Re: [PATCH v2 1/4] tools: iio: Move printf failure messages to stderr

[Cristina Georgiana Opriceana]

On Sat, Jul 11, 2015 at 12:42 AM, Hartmut Knaack <knaack.h@xxxxxx> wrote:
> Cristina Opriceana schrieb am 10.07.2015 um 12:56:
>> Replace printf error messages with fprintf(stderr, ...) in order
>> to ensure consistency and to make faults easier to identify.
>> This patch uses coccinelle to detect and apply the changes.
>>
>
> Hi Cristina,
> I just had a look at the series. You have all cases I regard necessary
> covered. There are however a few cases which probably qualify as error
> messages, too. Please see inline.
> However, for my personal taste, this could have been merged all in a
> single patch. Especially the third patch should have been included in
> this one (as during review, people certainly think that you missed the
> second line, just to find it fixed two patches later).

Hi,

Yes, I could have included all in a single patch, but I tried to
automatize this task and build a rather generic semantic patch in
coccinelle for the substitutions. Had I included all in one patch, the
changes with coccinelle wouldn't have been differentiated from the
other ones. If that is okay, I think I can merge them in one patch.

>> Signed-off-by: Cristina Opriceana <cristina.opriceana@xxxxxxxxx>
>> ---
>> Changes in v2:
>>  - s/failiure/failure
>>
>>  tools/iio/generic_buffer.c    | 17 ++++++++++-------
>>  tools/iio/iio_event_monitor.c |  6 +++---
>>  tools/iio/iio_utils.c         | 34 ++++++++++++++++++++--------------
>>  3 files changed, 33 insertions(+), 24 deletions(-)
>>
>> diff --git a/tools/iio/generic_buffer.c b/tools/iio/generic_buffer.c
>> index 0e73723..2f4e12f 100644
>> --- a/tools/iio/generic_buffer.c
>> +++ b/tools/iio/generic_buffer.c
>> @@ -271,7 +271,7 @@ int main(int argc, char **argv)
>>       }
>>
>>       if (device_name == NULL) {
>> -             printf("Device name not set\n");
>> +             fprintf(stderr, "Device name not set\n");
>>               print_usage();
>>               return -1;
>>       }
>> @@ -279,7 +279,7 @@ int main(int argc, char **argv)
>>       /* Find the device requested */
>>       dev_num = find_type_by_name(device_name, "iio:device");
>>       if (dev_num < 0) {
>> -             printf("Failed to find the %s\n", device_name);
>> +             fprintf(stderr, "Failed to find the %s\n", device_name);
>>               return dev_num;
>>       }
>>
>> @@ -307,7 +307,8 @@ int main(int argc, char **argv)
>>               /* Verify the trigger exists */
>>               trig_num = find_type_by_name(trigger_name, "trigger");
>>               if (trig_num < 0) {
>> -                     printf("Failed to find the trigger %s\n", trigger_name);
>> +                     fprintf(stderr, "Failed to find the trigger %s\n",
>> +                             trigger_name);
>>                       ret = trig_num;
>>                       goto error_free_triggername;
>>               }
>> @@ -323,7 +324,7 @@ int main(int argc, char **argv)
>>        */
>>       ret = build_channel_array(dev_dir_name, &channels, &num_channels);
>>       if (ret) {
>> -             printf("Problem reading scan element information\n");
>> +             fprintf(stderr, "Problem reading scan element information\n");
>>               printf("diag %s\n", dev_dir_name);
>
> My preference would even be to print it all in just one fprintf.

I thought so, also, but the string would go beyond 80 characters and
would have to be split which is ugly and brings a warning on it.

>>               goto error_free_triggername;
>>       }
>> @@ -350,7 +351,8 @@ int main(int argc, char **argv)
>>                                                   dev_dir_name,
>>                                                   trigger_name);
>>               if (ret < 0) {
>> -                     printf("Failed to write current_trigger file\n");
>> +                     fprintf(stderr,
>> +                             "Failed to write current_trigger file\n");
>>                       goto error_free_buf_dir_name;
>>               }
>>       }
>> @@ -382,7 +384,7 @@ int main(int argc, char **argv)
>>       fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
>>       if (fp == -1) { /* TODO: If it isn't there make the node */
>>               ret = -errno;
>> -             printf("Failed to open %s\n", buffer_access);
>> +             fprintf(stderr, "Failed to open %s\n", buffer_access);
>>               goto error_free_buffer_access;
>>       }
>>
>
> At line 410 we have a block:
>                 read_size = read(fp, data, toread * scan_size);
>                 if (read_size < 0) {
>                         if (errno == EAGAIN) {
>                                 printf("nothing available\n");
>                                 continue;
>
> I'm tempted to say,that this should go to stderr, as well. Any opinions?

