diff options
author | Markus F.X.J. Oberhumer <markus@oberhumer.com> | 2021-04-15 07:43:13 +0200 |
---|---|---|
committer | Markus F.X.J. Oberhumer <markus@oberhumer.com> | 2021-04-15 07:43:13 +0200 |
commit | 68622a02adfa7ebd3a195667d3fbf8e1f10ca93f (patch) | |
tree | 8dd77202cd9cdbf5f59ae42dd3293d87fbabcfbb | |
parent | 1d8bbdc1a59fd5246ec60bc3db1ece055ef83639 (diff) | |
download | bfs-68622a02adfa7ebd3a195667d3fbf8e1f10ca93f.tar.xz |
util: introduce safe versions of read & write that handle interrupted
systems calls.
-rw-r--r-- | bar.c | 2 | ||||
-rw-r--r-- | spawn.c | 11 | ||||
-rw-r--r-- | util.c | 20 | ||||
-rw-r--r-- | util.h | 10 |
4 files changed, 35 insertions, 8 deletions
@@ -60,7 +60,7 @@ static int ass_puts(int fd, const char *str) { size_t len = strlen(str); while (len > 0) { - ssize_t ret = write(fd, str, len); + ssize_t ret = safe_write(fd, str, len); if (ret <= 0) { return -1; } @@ -189,12 +189,9 @@ static void bfs_spawn_exec(const char *exe, const struct bfs_spawn *ctx, char ** fail: error = errno; - while (write(pipefd[1], &error, sizeof(error)) < 0) { - if (errno != EINTR) { - // Parent will still see that we exited unsuccessfully, but won't know why - break; - } - } + // In case of write error parent will still see that we exited + // unsuccessfully, but won't know why. + safe_write(pipefd[1], &error, sizeof(error)); close(pipefd[1]); _Exit(127); @@ -224,7 +221,7 @@ pid_t bfs_spawn(const char *exe, const struct bfs_spawn *ctx, char **argv, char // Parent close(pipefd[1]); - ssize_t nbytes = read(pipefd[0], &error, sizeof(error)); + ssize_t nbytes = safe_read(pipefd[0], &error, sizeof(error)); close(pipefd[0]); if (nbytes == sizeof(error)) { int wstatus; @@ -368,3 +368,23 @@ int bfs_minor(dev_t dev) { return dev & 0xFF; #endif } + +ssize_t safe_read(int fd, void *buf, size_t nbytes) { + for (;;) { + ssize_t ret = read(fd, buf, nbytes); + if (ret < 0 && errno == EINTR) { + continue; + } + return ret; + } +} + +ssize_t safe_write(int fd, const void *buf, size_t nbytes) { + for (;;) { + ssize_t ret = write(fd, buf, nbytes); + if (ret < 0 && errno == EINTR) { + continue; + } + return ret; + } +} @@ -225,4 +225,14 @@ int bfs_major(dev_t dev); */ int bfs_minor(dev_t dev); +/** + * A safe version of read() that handles interrupted system calls. + */ +ssize_t safe_read(int fd, void *buf, size_t nbytes); + +/** + * A safe version of write() that handles interrupted system calls. + */ +ssize_t safe_write(int fd, const void *buf, size_t nbytes); + #endif // BFS_UTIL_H |