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af7bd80430
This change introduces a new deadlock detector for Cosmo's POSIX threads implementation. Error check mutexes will now track a DAG of nested locks and report EDEADLK when a deadlock is theoretically possible. These will occur rarely, but it's important for production hardening your code. You don't even need to change your mutexes to use the POSIX error check mode because `cosmocc -mdbg` will enable error checking on mutexes by default globally. When cycles are found, an error message showing your demangled symbols describing the strongly connected component are printed and then the SIGTRAP is raised, which means you'll also get a backtrace if you're using ShowCrashReports() too. This new error checker is so low-level and so pure that it's able to verify the relationships of every libc runtime lock, including those locks upon which the mutex implementation depends.
49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
#ifndef COSMOPOLITAN_LIBC_STDIO_INTERNAL_H_
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#define COSMOPOLITAN_LIBC_STDIO_INTERNAL_H_
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#include "libc/atomic.h"
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#include "libc/intrin/dll.h"
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#include "libc/stdio/stdio.h"
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#include "libc/thread/thread.h"
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#define PUSHBACK 12
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#define FILE_CONTAINER(e) DLL_CONTAINER(struct FILE, elem, e)
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COSMOPOLITAN_C_START_
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struct FILE {
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char bufmode; /* _IOFBF, _IOLBF, or _IONBF */
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char freethis; /* fclose() should free(this) */
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char freebuf; /* fclose() should free(this->buf) */
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char forking; /* used by fork() implementation */
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int oflags; /* O_RDONLY, etc. */
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int state; /* 0=OK, -1=EOF, >0=errno */
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int fd; /* ≥0=fd, -1=closed|buffer */
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int pid;
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atomic_int refs;
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unsigned size;
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unsigned beg;
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unsigned end;
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char *buf;
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pthread_mutex_t lock;
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struct Dll elem;
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char *getln;
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};
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struct Stdio {
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pthread_mutex_t lock; /* Subordinate to FILE::lock */
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struct Dll *files;
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};
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extern struct Stdio __stdio;
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void __stdio_lock(void);
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void __stdio_unlock(void);
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void __stdio_ref(FILE *);
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void __stdio_unref(FILE *);
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void __stdio_unref_unlocked(FILE *);
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bool __stdio_isok(FILE *);
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FILE *__stdio_alloc(void);
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COSMOPOLITAN_C_END_
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#endif /* COSMOPOLITAN_LIBC_STDIO_INTERNAL_H_ */
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