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| Rev | Author | Line No. | Line |
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| 2 | pj | 1 | /* |
| 2 | * xfermem.c |
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| 3 | * |
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| 4 | * Oliver Fromme <oliver.fromme@heim3.tu-clausthal.de> |
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| 5 | * Sun Apr 6 02:26:26 MET DST 1997 |
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| 6 | * |
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| 7 | * See xfermem.h for documentation/description. |
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| 8 | */ |
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| 9 | |||
| 10 | #include <stdio.h> |
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| 11 | #include <stdlib.h> |
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| 12 | #include <string.h> |
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| 13 | #include <unistd.h> |
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| 14 | #include <errno.h> |
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| 15 | #include <sys/types.h> |
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| 16 | #include <sys/time.h> |
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| 17 | #include <sys/uio.h> |
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| 18 | #include <sys/mman.h> |
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| 19 | #include <sys/socket.h> |
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| 20 | #include <fcntl.h> |
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| 21 | |||
| 22 | #include "xfermem.h" |
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| 23 | #include "mpg123.h" |
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| 24 | |||
| 25 | #ifndef USE_MMAP |
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| 26 | #include <sys/ipc.h> |
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| 27 | #include <sys/shm.h> |
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| 28 | #endif |
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| 29 | |||
| 30 | extern int errno; |
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| 31 | |||
| 32 | #if defined (USE_MMAP) && defined(MAP_ANONYMOUS) && !defined(MAP_ANON) |
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| 33 | #define MAP_ANON MAP_ANONYMOUS |
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| 34 | #endif |
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| 35 | |||
| 36 | void xfermem_init (txfermem **xf, int bufsize, int msize) |
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| 37 | { |
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| 38 | int regsize = bufsize + msize + sizeof(txfermem); |
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| 39 | |||
| 40 | #ifdef USE_MMAP |
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| 41 | # ifdef MAP_ANON |
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| 42 | if ((*xf = (txfermem *) mmap(0, regsize, PROT_READ | PROT_WRITE, |
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| 43 | MAP_ANON | MAP_SHARED, -1, 0)) == (txfermem *) -1) { |
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| 44 | perror ("mmap()"); |
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| 45 | exit (1); |
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| 46 | } |
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| 47 | # else |
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| 48 | int devzero; |
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| 49 | if ((devzero = open("/dev/zero", O_RDWR, 0)) == -1) { |
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| 50 | perror ("open(/dev/zero)"); |
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| 51 | exit (1); |
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| 52 | } |
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| 53 | if ((*xf = (txfermem *) mmap(0, regsize, PROT_READ | PROT_WRITE, |
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| 54 | MAP_SHARED, devzero, 0)) == (txfermem *) -1) { |
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| 55 | perror ("mmap()"); |
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| 56 | exit (1); |
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| 57 | } |
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| 58 | close (devzero); |
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| 59 | # endif |
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| 60 | #else |
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| 61 | struct shmid_ds shmemds; |
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| 62 | int shmemid; |
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| 63 | if ((shmemid = shmget(IPC_PRIVATE, regsize, IPC_CREAT | 0600)) == -1) { |
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| 64 | perror ("shmget()"); |
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| 65 | exit (1); |
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| 66 | } |
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| 67 | if ((*xf = (txfermem *) shmat(shmemid, 0, 0)) == (txfermem *) -1) { |
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| 68 | perror ("shmat()"); |
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| 69 | shmctl (shmemid, IPC_RMID, &shmemds); |
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| 70 | exit (1); |
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| 71 | } |
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| 72 | if (shmctl(shmemid, IPC_RMID, &shmemds) == -1) { |
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| 73 | perror ("shmctl()"); |
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| 74 | xfermem_done (*xf); |
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| 75 | exit (1); |
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| 76 | } |
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| 77 | #endif |
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| 78 | if (socketpair(AF_UNIX, SOCK_STREAM, 0, (*xf)->fd) < 0) { |
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| 79 | perror ("socketpair()"); |
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| 80 | xfermem_done (*xf); |
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| 81 | exit (1); |
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| 82 | } |
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| 83 | (*xf)->freeindex = (*xf)->readindex = 0; |
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| 84 | (*xf)->wakeme[0] = (*xf)->wakeme[1] = FALSE; |
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| 85 | (*xf)->data = ((byte *) *xf) + sizeof(txfermem) + msize; |
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| 86 | (*xf)->metadata = ((byte *) *xf) + sizeof(txfermem); |
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| 87 | (*xf)->size = bufsize; |
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| 88 | (*xf)->metasize = msize; |
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| 89 | } |
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| 90 | |||
| 91 | void xfermem_done (txfermem *xf) |
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| 92 | { |
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| 93 | #ifdef USE_MMAP |
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| 94 | munmap ((caddr_t) xf, xf->size + xf->metasize + sizeof(txfermem)); |
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| 95 | #else |
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| 96 | if (shmdt((void *) xf) == -1) { |
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| 97 | perror ("shmdt()"); |
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| 98 | exit (1); |
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| 99 | } |
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| 100 | #endif |
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| 101 | } |
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| 102 | |||
| 103 | void xfermem_init_writer (txfermem *xf) |
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| 104 | { |
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| 105 | close (xf->fd[XF_READER]); |
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| 106 | } |
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| 107 | |||
| 108 | void xfermem_init_reader (txfermem *xf) |
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| 109 | { |
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| 110 | close (xf->fd[XF_WRITER]); |
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| 111 | } |
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| 112 | |||
| 113 | int xfermem_get_freespace (txfermem *xf) |
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| 114 | { |
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| 115 | int freeindex, readindex; |
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| 116 | |||
| 117 | if ((freeindex = xf->freeindex) < 0 |
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| 118 | || (readindex = xf->readindex) < 0) |
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| 119 | return (0); |
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| 120 | if (readindex > freeindex) |
