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Have ReExec read environment from /proc/self/environ

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It is possible for ReExec to be called before the C standard library
has initialised itself sufficiently for execv to work properly.
Fix this by parsing the environment ourselves and using execve.

Differential Revision: http://llvm-reviews.chandlerc.com/D304

llvm-svn: 172748
This commit is contained in:
Peter Collingbourne 2013-01-17 19:50:42 +00:00
parent 94b8cdbf55
commit 6600516a58
1 changed files with 20 additions and 13 deletions
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33
compiler-rt/lib/sanitizer_common/sanitizer_linux.cc
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@ -201,24 +201,31 @@ const char *GetEnv(const char *name) {
return 0; // Not found.
}
void ReExec() {
static const int kMaxArgv = 100;
InternalScopedBuffer<char*> argv(kMaxArgv + 1);
static char *buff;
static void ReadNullSepFileToArray(const char *path, char ***arr,
int arr_size) {
char *buff;
uptr buff_size = 0;
ReadFileToBuffer("/proc/self/cmdline", &buff, &buff_size, 1024 * 1024);
argv[0] = buff;
int argc, i;
for (argc = 1, i = 1; ; i++) {
*arr = (char **)MmapOrDie(arr_size * sizeof(char *), "NullSepFileArray");
ReadFileToBuffer(path, &buff, &buff_size, 1024 * 1024);
(*arr)[0] = buff;
int count, i;
for (count = 1, i = 1; ; i++) {
if (buff[i] == 0) {
if (buff[i+1] == 0) break;
argv[argc] = &buff[i+1];
CHECK_LE(argc, kMaxArgv); // FIXME: make this more flexible.
argc++;
(*arr)[count] = &buff[i+1];
CHECK_LE(count, arr_size - 1); // FIXME: make this more flexible.
count++;
}
}
argv[argc] = 0;
execv(argv[0], argv.data());
(*arr)[count] = 0;
}
void ReExec() {
static const int kMaxArgv = 100, kMaxEnvp = 1000;
char **argv, **envp;
ReadNullSepFileToArray("/proc/self/cmdline", &argv, kMaxArgv);
ReadNullSepFileToArray("/proc/self/environ", &envp, kMaxEnvp);
execve(argv[0], argv, envp);
}
void PrepareForSandboxing() {