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Message-ID: <20130128163300.GI20323@brightrain.aerifal.cx>
Date: Mon, 28 Jan 2013 11:33:00 -0500
From: Rich Felker <dalias@...ifal.cx>
To: musl@...ts.openwall.com
Subject: Re: [PATCH] Add support for mkostemp, mkstemps and mkostemps
On Mon, Jan 28, 2013 at 12:06:23AM -0500, Anthony G. Basile wrote:
> From: "Anthony G. Basile" <basile@...nsource.dyc.edu>
>
> Signed-off-by: Anthony G. Basile <blueness@...too.org>
> ---
> include/stdlib.h | 6 ++++++
> src/temp/mkostemp.c | 18 ++++++++++++++++++
> src/temp/mkostemps.c | 18 ++++++++++++++++++
> src/temp/mkstemp.c | 15 ++-------------
> src/temp/mkstemps.c | 18 ++++++++++++++++++
> src/temp/mktemp.c | 7 +++----
> src/temp/randname.c | 22 ++++++++++++++++++++++
> src/temp/tempfile.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 8 files changed, 129 insertions(+), 17 deletions(-)
> create mode 100644 src/temp/mkostemp.c
> create mode 100644 src/temp/mkostemps.c
> create mode 100644 src/temp/mkstemps.c
> create mode 100644 src/temp/randname.c
> create mode 100644 src/temp/tempfile.c
>
> diff --git a/include/stdlib.h b/include/stdlib.h
> index 671d188..4210f40 100644
> --- a/include/stdlib.h
> +++ b/include/stdlib.h
> @@ -95,6 +95,9 @@ int posix_memalign (void **, size_t, size_t);
> int setenv (const char *, const char *, int);
> int unsetenv (const char *);
> int mkstemp (char *);
> +int mkostemp (char *, int);
> +int mkstemps (char *, int);
> +int mkostemps (char *, int, int);
> char *mkdtemp (char *);
> int getsubopt (char **, char *const *, char **);
> int rand_r (unsigned *);
> @@ -150,6 +153,9 @@ char *gcvt(double, int, char *);
>
> #if defined(_LARGEFILE64_SOURCE) || defined(_GNU_SOURCE)
> #define mkstemp64 mkstemp
> +#define mkostemp64 mkostemp
> +#define mkstemps64 mkstemps
> +#define mkostemps64 mkostemps
> #endif
>
> #ifdef __cplusplus
> diff --git a/src/temp/mkostemp.c b/src/temp/mkostemp.c
> new file mode 100644
> index 0000000..750d880
> --- /dev/null
> +++ b/src/temp/mkostemp.c
> @@ -0,0 +1,18 @@
> +#define _GNU_SOURCE
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <limits.h>
> +#include <errno.h>
> +#include "libc.h"
> +
> +int __open_tempfile (char *, int, int);
> +
> +int __mkostemp(char *template, int flags)
> +{
> + return __open_tempfile (template, 0, flags);
> +}
> +
> +weak_alias(__mkostemp, mkostemp);
> diff --git a/src/temp/mkostemps.c b/src/temp/mkostemps.c
> new file mode 100644
> index 0000000..8c810ce
> --- /dev/null
> +++ b/src/temp/mkostemps.c
> @@ -0,0 +1,18 @@
> +#define _GNU_SOURCE
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <limits.h>
> +#include <errno.h>
> +#include "libc.h"
> +
> +int __open_tempfile (char *, int, int);
> +
> +int __mkostemps(char *template, int len, int flags)
> +{
> + return __open_tempfile (template, len, flags);
> +}
> +
> +weak_alias(__mkostemps, mkostemps);
Sorry, I think I wasn't clear about my comments on the alias. I was
just saying the actual function can be named __mkostemps (rather than
__open_tempfile or whatever) with weak_alias(__mkostemps, mkostemps);
so that it also provides the publicly visible mkostemps. That avoids
having an extra wrapper layer.