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| 121 | return ((readindex - freeindex) - 1); |
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| 122 | else |
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| 123 | return ((xf->size - (freeindex - readindex)) - 1); |
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| 124 | } |
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| 125 | |||
| 126 | int xfermem_get_usedspace (txfermem *xf) |
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| 127 | { |
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| 128 | int freeindex, readindex; |
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| 129 | |||
| 130 | if ((freeindex = xf->freeindex) < 0 |
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| 131 | || (readindex = xf->readindex) < 0) |
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| 132 | return (0); |
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| 133 | if (freeindex >= readindex) |
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| 134 | return (freeindex - readindex); |
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| 135 | else |
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| 136 | return (xf->size - (readindex - freeindex)); |
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| 137 | } |
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| 138 | |||
| 139 | int xfermem_write (txfermem *xf, byte *data, int count) |
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| 140 | { |
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| 141 | int nbytes; |
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| 142 | |||
| 143 | if ((nbytes = xfermem_get_freespace(xf))> count) |
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| 144 | nbytes = count; |
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| 145 | if (nbytes) { |
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| 146 | if (xf->freeindex + nbytes > xf->size) { |
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| 147 | int first = xf->size - xf->freeindex; |
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| 148 | memcpy (xf->data + xf->freeindex, data, first); |
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| 149 | memcpy (xf->data, data + first, nbytes - first); |
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| 150 | } |
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| 151 | else |
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| 152 | memcpy (xf->data + xf->freeindex, data, nbytes); |
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| 153 | xf->freeindex = (xf->freeindex + nbytes) % xf->size; |
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| 154 | } |
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| 155 | return (nbytes); |
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| 156 | } |
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| 157 | |||
| 158 | int xfermem_read (txfermem *xf, byte *data, int count) |
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| 159 | { |
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| 160 | int nbytes; |
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| 161 | |||
| 162 | if ((nbytes = xfermem_get_usedspace(xf))> count) |
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| 163 | nbytes = count; |
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| 164 | if (nbytes) { |
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| 165 | if (xf->readindex + nbytes > xf->size) { |
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| 166 | int first = xf->size - xf->readindex; |
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| 167 | memcpy (data, xf->data + xf->readindex, first); |
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| 168 | memcpy (data + first, xf->data, nbytes - first); |
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| 169 | } |
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| 170 | else |
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| 171 | memcpy (data, xf->data + xf->readindex, nbytes); |
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| 172 | xf->readindex = (xf->readindex + nbytes) % xf->size; |
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| 173 | } |
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| 174 | return (nbytes); |
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| 175 | } |
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| 176 | |||
| 177 | int xfermem_getcmd (int fd, int block) |
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| 178 | { |
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| 179 | fd_set selfds; |
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| 180 | struct timeval selto = {0, 0}; |
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| 181 | byte cmd; |
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| 182 | |||
| 183 | for (;;) { |
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| 184 | FD_ZERO (&selfds); |
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| 185 | FD_SET (fd, &selfds); |
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| 186 | switch (select(FD_SETSIZE, &selfds, NULL, NULL, block ? NULL : &selto)) { |
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| 187 | case 0: |
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| 188 | if (!block) |
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| 189 | return (0); |
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| 190 | continue; |
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| 191 | case -1: |
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| 192 | if (errno == EINTR) |
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| 193 | continue; |
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| 194 | return (-2); |
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| 195 | case 1: |
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| 196 | if (FD_ISSET(fd, &selfds)) |
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| 197 | switch (read(fd, &cmd, 1)) { |
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| 198 | case 0: /* EOF */ |
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| 199 | return (-1); |
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| 200 | case -1: |
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| 201 | if (errno == EINTR) |
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| 202 | continue; |
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| 203 | return (-3); |
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| 204 | case 1: |
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| 205 | return (cmd); |
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| 206 | default: /* ?!? */ |
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| 207 | return (-4); |
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| 208 | } |
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| 209 | else /* ?!? */ |
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| 210 | return (-5); |
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| 211 | default: /* ?!? */ |
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| 212 | return (-6); |
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| 213 | } |
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| 214 | } |
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| 215 | } |
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| 216 | |||
| 217 | int xfermem_putcmd (int fd, byte cmd) |
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| 218 | { |
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| 219 | for (;;) |
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| 220 | switch (write(fd, &cmd, 1)) { |
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| 221 | case 1: |
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| 222 | return (1); |
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| 223 | case -1: |
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| 224 | if (errno != EINTR) |
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| 225 | return (-1); |
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| 226 | } |
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| 227 | } |
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| 228 | |||
| 229 | int xfermem_block (int readwrite, txfermem *xf) |
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| 230 | { |
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| 231 | int myfd = xf->fd[readwrite]; |
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| 232 | int result; |
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| 233 | |||
| 234 | xf->wakeme[readwrite] = TRUE; |
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| 235 | if (xf->wakeme[1 - readwrite]) |
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| 236 | xfermem_putcmd (myfd, XF_CMD_WAKEUP); |
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| 237 | result = xfermem_getcmd(myfd, TRUE); |
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| 238 | xf->wakeme[readwrite] = FALSE; |
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| 239 | return ((result <= 0) ? -1 : result); |
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| 240 | } |
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| 241 | |||
| 242 | /* EOF */ |