From ac1307abfe63ac93a9289e773116bb0de07c335b Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Tue, 22 Apr 2014 13:36:11 +0800 Subject: [PATCH] qemu-img: Improve error messages Previously, when there is a user error in argv parsing, qemu-img prints help text and exits. Add an error_exit function to print a helpful error message and a hint to run 'qemu-img --help' for more information. As a bonus, "qemu-img --help" now has a more reasonable exit code 0. In the future the help text should be split by sub command, and only print the information for the specified command. Signed-off-by: Fam Zheng Signed-off-by: Kevin Wolf --- qemu-img.c | 74 +++++++++++++++++++++++++++++++++--------------------- 1 file changed, 46 insertions(+), 28 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index fb626aceb4..4dae84a182 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -57,8 +57,22 @@ static void format_print(void *opaque, const char *name) printf(" %s", name); } +static void QEMU_NORETURN GCC_FMT_ATTR(1, 2) error_exit(const char *fmt, ...) +{ + va_list ap; + + error_printf("qemu-img: "); + + va_start(ap, fmt); + error_vprintf(fmt, ap); + va_end(ap); + + error_printf("\nTry 'qemu-img --help' for more information\n"); + exit(EXIT_FAILURE); +} + /* Please keep in synch with qemu-img.texi */ -static void help(void) +static void QEMU_NORETURN help(void) { const char *help_msg = "qemu-img version " QEMU_VERSION ", Copyright (c) 2004-2008 Fabrice Bellard\n" @@ -129,7 +143,7 @@ static void help(void) printf("%s\nSupported formats:", help_msg); bdrv_iterate_format(format_print, NULL); printf("\n"); - exit(1); + exit(EXIT_SUCCESS); } static int GCC_FMT_ATTR(2, 3) qprintf(bool quiet, const char *fmt, ...) @@ -399,7 +413,7 @@ static int img_create(int argc, char **argv) } if (optind >= argc) { - help(); + error_exit("Expecting image file name"); } optind++; @@ -422,7 +436,7 @@ static int img_create(int argc, char **argv) img_size = (uint64_t)sval; } if (optind != argc) { - help(); + error_exit("Unexpected argument: %s", argv[optind]); } bdrv_img_create(filename, fmt, base_filename, base_fmt, @@ -591,7 +605,8 @@ static int img_check(int argc, char **argv) } else if (!strcmp(optarg, "all")) { fix = BDRV_FIX_LEAKS | BDRV_FIX_ERRORS; } else { - help(); + error_exit("Unknown option value for -r " + "(expecting 'leaks' or 'all'): %s", optarg); } break; case OPTION_OUTPUT: @@ -603,7 +618,7 @@ static int img_check(int argc, char **argv) } } if (optind != argc - 1) { - help(); + error_exit("Expecting one image file name"); } filename = argv[optind++]; @@ -714,7 +729,7 @@ static int img_commit(int argc, char **argv) } } if (optind != argc - 1) { - help(); + error_exit("Expecting one image file name"); } filename = argv[optind++]; @@ -960,7 +975,7 @@ static int img_compare(int argc, char **argv) if (optind != argc - 2) { - help(); + error_exit("Expecting two image file names"); } filename1 = argv[optind++]; filename2 = argv[optind++]; @@ -1276,7 +1291,7 @@ static int img_convert(int argc, char **argv) } if (bs_n < 1) { - help(); + error_exit("Must specify image file name"); } @@ -1886,7 +1901,7 @@ static int img_info(int argc, char **argv) } } if (optind != argc - 1) { - help(); + error_exit("Expecting one image file name"); } filename = argv[optind++]; @@ -2050,10 +2065,10 @@ static int img_map(int argc, char **argv) break; } } - if (optind >= argc) { - help(); + if (optind != argc - 1) { + error_exit("Expecting one image file name"); } - filename = argv[optind++]; + filename = argv[optind]; if (output && !strcmp(output, "json")) { output_format = OFORMAT_JSON; @@ -2142,7 +2157,7 @@ static int img_snapshot(int argc, char **argv) return 0; case 'l': if (action) { - help(); + error_exit("Cannot mix '-l', '-a', '-c', '-d'"); return 0; } action = SNAPSHOT_LIST; @@ -2150,7 +2165,7 @@ static int img_snapshot(int argc, char **argv) break; case 'a': if (action) { - help(); + error_exit("Cannot mix '-l', '-a', '-c', '-d'"); return 0; } action = SNAPSHOT_APPLY; @@ -2158,7 +2173,7 @@ static int img_snapshot(int argc, char **argv) break; case 'c': if (action) { - help(); + error_exit("Cannot mix '-l', '-a', '-c', '-d'"); return 0; } action = SNAPSHOT_CREATE; @@ -2166,7 +2181,7 @@ static int img_snapshot(int argc, char **argv) break; case 'd': if (action) { - help(); + error_exit("Cannot mix '-l', '-a', '-c', '-d'"); return 0; } action = SNAPSHOT_DELETE; @@ -2179,7 +2194,7 @@ static int img_snapshot(int argc, char **argv) } if (optind != argc - 1) { - help(); + error_exit("Expecting one image file name"); } filename = argv[optind++]; @@ -2292,8 +2307,11 @@ static int img_rebase(int argc, char **argv) progress = 0; } - if ((optind != argc - 1) || (!unsafe && !out_baseimg)) { - help(); + if (optind != argc - 1) { + error_exit("Expecting one image file name"); + } + if (!unsafe && !out_baseimg) { + error_exit("Must specify backing file (-b) or use unsafe mode (-u)"); } filename = argv[optind++]; @@ -2553,7 +2571,7 @@ static int img_resize(int argc, char **argv) /* Remove size from argv manually so that negative numbers are not treated * as options by getopt. */ if (argc < 3) { - help(); + error_exit("Not enough arguments"); return 1; } @@ -2580,7 +2598,7 @@ static int img_resize(int argc, char **argv) } } if (optind != argc - 1) { - help(); + error_exit("Expecting one image file name"); } filename = argv[optind++]; @@ -2697,7 +2715,7 @@ static int img_amend(int argc, char **argv) } if (!options) { - help(); + error_exit("Must specify options (-o)"); } filename = (optind == argc - 1) ? argv[argc - 1] : NULL; @@ -2709,7 +2727,7 @@ static int img_amend(int argc, char **argv) } if (optind != argc - 1) { - help(); + error_exit("Expecting one image file name"); } bs = bdrv_new_open("image", filename, fmt, @@ -2781,8 +2799,9 @@ int main(int argc, char **argv) qemu_init_main_loop(); bdrv_init(); - if (argc < 2) - help(); + if (argc < 2) { + error_exit("Not enough arguments"); + } cmdname = argv[1]; argc--; argv++; @@ -2794,6 +2813,5 @@ int main(int argc, char **argv) } /* not found */ - help(); - return 0; + error_exit("Command not found: %s", cmdname); } -- GitLab