5816592389
it should be noted that only the actual underlying buffer flush and fill operations are cancellable, not reads from or writes to the buffer. this behavior is compatible with POSIX, which makes all cancellation points in stdio optional, and it achieves the goal of allowing cancellation of a thread that's "stuck" on IO (due to a non-responsive socket/pipe peer, slow/stuck hardware, etc.) without imposing any measurable performance cost.
34 lines
689 B
C
34 lines
689 B
C
#include "stdio_impl.h"
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FILE *fopen(const char *filename, const char *mode)
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{
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FILE *f;
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int fd;
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int flags;
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int plus = !!strchr(mode, '+');
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/* Check for valid initial mode character */
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if (!strchr("rwa", *mode)) {
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errno = EINVAL;
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return 0;
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}
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/* Compute the flags to pass to open() */
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if (plus) flags = O_RDWR;
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else if (*mode == 'r') flags = O_RDONLY;
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else flags = O_WRONLY;
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if (*mode != 'r') flags |= O_CREAT;
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if (*mode == 'w') flags |= O_TRUNC;
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if (*mode == 'a') flags |= O_APPEND;
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fd = syscall_cp(SYS_open, filename, flags|O_LARGEFILE, 0666);
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if (fd < 0) return 0;
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f = __fdopen(fd, mode);
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if (f) return f;
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__syscall(SYS_close, fd);
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return 0;
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}
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LFS64(fopen);
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