From ffb84fc1bf1d138d1ac1bb8ece0b7d625f288d97 Mon Sep 17 00:00:00 2001 From: Jeremy Kerr Date: Thu, 20 Feb 2014 09:22:58 +0800 Subject: lib/process: Don't abort stdout reads on EINTR If our read() of the process stdout pipe fails with EINTR (eg, if we receive a SIGCHLD because the process exited), then process_read_stdout_once will return a non-zero exit code, and we'll abort any further stdout collection. Instead, we should check for EINTR, and allow the reads to continue. This change normalises the return value from process_read_stdout_once to return positive on success, negative on failure, and zero on competion. We use a positive return value for the non-error EINTR case. Also, add a pb_log if the read fails for non-EINTR reasons. Signed-off-by: Jeremy Kerr --- lib/process/process.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/process/process.c b/lib/process/process.c index 86c7fbb..081a48c 100644 --- a/lib/process/process.c +++ b/lib/process/process.c @@ -61,7 +61,13 @@ static struct process_info *get_info(struct process *process) } /* Read as much as possible into the currently-allocated stdout buffer, and - * possibly realloc it for the next read */ + * possibly realloc it for the next read + * + * Returns: + * > 0 on success (even though no bytes may have been read) + * 0 on EOF (no error, but no more reads can be performed) + * < 0 on error + **/ static int process_read_stdout_once(struct process_info *procinfo) { struct process *process = &procinfo->process; @@ -74,8 +80,14 @@ static int process_read_stdout_once(struct process_info *procinfo) max_len = procinfo->stdout_buf_len - process->stdout_len - 1; rc = read(fd, process->stdout_buf + process->stdout_len, max_len); - if (rc <= 0) + if (rc == 0) + return 0; + if (rc < 0) { + if (errno == EINTR) + return 1; + pb_log("%s: read failed: %s\n", __func__, strerror(errno)); return rc; + } process->stdout_len += rc; if (process->stdout_len == procinfo->stdout_buf_len - 1) { @@ -85,7 +97,7 @@ static int process_read_stdout_once(struct process_info *procinfo) procinfo->stdout_buf_len); } - return rc; + return 1; } static int process_setup_stdout_pipe(struct process_info *procinfo) -- cgit v1.2.1