;
+ } else if (find_vbd_device_prefix(uevent->path, &device)) {
type = "vbd";
} else {
- return NULL;
+ return {};
}
- char **links = (char**) malloc(sizeof(char *) * 4);
- if (!links)
- return NULL;
- memset(links, 0, sizeof(char *) * 4);
+ std::vector<std::string> links;
LOG(VERBOSE) << "found " << type << " device " << device;
- snprintf(link_path, sizeof(link_path), "/dev/block/%s/%s", type, device);
+ auto link_path = "/dev/block/" + type + "/" + device;
if (uevent->partition_name) {
- p = strdup(uevent->partition_name);
- sanitize_partition_name(p);
- if (strcmp(uevent->partition_name, p)) {
- LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '" << p << "'";
+ std::string partition_name_sanitized(uevent->partition_name);
+ sanitize_partition_name(&partition_name_sanitized);
+ if (partition_name_sanitized != uevent->partition_name) {
+ LOG(VERBOSE) << "Linking partition '" << uevent->partition_name << "' as '"
+ << partition_name_sanitized << "'";
}
- if (asprintf(&links[link_num], "%s/by-name/%s", link_path, p) > 0)
- link_num++;
- else
- links[link_num] = NULL;
- free(p);
+ links.emplace_back(link_path + "/by-name/" + partition_name_sanitized);
}
if (uevent->partition_num >= 0) {
- if (asprintf(&links[link_num], "%s/by-num/p%d", link_path, uevent->partition_num) > 0)
- link_num++;
- else
- links[link_num] = NULL;
+ links.emplace_back(link_path + "/by-num/p" + std::to_string(uevent->partition_num));
}
- slash = strrchr(uevent->path, '/');
- if (asprintf(&links[link_num], "%s/%s", link_path, slash + 1) > 0)
- link_num++;
- else
- links[link_num] = NULL;
+ // TODO: remove uevent_path when uevent->path is an std::string
+ std::string uevent_path = uevent->path;
+ auto last_slash = uevent_path.rfind('/');
+ links.emplace_back(link_path + "/" + uevent_path.substr(last_slash + 1));
return links;
}
@@ -616,33 +577,21 @@
if (android::base::Readlink(newpath, &path) && path == oldpath) unlink(newpath);
}
-static void handle_device(const char *action, const char *devpath,
- const char *path, int block, int major, int minor, char **links)
-{
+static void handle_device(const char* action, const char* devpath, const char* path, int block,
+ int major, int minor, const std::vector<std::string>& links) {
if(!strcmp(action, "add")) {
- make_device(devpath, path, block, major, minor, (const char **)links);
- if (links) {
- for (int i = 0; links[i]; i++) {
- make_link_init(devpath, links[i]);
- }
+ make_device(devpath, path, block, major, minor, links);
+ for (const auto& link : links) {
+ make_link_init(devpath, link.c_str());
}
}
if(!strcmp(action, "remove")) {
- if (links) {
- for (int i = 0; links[i]; i++) {
- remove_link(devpath, links[i]);
- }
+ for (const auto& link : links) {
+ remove_link(devpath, link.c_str());
}
unlink(devpath);
}
-
- if (links) {
- for (int i = 0; links[i]; i++) {
- free(links[i]);
- }
- free(links);
- }
}
static void handle_platform_device_event(struct uevent *uevent)
@@ -686,7 +635,6 @@
const char *base = "/dev/block/";
const char *name;
char devpath[DEVPATH_LEN];
- char **links = NULL;
name = parse_device_name(uevent, MAX_DEV_NAME);
if (!name)
@@ -695,6 +643,7 @@
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
make_dir(base, 0755);
+ std::vector<std::string> links;
if (!strncmp(uevent->path, "/devices/", 9))
links = get_block_device_symlinks(uevent);
@@ -733,7 +682,6 @@
const char *base;
const char *name;
char devpath[DEVPATH_LEN] = {0};
- char **links = NULL;
name = parse_device_name(uevent, MAX_DEV_NAME);
if (!name)
@@ -818,7 +766,7 @@
name += 4;
} else
base = "/dev/";
- links = get_character_device_symlinks(uevent);
+ auto links = get_character_device_symlinks(uevent);
if (!devpath[0])
snprintf(devpath, sizeof(devpath), "%s%s", base, name);
diff --git a/init/devices.h b/init/devices.h
index abf1e7c..f6183c9 100644
--- a/init/devices.h
+++ b/init/devices.h
@@ -20,6 +20,8 @@
#include <sys/stat.h>
#include <functional>
+#include <string>
+#include <vector>
enum coldboot_action_t {
// coldboot continues without creating the device for the uevent