I see it more as an informing note, since the device continues looping
for data, but it could be considered an error as well.

>> @@ -431,7 +433,8 @@ int main(int argc, char **argv)
>>               ret = write_sysfs_string("trigger/current_trigger",
>>                                        dev_dir_name, "NULL");
>>               if (ret < 0)
>> -                     printf("Failed to write to %s\n", dev_dir_name);
>> +                     fprintf(stderr, "Failed to write to %s\n",
>> +                             dev_dir_name);
>>
>>  error_close_buffer_access:
>>       if (close(fp) == -1)
>> diff --git a/tools/iio/iio_event_monitor.c b/tools/iio/iio_event_monitor.c
>> index 703f4cb..843bc4c 100644
>> --- a/tools/iio/iio_event_monitor.c
>> +++ b/tools/iio/iio_event_monitor.c
>
> At line 217:
>         if (!event_is_known(event)) {
>                 printf("Unknown event: time: %lld, id: %llx\n",
>                        event->timestamp, event->id);
>
>                 return;
> Better have this on stderr, as well?

This is more suitable for stderr, indeed.

>> @@ -278,14 +278,14 @@ int main(int argc, char **argv)
>>       fd = open(chrdev_name, 0);
>>       if (fd == -1) {
>>               ret = -errno;
>> -             fprintf(stdout, "Failed to open %s\n", chrdev_name);
>> +             fprintf(stderr, "Failed to open %s\n", chrdev_name);
>>               goto error_free_chrdev_name;
>>       }
>>
>>       ret = ioctl(fd, IIO_GET_EVENT_FD_IOCTL, &event_fd);
>>       if (ret == -1 || event_fd == -1) {
>>               ret = -errno;
>> -             fprintf(stdout, "Failed to retrieve event fd\n");
>> +             fprintf(stderr, "Failed to retrieve event fd\n");
>>               if (close(fd) == -1)
>>                       perror("Failed to close character device file");
>>
>
> A similar borderline case as above in line 301:
>                 ret = read(event_fd, &event, sizeof(event));
>                 if (ret == -1) {
>                         if (errno == EAGAIN) {
>                                 printf("nothing available\n");
>                                 continue;
>
>> @@ -311,7 +311,7 @@ int main(int argc, char **argv)
>>               }
>>
>>               if (ret != sizeof(event)) {
>> -                     printf("Reading event failed!\n");
>> +                     fprintf(stderr, "Reading event failed!\n");
>>                       ret = -EIO;
>>                       break;
>>               }
>> diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
>> index 8fb3214..46dfa3f 100644
>> --- a/tools/iio/iio_utils.c
>> +++ b/tools/iio/iio_utils.c
>> @@ -140,7 +140,8 @@ int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
>>                       sysfsfp = fopen(filename, "r");
>>                       if (sysfsfp == NULL) {
>>                               ret = -errno;
>> -                             printf("failed to open %s\n", filename);
>> +                             fprintf(stderr, "failed to open %s\n",
>> +                                     filename);
>>                               goto error_free_filename;
>>                       }
>>
>> @@ -152,7 +153,8 @@ int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
>>                                    &padint, shift);
>>                       if (ret < 0) {
>>                               ret = -errno;
>> -                             printf("failed to pass scan type description\n");
>> +                             fprintf(stderr,
>> +                                     "failed to pass scan type description\n");
>>                               goto error_close_sysfsfp;
>>                       } else if (ret != 5) {
>>                               ret = -EIO;
>> @@ -170,7 +172,8 @@ int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
>>                       *is_signed = (signchar == 's');
>>                       if (fclose(sysfsfp)) {
>>                               ret = -errno;
>> -                             printf("Failed to close %s\n", filename);
>> +                             fprintf(stderr, "Failed to close %s\n",
>> +                                     filename);
>>                               goto error_free_filename;
>>                       }
>>
>> @@ -454,7 +457,8 @@ int build_channel_array(const char *device_dir,
>>                       sysfsfp = fopen(filename, "r");
