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Replace fixed arrays with vectors

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This effectively removes limit on length and count
  of LD_LIBRARY_PATH and LD_PRELOAD entries.

Change-Id: Ie7ea34a50d99c4018f9dd1a33aaebc4049a7f424
This commit is contained in:
Dmitriy Ivanov 2015-03-23 18:43:02 -07:00
parent ee4997ecc3
commit d165f56fb6
1 changed files with 70 additions and 52 deletions
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122
linker/linker.cpp
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@ -40,6 +40,8 @@
#include <unistd.h>
#include <new>
#include <string>
#include <vector>
// Private C library headers.
#include "private/bionic_tls.h"
@ -98,19 +100,10 @@ static const char* const kDefaultLdPaths[] = {
nullptr
};
#define LDPATH_BUFSIZE (LDPATH_MAX*64)
#define LDPATH_MAX 8
static std::vector<std::string> g_ld_library_paths;
static std::vector<std::string> g_ld_preload_names;
#define LDPRELOAD_BUFSIZE (LDPRELOAD_MAX*64)
#define LDPRELOAD_MAX 8
static char g_ld_library_paths_buffer[LDPATH_BUFSIZE];
static const char* g_ld_library_paths[LDPATH_MAX + 1];
static char g_ld_preloads_buffer[LDPRELOAD_BUFSIZE];
static const char* g_ld_preload_names[LDPRELOAD_MAX + 1];
static soinfo* g_ld_preloads[LDPRELOAD_MAX + 1];
static std::vector<soinfo*> g_ld_preloads;
__LIBC_HIDDEN__ int g_ld_debug_verbosity;
@ -295,39 +288,36 @@ static void soinfo_free(soinfo* si) {
}
static void parse_path(const char* path, const char* delimiters,
const char** array, char* buf, size_t buf_size, size_t max_count) {
std::vector<std::string>* paths) {
if (path == nullptr) {
return;
}
size_t len = strlcpy(buf, path, buf_size);
paths->clear();
size_t i = 0;
char* buf_p = buf;
while (i < max_count && (array[i] = strsep(&buf_p, delimiters))) {
if (*array[i] != '\0') {
++i;
}
for (const char *p = path; ; ++p) {
size_t len = strcspn(p, delimiters);
// skip empty tokens
if (len == 0) {
continue;
}
// Forget the last path if we had to truncate; this occurs if the 2nd to
// last char isn't '\0' (i.e. wasn't originally a delimiter).
if (i > 0 && len >= buf_size && buf[buf_size - 2] != '\0') {
array[i - 1] = nullptr;
} else {
array[i] = nullptr;
paths->push_back(std::string(p, len));
p += len;
if (*p == '\0') {
break;
}
}
}
static void parse_LD_LIBRARY_PATH(const char* path) {
parse_path(path, ":", g_ld_library_paths,
g_ld_library_paths_buffer, sizeof(g_ld_library_paths_buffer), LDPATH_MAX);
parse_path(path, ":", &g_ld_library_paths);
}
static void parse_LD_PRELOAD(const char* path) {
// We have historically supported ':' as well as ' ' in LD_PRELOAD.
