[Libvir] [PATCH] Add signal-safe read/write wrappers

Adds saferead() and safewrite(), which are like read() and write() except that they retry in case of EINTR. Signed-off-by: Jim Paris <jim(a)jtan.com&gt; --- src/util.c | 37 +++++++++++++++++++++++++++++++++++++ src/util.h | 2 ++ 2 files changed, 39 insertions(+), 0 deletions(-) diff --git a/src/util.c b/src/util.c index 4f80eef..eb57859 100644 --- a/src/util.c +++ b/src/util.c @@ -189,3 +189,40 @@ virExecNonBlock(virConnectPtr conn, return(_virExec(conn, argv, retpid, infd, outfd, errfd, 1)); } +/* Like read(), but restarts after EINTR */ +int saferead(int fd, void *buf, size_t count) +{ + size_t nread = 0; + while (count > 0) { + int r = read(fd, buf, count); + if (r < 0 && errno == EINTR) + continue; + if (r < 0) + return r; + if (r == 0) + return nread; + buf = (unsigned char *)buf + r; + count -= r; + nread += r; + } + return nread; +} + +/* Like write(), but restarts after EINTR */ +ssize_t safewrite(int fd, const void *buf, size_t count) +{ + size_t nwritten = 0; + while (count > 0) { + int r = write(fd, buf, count); + if (r < 0 && errno == EINTR) + continue; + if (r < 0) + return r; + if (r == 0) + return nwritten; + buf = (unsigned char *)buf + r; + count -= r; + nwritten += r; + } + return nwritten; +} diff --git a/src/util.h b/src/util.h index d11e6d9..f69fac8 100644 --- a/src/util.h +++ b/src/util.h @@ -24,3 +24,5 @@ int virExec(virConnectPtr conn, char **argv, int *retpid, int infd, int *outfd, int *errfd); int virExecNonBlock(virConnectPtr conn, char **argv, int *retpid, int infd, int *outfd, int *errfd); +int saferead(int fd, void *buf, size_t count); +ssize_t safewrite(int fd, const void *buf, size_t count); -- 1.5.3.rc4