| 1 | |
| 2 | * linux/lib/kasprintf.c
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| 3 | *
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| 4 | * Copyright (C) 1991, 1992 Linus Torvalds
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| 5 |
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| 6 |
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| 7 | #include <stdarg.h>
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| 8 | #include <linux/export.h>
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| 9 | #include <linux/slab.h>
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| 10 | #include <linux/types.h>
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| 11 | #include <linux/string.h>
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| 12 |
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| 13 |
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| 14 | char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
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| 15 | {
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| 16 | unsigned int first, second;
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| 17 | char *p;
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| 18 | va_list aq;
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| 19 |
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| 20 | va_copy(aq, ap);
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| 21 | first = vsnprintf(NULL, 0, fmt, aq);
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| 22 | va_end(aq);
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| 23 |
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| 24 | p = kmalloc_track_caller(first+1, gfp);
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| 25 | if (!p)
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| 26 | return NULL;
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| 27 |
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| 28 | second = vsnprintf(p, first+1, fmt, ap);
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| 29 | WARN(first != second, "different return values (%u and %u) from vsnprintf(\"%s\", ...)",
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| 30 | first, second, fmt);
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| 31 |
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| 32 | return p;
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| 33 | }
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| 34 | EXPORT_SYMBOL(kvasprintf);
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| 35 |
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| 36 | |
| 37 | * If fmt contains no % (or is exactly %s), use kstrdup_const. If fmt
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| 38 | * (or the sole vararg) points to rodata, we will then save a memory
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| 39 | * allocation and string copy. In any case, the return value should be
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| 40 | * freed using kfree_const().
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| 41 |
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| 42 | const char *kvasprintf_const(gfp_t gfp, const char *fmt, va_list ap)
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| 43 | {
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| 44 | if (!strchr(fmt, '%'))
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| 45 | return kstrdup_const(fmt, gfp);
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| 46 | if (!strcmp(fmt, "%s"))
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| 47 | return kstrdup_const(va_arg(ap, const char*), gfp);
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| 48 | return kvasprintf(gfp, fmt, ap);
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| 49 | }
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| 50 | EXPORT_SYMBOL(kvasprintf_const);
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| 51 |
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| 52 | char *kasprintf(gfp_t gfp, const char *fmt, ...)
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| 53 | {
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| 54 | va_list ap;
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| 55 | char *p;
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| 56 |
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| 57 | va_start(ap, fmt);
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| 58 | p = kvasprintf(gfp, fmt, ap);
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| 59 | va_end(ap);
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| 60 |
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| 61 | return p;
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| 62 | }
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| 63 | EXPORT_SYMBOL(kasprintf);
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