Hi Xi! On 5/18/23 19:25, Xi Ruoyao via Libc-alpha wrote: > During the review of a GCC analyzer test case, we found most stdio > functions accepting a FILE * argument expect it to be nonnull and just > segfault when the argument is NULL. Add nonnull attribute for them. > > setbuf is well defined when __stream is NULL so it's not touched. > > For fputs, fgets, fread, fwrite, fprintf, vfprintf, and their unlocked > version, if __stream is empty but there is nothing to read or write, > they don't segfault and I'm not sure if the standard allows such a use > so I left them out. > --- > libio/stdio.h | 119 ++++++++++++++++++++++++++------------------------ > 1 file changed, 62 insertions(+), 57 deletions(-) > > diff --git a/libio/stdio.h b/libio/stdio.h > index 4cf9f1c012..ae3d7295d4 100644 > --- a/libio/stdio.h > +++ b/libio/stdio.h > @@ -232,7 +232,7 @@ extern char *tempnam (const char *__dir, const char *__pfx) > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern int fflush (FILE *__stream); > +extern int fflush (FILE *__stream) __nonnull ((1)); flush(NULL) is well defined. It flushes all streams that can be flushed. This reminds me that I should document that in the SYNOPSIS section of the manual page; an oversight on my side. > > #ifdef __USE_MISC > /* Faster versions when locking is not required. > @@ -241,7 +241,7 @@ extern int fflush (FILE *__stream); > cancellation point. But due to similarity with an POSIX interface > or due to the implementation it is a cancellation point and > therefore not marked with __THROW. */ > -extern int fflush_unlocked (FILE *__stream); > +extern int fflush_unlocked (FILE *__stream) __nonnull ((1)); Without checking, I'll guess that fflush_unlocked(NULL) is also well defined. I didn't see any other similar cases, but I may have missed some; I didn't revise them all thoroughly; please check. > #endif > > #ifdef __USE_GNU > @@ -278,7 +278,7 @@ extern FILE *__REDIRECT (fopen, (const char *__restrict __filename, > extern FILE *__REDIRECT (freopen, (const char *__restrict __filename, > const char *__restrict __modes, > FILE *__restrict __stream), freopen64) > - __wur; > + __wur __nonnull ((3)); > # else > # define fopen fopen64 > # define freopen freopen64 > @@ -335,16 +335,16 @@ extern void setbuf (FILE *__restrict __stream, char *__restrict __buf) __THROW; > If BUF is not NULL, use N bytes of it for buffering; > else allocate an internal buffer N bytes long. */ > extern int setvbuf (FILE *__restrict __stream, char *__restrict __buf, > - int __modes, size_t __n) __THROW; > + int __modes, size_t __n) __THROW __nonnull ((1)); > > #ifdef __USE_MISC > /* If BUF is NULL, make STREAM unbuffered. > Else make it use SIZE bytes of BUF for buffering. */ > extern void setbuffer (FILE *__restrict __stream, char *__restrict __buf, > - size_t __size) __THROW; > + size_t __size) __THROW __nonnull ((1)); > > /* Make STREAM line-buffered. */ > -extern void setlinebuf (FILE *__stream) __THROW; > +extern void setlinebuf (FILE *__stream) __THROW __nonnull ((1)); > #endif > > > @@ -418,7 +418,7 @@ extern int dprintf (int __fd, const char *__restrict __fmt, ...) > This function is a possible cancellation point and therefore not > marked with __THROW. */ > extern int fscanf (FILE *__restrict __stream, > - const char *__restrict __format, ...) __wur; > + const char *__restrict __format, ...) __wur __nonnull ((1)); > /* Read formatted input from stdin. > > This function is a possible cancellation point and therefore not > @@ -439,7 +439,7 @@ extern int sscanf (const char *__restrict __s, > # ifdef __REDIRECT > extern int __REDIRECT (fscanf, (FILE *__restrict __stream, > const char *__restrict __format, ...), > - __isoc23_fscanf) __wur; > + __isoc23_fscanf) __wur __nonnull ((1)); > extern int __REDIRECT (scanf, (const char *__restrict __format, ...), > __isoc23_scanf) __wur; > extern int __REDIRECT_NTH (sscanf, (const char *__restrict __s, > @@ -447,7 +447,7 @@ extern int __REDIRECT_NTH (sscanf, (const char *__restrict __s, > __isoc23_sscanf); > # else > extern int __isoc23_fscanf (FILE *__restrict __stream, > - const char *__restrict __format, ...) __wur; > + const char *__restrict __format, ...) __wur __nonnull ((1)); > extern int __isoc23_scanf (const char *__restrict __format, ...) __wur; > extern int __isoc23_sscanf (const char *__restrict __s, > const char *__restrict __format, ...) __THROW; > @@ -459,7 +459,7 @@ extern int __isoc23_sscanf (const char *__restrict __s, > # ifdef __REDIRECT > extern int __REDIRECT (fscanf, (FILE *__restrict __stream, > const char *__restrict __format, ...), > - __isoc99_fscanf) __wur; > + __isoc99_fscanf) __wur __nonnull ((1)); > extern int __REDIRECT (scanf, (const char *__restrict __format, ...), > __isoc99_scanf) __wur; > extern int __REDIRECT_NTH (sscanf, (const char *__restrict __s, > @@ -467,7 +467,7 @@ extern int __REDIRECT_NTH (sscanf, (const char *__restrict __s, > __isoc99_sscanf); > # else > extern int __isoc99_fscanf (FILE *__restrict __stream, > - const char *__restrict __format, ...) __wur; > + const char *__restrict __format, ...) __wur __nonnull ((1)); > extern int __isoc99_scanf (const char *__restrict __format, ...) __wur; > extern int __isoc99_sscanf (const char *__restrict __s, > const char *__restrict __format, ...) __THROW; > @@ -485,7 +485,7 @@ extern int __isoc99_sscanf (const char *__restrict __s, > marked with __THROW. */ > extern int vfscanf (FILE *__restrict __s, const char *__restrict __format, > __gnuc_va_list __arg) > - __attribute__ ((__format__ (__scanf__, 2, 0))) __wur; > + __attribute__ ((__format__ (__scanf__, 2, 0))) __wur __nonnull ((1)); > > /* Read formatted input from stdin into argument list ARG. > > @@ -508,7 +508,7 @@ extern int __REDIRECT (vfscanf, > (FILE *__restrict __s, > const char *__restrict __format, __gnuc_va_list __arg), > __isoc23_vfscanf) > - __attribute__ ((__format__ (__scanf__, 2, 0))) __wur; > + __attribute__ ((__format__ (__scanf__, 2, 0))) __wur __nonnull ((1)); > extern int __REDIRECT (vscanf, (const char *__restrict __format, > __gnuc_va_list __arg), __isoc23_vscanf) > __attribute__ ((__format__ (__scanf__, 1, 0))) __wur; > @@ -520,7 +520,7 @@ extern int __REDIRECT_NTH (vsscanf, > # elif !defined __REDIRECT > extern int __isoc23_vfscanf (FILE *__restrict __s, > const char *__restrict __format, > - __gnuc_va_list __arg) __wur; > + __gnuc_va_list __arg) __wur __nonnull ((1)); > extern int __isoc23_vscanf (const char *__restrict __format, > __gnuc_va_list __arg) __wur; > extern int __isoc23_vsscanf (const char *__restrict __s, > @@ -537,7 +537,7 @@ extern int __REDIRECT (vfscanf, > (FILE *__restrict __s, > const char *__restrict __format, __gnuc_va_list __arg), > __isoc99_vfscanf) > - __attribute__ ((__format__ (__scanf__, 2, 0))) __wur; > + __attribute__ ((__format__ (__scanf__, 2, 0))) __wur __nonnull ((1)); > extern int __REDIRECT (vscanf, (const char *__restrict __format, > __gnuc_va_list __arg), __isoc99_vscanf) > __attribute__ ((__format__ (__scanf__, 1, 0))) __wur; > @@ -549,7 +549,7 @@ extern int __REDIRECT_NTH (vsscanf, > # elif !defined __REDIRECT > extern int __isoc99_vfscanf (FILE *__restrict __s, > const char *__restrict __format, > - __gnuc_va_list __arg) __wur; > + __gnuc_va_list __arg) __wur __nonnull ((1)); > extern int __isoc99_vscanf (const char *__restrict __format, > __gnuc_va_list __arg) __wur; > extern int __isoc99_vsscanf (const char *__restrict __s, > @@ -568,8 +568,8 @@ extern int __isoc99_vsscanf (const char *__restrict __s, > > These functions are possible cancellation points and therefore not > marked with __THROW. */ > -extern int fgetc (FILE *__stream); > -extern int getc (FILE *__stream); > +extern int fgetc (FILE *__stream) __nonnull ((1)); > +extern int getc (FILE *__stream) __nonnull ((1)); > > /* Read a character from stdin. > > @@ -582,7 +582,7 @@ extern int getchar (void); > > These functions are possible cancellation points and therefore not > marked with __THROW. */ > -extern int getc_unlocked (FILE *__stream); > +extern int getc_unlocked (FILE *__stream) __nonnull ((1)); > extern int getchar_unlocked (void); > #endif /* Use POSIX. */ > > @@ -593,7 +593,7 @@ extern int getchar_unlocked (void); > cancellation point. But due to similarity with an POSIX interface > or due to the implementation it is a cancellation point and > therefore not marked with __THROW. */ > -extern int fgetc_unlocked (FILE *__stream); > +extern int fgetc_unlocked (FILE *__stream) __nonnull ((1)); > #endif /* Use MISC. */ > > > @@ -604,8 +604,8 @@ extern int fgetc_unlocked (FILE *__stream); > > These functions is a possible cancellation point and therefore not Aside: here's a typo mixing plural and singular in the sentence (not part of your commit). I'll prepare a patch for it. > marked with __THROW. */ > -extern int fputc (int __c, FILE *__stream); > -extern int putc (int __c, FILE *__stream); > +extern int fputc (int __c, FILE *__stream) __nonnull ((2)); > +extern int putc (int __c, FILE *__stream) __nonnull ((2)); > > /* Write a character to stdout. > > @@ -620,7 +620,7 @@ extern int putchar (int __c); > cancellation point. But due to similarity with an POSIX interface > or due to the implementation it is a cancellation point and > therefore not marked with __THROW. */ > -extern int fputc_unlocked (int __c, FILE *__stream); > +extern int fputc_unlocked (int __c, FILE *__stream) __nonnull ((2)); > #endif /* Use MISC. */ > > #ifdef __USE_POSIX199506 > @@ -628,7 +628,7 @@ extern int fputc_unlocked (int __c, FILE *__stream); > > These functions are possible cancellation points and therefore not > marked with __THROW. */ > -extern int putc_unlocked (int __c, FILE *__stream); > +extern int putc_unlocked (int __c, FILE *__stream) __nonnull ((2)); > extern int putchar_unlocked (int __c); > #endif /* Use POSIX. */ > > @@ -636,10 +636,10 @@ extern int putchar_unlocked (int __c); > #if defined __USE_MISC \ > || (defined __USE_XOPEN && !defined __USE_XOPEN2K) > /* Get a word (int) from STREAM. */ > -extern int getw (FILE *__stream); > +extern int getw (FILE *__stream) __nonnull ((1)); > > /* Write a word (int) to STREAM. */ > -extern int putw (int __w, FILE *__stream); > +extern int putw (int __w, FILE *__stream) __nonnull ((2)); > #endif > > > @@ -689,10 +689,10 @@ extern char *fgets_unlocked (char *__restrict __s, int __n, > therefore not marked with __THROW. */ > extern __ssize_t __getdelim (char **__restrict __lineptr, > size_t *__restrict __n, int __delimiter, > - FILE *__restrict __stream) __wur; > + FILE *__restrict __stream) __wur __nonnull ((4)); > extern __ssize_t getdelim (char **__restrict __lineptr, > size_t *__restrict __n, int __delimiter, > - FILE *__restrict __stream) __wur; > + FILE *__restrict __stream) __wur __nonnull ((4)); > > /* Like `getdelim', but reads up to a newline. > > @@ -702,7 +702,7 @@ extern __ssize_t getdelim (char **__restrict __lineptr, > therefore not marked with __THROW. */ > extern __ssize_t getline (char **__restrict __lineptr, > size_t *__restrict __n, > - FILE *__restrict __stream) __wur; > + FILE *__restrict __stream) __wur __nonnull ((3)); > #endif > > > @@ -723,7 +723,7 @@ extern int puts (const char *__s); > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern int ungetc (int __c, FILE *__stream); > +extern int ungetc (int __c, FILE *__stream) __nonnull ((2)); > > > /* Read chunks of generic data from STREAM. > @@ -768,17 +768,17 @@ extern size_t fwrite_unlocked (const void *__restrict __ptr, size_t __size, > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern int fseek (FILE *__stream, long int __off, int __whence); > +extern int fseek (FILE *__stream, long int __off, int __whence) __nonnull ((1)); > /* Return the current position of STREAM. > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern long int ftell (FILE *__stream) __wur; > +extern long int ftell (FILE *__stream) __wur __nonnull ((1)); > /* Rewind to the beginning of STREAM. > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern void rewind (FILE *__stream); > +extern void rewind (FILE *__stream) __nonnull ((1)); > > /* The Single Unix Specification, Version 2, specifies an alternative, > more adequate interface for the two functions above which deal with > @@ -791,18 +791,19 @@ extern void rewind (FILE *__stream); > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern int fseeko (FILE *__stream, __off_t __off, int __whence); > +extern int fseeko (FILE *__stream, __off_t __off, int __whence) __nonnull ((1)); > /* Return the current position of STREAM. > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern __off_t ftello (FILE *__stream) __wur; > +extern __off_t ftello (FILE *__stream) __wur __nonnull ((1)); > # else > # ifdef __REDIRECT > extern int __REDIRECT (fseeko, > (FILE *__stream, __off64_t __off, int __whence), > - fseeko64); > -extern __off64_t __REDIRECT (ftello, (FILE *__stream), ftello64); > + fseeko64) __nonnull ((1)); > +extern __off64_t __REDIRECT (ftello, (FILE *__stream), ftello64) > + __nonnull ((1)); > # else > # define fseeko fseeko64 > # define ftello ftello64 > @@ -815,18 +816,20 @@ extern __off64_t __REDIRECT (ftello, (FILE *__stream), ftello64); > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern int fgetpos (FILE *__restrict __stream, fpos_t *__restrict __pos); > +extern int fgetpos (FILE *__restrict __stream, fpos_t *__restrict __pos) > + __nonnull ((1)); > /* Set STREAM's position. > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern int fsetpos (FILE *__stream, const fpos_t *__pos); > +extern int fsetpos (FILE *__stream, const fpos_t *__pos) __nonnull ((1)); > #else > # ifdef __REDIRECT > extern int __REDIRECT (fgetpos, (FILE *__restrict __stream, > - fpos_t *__restrict __pos), fgetpos64); > + fpos_t *__restrict __pos), fgetpos64) __nonnull ((1)); > extern int __REDIRECT (fsetpos, > - (FILE *__stream, const fpos_t *__pos), fsetpos64); > + (FILE *__stream, const fpos_t *__pos), fsetpos64) > + __nonnull ((1)); > # else > # define fgetpos fgetpos64 > # define fsetpos fsetpos64 > @@ -834,24 +837,26 @@ extern