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36 * @(#)findfp.c 8.2 (Berkeley) 1/4/94
37 * $FreeBSD: src/lib/libc/stdio/findfp.c,v 1.7.2.3 2001/08/17 02:56:31 peter Exp $
38 * $DragonFly: src/lib/libcr/stdio/Attic/findfp.c,v 1.3 2003/11/12 20:21:28 eirikn Exp $
41 #include <sys/param.h>
48 #include <libc_private.h>
56 #define NDYNAMIC 10 /* add ten more whenever necessary */
58 #define std(flags, file) \
59 {0,0,0,flags,file,{0},0,__sF+file,__sclose,__sread,__sseek,__swrite}
60 /* p r w flags file _bf z cookie close read seek write */
62 /* the usual - (stdin + stdout + stderr) */
63 static FILE usual[FOPEN_MAX - 3];
64 static struct glue uglue = { 0, FOPEN_MAX - 3, usual };
67 std(__SRD, STDIN_FILENO), /* stdin */
68 std(__SWR, STDOUT_FILENO), /* stdout */
69 std(__SWR|__SNBF, STDERR_FILENO) /* stderr */
71 struct glue __sglue = { &uglue, 3, __sF };
74 * The following kludge is done to ensure enough binary compatibility
75 * with future versions of libc. Or rather it allows us to work with
76 * libraries that have been built with a newer libc that defines these
77 * symbols and expects libc to provide them. We only have need to support
78 * i386 and alpha because they are the only "old" systems we have deployed.
80 FILE *__stdinp = &__sF[0];
81 FILE *__stdoutp = &__sF[1];
82 FILE *__stderrp = &__sF[2];
84 static struct glue * moreglue (int);
86 static spinlock_t thread_lock = _SPINLOCK_INITIALIZER;
87 #define THREAD_LOCK() if (__isthreaded) _SPINLOCK(&thread_lock)
88 #define THREAD_UNLOCK() if (__isthreaded) _SPINUNLOCK(&thread_lock)
94 register struct glue *g;
98 g = (struct glue *)malloc(sizeof(*g) + ALIGNBYTES + n * sizeof(FILE));
101 p = (FILE *)ALIGN(g + 1);
111 * Find a free FILE for fopen et al.
118 register struct glue *g;
123 for (g = &__sglue;; g = g->next) {
124 for (fp = g->iobs, n = g->niobs; --n >= 0; fp++)
127 if (g->next == NULL && (g->next = moreglue(NDYNAMIC)) == NULL)
133 fp->_flags = 1; /* reserve this slot; caller sets real flags */
135 fp->_p = NULL; /* no current pointer */
136 fp->_w = 0; /* nothing to read or write */
138 fp->_bf._base = NULL; /* no buffer */
140 fp->_lbfsize = 0; /* not line buffered */
141 fp->_file = -1; /* no file */
142 /* fp->_cookie = <any>; */ /* caller sets cookie, _read/_write etc */
143 fp->_ub._base = NULL; /* no ungetc buffer */
145 fp->_lb._base = NULL; /* no line buffer */
151 * XXX. Force immediate allocation of internal memory. Not used by stdio,
152 * but documented historically for certain applications. Bad applications.
154 __warn_references(f_prealloc,
155 "warning: this program uses f_prealloc(), which is not recommended.");
160 register struct glue *g;
163 n = getdtablesize() - FOPEN_MAX + 20; /* 20 for slop. */
164 for (g = &__sglue; (n -= g->niobs) > 0 && g->next; g = g->next)
167 g->next = moreglue(n);
171 * exit() calls _cleanup() through *__cleanup, set whenever we
172 * open or buffer a file. This chicanery is done so that programs
173 * that do not use stdio need not link it all in.
175 * The name `_cleanup' is, alas, fairly well known outside stdio.
180 /* (void) _fwalk(fclose); */
181 (void) _fwalk(__sflush); /* `cheating' */
185 * __sinit() is called whenever stdio's internal variables must be set up.
190 /* make sure we clean up on exit */
191 __cleanup = _cleanup; /* conservative */