X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Futils.c;h=6938a5ae52f6cac2e12465b37e3caafe8ae61d23;hp=dd9967312aca1be20253df8fd881c485858d0e6f;hb=116f95d94575a68aee90fff79c064119729d0d24;hpb=309167d2a6f59d0c8cbf64eb23ba912cdea76a34 diff --git a/src/common/utils.c b/src/common/utils.c index dd9967312..6938a5ae5 100644 --- a/src/common/utils.c +++ b/src/common/utils.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -34,6 +35,74 @@ #include "utils.h" #include "defaults.h" +/* + * Resolve the './' and '../' strings in the middle of a path using + * our very own way to do it, so that it works even if the directory + * does not exist + */ +LTTNG_HIDDEN +char *utils_resolve_relative(const char *path) +{ + char *next, *previous, *slash, *start_path, *absolute_path = NULL; + + /* Safety net */ + if (path == NULL) { + goto error; + } + + /* Allocate memory for the absolute path */ + absolute_path = zmalloc(PATH_MAX); + if (absolute_path == NULL) { + PERROR("zmalloc expand path"); + goto error; + } + + /* Copy the path in the absolute path */ + strncpy(absolute_path, path, PATH_MAX); + + /* As long as we find '/./' in the path string */ + while ((next = strstr(absolute_path, "/./"))) { + + /* We prepare the start_path not containing it */ + start_path = strndup(absolute_path, next - absolute_path); + + /* And we concatenate it with the part after this string */ + snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 2); + + free(start_path); + } + + /* As long as we find '/../' in the path string */ + while ((next = strstr(absolute_path, "/../"))) { + /* If the path starts with '/../', there's a problem */ + if (next == absolute_path) { + ERR("%s: Path cannot be resolved", path); + goto error; + } + + /* We find the last level of directory */ + previous = absolute_path; + while ((slash = strpbrk(previous + 1, "/")) && slash != next) { + previous = slash; + } + + /* Then we prepare the start_path not containing it */ + start_path = strndup(absolute_path, previous - absolute_path); + + /* And we concatenate it with the part after the '/../' */ + snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 3); + + free(start_path); + } + + return absolute_path; + +error: + free(absolute_path); + return NULL; +} + + /* * Return the realpath(3) of the path even if the last directory token does not * exist. For example, with /tmp/test1/test2, if test2/ does not exist but the @@ -43,7 +112,7 @@ LTTNG_HIDDEN char *utils_expand_path(const char *path) { - const char *end_path = path; + const char *end_path = NULL; char *next, *cut_path = NULL, *expanded_path = NULL; /* Safety net */ @@ -51,38 +120,80 @@ char *utils_expand_path(const char *path) goto error; } - /* Find last token delimited by '/' */ - while ((next = strpbrk(end_path + 1, "/"))) { - end_path = next; - } - - /* Cut last token from original path */ - cut_path = strndup(path, end_path - path); - + /* Allocate memory for the expanded path */ expanded_path = zmalloc(PATH_MAX); if (expanded_path == NULL) { PERROR("zmalloc expand path"); goto error; } - expanded_path = realpath((char *)cut_path, expanded_path); - if (expanded_path == NULL) { - switch (errno) { - case ENOENT: - ERR("%s: No such file or directory", cut_path); - break; - default: - PERROR("realpath utils expand path"); - break; + /* If given path is already absolute */ + if (*path == '/') { + strncpy(expanded_path, path, PATH_MAX); + /* Else, we have some work to do */ + } else { + /* Pointer to the last char of the path */ + const char *last_char = path + strlen(path) - 1; + + end_path = path; + + /* Split part that will be resolved by realpath (relative path from + * current directory using ./ or ../ only) and part that could not + * (directory names) + */ + while ((next = strpbrk(end_path, "/")) && (next != last_char)) { + end_path = next + 1; + if (strncmp(end_path, "./", 2) != 0 && + strncmp(end_path, "../", 3) != 0) { + break; + } + } + + /* If this is the end of the string, and we still can resolve it */ + if (strncmp(end_path, "..\0", 3) == 0 || + strncmp(end_path, ".\0", 2) == 0) { + end_path += strlen(end_path); + } + + /* If the end part is the whole path, we are in the current dir */ + if (end_path == path) { + cut_path = strdup("."); + /* Else, cut the resolvable part from original path */ + } else { + cut_path = strndup(path, end_path - path); + } + + /* Resolve the canonical path of the first part of the path */ + expanded_path = realpath((char *)cut_path, expanded_path); + if (expanded_path == NULL) { + switch (errno) { + case ENOENT: + ERR("%s: No such file or directory", cut_path); + break; + default: + PERROR("realpath utils expand path"); + break; + } + goto error; + } + + /* Add end part to expanded path if not empty */ + if (*end_path != 0) { + strncat(expanded_path, "/", PATH_MAX - strlen(expanded_path) - 1); + strncat(expanded_path, end_path, + PATH_MAX - strlen(expanded_path) - 1); } - goto error; } - /* Add end part to expanded path */ - strncat(expanded_path, end_path, PATH_MAX - strlen(expanded_path) - 1); + /* Resolve the internal './' and '../' strings */ + next = utils_resolve_relative(expanded_path); + if (next == NULL) { + goto error; + } + free(expanded_path); free(cut_path); - return expanded_path; + return next; error: free(expanded_path); @@ -694,3 +805,24 @@ size_t utils_get_current_time_str(const char *format, char *dst, size_t len) return ret; } + +/* + * Return the group ID matching name, else 0 if it cannot be found. + */ +LTTNG_HIDDEN +gid_t utils_get_group_id(const char *name) +{ + struct group *grp; + + grp = getgrnam(name); + if (!grp) { + static volatile int warn_once; + + if (!warn_once) { + WARN("No tracing group detected"); + warn_once = 1; + } + return 0; + } + return grp->gr_gid; +}