int __REDIRECT (fsetpos, > #endif > > #ifdef __USE_LARGEFILE64 > -extern int fseeko64 (FILE *__stream, __off64_t __off, int __whence); > -extern __off64_t ftello64 (FILE *__stream) __wur; > -extern int fgetpos64 (FILE *__restrict __stream, fpos64_t *__restrict __pos); > -extern int fsetpos64 (FILE *__stream, const fpos64_t *__pos); > +extern int fseeko64 (FILE *__stream, __off64_t __off, int __whence) > + __nonnull ((1)); > +extern __off64_t ftello64 (FILE *__stream) __wur __nonnull ((1)); > +extern int fgetpos64 (FILE *__restrict __stream, fpos64_t *__restrict __pos) > + __nonnull ((1)); > +extern int fsetpos64 (FILE *__stream, const fpos64_t *__pos) __nonnull ((1)); > #endif > > /* Clear the error and EOF indicators for STREAM. */ > -extern void clearerr (FILE *__stream) __THROW; > +extern void clearerr (FILE *__stream) __THROW __nonnull ((1)); > /* Return the EOF indicator for STREAM. */ > -extern int feof (FILE *__stream) __THROW __wur; > +extern int feof (FILE *__stream) __THROW __wur __nonnull ((1)); > /* Return the error indicator for STREAM. */ > -extern int ferror (FILE *__stream) __THROW __wur; > +extern int ferror (FILE *__stream) __THROW __wur __nonnull ((1)); > > #ifdef __USE_MISC > /* Faster versions when locking is not required. */ > -extern void clearerr_unlocked (FILE *__stream) __THROW; > -extern int feof_unlocked (FILE *__stream) __THROW __wur; > -extern int ferror_unlocked (FILE *__stream) __THROW __wur; > +extern void clearerr_unlocked (FILE *__stream) __THROW __nonnull ((1)); > +extern int feof_unlocked (FILE *__stream) __THROW __wur __nonnull ((1)); > +extern int ferror_unlocked (FILE *__stream) __THROW __wur __nonnull ((1)); > #endif > > > @@ -864,12 +869,12 @@ extern void perror (const char *__s) __COLD; > > #ifdef __USE_POSIX > /* Return the system file descriptor for STREAM. */ > -extern int fileno (FILE *__stream) __THROW __wur; > +extern int fileno (FILE *__stream) __THROW __wur __nonnull ((1)); > #endif /* Use POSIX. */ > > #ifdef __USE_MISC > /* Faster version when locking is not required. */ > -extern int fileno_unlocked (FILE *__stream) __THROW __wur; > +extern int fileno_unlocked (FILE *__stream) __THROW __wur __nonnull ((1)); > #endif > > > @@ -878,7 +883,7 @@ extern int fileno_unlocked (FILE *__stream) __THROW __wur; > > This function is a possible cancellation point and therefore not > marked with __THROW. */ > -extern int pclose (FILE *__stream); > +extern int pclose (FILE *__stream) __nonnull ((1)); You didn't patch fclose(3). Any reason? I guess it's similarly UB to call fclose(NULL). Cheers, Alex > > /* Create a new stream connected to a pipe running the given command. > > @@ -922,14 +927,14 @@ extern int obstack_vprintf (struct obstack *__restrict __obstack, > /* These are defined in POSIX.1:1996. */ > > /* Acquire ownership of STREAM. */ > -extern void flockfile (FILE *__stream) __THROW; > +extern void flockfile (FILE *__stream) __THROW __nonnull ((1)); > > /* Try to acquire ownership of STREAM but do not block if it is not > possible. */ > -extern int ftrylockfile (FILE *__stream) __THROW __wur; > +extern int ftrylockfile (FILE *__stream) __THROW __wur __nonnull ((1)); > > /* Relinquish the ownership granted for STREAM. */ > -extern void funlockfile (FILE *__stream) __THROW; > +extern void funlockfile (FILE *__stream) __THROW __nonnull ((1)); > #endif /* POSIX */ > > #if defined __USE_XOPEN && !defined __USE_XOPEN2K && !defined __USE_GNU -- GPG key fingerprint: A9348594CE31283A826FBDD8D57633D441E25BB5