[systemd-devel] [RFC 22/25] support POSIX strerror_r returning int

[Zbigniew Jędrzejewski-Szmek]

Why do you define both posix_strerror_r and gnu_strerror_r? Isn't it enough
to define the second one for compatibility purposes?

Zbyszek


On Thu, Sep 18, 2014 at 03:24:58PM +0200, Emil Renner Berthing wrote:
> ---
>  configure.ac                      |  2 ++
>  src/journal/journal-send.c        | 36 +++++++++++++++++++++++++++---------
>  src/libsystemd/sd-bus/bus-error.c | 14 +++++++++++++-
>  3 files changed, 42 insertions(+), 10 deletions(-)
> 
> diff --git a/configure.ac b/configure.ac
> index 9cd4c05..3f17833 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -336,6 +336,8 @@ AC_CHECK_DECLS([IFLA_MACVLAN_FLAGS,
>  #include <linux/if_bridge.h>
>  ]])
>  
> +AC_FUNC_STRERROR_R
> +
>  # This makes sure pkg.m4 is available.
>  m4_pattern_forbid([^_?PKG_[A-Z_]+$],[*** pkg.m4 missing, please install pkg-config])
>  
> diff --git a/src/journal/journal-send.c b/src/journal/journal-send.c
> index 9ca4a0b..62b40b2 100644
> --- a/src/journal/journal-send.c
> +++ b/src/journal/journal-send.c
> @@ -341,6 +341,29 @@ _public_ int sd_journal_sendv(const struct iovec *iov, int n) {
>          return 0;
>  }
>  
> +#ifdef STRERROR_R_CHAR_P
> +static int posix_strerror_r(int errnum, char *buf, size_t buflen) {
> +        char *res;
> +
> +        errno = 0;
> +        res = strerror_r(errnum, buf, buflen);
> +        if (errno)
> +                return errno;
> +
> +        if (res != buf) {
> +                size_t len = strlen(res)+1;
> +
> +                if (len > buflen)
> +                        return ERANGE;
> +
> +                memmove(buf, res, len);
> +        }
> +        return 0;
> +}
> +#else
> +#define posix_strerror_r strerror_r
> +#endif
> +
>  static int fill_iovec_perror_and_send(const char *message, int skip, struct iovec iov[]) {
>          PROTECT_ERRNO;
>          size_t n, k;
> @@ -350,16 +373,11 @@ static int fill_iovec_perror_and_send(const char *message, int skip, struct iove
>  
>          for (;;) {
>                  char buffer[n];
> -                char* j;
> +                int ret = posix_strerror_r(_saved_errno_, buffer + 8 + k, n - 8 - k);
>  
> -                errno = 0;
> -                j = strerror_r(_saved_errno_, buffer + 8 + k, n - 8 - k);
> -                if (errno == 0) {
> +                if (ret == 0) {
>                          char error[6 + 10 + 1]; /* for a 32bit value */
>  
> -                        if (j != buffer + 8 + k)
> -                                memmove(buffer + 8 + k, j, strlen(j)+1);
> -
>                          memcpy(buffer, "MESSAGE=", 8);
>  
>                          if (k > 0) {
> @@ -377,8 +395,8 @@ static int fill_iovec_perror_and_send(const char *message, int skip, struct iove
>                          return sd_journal_sendv(iov, skip + 3);
>                  }
>  
> -                if (errno != ERANGE)
> -                        return -errno;
> +                if (ret != ERANGE)
> +                        return -ret;
>  
>                  n *= 2;
>          }
> diff --git a/src/libsystemd/sd-bus/bus-error.c b/src/libsystemd/sd-bus/bus-error.c
> index c2e41fb..14bbaca 100644
> --- a/src/libsystemd/sd-bus/bus-error.c
> +++ b/src/libsystemd/sd-bus/bus-error.c
> @@ -291,6 +291,18 @@ _public_ int sd_bus_error_get_errno(const sd_bus_error* e) {
>          return bus_error_name_to_errno(e->name);
>  }
>  
> +#ifdef STRERROR_R_CHAR_P
> +#define gnu_strerror_r strerror_r
> +#else
> +static char *gnu_strerror_r(int errnum, char *buf, size_t buflen) {
> +        int ret = strerror_r(errnum, buf, buflen);
> +
> +        if (ret)
> +                errno = ret;
> +        return buf;
> +}
> +#endif
> +
>  static void bus_error_strerror(sd_bus_error *e, int error) {
>          size_t k = 64;
>          char *m;
> @@ -305,7 +317,7 @@ static void bus_error_strerror(sd_bus_error *e, int error) {
>                          return;
>  
>                  errno = 0;
> -                x = strerror_r(error, m, k);
> +                x = gnu_strerror_r(error, m, k);
>                  if (errno == ERANGE || strlen(x) >= k - 1) {
>                          free(m);
>                          k *= 2;
> -- 
> 2.1.0
> 
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