> diff --git a/src/temp/mkstemps.c b/src/temp/mkstemps.c
> new file mode 100644
> index 0000000..53fea07
> --- /dev/null
> +++ b/src/temp/mkstemps.c
> @@ -0,0 +1,18 @@
> +#define _GNU_SOURCE
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <limits.h>
> +#include <errno.h>
> +#include "libc.h"
I don't think all these headers are needed for just a one-line wrapper
function. :)
> +
> +int __open_tempfile (char *, int, int);
> +
> +int __mkstemps(char *template, int len)
> +{
> + return __open_tempfile (template, len, O_RDWR);
> +}
> +
> +weak_alias(__mkstemps, mkstemps);
These aliases aren't needed since mkstemps, et.c aren't used
internally. The __-prefixed version of a function, with the "real"
name being a weak alias for it, is needed only when you want to be
able to call a nonstandard function from within the standard library,
or if it's being defined in the same source file as a standard
function.
> diff --git a/src/temp/mktemp.c b/src/temp/mktemp.c
> index c0e06f5..de1afb4 100644
> --- a/src/temp/mktemp.c
> +++ b/src/temp/mktemp.c
> @@ -8,6 +8,8 @@
> #include <stdint.h>
> #include "libc.h"
>
> +char *__randname(char *);
> +
> char *__mktemp(char *template)
> {
> struct timespec ts;
> @@ -21,10 +23,7 @@ char *__mktemp(char *template)
> return template;
> }
> while (retries--) {
> - clock_gettime(CLOCK_REALTIME, &ts);
> - r = ts.tv_nsec + (uintptr_t)&ts / 16 + (uintptr_t)template;
> - for (i=1; i<=6; i++, r>>=4)
> - template[l-i] = 'A'+(r&15);
> + __randname(template);
> if (access(template, F_OK) < 0) return template;
> }
> *template = 0;
> diff --git a/src/temp/randname.c b/src/temp/randname.c
> new file mode 100644
> index 0000000..4d3476f
> --- /dev/null
> +++ b/src/temp/randname.c
> @@ -0,0 +1,22 @@
> +#include <string.h>
> +#include <unistd.h>
> +#include <errno.h>
> +#include <time.h>
> +#include <stdint.h>
> +#include "libc.h"
> +
> +char *__randname(char *template)
> +{
> + struct timespec ts;
> + size_t i, l = strlen(template);
> + unsigned long r;
> +
> + /* This assumes that a check for the template
> + size has alrady been made */
> + clock_gettime(CLOCK_REALTIME, &ts);
> + r = ts.tv_nsec + (uintptr_t)&ts / 16 + (uintptr_t)template;
> + for (i=1; i<=6; i++, r>>=4)
> + template[l-i] = 'A'+(r&15);
> +
> + return template;
> +}
> diff --git a/src/temp/tempfile.c b/src/temp/tempfile.c
> new file mode 100644
> index 0000000..93808a6
> --- /dev/null
> +++ b/src/temp/tempfile.c
> @@ -0,0 +1,42 @@
> +#include <string.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <limits.h>
> +#include <errno.h>
> +#include "libc.h"
> +
> +char *__randname(char *);
> +
> +int __open_tempfile (char *template, int len, int flags)
> +{
> + if (len < 0) return EINVAL;
> +
> + int l = strlen(template)-len;
> + if (l < 6 || strncmp(template+l-6, "XXXXXX",6)) {
> + errno = EINVAL;
> + *template = 0;
> + return -1;
> + }
> +
> + /* Null terminate the template before the suffix,
> + and save the char for adding back the suffix */
> + char suffix = template[l];
> + template[l] = '\0';
> +
> + int fd, retries = 100, t0 = *template;
> + while (retries--) {
> + if (!*__randname(template)) return -1;
> + /* Add back the suffix */
> + template[l] = suffix;
> + if ((fd = open(template, flags | O_CREAT | O_EXCL, 0600))>=0)
> + return fd;
> + if (errno != EEXIST) return -1;
> + /* this is safe because mktemp verified
> + * that we have a valid template string */
> + template[0] = t0;
> + strcpy(template+l-6, "XXXXXX");
Since your __randname is not checking for XXXXXX like __mktemp was
doing, this strcpy is probably not needed. I'm not sure whether it
would be cleaner to keep this strcpy and put the template check back
in __randname (so that mktemp and __mkostemps don't duplicate the
check) or just get rid of the strcpy here. What do you think?
Rich
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