>>                       if (sysfsfp == NULL) {
>>                               ret = -errno;
>> -                             printf("failed to open %s\n", filename);
>> +                             fprintf(stderr, "failed to open %s\n",
>> +                                     filename);
>>                               free(filename);
>>                               goto error_cleanup_array;
>>                       }
>> @@ -581,11 +585,13 @@ int find_type_by_name(const char *name, const char *type)
>>                       ret = sscanf(ent->d_name + strlen(type), "%d", &number);
>>                       if (ret < 0) {
>>                               ret = -errno;
>> -                             printf("failed to read element number\n");
>> +                             fprintf(stderr,
>> +                                     "failed to read element number\n");
>>                               goto error_close_dir;
>>                       } else if (ret != 1) {
>>                               ret = -EIO;
>> -                             printf("failed to match element number\n");
>> +                             fprintf(stderr,
>> +                                     "failed to match element number\n");
>>                               goto error_close_dir;
>>                       }
>>
>> @@ -664,7 +670,7 @@ static int _write_sysfs_int(const char *filename, const char *basedir, int val,
>>       sysfsfp = fopen(temp, "w");
>>       if (sysfsfp == NULL) {
>>               ret = -errno;
>> -             printf("failed to open %s\n", temp);
>> +             fprintf(stderr, "failed to open %s\n", temp);
>>               goto error_free;
>>       }
>>
>> @@ -685,7 +691,7 @@ static int _write_sysfs_int(const char *filename, const char *basedir, int val,
>>               sysfsfp = fopen(temp, "r");
>>               if (sysfsfp == NULL) {
>>                       ret = -errno;
>> -                     printf("failed to open %s\n", temp);
>> +                     fprintf(stderr, "failed to open %s\n", temp);
>>                       goto error_free;
>>               }
>>
>> @@ -750,7 +756,7 @@ static int _write_sysfs_string(const char *filename, const char *basedir,
>>       char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
>>
>>       if (temp == NULL) {
>> -             printf("Memory allocation failed\n");
>> +             fprintf(stderr, "Memory allocation failed\n");
>>               return -ENOMEM;
>>       }
>>
>> @@ -761,7 +767,7 @@ static int _write_sysfs_string(const char *filename, const char *basedir,
>>       sysfsfp = fopen(temp, "w");
>>       if (sysfsfp == NULL) {
>>               ret = -errno;
>> -             printf("Could not open %s\n", temp);
>> +             fprintf(stderr, "Could not open %s\n", temp);
>>               goto error_free;
>>       }
>>
>> @@ -782,7 +788,7 @@ static int _write_sysfs_string(const char *filename, const char *basedir,
>>               sysfsfp = fopen(temp, "r");
>>               if (sysfsfp == NULL) {
>>                       ret = -errno;
>> -                     printf("Could not open file to verify\n");
>> +                     fprintf(stderr, "Could not open file to verify\n");
>>                       goto error_free;
>>               }
>>
>> @@ -856,7 +862,7 @@ int read_sysfs_posint(const char *filename, const char *basedir)
>>       char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
>>
>>       if (temp == NULL) {
>> -             printf("Memory allocation failed");
>> +             fprintf(stderr, "Memory allocation failed");
>>               return -ENOMEM;
>>       }
>>
>> @@ -903,7 +909,7 @@ int read_sysfs_float(const char *filename, const char *basedir, float *val)
>>       char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
>>
>>       if (temp == NULL) {
>> -             printf("Memory allocation failed");
>> +             fprintf(stderr, "Memory allocation failed");
>>               return -ENOMEM;
>>       }
>>
>> @@ -950,7 +956,7 @@ int read_sysfs_string(const char *filename, const char *basedir, char *str)
>>       char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
>>
>>       if (temp == NULL) {
>> -             printf("Memory allocation failed");
>> +             fprintf(stderr, "Memory allocation failed");
>>               return -ENOMEM;
>>       }
>>
>>
>
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