[libosmocore PATCH v3] src/serial.c: Add serial helper read and write function

From: Álvaro Neira Ayuso &lt;anayuso(a)sysmocom.de&gt; This patch provide two new functions for reading and writing from the serial interface. I think this two functions makes it easy reading and writing from the serial interface. Signed-off-by: Alvaro Neira Ayuso &lt;anayuso(a)sysmocom.de&gt; --- v3: Fixed the bug that i send errno when in this case errno don't return anything. Fixed some format error for having consistency with the others function and now, I control when read function return the value 0 for saying the end of the file. v2: Fixed the write function for don't supposing that i will write all the msg in one time. I have studied the limit in the read function and i have used the -errno like the other functions inside serial.c for having consistency. The previous version, i have supposed that we need to liberate the info in case of error, now if we have a error we can check the info that we have received or we must to send again. include/osmocom/core/serial.h | 4 +++ src/serial.c | 53 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) diff --git a/include/osmocom/core/serial.h b/include/osmocom/core/serial.h index 1640a6d..056010b 100644 --- a/include/osmocom/core/serial.h +++ b/include/osmocom/core/serial.h @@ -33,10 +33,14 @@ #include <termios.h> +struct msgb; + int osmo_serial_init(const char *dev, speed_t baudrate); int osmo_serial_set_baudrate(int fd, speed_t baudrate); int osmo_serial_set_custom_baudrate(int fd, int baudrate); int osmo_serial_clear_custom_baudrate(int fd); +int osmo_serial_write(int fd, struct msgb *msg); +int osmo_serial_read(int fd, struct msgb *msg, int numbytes); /*! @} */ diff --git a/src/serial.c b/src/serial.c index 66ee756..8c28e7a 100644 --- a/src/serial.c +++ b/src/serial.c @@ -43,6 +43,7 @@ #endif #include <osmocom/core/serial.h> +#include <osmocom/core/msgb.h> #if 0 @@ -226,4 +227,56 @@ osmo_serial_clear_custom_baudrate(int fd) return 0; } +/*! \brief Read data from Serial interface + * \param[in] fd File descriptor of the open device + * \param[in] msg Struct where we save the info + * \param[in] numbytes Number of bytes that we want read + * \returns 0 for success or negative errno. + */ +int +osmo_serial_read(int fd, struct msgb *msg, int numbytes) +{ + int rc, bread = 0; + + if (numbytes > msg->data_len) + return -ENOSPC; + + while (bread < numbytes) { + rc = read(fd, msg->tail, numbytes - bread); + if (rc < 0) + return -errno; + if (rc == 0) + break; + + bread += rc; + msgb_put(msg, rc); + } + + return bread; +} + +/*! \brief Write data to Serial interface + * \param[in] fd File descriptor of the open device + * \param[in] msg Struct where we have the info for writing + * \returns 0 for success or negative errno. + * + * The msgb->data pointer is updated when consuming this message + */ +int +osmo_serial_write(int fd, struct msgb *msg) +{ + int rc, bwritten = 0; + + while (msg->len > 0) { + rc = write(fd, msg->data, msg->len); + if (rc < 0) + return -errno; + + msgb_pull(msg, rc); + bwritten += rc; + } + + return bwritten; +} + /*! @} */