@@ -59,8 +61,8 @@
// Exposed for testing
void add_platform_device(const char* path);
void remove_platform_device(const char* path);
-char** get_character_device_symlinks(uevent* uevent);
-char** get_block_device_symlinks(struct uevent* uevent);
-void sanitize_partition_name(char* s);
+std::vector<std::string> get_character_device_symlinks(uevent* uevent);
+std::vector<std::string> get_block_device_symlinks(uevent* uevent);
+void sanitize_partition_name(std::string* string);
#endif /* _INIT_DEVICES_H */
diff --git a/init/devices_test.cpp b/init/devices_test.cpp
index f79c96d..5be0d88 100644
--- a/init/devices_test.cpp
+++ b/init/devices_test.cpp
@@ -22,36 +22,22 @@
#include <android-base/scopeguard.h>
#include <gtest/gtest.h>
-template <char** (*Function)(uevent*)>
+template <std::vector<std::string> (*Function)(uevent*)>
void test_get_symlinks(const std::string& platform_device_name, uevent* uevent,
const std::vector<std::string> expected_links) {
add_platform_device(platform_device_name.c_str());
auto platform_device_remover = android::base::make_scope_guard(
[&platform_device_name]() { remove_platform_device(platform_device_name.c_str()); });
- char** result = Function(uevent);
- auto result_freer = android::base::make_scope_guard([result]() {
- if (result) {
- for (int i = 0; result[i]; i++) {
- free(result[i]);
- }
- free(result);
- }
- });
+ std::vector<std::string> result = Function(uevent);
auto expected_size = expected_links.size();
- if (expected_size == 0) {
- ASSERT_EQ(nullptr, result);
- } else {
- ASSERT_NE(nullptr, result);
- // First assert size is equal, so we don't overrun expected_links
- unsigned int size = 0;
- while (result[size]) ++size;
- ASSERT_EQ(expected_size, size);
+ ASSERT_EQ(expected_size, result.size());
+ if (expected_size == 0) return;
- for (unsigned int i = 0; i < size; ++i) {
- EXPECT_EQ(expected_links[i], result[i]);
- }
+ // Explicitly iterate so the results are visible if a failure occurs
+ for (unsigned int i = 0; i < expected_size; ++i) {
+ EXPECT_EQ(expected_links[i], result[i]);
}
}
@@ -208,6 +194,16 @@
test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
}
+TEST(devices, get_block_device_symlinks_pci_bad_format) {
+ const char* platform_device = "/devices/do/not/match";
+ uevent uevent = {
+ .path = "/devices/pci//mmcblk0", .partition_name = nullptr, .partition_num = -1,
+ };
+ std::vector<std::string> expected_result{};
+
+ test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
TEST(devices, get_block_device_symlinks_success_vbd) {
const char* platform_device = "/devices/do/not/match";
uevent uevent = {
@@ -218,6 +214,16 @@
test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
}
+TEST(devices, get_block_device_symlinks_vbd_bad_format) {
+ const char* platform_device = "/devices/do/not/match";
+ uevent uevent = {
+ .path = "/devices/vbd-/mmcblk0", .partition_name = nullptr, .partition_num = -1,
+ };
+ std::vector<std::string> expected_result{};
+
+ test_get_symlinks<get_block_device_symlinks>(platform_device, &uevent, expected_result);
+}
+
TEST(devices, get_block_device_symlinks_no_matches) {
const char* platform_device = "/devices/soc.0/f9824900.sdhci";
uevent uevent = {
@@ -236,7 +242,7 @@
TEST(devices, sanitize_empty) {
std::string empty;
- sanitize_partition_name(&empty[0]);
+ sanitize_partition_name(&empty);
EXPECT_EQ(0u, empty.size());
}
@@ -247,24 +253,24 @@
"0123456789"
"_-.";
std::string good_copy = good;
- sanitize_partition_name(&good[0]);
+ sanitize_partition_name(&good);
EXPECT_EQ(good_copy, good);
}
TEST(devices, sanitize_somebad) {
std::string string = "abc!@#$%^&*()";
- sanitize_partition_name(&string[0]);
+ sanitize_partition_name(&string);
EXPECT_EQ("abc__________", string);
}
TEST(devices, sanitize_allbad) {
std::string string = "!@#$%^&*()";
- sanitize_partition_name(&string[0]);
+ sanitize_partition_name(&string);
EXPECT_EQ("__________", string);
}
TEST(devices, sanitize_onebad) {
std::string string = ")";
- sanitize_partition_name(&string[0]);
+ sanitize_partition_name(&string);
EXPECT_EQ("_", string);
}