parse_path(path, " :", g_ld_preload_names,
g_ld_preloads_buffer, sizeof(g_ld_preloads_buffer), LDPRELOAD_MAX);
parse_path(path, " :", &g_ld_preload_names);
}
#if defined(__arm__)
@ -883,23 +873,43 @@ static int open_library_in_zipfile(const char* const path,
return fd;
}
static int open_library_on_path(const char* name,
const char* const paths[],
off64_t* file_offset) {
char buf[512];
int fd = -1;
for (size_t i = 0; paths[i] != nullptr && fd == -1; ++i) {
const char* const path = paths[i];
int n = __libc_format_buffer(buf, sizeof(buf), "%s/%s", path, name);
if (n < 0 || n >= static_cast<int>(sizeof(buf))) {
static bool format_path(char* buf, size_t buf_size, const char* path, const char* name) {
int n = __libc_format_buffer(buf, buf_size, "%s/%s", path, name);
if (n < 0 || n >= static_cast<int>(buf_size)) {
PRINT("Warning: ignoring very long library path: %s/%s", path, name);
return -1;
return false;
}
const char* separator = strchr(path, '!');
return true;
}
if (separator != nullptr) {
static int open_library_on_default_path(const char* name, off64_t* file_offset) {
for (size_t i = 0; kDefaultLdPaths[i] != nullptr; ++i) {
char buf[512];
if(!format_path(buf, sizeof(buf), kDefaultLdPaths[i], name)) {
continue;
}
int fd = TEMP_FAILURE_RETRY(open(buf, O_RDONLY | O_CLOEXEC));
if (fd != -1) {
*file_offset = 0;
return fd;
}
}
return -1;
}
static int open_library_on_ld_library_path(const char* name, off64_t* file_offset) {
for (const auto& path_str : g_ld_library_paths) {
char buf[512];
const char* const path = path_str.c_str();
if (!format_path(buf, sizeof(buf), path, name)) {
continue;
}
int fd = -1;
if (strchr(buf, '!') != nullptr) {
fd = open_library_in_zipfile(buf, file_offset);
}
@ -909,9 +919,13 @@ static int open_library_on_path(const char* name,
*file_offset = 0;
}
}
if (fd != -1) {
return fd;
}
}
return fd;
return -1;
}
static int open_library(const char* name, off64_t* file_offset) {
@ -934,9 +948,9 @@ static int open_library(const char* name, off64_t* file_offset) {
}
// Otherwise we try LD_LIBRARY_PATH first, and fall back to the built-in well known paths.
int fd = open_library_on_path(name, g_ld_library_paths, file_offset);
int fd = open_library_on_ld_library_path(name, file_offset);
if (fd == -1) {
fd = open_library_on_path(name, kDefaultLdPaths, file_offset);
fd = open_library_on_default_path(name, file_offset);
}
return fd;
}
@ -1086,8 +1100,9 @@ static soinfo::soinfo_list_t make_global_group() {
return global_group;
}
static bool find_libraries(soinfo* start_with, const char* const library_names[], size_t library_names_count, soinfo* soinfos[],
soinfo* ld_preloads[], size_t ld_preloads_count, int rtld_flags, const android_dlextinfo* extinfo) {
static bool find_libraries(soinfo* start_with, const char* const library_names[],
size_t library_names_count, soinfo* soinfos[], std::vector<soinfo*>* ld_preloads,
size_t ld_preloads_count, int rtld_flags, const android_dlextinfo* extinfo) {
// Step 0: prepare.
LoadTaskList load_tasks;
for (size_t i = 0; i < library_names_count; ++i) {
@ -1150,7 +1165,7 @@ static bool find_libraries(soinfo* start_with, const char* const library_names[]
// for this run because they are going to appear in the local
// group in the correct order.
si->set_dt_flags_1(si->get_dt_flags_1() | DF_1_GLOBAL);
ld_preloads[soinfos_count] = si;
ld_preloads->push_back(si);
}
if (soinfos_count < library_names_count) {
@ -2674,8 +2689,9 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
StringLinkedList needed_library_name_list;
size_t needed_libraries_count = 0;
size_t ld_preloads_count = 0;
while (g_ld_preload_names[ld_preloads_count] != nullptr) {
needed_library_name_list.push_back(g_ld_preload_names[ld_preloads_count++]);
for (const auto& ld_preload_name : g_ld_preload_names) {
needed_library_name_list.push_back(ld_preload_name.c_str());
++needed_libraries_count;
}
@ -2689,7 +2705,9 @@ static ElfW(Addr) __linker_init_post_relocation(KernelArgumentBlock& args, ElfW(
memset(needed_library_names, 0, sizeof(needed_library_names));
needed_library_name_list.copy_to_array(needed_library_names, needed_libraries_count);
if (needed_libraries_count > 0 && !find_libraries(si, needed_library_names, needed_libraries_count, nullptr, g_ld_preloads, ld_preloads_count, RTLD_GLOBAL, nullptr)) {
if (needed_libraries_count > 0 &&
!find_libraries(si, needed_library_names, needed_libraries_count, nullptr,
&g_ld_preloads, ld_preloads_count, RTLD_GLOBAL, nullptr)) {
__libc_format_fd(2, "CANNOT LINK EXECUTABLE: %s\n", linker_get_error_buffer());
exit(EXIT_FAILURE);
} else if (needed_libraries_count == 0) {