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Crashlog: Support gdb read when /dev/null is missing

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This commit is contained in:
Jonathan G Rennison
2022-05-31 22:58:16 +01:00
parent d83f0d0cda
commit 220390ed3e
1 changed files with 67 additions and 23 deletions
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90
src/os/unix/crashlog_unix.cpp
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@@ -72,16 +72,66 @@ static void LogStacktraceSigSegvHandler(int sig)
} }
#endif #endif
static int GetTemporaryFD()
{
char name[MAX_PATH];
extern std::string _personal_dir;
seprintf(name, lastof(name), "%sopenttd-tmp-XXXXXX", _personal_dir.c_str());
int fd = mkstemp(name);
if (fd != -1) {
/* Unlink file but leave fd open until finished with */
unlink(name);
}
return fd;
}
struct ExecReadNullHandler {
int fd[2] = { -1, -1 };
bool Init() {
this->fd[0] = open("/dev/null", O_RDWR);
if (this->fd[0] == -1) {
this->fd[0] = GetTemporaryFD();
if (this->fd[0] == -1) {
return false;
}
this->fd[1] = GetTemporaryFD();
if (this->fd[1] == -1) {
this->Close();
return false;
}
} else {
this->fd[1] = this->fd[0];
}
return true;
}
void Close() {
if (this->fd[0] != -1) close(this->fd[0]);
if (this->fd[1] != -1 && this->fd[0] != this->fd[1]) close(this->fd[1]);
this->fd[0] = -1;
this->fd[1] = -1;
}
};
static bool ExecReadStdout(const char *file, char *const *args, char *&buffer, const char *last) static bool ExecReadStdout(const char *file, char *const *args, char *&buffer, const char *last)
{ {
int null_fd = open("/dev/null", O_RDWR); ExecReadNullHandler nulls;
if (null_fd == -1) return false; if (!nulls.Init()) return false;
int pipefd[2]; int pipefd[2];
if (pipe(pipefd) == -1) return false; if (pipe(pipefd) == -1) {
nulls.Close();
return false;
}
int pid = fork(); int pid = fork();
if (pid < 0) return false; if (pid < 0) {
nulls.Close();
close(pipefd[0]);
close(pipefd[1]);
return false;
}
if (pid == 0) { if (pid == 0) {
/* child */ /* child */
@@ -89,9 +139,9 @@ static bool ExecReadStdout(const char *file, char *const *args, char *&buffer, c
close(pipefd[0]); /* Close unused read end */ close(pipefd[0]); /* Close unused read end */
dup2(pipefd[1], STDOUT_FILENO); dup2(pipefd[1], STDOUT_FILENO);
close(pipefd[1]); close(pipefd[1]);
dup2(null_fd, STDERR_FILENO); dup2(nulls.fd[0], STDERR_FILENO);
dup2(null_fd, STDIN_FILENO); dup2(nulls.fd[1], STDIN_FILENO);
close(null_fd); nulls.Close();
execvp(file, args); execvp(file, args);
exit(42); exit(42);
@@ -99,7 +149,7 @@ static bool ExecReadStdout(const char *file, char *const *args, char *&buffer, c
/* parent */ /* parent */
close(null_fd); nulls.Close();
close(pipefd[1]); /* Close unused write end */ close(pipefd[1]); /* Close unused write end */
while (buffer < last) { while (buffer < last) {
@@ -130,24 +180,18 @@ static bool ExecReadStdout(const char *file, char *const *args, char *&buffer, c
static bool ExecReadStdoutThroughFile(const char *file, char *const *args, char *&buffer, const char *last) static bool ExecReadStdoutThroughFile(const char *file, char *const *args, char *&buffer, const char *last)
{ {
int null_fd = open("/dev/null", O_RDWR); ExecReadNullHandler nulls;
if (null_fd == -1) return false; if (!nulls.Init()) return false;
char name[MAX_PATH]; int fd = GetTemporaryFD();
extern std::string _personal_dir;
seprintf(name, lastof(name), "%sopenttd-tmp-XXXXXX", _personal_dir.c_str());
int fd = mkstemp(name);
if (fd == -1) { if (fd == -1) {
close(null_fd); nulls.Close();
return false; return false;
} }
/* Unlink file but leave fd open until finished with */
unlink(name);
int pid = fork(); int pid = fork();
if (pid < 0) { if (pid < 0) {
close(null_fd); nulls.Close();
close(fd); close(fd);
return false; return false;
} }
@@ -157,9 +201,9 @@ static bool ExecReadStdoutThroughFile(const char *file, char *const *args, char
dup2(fd, STDOUT_FILENO); dup2(fd, STDOUT_FILENO);
close(fd); close(fd);
dup2(null_fd, STDERR_FILENO); dup2(nulls.fd[0], STDERR_FILENO);
dup2(null_fd, STDIN_FILENO); dup2(nulls.fd[1], STDIN_FILENO);
close(null_fd); nulls.Close();
execvp(file, args); execvp(file, args);
exit(42); exit(42);
@@ -167,7 +211,7 @@ static bool ExecReadStdoutThroughFile(const char *file, char *const *args, char
/* parent */ /* parent */
close(null_fd); nulls.Close();
int status; int status;
int wait_ret = waitpid(pid, &status, 0); int wait_ret = waitpid(pid, &status, 0);